WO2007006895A2

WO2007006895A2 - Optical plotting system, emitting device, detecting and determining device and corresponding methods

Info

Publication number: WO2007006895A2
Application number: PCT/FR2006/001569
Authority: WO
Inventors: Olivier Bouchet; Jean-Claude Carlach
Original assignee: France Telecom S.A.
Priority date: 2005-07-08
Filing date: 2006-07-03
Publication date: 2007-01-18
Also published as: WO2007006895A3; FR2888338A1

Abstract

The invention concerns an optical plotting system (100) designed to determine the coordinates of an object in a coordinate system (O, X, Y, Z), said optical plotting system (10) comprising: at least one emitting device (102) adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, an optical code word linked with that direction: at least one detecting device (114, 116) capable of determining each of said emitted light beams; each emitting device (102) being fixed to said object or stationary in the coordinate system and each detecting device (114, 116) being respectively stationary in said coordinate system or fixed to said object; and a processing unit (110) connected to said or each detecting device (114, 116) and adapted to determine the coordinates of said object in the coordinate system based on said at least two light beams thus detected by said or each detecting device (114, 116) and the knowledge of said optical code; the optical plotting system (100) being such that the optical code results from multiplexing said at least two light beams. The invention also concerns an emitting device, a detecting and determining device and the corresponding methods.

Description

Optical tracer system, emitting device, detection and determination device and corresponding methods

The invention relates to an optical tracer system and an emitting device for such an optical tracer system. The invention also relates to a method for determining the coordinates of an emitting device of such an optical tracer system and a computer program for the implementation of such a method. It finds application, for example, in the field of virtual reality or augmented reality.

Virtual reality is a way for humans to visualize, manipulate and interact with complex data using a computer, by immersing themselves in a virtual world. These data make it possible to modify the virtual environment according to the real movements and displacements (according to six degrees of freedom) of the user, so as to recreate the conditions of vision, in the virtual environment, associated with these movements and displacements. , the six degrees of freedom being three translations along three axes of an orthogonal reference and three rotations around these same axes. In augmented reality, the notion of immersion is less because it is a question of obtaining a vision of the virtual environment superimposed on the real environment; said virtual environment is a complement, an enrichment of the real environment.

The implementation of these two principles requires the implementation of position sensors ("position sensor", "position tracking device") that allow the integration of data relating to sensor movements. Thus, any displacement of a sensor implies a modification of the virtual environment.

To visualize this virtual environment, there are viewing helmets which comprise a visor where a display device is housed and which are provided with position sensors. The modification of the virtual environment then involves a modification of the display on the visor display device in connection with the software application of the computer. The user can modify and interact with the virtual environment using an external device (glove, mouse, ...) which is also provided with one or more sensors. Position determination systems use different technologies.

There are ultrasonic systems that determine the position and inclination of a moving object using a low frequency field generated from a transmitter with a source of emission. The main defect of this type of sensor is the great sensitivity of the emitted field to surrounding objects and in particular to metal objects.

There are inertial systems that are based on pressure or capacitive sensors to derive a relative position movement related to a specific initial calibration through the actions of the user on the sensors. The problem of this solution is mainly an increase in the dynamic error over time which requires frequent recalibration of the system. The dynamic error is due to the instability of the sensors that deliver displacement information even in the absence of displacement.

There are also optical systems, consisting of:

or reflective markers fixed on a user and illuminated by infrared light-emitting diodes, the positions of these sensors being read by at least one camera and from which the movements of the user are deduced; .

or markers consisting of infrared light-emitting diodes fixed on a user whose positions are read by at least one camera and from which are deducted the movements of the user. A computer correlates the images delivered by laκm each camera system and, from these ₅ images 2D computer determines the 3D position of the various markers. It is then necessary to have complex processing tools to be able to perform the correlation in real time between the 2D images obtained and the 3D positions of the user while meeting the needs of short response time.

Also known is the patent application US-A-2003/0002033 which discloses an optical tracer system in a three-dimensional environment which comprises:

a mobile emissive device emitting at least one light beam through a filter producing a radially symmetrical or unsymmetrical profile;

at least three detection devices capable of detecting the characteristics of the beams thus emitted; and

a processing unit connected to the detection devices and adapted to determine the different spatial coordinates of the emitting device according to the characteristics of the beams received.

An object of the present invention is to provide an optical tracer system which does not have the drawbacks of the prior art.

For this purpose, an optical tracer system is provided for determining the coordinates of an object in a marker, said optical tracer system comprising: at least one emitting device adapted to emit, in a given direction, at least two beams illuminated so that said at least two light beams form, in said direction, a word of an optical code related to said direction;

at least one detection device capable of determining each of said emitted light beams;

each emissive device being fixed to said object or fixed in said mark and each detection device being respectively fixed in said mark or fixed to said object; and

a processing unit connected to said or each detection device and adapted to determine the coordinates of said object in the marker according to said at least two light beams thus detected by said or each detection device and knowledge of said optical code. The optical tracer system is such that the word of said optical code results from a multiplexing of said at least two light beams, allowing precise determination of the coordinates.

According to a particular embodiment, the multiplexing is a wavelength division multiplexing.

According to a particular embodiment, the multiplexing is a time multiplexing.

According to a particular embodiment, when the multiplexing is a wavelength division multiplexing, the optical code is generated by a plurality of light beam generators, each light beam consisting of a wavelength different from the wavelengths. waves of the other light beams, and a plurality of masks, each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one zone transparent to said beam thus received and at least one opaque zone to said beam and received.

According to a particular embodiment, when the multiplexing is a time division multiplexing, the optical code is generated by a light beam generator, the light beam consisting of a wavelength, and a mask receiving the light beam and comprising respectively at least one zone transparent to said beam and at least one opaque zone to said beam and the geometries of the transparent and opaque zones vary over time.

According to a particular embodiment, when the multiplexing is a wavelength multiplexing, the optical code is generated by a plurality of light beam generators arranged in bands that can be respectively on or off.

According to a particular embodiment, the wavelengths of the light beams emitted by each band are different.

According to a particular embodiment, the position and / or the number of bands on or off vary over time. According to a particular embodiment, when the multiplexing is a time multiplexing, the optical code is generated by a plurality of light beam generators which are successively switched on and off, the set of beams consisting of the same wavelength , and a plurality of masks, each mask receiving the light beam emitted by one of the generators of light beam and comprising respectively at least one zone, transparent to said beam thus received and at least one opaque zone to said beam thus received.

According to a particular embodiment, the geometry of each mask is different from the geometry of the other masks. The invention also proposes an emitting device for optical tracer system, the emitting device being adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code representative of said direction and which results from a multiplexing of said at least two light beams. According to a particular embodiment, the optical code is generated by a plurality of light beam generators and a plurality of masks, each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one transparent zone. beam thus received and at least one opaque zone to said beam thus received. Advantageously, each light beam consists of a wavelength different from the wavelengths of the other light beams.

According to a particular embodiment, the optical code is generated by a light beam generator, the light beam consisting of a wavelength, and a mask receiving the light beam and comprising respectively at least one zone transparent to said beam and at least one opaque zone to said beam.

Advantageously, the geometries of the transparent and opaque zones vary over time.

According to a particular embodiment, the optical code is generated by a plurality of light beam generators arranged in bands that can be respectively on or off.

Advantageously, the position and / or the number of bands on or off vary over time.

According to a particular embodiment, the optical code is generated by a plurality of light beam generators which are successively switched on and off, the set of beams consisting of the same wavelength, and a plurality of masks, each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one zone transparent to said beam thus received and at least one opaque zone to said beam thus received.

The invention also proposes a method for emitting light beams in a given direction, the method comprising a step of multiplexing at least two light beams so that said at least two light beams form, in said direction, a word of an optical code representative of said direction and a step of transmitting the light beams thus multiplexed.

The invention also proposes a detection and determination device capable, on the one hand, of determining the values of the wavelengths of at least two light beams emitted by an emitting device in a given direction, and multiplexing so as to said at least two light beams form, in said direction, a word of an optical code representative of said direction, and secondly, determining the coordinates of said emitting device according to the knowledge of said wavelengths. determined and knowledge of said optical code. The invention also proposes a detection and determination method comprising:

a step of receiving at least two light beams emitted by an emitting device in a given direction, and multiplexing so that said at least two light beams form, in said direction, a word of an optical code representative of said direction

a step of analysis of the light beams thus received,

a step of determining the values of the wavelengths of said light beams,

a step of determining the coordinates of said emissive device as a function of the knowledge of said determined wavelengths and of the knowledge of said optical code.

The invention also proposes a computer program comprising the instructions necessary for implementing the previous transmission method.

The invention also proposes a computer program comprising the instructions necessary for implementing the preceding detection and determination method.

The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an example of realization, said description being made in relation to the two joints, among which: FIG. 1 represents an optical tracer system according to the invention in a spatial environment;

FIG. 2 is a schematic view of an optical tracer system with two wavelengths whose emitting device moves rectilinearly; FIG. 3 is a schematic view of a three-wavelength optical tracer system whose emitting device moves in a rectilinear manner; FIG. 4a and FIG. 4b are examples of masks for an optical tracer system; FIG. 4c represents an emissive device provided with the masks of FIGS. 4a and 4b and whose coordinates in a plane can be determined; FIG. 5 shows an exemplary code resulting from the use of an optical tracer system comprising the set of masks of FIGS. 4a and 4b; FIG. 6 is a schematic view of an eight-wavelength optical tracer system for a cylindrical emitting device; FIG. 7a and FIG. 7b show a set of masks for an optical tracer system with a cylindrical emissive device; FIG. 8a and FIG. 8b show a set of masks for a system of 0 optical tracer in a coordinate system in spherical coordinates; FIG. 9a, FIG. 9b and 9c are schematic representations of masks for an optical tracer system whose emitting device can perform any rotations on itself; FIG. 10 shows an embodiment of a detection device of an optical tracer system; FIG. 11 represents an emitting device of an optical tracer system according to the invention; FIG. 12 shows another embodiment of an emitting device of an optical tracer system; FIG. 13 shows another embodiment of an emitting device of an optical tracer system; FIG. 14 shows another embodiment of an emitting device of an optical tracer system; FIG. 15 represents an algorithm for determining the linear and / or angular position of an emitting device.

In the remainder of the description, a light beam will be said at a wavelength λ if the light of this beam has a spectral width centered on this wavelength λ and two light beams will be said to have different wavelengths if their spectral widths do not overlap.

In the remainder of the description, the optical tracer system is more precisely described in the case of a determination of the coordinates of one or more emitting systems, but the invention applies in the same way when the or each emitting system is attached to an object. The optical tracer system then makes it possible to determine the coordinates of said object.

Fig. 1 shows an optical tracer system 100 comprising an emitting device 102, two detecting devices 114 and 116 and a processing unit 110, connected to the detecting devices 114 and 116. In the exemplary embodiment of FIG. 1, the detection devices 114 and 116 have been set up on two non-coplanar walls defining a space 108. An orthonormal fixed reference (O, X ₅ Y, Z) is defined in the space 108 so that the XOZ plane is parallel to one of the walls and the YOZ plane is parallel to the other wall. In the embodiment of the invention shown in FIG. 1, the emitting device 102 is movable in the reference (O, X, Y, Z) while the detection devices 114 and 116 are fixed in this same frame.

The detection devices 114 and 116 consist, for example, of CCD sensors ("Charge Charge Device" in English or "Charge Transfer Device" in French), of photosensitive linear CMOS strips ("Complementary Metal Oxide Semi-conductor" in English). ), PIN diodes or APD diodes ("Avalanche Photo Diode" in English), with which is associated a detection unit (not shown) which allows the detection of one or more lengths -d wave. The detection devices may also consist of spectrometers or lambda-meters. Each detection device 114, 116 can thus determine the values of several wavelengths simultaneously or the value of each of them during fast sequences. By construction, the wavelength detecting devices have an angular detection aperture which is centered around a main detection direction which is preferably; oriented parallel to one of the axes of the reference (O, X, Y, Z). Each detection device 114, 116 is thus capable of determining the light beams emitted by each of the emitting devices.

Fig. 2 is a schematic view of a two-wavelength optical tracer system whose emitting device 102 moves in a rectilinear manner.

In the embodiment of FIG. 2, the emitting device 102 moves only parallel to an axis X in the XY plane and consists here of two light beam generators 201 and 202. The light beam generator 201 emits a beam at a wavelength λi and the light beam generator 202 emits a beam at a wavelength λ ₂ different from X ₁ . The emitting device 102 also comprises two masks 206 and 208, the mask 206 receiving the wavelength beam λ i and the mask 208 receiving the wavelength beam λ ₂ . Each of these masks is preferably arranged parallel to the X axis.

A single detection device 212 has been arranged on the X axis so as to be able to capture the light beams coming from the emitting device 102 and to determine the values of the wavelengths received.

Each of the masks 206, 208 has a geometry different from that of the other mask.

The mask 206 is divided into a transparent zone 206a for the wavelength λj and an opaque zone 206b for the wavelength

The mask 208 is divided into a transparent zone 208b for the wavelength λ ₂ and two zones 208a and 208c that are opaque for the wavelength

Each of the transparent and opaque areas extends orthogonally to the XY plane. To facilitate the understanding of the invention, it is considered here that the masks

206, 208 have the same surface. The transparent zone 206a and the opaque zone 206b of the mask 206 also have the same surface, that is to say that each of them has a surface equal to half the surface of the mask 206. The mask 208 consists of the first opaque zone 208a, the transparent zone 208b and the second opaque zone 208c. The area of the transparent area 208b is equal to the sum of the areas of the two opaque areas 208a and 208c, i.e., each opaque area 208a, 208c has an area equal to one quarter of the area of the mask 208 and that the surface of the transparent zone 208b is equal to half of the surface of the mask 208. The transparent zones are thus emission zones of the corresponding light beams and the opaque zones are zones of non-emission of the corresponding light beams.

This configuration makes it possible to create a code 210 with four "words" 210a, 21Ob ₃ 210c and 21Od, each consisting of the superposition of the beams emitted by the light beam generators 201 and 202 after they pass through the masks.

206 and 208. The code 210 is fixed but it moves at the same time as the emitting device 102. Thus, when the emitting device 102 moves, the detection device 212 successively sees the four words 210a, 210b, 210c and 21Od of the code 210 and the processing unit can determine the absolute position of the emitting device

102 relative to the detection device 212 as a function of the word received by it.

The first word 210a is representative of the reception by the detection device 212 of the wavelength beam λι through the transparent zone 206a and of no beam through the mask 208 since the wavelength beam λ ₂ is stopped by the opaque zone 208a. The first word 210a can thus be represented by the binary code "10".

The second word 210b is representative of the reception by the detection device 212 of the wavelength beam λi through the transparent zone 206a and the wavelength beam λz through the transparent zone 208b. The second word 210b can thus be represented by "11".

The third word 210c is representative of the reception by the detection device 212 of the wavelength beam λ ₂ through the transparent zone 208b and of no beam through the mask 206 since the wavelength beam λi is stopped by the opaque zone 206b. The third word 210c can thus be represented by "01".

The fourth word 21Od is representative of the reception by the detection device 212 of no beam through the mask 206 since the wavelength beam Xi is stopped by the opaque zone 206b and no beam through the mask

208 since the wavelength beam λ ₂ is stopped by the opaque zone 208c. The fourth word 21 Od can thus be represented by "00".

The light beams emanating from the emitting device 102 are thus multiplexed into wavelengths. Indeed, each component of each word 210a, 210b, 210c, 21Od represents the state (emission or non-emission) of one of the light beams from the emitting device 102. The four words 210a, 210b, 210c, 21Od thus determine four directions in which the emitting device 102 emits, for each, two multiplexed light beams. Each word 210a, 210b, 210c, 21Od of the code 210 is then linked to a particular direction. In general, if the number detection device i is illuminated

(respectively unlit) by the transmission device (transmission area i, respectively non-emission area i) on a wavelength λj, then the output bit bj of the detection device is 1 (respectively 0 ). For a number of wavelengths of different number of possible words for the optical code

is of

Preferably, the optical codes generated are so-called Gray codes, that is to say that the passage of a word from the code to the next word during the linear and / or angular displacement of an emitting device entails the modification of one bit, reducing the possibility of errors during measurements. Every word of Gray code is a binary word N _λ bits "V whose rank is:

In addition, the codes of

Gray thus defined have a cyclic structure particularly interesting in the case of circular or spherical geometry.

To facilitate data processing and to avoid redundancy of information, it is preferable that the dimension of the detection device 212 in the X-axis direction is smaller than the width of the smaller transpatent or opaque zone.

In the example of FIG. 2, the smallest width is the width of the opaque areas

208a, 208c.

In fact, each mask 206, 208 is broken down into elementary elements, each of which represents a bit. The size of each elementary element is here that of the opaque areas of mask referenced 208 and is represented by dashed lines. The transparent areas of each mask and the opaque zone of the mask referenced 206 then have here sizes equivalent to two elementary elements.

The processing unit (not shown in this embodiment) connected to the detection device 212 thus determines the absolute coordinates and, in particular, the absolute linear position of the emitting device 102 from the values of each of the wavelengths received and the knowledge of the code 210. Indeed, the determination of the wavelengths received makes it possible to determine the received word and therefore the position of the emitting device 102. ^{r ~} Fig. 3 is a schematic view of a three-wavelength optical tracer system whose emitting device 102 moves in a rectilinear manner parallel to an X axis in an XY plane on which a detection device 312 has been arranged so as to it is possible to pick up the light beams coming from the emitting device 102 and to determine the values of the wavelengths.

The emitting device 102 here consists of three light beam generators 302a, 302b and 302c. The light beam generator 302a emits a beam at a wavelength. The light beam generator 302b emits a beam at a wavelength. light beam 302c emits a beam at a wavelength The three wavelengths are all

different from each other. The emissive device 102 also includes three masks

304a, 304b and 304c. The mask 304a receiving the wavelength beam X ₁ , the mask 304b receiving the wavelength beam λ ₂ and the mask 304c receiving the wavelength beam

Each of these masks is preferably arranged parallel to the X axis.

For the sake of clarity in FIG. 3, the three light beam generators 302a, 302b and 302c have been shown with different sizes and arranged at the same point, but they are preferably of the same size and are distributed along the Z axis. The three cones of FIG. diffusion 312a, 312b and 312c from the three light beam generators respectively 302a, 302b and 302c are superimposed.

Each of the masks 304a, 304b, 304c has a different geometry than the other masks.

An embodiment of masks 304a, 304b, 304c is given in FIG. 4a. The mask 304a divides into a transparent zone 406b for the wavelength λi and a zone 406a opaque for the wavelength

The mask 304b is divided into a transparent zone 408b for the wavelength λ ₂ and two zones 408a and 408c opaque for the wavelength

The mask 304c is divided into two zones 410b and 41Od transparent for the wavelength three zones 410a, 410c and 410e opaque for the wavelength

To facilitate the understanding of the invention, the masks 304a, 304b, 304c have the same surface. The transparent area 406b and the opaque area 406a of the mask 304a also have the same area, i.e., each of them has a surface equal to half of the area of the mask 304a.

The mask 304b consists of the first opaque zone 408a, the transparent zone 408b and the second opaque zone 408c. The area of the transparent area 408b is equal to the sum of the areas of the two opaque areas 408a and 408b, i.e., each opaque area 408a, 408b has an area equal to one quarter of the area of the mask 304b and that the surface of the transparent zone 408b is equal to half of the surface of the mask 304b. The mask 304c consists of the first opaque zone 410a, the first transparent zone 410b, the second opaque zone 410c, the second transparent zone 41OD and then the third opaque zone 410e. The different zones are distributed symmetrically on the mask 304c. Thus, the area of each transparent area 410b, 41Od and the area of the central opaque area 410c is equal to one quarter of the area of the mask 304c and the area of each lateral opaque area 410a, 410e is one-eighth of the area of the mask 304c.

The areas transparent to the wavelengths are thus emission zones of the corresponding light beams and the opaque zones at the wavelengths are zones of non-emission of the corresponding light beams. Each of the transparent and opaque areas extends orthogonally to the plane

XY. In fact, each mask consists of elementary elements each of which represents a bit. The size of each elementary element is here the size of the smallest areas and each of these elementary elements is represented by dashed lines. The areas whose dimensions are greater than those of these elementary elements are, in fact, made up of a plurality of these elementary elements.

The processing unit (not shown in this embodiment) connected to the detection device 312 of the Fig. 4 thus determines the absolute coordinates and, in particular, the linear position of the emitting device 102 from the values of each of the received wavelengths and the knowledge of the code 308. In FIG. 4, the line referenced 306a is a binary representation of the mask

304a receiving the wavelength beam λj. The line referenced 306b is a binary representation of the mask 304b receiving the wavelength beam \%. The line referenced 306c is a binary representation of the mask 304c receiving the wavelength beam λ ₃ . In the same way as for the exemplary embodiment of FIG. 2, the configuration of FIG. 3 makes it possible to create a code 308 for eight 310a words, 310b, 310c, 31Od ₅ 310e, 310F, 310g and 310h consist of light beams resulting from the superposition of the beams emitted by the generators of light beams 302a, 302b, 302c after passing through the masks 304a, 304b, 304c. T, e code 308 is frozen but it moves along with the emitting device 102. Thus the detection device 312 always receives one of the code words 308 and the processing unit can determine the position of the emitting device 102 with respect to the detection device 312 as a function of the word received by it. The words are here represented by a triplet of bits, each element being representative of the masking or not of the wavelength considered.

The word referenced 310a, represented by the triplet (0, 0, 0) shows that the detector 312 receives no light beam from the three light beam generators 302a, 302b, 302c. The referenced word 310b, represented by the triplet (0, 0, 1), shows that the detector

312 receives no light beam from the light beam generators 302a and 302b and receives a light beam from the light beam generator 302c.

The light beams emanating from the emitting device 102 are thus multiplexed into wavelengths. Indeed, each component of each word 310a, 310b, ... 31Oh, represents the state (emission or non-emission) of one of the light beams from the emitting device 102.

Each word of the code 308 thus each determines a direction in which the emitting device 102 emits three multiplexed light beams. Each word of the code 308 is then linked to a particular direction. Let "f" distance generators light beams 302a, 302b 302c at their ₅ mask 304a, 304b, 304c respectively.

Let "F" be the distance of the masks 304a, 304b, 304c to the XZ plane on which the detection device or devices 312 are located.

Let 'Ω' be the half divergence angle of each light beam generator 302a, 302b, 302c

Let "Nχ" be the number of wavelengths emitted (in the embodiment of Fig. 3, N _λ = 3)

Let "bj" be the output bit of the detection device corresponding to the wavelength λ 1. ^{r -} The total length L covered by the emission devices is an angle of 2Ω in terms of

In the case where there are wavelengths, the total length L is divided into

elementary elements of length

In fact, the number of elements

elementary is the number of possible words for the optical code. We then have:

By positioning the origin of the X axis at the level of the first word of the optical code, the detection of a word of rank "j" by the detection device makes it possible to determine the distance AX traversed by the disp ir of the formula:

In the case of a binary code

elements, the rank j is given by the formula:

Thus the distance traveled by the emissive device is written:

An example of a numerical application gives for: f + F = 1000mm, 45 °, and

8

SK is 7.81 mm, which is the smallest distance that can be detected. The uncertainty of the measure is

In a particular example where the binary code is written (0,1,0,0,1,1,0,0,0), the rank j is 72 and the distance AX is 562.5 mm. Since in the first interval none of the detectors receives a light beam, the equivalent binary code is identical to the binary code when the

• Emissive device is out of scope. Thus, the maximum value of the distance that can be detected is written

with 1992.19 mm.

As explained above, FIG. 4a represents an example of

T - masks of a first type 304a, 304b, 304c. Fig. 4b represents an example of masks of a second type 404a, 404b, 404c whose transparent and opaque areas have been rotated by 90 ° compared to masks of the first type of Fig.4a.

The mask 404a splits into a transparent area 412b for the wavelength

and an opaque area 412a for the wavelength

The mask 404b divides into a transparent zone 414b for the wavelength two zones 414a and 414c opaque for the wavelength λ ₅ .

asq 4c splits into two transparent 416b and 416d zones for the wavelength

t three zones 416a, 416c and 416e opaque for the wavelength

Fig. 4c represents an emitting device 102 comprising six light beam generators at different wavelengths

and six masks 304a, 304b, 304c, 404a, 404b and 404c.

To illustrate the embodiment of the invention, the masks are arranged on the same face of the emitting device 102 which is supposed to be able to move in an XY plane parallel to this face. A detection device is arranged at a certain distance from the face along the axis Z so as to receive the different light beams.

In a particular embodiment, the three masks of the first type 304a, 304b and 304c are arranged along the axis X to allow the determination of the position of the emitting device 102 along the axis X. The masks of the second type

404a, 404b, and 404c are disposed along the Y axis to enable determination of the position of the emitting device 102 along the Y axis.

Fig. 5 represents the optical code 502 generated by the emitting device 102 of FIG. 4c.

Each box 504 represents a word of the code 502 received by the detection device. Each word of the code 502 consists of a sextupled binary whose first three digits represent the beams received from the masks of the first type 304a, 304b and 304c and whose last three digits represent the beams received from the masks of the second type 404a, 404b and 404c. Each word being unique, the reading of the word by the detection device, that is to say the determination of the wavelengths received and the knowledge of the code 502, makes it possible to determine the absolute coordinates of the emitting device 102. The code 502 is fixed but it moves at the same time as the emitting device

102. Thus, when the emitting device 102 moves, the detection device sees displacements by reading one word then another and the processing unit can determine the position of the emitting device 102 with respect to the detection device. function of the word received by it.

Each word of the code 502 thus each determines a direction in which the emitting device 102 emits a plurality of multiplexed light beams. Each word of the code 502 is then linked to a particular direction.

Fig. 6 is a schematic view of an optical tracer system with eight wavelengths

for an emitting device 102.

The emitting device 102 can move in translation along an axis of displacement 602 and in rotation about this axis of displacement 602.

The emitting device 102 consists of eight light beam generators.

Each light beam generator emits a beam at a wavelength different from that of the other beams. Each light beam generator is disposed inside a mask 606a, 606b, 606c, 606d, 608a, 608b, 608c, 608d of cylindrical shape whose axis coincides with the axis of displacement 602.

Each of the masks 606a, 606b, 606c, 606d, 608a, 608b, 608c, 608d has a geometry different from that of the other mask. One or more detection devices 610a, 610b, 610c, 61d, 610e, 61of,

610g and 610h are arranged at a distance from the axis of movement 602. In the example of FIG. 6, the detection devices are arranged on an axis 604 parallel to the axis of displacement 602 but any other distribution is possible. For example, it is possible to distribute the detection devices around the movement axis 602.

The linear position of the emitting device 102 along the axis of displacement

602 is determined by the analysis of the light beams received from the masks of the first type 606a, 606b, 606c, 606d and the angular position of the emitting device 102 around the axis of displacement 602 is determined by the analysis of the light beams received from the masks of the second type 608a, 608b, 608c, 608d.

An exemplary embodiment of masks of the first type 606a, 606b, 606c, 606d is given in FIG. 7a. An exemplary embodiment of masks of the second type 608a, 608b, 608c, 608d is given in FIG. 7b. Fig. 7a shows four examples of masks of the first type 606a, 606b, 606c, 606d.

The mask 606a is divided into a transparent area 712a for the wavelength λi and an area 712b that is opaque for the wavelength

The mask 606b is divided into a transparent central zone for the wavelength λ ₂ and two opaque lateral zones 714b for the wavelength

The mask 606c is divided into two transparent lateral zones 716a for the wavelength λ ₃ and a central zone 716b that is opaque for the wavelength

The mask 606d is divided into four transparent zones 718a for the wavelength λ4 and three opaque zones 718b for the wavelength

The transparent and opaque areas of the masks of the first type have the shape of a cylinder portion.

Fig. 7b shows four examples of masks of the second type 608a, 608b, 608c, 608d. The mask 608a splits into a transparent zone 762a for the wavelength and an opaque zone 762b for the wavelength

The 608b mask is divided into a 764a area that is tra nient for the length

ond

t an opaque 764b area for the wav length

The 608c mask is divided into two transparent 766a areas for the wavelength

and two opaque areas 766b for the wavelength

The mask 608d is divided into four areas 768A transparent for the wavelength λ ₈ and four opaque areas 768B to the length ond

The areas transparent to the wavelengths are thus emission zones of the corresponding light beams and the opaque zones at the wavelengths are zones of non-emission of the corresponding light beams.

The transparent and opaque areas of the masks of the second type have the shape of a cylinder arc.

As before, the light beams coming from the emitting device 102 are multiplexed into wavelengths. Indeed, each component of each code word represents the state (emission or non-emission) of one of the light beams from the emitting device 102.

The optical code is representative of the various linear and angular positional combinations that can be taken by the emitting device 102.

T- - The code is fixed but it moves at the same time as the emitting device 102.

Thus, when the emitting device 102 moves, the detection device sees displacements by reading one word and then another, and the processing unit can determine the position of the emitting device 102 with respect to the detection device according to of the word received by this one.

In the case of a linear displacement along the Z axis, formulas (1), (2) and (3) above remain valid.

In the case of angular displacement, the rotation angle θ can vary from 0 to 2π. In the case where there are Nχ wavelengths, the total rotation angle

st divided into elementary corner elements

In fact, the number of elementary elements corresponds to the number of possible words for the optical code.

We then have:

By positioning the origin of the angles at the first word of the optical code, the detection of a word of rank "j" by the detection device makes it possible to determine the angle

arcouru by the emissive device from the formula:

In the case of a binary code rank j is given by the formula:

So the angle traveled

An example of a numerical application gives for: f + F = 1000mm, t

δθ is 1.406 °, which corresponds to the smallest angle that can be detected.

The uncertainty of the measure vau

In a particular example where the binary code is written (0,1,0,0,1,1,0,0,0), the rank j is 72 and the angle Aθ is 101,25 °. Fig. 8a and FIG. 8b show a set of masks for an optical tracer system whose emitting device moves in a coordinate system in spherical coordinates.

In a coordinate system in spherical coordinates (O ₃ R, φ, θ), the position of an emitting device with respect to the origin O of the reference is given by its distance R from the point O, by the angle φ which is the angle of the object in the XY plane and angle θ which is the elevation angle between the plane XY and the line connecting the point O to the emitting device.

FIG. 8a represents four masks 802a, 802b, 802c, 802d which make it possible to determine the angle φ. An emissive device which would be desired to know the angular displacement according to the angle φ, would comprise one or more of the masks

802a, 802b, 802c, 802d. These masks here have the shape of spheres comprising at least one emission zone, a light beam at a wavelength and at least one non-emission zone of this light beam. In an exemplary embodiment, each mask comprises a light beam generator at a wavelength λ, each wavelength preferably being different from the others.

The mask 802a surrounds a light beam generator at a wavelength λ ₁ and comprises a transparent area 812a at the wavelength λ ₁ and an area 812b that is opaque at the wavelength λ 1. The transparent zone 812a and the opaque zone 812b here have the shape of two half-spheres. The mask 802b surrounds a light beam generator at a wavelength λ ₂ and comprises a transparent central zone 814a at the wavelength λz and two opaque lateral zones 814b at the wavelength

The mask 802c surrounds a light beam generator at a wavelength λ ₃ and comprises a central zone 816b that is opaque at the wavelength λ3 and two side zones 816a that are transparent at the wavelength.

The mask 802d surrounds a light beam generator at a wavelength λ ₄ and comprises four transparent areas 818a at the wavelength λ ₄ and three opaque areas 818b at the wavelength

To allow the determination of the angle φ, a remote detecting device emitting device must be able to determine a change in wavelength when the rotation of the emissive device about an axis parallel to Z Z ¹ and passing through the center of the spheres. Thus, the masks must not be invariant by a rotation around the axis Z '.

Fig. 9b represents four masks 852a, 852b, 852c and 852d which make it possible to determine the angle θ. An emissive device whose angular displacement would be desired to know at the angle θ, would comprise one or more of the masks 852a,

852b, 852c and 852d. These masks here have the shape of spheres comprising at least one emission zone of a light beam at a wavelength and at least one non-emission zone of this light beam. In an exemplary embodiment, each mask comprises a light beam generator at a wavelength λ, each wavelength preferably being different from the others.

The mask 852a surrounds a light beam generator at a wavelength λs and comprises an area 862a transparent to the wavelength λ ₅ and an area 862b opaque to the wavelength λs, the transparent area 862a and the area opaque 862b here have the shape of two half-spheres. The mask 852b surrounds a light beam generator at a wavelength λ ₆ and comprises a central zone 864a transparent to the wavelength λβ and two opaque lateral zones 864b at the wavelength λ (,.

The mask 852c surrounds a light beam generator at a wavelength λj and comprises a central zone 866b that is opaque at the wavelength λ ₇ and two lateral zones 866a that are transparent at the wavelength λ ₇ .

The mask 852d surrounds a light beam generator at a wavelength λs and comprises four transparent areas 868a at the wavelength λ ₈ and three opaque areas 868b at the wavelength λ ₈ .

To enable the determination of the angle θ, a remote detection device of the emitting device must be able to determine a change of wavelength during the rotation of the emitting device around the point O.

The calculations which follow make it possible to determine the angular displacement Δφ and Δθ in the cases where the emitting device moves only in translation with respect to aurepère (O, X, Y ₃ Z) ₃ that is to say when it does not rotate on itself, and to deduce the coordinates of the emissive device.

In the coordinate system in spherical coordinates, the angle φ can vary from 0 to 2π while the angle θ can vary from 0 to π (or from

In the case where there are N wavelengths, the total rotation angle 2 # - is divided into 2 ^N * elementary elements of angle δφ and the total rotation angle π is divided into elementary elements of angle δθ. In fact, the number of elementary elements corresponds to the number of possible words for the optical code. ; We then have:

By positioning the origin of the angles at the level of the first word of the optical code, the detection of a word of rank "j" by the detection device makes it possible to determine the angl and the angle traveled by the emitting device from the formulas:

In the case of a binary code at Nj. elements, the rank j is given by the formula:

Thus the angles traveled by the emissive device are written:

An example of a numerical application gives for: f + F = 1000mm, Ω≈45 °, and

N _λ = 8, δφ is 1.406 °, which corresponds to the smallest angle that can be detected.

The uncertainty of the measurement is worth δθ is 0.7 °, which c at the smallest angle that can be detected.

The uncertainty of the measure vau

In a particular example where the binary code is written (0,1,0,0,1,1,0,0,0), the rank j is 72 and the angle Aφ is equal to 101,25 ° and the angle Aθ is 50.625 °.

The following calculation makes it possible to find the Cartesian coordinates of the emitting device knowing the Cartesian coordinates of two emissive devices and the values of the angles φ and θ determined by each of the emitting devices.

The Cartesian coordinates of the emissive device are (x, y, z). The Cartesian coordinates of the first detection device

and the angles determined from this detection device so

The Cartesian coordinates of the first detection device are

and the angles determined from this sound detection device

We then obtain:

The only unknowns to be determined are therefore n and r ₂ .

By equality of equations two by two we obtain:

We then deduce:

It is then possible to determine the numerical values of r ₁ and r ₂ and then reinject them into equations (8).

An example of a digital application for

Fig. 9a, FIG. 9b and FIG. 9c are schematic representations of masks for an optical tracer system whose emitting device can perform any rotations on itself without linear displacement.

The emitting device comprises ts 902a, 902b and 902c which are centered on the point O ', origin of the reference

linked to the emissive device. Fig. 1 represents such an emitting device 102 only one of the spheres is shown.

The landmark

is linked to the emissive device so that any translation of the latter causes a displacement of the marker while a rotation of the emitting device does not cause any rotation of the marker. Thus, the guide vectors of the marker have parallel to the direction vectors of the space 108 represented

y- by (O ₅ X ₅ Y, Z) and remain whatever the movement of the emitting device while moving relative to it.

Within the spheres are light beam generators that emit wavelength light beams

n direction of a detection device 904.

Figs. 9a, 9b and 9c are not shown in scale. Indeed, the three spheres can not be physically all three centered at the same point o, but given the distance between the point o and the detection device 904 which is very large compared to the dimensions of the emitting device, it is possible to make the approximation that the three spheres are centered at the same point o.

We note oD the line passing through o and by the detection device. The position of the emitting device with respect to the detection device is determined by the calculation of three angles denoted ΘX, ΘY and ΘZ.

The point referenced 904a represents the projection of the detection device in the XoZ plane and the angle ΘZ (Fig. 9a) is the elevation angle of the line oD with respect to the XY plane.

The point referenced 904b represents the projection of the detection device in the XoZ plane and the angle ΘX (Fig. 9b) is the elevation angle of the line oD with respect to the YZ plane. The point referenced 904c represents the projection of the detection device in the plane YoZ and the angle ΘY (Fig. 9c) is the elevation angle of the line oD with respect to the plane XZ ₅ .

The sphere 902a forms a mask having transparent areas and opaque areas at the wavelength λi. These transparent areas and these opaque zones take the form of strips 906 parallel to the XY plane and are invariant by rotation around the Z axis.

Rotation other than that around the Z axis results in a change in the value of the wavelength received by the detection device 904 and can calculate the ^'value of the angle ΘZ at a time t. Sphere 902b forms a mask with transparent areas and opaque areas at the length of one

These transparent zones take the form of strips 908 parallel to the YZ plane and are invariant by rotation about the X axis. Any rotation other than that around the X axis causes a change in the value of the wavelength received by the detection device 904 and makes it possible to calculate the value of the angle ΘX at a time t.

The sphere 902c forms a mask comprising transparent zones and opaque zones at the wavelength λ ₃ . These transparent areas and these opaque areas take the form of 910 strips parallel to the XZ plane and are invariant by rotation around the Y axis.

Any rotation other than that around the Y axis causes a change in the value of the wavelength received by the detection device 904 and makes it possible to calculate the value of the angle θ Y at a time t.

The following calculations make it possible to determine the angular positioning of the emitting device in the leper (O,

The three vectors of elevation above the emissive device are written

so:

The direction of the right oD is then given by the vecteu

Which means:

and noting:

we get: (9)

The values of the rotation angles of the emitting device on each of the axes OX ₅ OY and OZ are written:

T-

In the case of FIG. 1 with an emitting device 102 with coordinates ^' (x, y, z) and two detecting devices 114, 116 respectively having coordinates in the coordinate system (O, X, Y, Z)

es following calculations to determine the position of the emissive device in the coordinate system (O, X, Y ₅ Z). In application of (9), the detection device 114 and the detection device ectively a vector

and a vector

which are representative of the directions of the direct optical paths,

The emitting device 102 is at the intersection of the line passing through the first detection device 114 and the direction vector V _x with the line passing through the second detection device 116 and the director vector V ₂ .

We can then write: f

J ^or

^and

are the coefficients

vector multipliers ur reach the emitting device 102 from

each of the detection devices 114, 116. That is to say that:

Fig. 10 shows a virtual detection device 1006 of an optical tracer system whose accuracy is improved. An emitting device 1002 moves in a space where a plurality of detection devices 1004a, 1004b and 1004c are disposed. The detection devices 1004a, 1004b and 1004c are on the same plane and the processing unit determines, for each detection device 1004a, 1004b, 1004c, the angles representative of the position of the emitting device 1002. To improve the accuracy of the measurements angles and therefore coordinates of the emitting device 1002, an average is performed on the plurality of angles previously determined.

The virtual detection device 1006 thus consists of a plurality of detection devices 1004a, 1004b and 1004c. Preferably, the positioning of the detection devices 1004a, 1004b and 1004c form a symmetrical geometric figure. In the exemplary embodiment of FIG. 10, the detection devices 1004a, 1004b and 1004c form an equilateral triangle and the virtual detection device 1006 is the center of gravity. Figs. 11 to 14 show a plurality of embodiments of emitting devices according to the invention. Each emitting device is adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code representative of said direction and which results from multiplexing said at least two light beams.

Fig. 11 shows an emitting device 102 comprising a plurality of light beam generators 1104a, 1104b, 1104c and 1104d and a plurality of masks 1108a, 1108b, 1108c and 1108d. Each of the light beams is a light beam at a wavelength different from the wavelengths of the other light beams, which avoids overlap of the wavelengths and uncertainty as to the position of the emitting device 102. Each mask 1108a, 1108b, 1108c, 1108d is arranged in the passage of one of the light beams in order to hide part of each of the light beams. The emitting device 102 may also include matching optics 1106a, 1106b, 1106c and 1106d which make it possible to focus each of the beams emitted by the generators 1104a, 1104b, 1104c and 1104d on the masks 1108a, 1108b, 1108c and 1108d. An optical 1110 may be disposed at the output of the emitting device 102 in order to focus the light beams coming from the masks 1108a, 1108b, 1108c, 1108d. Each mask 1108a, 1108b, 1108c, 1108d comprises at least one zone transparent to the beam that it receives and at least one zone opaque to this same beam. Thus, the emission zones consist of the light beam generators 1104a, 1104b, 1104c, 1104d combined with the transparent zones of each mask 1108a, 1108b, 1108c, 1108d and the non-emission zones consist of light beam generators 1104a. , 1104b, 1104c, 1104d combined with the opaque areas of each mask 1108a, 1108b, 1108c, 1108d.

The optical code is thus generated by the plurality of light beam generators 1104a, 1104b, 1104c, 1104d, each light beam consisting of a wavelength different from the wavelengths of the other light beams and the plurality of masks 1108a. , 1108b, 1108c, 1108d, each maskTeceving the light beam emitted by one of the light beam generators and comprising respectively at least one zone transparent to said beam thus received and at least one opaque zone to said beam thus received.

The light beams emanating from the emitting device 102 are thus multiplexed into wavelengths. Indeed, each component of each word of the code generated by the emitting device 102 represents the state (emission or non-emission) of one of the light beams coming from the emitting device 102.

In cases where the determination of the motion of an object in space 108 of FIG. 1 requires the establishment of a plurality of emitting devices 102, 104, 106 on the object, each detection device 114, 116 must be able to distinguish the beam from one or the other of the emitting devices 102, 104 , 106 to avoid a misinterpretation of the movement.

To personalize each of the emitting devices 102, 104, 106 and in particular the light beam emitted by each of them, each emitting device 102 modifies the light beam emitted, different from that produced by the other emitting devices 104. 106. The detection devices 114, 116 must then be adapted to recognize this change.

This modification of the light beam can take the appearance of a modification of the light beam emitted in amplitude modulation, frequency, pulsation, phase or other.

To achieve this modification on the emitted light beam, the emitting device 102 is provided with an identification module 1102 shown in FIG. 11 and which is adapted to modify the emitted light beam. For example, two emitting devices 102, 104 can be distinguished by the fact that the frequency modulation characteristics of the light beams emitted by one of the emitting devices are not the same as the frequency modulation characteristics of the light beams emitted by the other emissive device.

Fig. 12 shows another embodiment of an emitting device 1300 whose size is reduced. The emitting device 1300 comprises a light beam generator 1304, a mask 1308 and matching optics 1306 and 1310 which make it possible to focus the generated light beams.

The light beam generator 1304 preferably generates a beam at a wavelength. The mask 1308 has areas transparent to the light beam thus generated and opaque areas to the same beam.

The emission zones thus consist of the light beam generator 1034 and the transparent zones of the mask 1308 and the non-emission zones consist of the light beam generator 1034 and the opaque zones of the mask 1308.

In order to obtain different geometries of bands, for example those of

Figs. 4a and 4b, the geometry of the transparent and opaque zones of the mask 1038 varies over time. Such a mask may take, for example, the form of a liquid crystal display associated with an electronic control device for switching on or off certain parts of the liquid crystal screen.

The light beams emanating from the emitting device 1300 are thus multiplexed in time. Indeed, each component of each word represents the state (emission or non-emission) of one of the light beams from the emitting device 1300 at a time t. The first component is determined with a first configuration of the mask 1038, then the second component is determined with a second configuration of the mask 1038, etc.

The optical code is thus generated by the light beam generator 1304, the light beam consisting of a wavelength, and the mask 1308 receiving the light beam and comprising respectively at least one transparent zone to said beam and at least one zone. opaque audit beam and the geometries of transparent and opaque areas vary over time.

Fig. 13 shows another embodiment of an emissive device that eliminates the use of the mask. The emitting device 1400 comprises a plurality of light beam generators 1402 arranged in strips 1404a to 1404f which can respectively be turned on or off. Such light beam generators may be light emitting diodes.

The emission zones and the non-emission zones thus consist of light beam generators in bands that are on or off.

The wavelengths of the light beams emitted by each band 1404a to 1404f are different from each other. In order to obtain different geometries of the emitting device, such as those of FIGS. 4a and 4b, the position and / or the number of bands on or off vary over time.

The light beams emanating from the emitting device 1400 are thus multiplexed into wavelengths and time. Indeed, each component of each word represents the state (emission or non-emission) of one of the light beams from the emitting device 1400 at a time t. The first component is determined with a first configuration of the light beam generators 1402, then the second component is determined with a second configuration of the light beam generators 1402, etc.

The optical code is thus generated by the plurality of light beam generators 1402 arranged in bands 1404a to 1404f and which can respectively be turned on or off.

Fig. 14 shows another embodiment of an emitting device 1500 which, with respect to the emitting device of FIG. 12 makes it possible to dispense with the use of a dynamic mask.

The emitting device 1500 comprises a plurality of light beam generators 1504a, 1504b, 1504c and 1504d, a plurality of masks 1508a, 1508b,

1508c and 1508d and adaptation optics 1506a, 1506b, 1506c, 1506d and 1510 which make it possible to focus the light beams at the output of each light beam generator and at the output of the emitting device 1500. Each of the light beams coming from the one light beam generators pass through one of the masks and all of the beams consist of the same wavelength.

Each mask receives the light beam emitted by one of the light beam generators and comprises at least one zone that is transparent to the beam thus received and at least one zone that is opaque to this same beam.

The ignition and the subsequent extinction of each of the light beam generators make it possible to create, in combination with the masks, emission zones and zones of non-emission of light beam. The light beams emanating from the emitting device 1500 are thus multiplexed in time. Indeed, each component of each word represents the state (emission or non-emission) of one of the light beams from the emitting device 1500 at a time t. The first component is determined with a first configuration of light beam generators, then the second component is determined with a second configuration of light beam generators, etc.

The optical code is thus generated by the plurality of light beam generators 1504a, 1504b, 1504c, 1504d which are successively switched on and off, the set of beams consisting of the same wavelength, and the plurality of masks 1508a. , 1508b, 1508c, 1508d, each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one zone transparent to said beam thus received and at least one opaque zone to said beam thus received. In order to obtain different geometries of the emitting device, such as those of FIGS. 4a and 4b ₃ the geometry of each mask is different from the geometry of the other masks.

The optical tracer system 100 can be integrated with a virtual reality or augmented reality system in combination with a mixing device adapted to represent the positioning or the inclination of the objects related to the emitting systems in a virtual space.

The processing unit 110 may be a microcomputer comprising, among other things, a memory, of the RAM, hard disk or other type, in which the values of the wavelengths of the beams received by each of the two detection devices 114 are stored. and 116 at a time t and software for determining the absolute coordinates and in particular the linear position and / or angular position of the emitting device 102 in the reference according to the wavelengths thus detected by the detection devices 114 and 116 and knowledge of the optical code.

In a particular embodiment, each detection device comprises the processing unit which can then take the form of a microprocessor. This set then constitutes a detection and determination device which can both receive and analyze the light beams emitted by the emitting devices and determine the coordinates of each emitting device.

Each detection and determination device is thus capable, on the one hand, of determining the wavelength values of at least two light beams emitted by an emitting device 102 in a given direction, and multiplexing so that said at least two light beams form, in said direction, a word of an optical code representative of said direction, and secondly, determine the coordinates of the emitting device 102 as a function of the knowledge of the determined wavelengths and the knowledge of the optical code.

Fig. 15 represents an algorithm for determining the linear and / or angular position of an emitting device 102 that can be applied to all of the optical tracer devices described above.

When it is turned on, the optical tracer system 100 is initialized and the processing unit 110 records the wavelength values received by the detection devices 114, 116 before any movement. This initialization phase makes it possible to know the linear and angular position of the emitting device 102 at power-up.

The method of determining the coordinates and, in particular, the linear and angular position of an emitting device 102 applies to an optical tracer system 100 comprising:

at least one emitting device 102 adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code representative of said direction and which results from a multiplexing of said at least two light beams;

at least one detection device 114, 116 capable of determining each of said light beams emitted;

each emitting device 102 being fixed to said object or fixed in said mark and each detection device 114, 116 being respectively fixed in said mark or fixed to said object; and

a processing unit 110 connected to said or each detection device 114, 116 and storing the values of the wavelengths of the light beams received by each of the detection devices 114, 116 and including the technical elements necessary for the execution of the determination method whose steps are described below.

The method comprises: a detection step 1602 of the wavelength values received from the emitting device 102 by each of the detection devices 114, 116, during which the detection devices and the associated detection unit determine the values wavelengths they receive and transmit them to the processing unit 110; ^{r ~} a step 1604 for calculating the coordinates of the emitting device 102 in the reference frame from the knowledge of the values of the wavelengths received and the knowledge of the optical code.

According to the use made of the optical tracer system 100, the calculation step 1604 can be followed by a transfer step 1608, during which the linear and / or angular position of the emitting device 102 is transmitted, for example to an imaging software.

The various emissive devices described above comprise the technical elements necessary for the implementation of a light beam emission method in a given direction. This transmission method, from an emitting device comprises a step of multiplexing at least two light beams so that said at least two light beams form, in said direction, a word of a representative optical code of said direction and a step of emitting light beams thus multiplexed. Each detection and determination device comprises the technical elements necessary for the implementation of a detection and determination method comprising:

a step of receiving at least two light beams emitted by an emitting device 102 in a given direction, and multiplexing so that said at least two light beams form, in said direction, a word of a representative optical code from said direction

a step of analysis of the light beams thus received,

a step of determining the wavelength values of said light beams, a step of determining the coordinates of said emitting device as a function of the knowledge of said determined wavelengths and of the knowledge of said optical code.

In the case where there are a plurality of emissive devices 102, 104, 106, each of these devices is distinguished from the others by a modification of the characteristics of the light beam that it emits via the identification module 202. This modification allows a differentiation of each emitting device 102, 104, - 106 and the method comprises, prior to the calculation step 1604, a recognition step 1606 of the modification for each of the received light beams and the calculation step 1604 is performed for each of emissive devices 102, ^" 104, 106. For this purpose, the calculation step 1604 is followed by a test step 1610 which determines whether the light beams of all the emitting devices. 102, 104, 106 were analyzed. If some emissive devices have not yet been processed, the process resumes the calculation step for another emissive device. If all the emissive devices have been processed, the process continues with the transfer step 1608 which transfers the linear and / or angular positions of the different emitting devices 102, 104, 106.

The transmission method described above is implemented by a computer program containing the instructions necessary for this implementation. The method of detection and determination described above is implemented by a computer program containing the instructions necessary for this implementation.

The initial calibration determines the coordinates

u first detection device positioned at the

the second detection device positioned at the point D ₂ in the orthogonal coordinate system (O, X, Y, Z).

The first detection device is disposed on a first wall parallel to the X axis and the second detection device is disposed on a second wall parallel to the Y axis, that is to say orthogonal to the first wall. H is the point of intersection between a first straight line passing through the first detection device and orthogonal to the first wall and a second straight line passing through the second detection device and orthogonal to the second wall. The origin O of the reference (O, X ₅ Y, Z) is the projection of the point H on the XY plane parallel to the Z axis.

We then have X ₁ = y_ = 0.

Let Ai be the coordinate point (0, -L, 0) and Bi be the coordinate point (0, L, 0).

Let A _{2 be} the coordinate point (-L ₅ 0, 0) and B ₂ the coordinate point (L, 0, 0).

Silk

Silk, The

We then obtain:

An example of a digital application for L = 0.5ra and for an 8-bit emitting device, the measurements of the wavelengths in Aj ₃ B ₁ , A ₂ , B ₂ give the following bit codes 183, 204, 168 and 181.

By posing that the binary code 0 represents the angle of and that the binary code

'

255 represents the angle so the knowledge of the four previous binary codes

allows to deduce that

Equations (10) above d

then: (Om, 1.95, 2m) e = (2.9m, Om, 1.85m).

By positioning the object at the origin of the space, the Euler angles denoted Θ,, Φ _t and Θ ₂ , Φ ₂ at the level of each detector are respectively:

In general, the wavelengths of the different light beams described above are preferably located in the infrared range.

To increase the accuracy of the measurement, it is possible to increase the number of zones of emission and non-emission.

In the case of information-carrying emitting devices, the beams can carry information, for example, by amplitude modulation. The number of emitting devices can be reduced to one or two, but when there are shadow areas due to the presence of objects in the space 108, it is preferable to increase the number of detection devices. In addition, an increase in the number of detection devices allows redundancy of information during the detection and thus an improvement in the quality of the detection.

For example, it is preferable to define the space 108 using at least a third detection device whose preferred detection direction is preferably not parallel to the preferred detection directions of the two, other devices detection. This or these detection devices then make it possible to take over when shadows prevent one of the other two detection devices from being in relation with the emitting device 102, but they also make it possible to create a redundancy of information. which reduces the uncertainty of measurements.

Thus, in general, the optical tracer system 100 provided for determining the coordinates of an object in a reference (O, X, Y, Z) comprises: at least one emitting device 102 adapted to emit, in one direction given, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code related to said direction and wherein said word of said optical code results from a multiplexing of said at least two light beams two light beams; at least one detection device 114, 116 capable of determining each of said light beams emitted;

each emitting device 102 being fixed to said object or fixed in said mark and each detection device 114, 116 being respectively fixed in said mark or fixed to said object; and a processing unit 110 connected to said or each detection device

114, 116 and adapted to determine the coordinates of said object in the reference according to said at least two light beams thus detected by said or each detection device 114, 116 and knowledge of said optical code.

The multiplexing can then be a wavelength division multiplexing, a time division multiplexing or a combination of both.

The use of optical transmissions between each emitting device 102, 104, 106 and the detection devices 114, 116 allows a great speed of data acquisition compared to the magnetic and ultrasonic acquisition systems, as well as that increased immunity in the presence of disturbing element of the kind metal element, radio source, ambient light.

The multiplexing of the light beams emitted by each emitting device allows an accurate determination of its coordinates and in particular of its linear and / or angular position.

When the emitting device 102 is stationary, the values of the wavelengths detected by each of the detection devices 114, 116 remain unchanged, and when the emitting device 102 has moved, these values change and the knowledge of the new values of the lengths of the detected beams combined with the knowledge of the optical code make it possible to determine the new linear and / or angular position of the emitting device 102. The calculation of the position and the inclination of the emitting system 102 is therefore done directly and these are the absolute coordinates that are thus defined.

To avoid any dispersion of the signal carried by the light beams between the emitting device 102 and each of the detection devices 114 and 116, it is preferable that the optical path followed by each beam is a direct optical path, that is to say without reflection for example on the walls constituting the space 108.

The extent of the processing of the received data is reduced compared to the systems of the state of the art since the knowledge of the wavelengths of the beams and the knowledge of the optical code allow a direct determination of the positioning of the emitting device in the space by geometry calculations and does not require data processing from 2D to 3D.

Of course, the present invention is not limited to the examples and embodiments described and shown, but it is capable of many variants accessible to those skilled in the art.

Throughout the description, the emissive devices attached to the object are mobile and the detection devices are fixed, but the invention applies in the same way when the detection devices attached to the object are mobile and fixed emissive devices.

Claims

An optical tracer system (100) for determining the coordinates of an object in a coordinate system (O ₃ X, Y, Z), said optical tracer system (100) comprising: at least one emitting device (102) adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code related to said direction;

at least one detection device (114, 116) capable of determining each of said transmitted light beams;

each emitting device (102) being fixed to said object or fixed in said mark and each detection device (114, 116) being respectively fixed in said mark or fixed to said object; and

a processing unit (110) connected to said or each detection device (114, 116) and adapted to determine the coordinates of said object in the frame according to said at least two light beams thus detected by said or each detection device ( 114, 116) and knowledge of said optical code; the optical tracer system (100) being characterized in that the word of said optical code results from a multiplexing of said at least two light beams.

2) optical tracer system (100) according to claim 1, characterized in that the multiplexing is a wavelength division multiplexing.

3) optical tracer system (100) according to one of claims 1 or 2, characterized in that the multiplexing is a time multiplexing.

4) Optical tracer system (100) according to claim 2, characterized in that the optical code is generated by a plurality of light beam generators.

(1104a, 1104b, 1104c, 1104d), each light beam consisting of a wavelength different from the wavelengths of the other light beams, and a plurality of masks (1108a, 1108b, 1108c, 1108d), each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one zone transparent to said beam thus received and at least one opaque zone to said beam thus received.

5) optical tracer system (100) according to claim 3, when it depends only on claim 1, characterized in that the optical code is generated by a light beam generator (1304), the light beam consisting of a wavelength, and a mask (1308) receiving the light beam and respectively comprising at least one zone transparent to said beam and at least one opaque zone to said beam and in that the geometries of the transparent and opaque zones vary during the time.

An optical tracer system (100) according to claim 3, when dependent on claim 2, characterized in that the optical code is generated by a plurality of light beam generators (1402) arranged in bands (1404a to 1404f). ) which can respectively be turned on or off.

7) optical tracer system (100) according to claim 6, characterized in that the wavelengths of the light beams emitted by each band (1404a to 1404f) are different.

8) optical tracer system (100) according to one of claims 6 or 7, characterized in that the position and / or the number of bands (1404a to 1404f) on or off vary over time.

9) optical tracer system (100) according to claim 3, when it depends only on claim 1, characterized in that the optical code is generated by a plurality of light beam generators (1504a, 1504b, 1504c, 1504d ) which are successively switched on and off, the set of beams consisting of the same wavelength, and a plurality of masks (1508a, 1508b, 1508c, 1508d), each mask receiving the light beam emitted by one generators of light beam and respectively comprising at least one zone transparent to said beam thus received and at least one opaque zone to said beam thus.received.

10) Optical tracer system (100) according to claim 9, characterized in that the geometry of each mask is different from the geometry of the other masks.

11) emitting device (102) for optical tracer system (100), characterized in that it is adapted to emit, in a given direction, at least two light beams so that said at least two light beams form, in said direction, a word of an optical code representative of said direction and which results from a multiplexing of said at least two light beams.

An emitting device (102) according to claim 11, characterized in that the optical code is generated by a plurality of light beam generators (1104a, 1104b, 1104c, 1104d) and a plurality of masks (1108a, 1108b, 1108c, 1108d), each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one transparent zone to said beam thus received and at least one opaque zone to said beam thus received.

13) emissive device (102) according to claim 12, characterized in that each light beam consists of a wavelength different from the wavelengths of other light beams.

14) Emissive device (102) according to claim 11, characterized in that the optical code is generated by a light beam generator (1304), the light beam - consisting of a wavelength, and a mask (1308 receiving the light beam and respectively comprising at least one zone transparent to said beam and at least one opaque zone to said beam.

15) Emissive device (102) according to claim 14, characterized in that the geometries of the transparent and opaque areas vary over time. 16) Emissive device (102) according to claim 11, characterized in that the optical code is generated by a plurality of light beam generators (1402) arranged in bands (1404a to 1404f) which can respectively be turned on or off.

17) emissive device (102) according to claim 16, characterized in that the position and / or the number of bands (1404a to 1404f) on or off vary over time.

18) emitting device (102) according to claim 11, characterized in that the optical code is generated by a plurality of light beam generators (1504a, 1504b, 1504c, 1504d) which are successively switched on and off, the set of beams being constituted of the same wavelength, and a plurality of masks (1508a, 1508b, 1508c, 1508d), each mask receiving the light beam emitted by one of the light beam generators and comprising respectively at least one transparent zone beam thus received and at least one opaque zone to said beam thus received.

19) A method of transmitting light beams in a given direction, the method comprising a step of multiplexing at least two light beams so that said at least two light beams form, in said direction, a word of a light. optical code representative of said direction and a step of transmitting light beams thus multiplexed.

20) Detection and determination device capable, on the one hand, of determining the values of the wavelengths of at least two light beams emitted by an emitting device (102) in a given direction, and multiplexing so as to said at least two light beams form, in said direction, a word of an optical code representative of said direction, and, secondly, to determine the coordinates of said emitting device (102) according to the knowledge of said lengths of light. determined waves and knowledge of said optical code. T - 21) Detection and determination method comprising:,

a step of receiving at least two light beams emitted by an emitting device (102) in a given direction, and multiplexing so that said at least two light beams form, in said direction, a word of a code optical representative of said direction

a step of analysis of the light beams thus received,

a step of determining the values of the wavelengths of said light beams,

a step of determining the coordinates of said emitting device (102) as a function of the knowledge of said determined wavelengths and of the knowledge of said optical code.

22) Computer program comprising the instructions necessary for carrying out the transmission method according to claim 19.

23) Computer program comprising the instructions necessary for carrying out the method of detection and determination according to claim 21.

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