WO2001062005A1

WO2001062005A1 - Remote surveillance system

Info

Publication number: WO2001062005A1
Application number: PCT/GB2001/000572
Authority: WO
Inventors: Stephen Albert Wilson
Original assignee: Stephen Albert Wilson
Priority date: 2000-02-16
Filing date: 2001-02-12
Publication date: 2001-08-23
Also published as: GB2359437A; GB0003419D0; GB2360898A; AU2001232082A1; GB0103365D0

Abstract

A remote surveillance system has a video camera connected (101) to a public communications network (202) such as the public switched telephone (PSTN), and a viewing station (205, 206), such as a personal computer, connected to the network. The viewing station establishes a call to the camera and makes a request for compressed image frames. The video camera answers the call and transmits compressed image frames to the viewing station. The viewing station receives the compressed frames from the camera and decompresses the frames so as to produce viewable images. In this way, a relatively low cost surveillance system is provided while making optimum use of the available transmission bandwidth.

Description

REMOTE SURVEILLANCE SYSTEM

Background of the Invention

1. Field of the Invention The present invention relates to a remote surveillance system using a video camera.

2. Description of the Related Art

Closed circuit video surveillance systems have been used for some time in which a video camera supplies video pictures to one or more video display monitors. Such systems are appropriate to closed environments in which appropriate cables for the transmission of video images may be positioned between the camera and the display monitors, with video amplifiers included where necessary. However, such systems are only applicable to closed environments and cannot be used in an open environment in which use must be made of a public telecommunications network. In particular, a problem with such networks is that transmission bandwidth is relatively limited. Alternatively, if a high bandwidth is required the cost of transmission becomes prohibitively expensive. In recent years, video cameras have been developed for distributing images over the world wide web. A video camera is connected to a personal computer that includes a web browser and a modem. In this way, it is possible for video images to be distributed over the Internet, often as a broadcast to many viewers. A problem with this approach is that the degree of equipment required at the transmission end becomes relatively large, in that it requires its own PC and browsing software etc. Consequently, it represents a significant overhead when used in surveillance applications. A further problem is that internet communication techniques require a significant degree of bandwidth overhead for the transmission of data and as such leave very little bandwidth available for the transmission of video images. Consequently, the images tend to be of relatively low spatial quality and are refreshed relatively infrequently. The video image therefore takes the form of a sequence of stills separated by significant periods of time. In many surveillance applications this would not be considered acceptable in that the image quality is too poor and that something of interest may be missed between the transmission of image frames.

Brief Summary of the Invention

According to an aspect of the present invention there is provided a remote surveillance system comprising a video camera connected to a public communications network and a viewing station connected to said network, wherein said viewing station is configured to establish a call to said camera and to request compressed image frames; said video camera is configured to answer said call and to transmit compressed image frames; and said viewing station is configured to receive compressed frames from said camera and to decompress said frames to produce viewable images.

Brief Description of the Several Views of the Drawings

Figure 1 shows a remote surveillance camera;

Figure 2 shows an overview of the environment for operation of the camera shown in Figure 1; Figure 3 shows operations performed by the camera of Figure 1 within the environment of Figure 2;

Figure 4 details the video camera identified in Figure 1; Figure 5 details operations performed by the PIC micro-controller;

Figure 6 details the viewing station identified in Figure 2;

Figure 7 details the main computer system shown in Figure 6;

Figure 8 details operations performed by the system shown in Figure 7;

Figure 9 shows a display window generated by the process shown in Figure 8;

Figure 10 shows processes for processing image data as shown in Figure 8; Figure 11 shows the display of images on the monitor shown in Figure

6;

Figure 12 shows procedures for disconnecting the system identified in Figure 8;

Best Mode for Carrying Out the Invention

A remote surveillance camera 101 is shown in Figure 1 that is connectable to a public communications network and is arranged to supply video images to a remote viewing station. The camera 101 receives power from a conventional mains outlet 102 or, alternatively, a camera may include internal batteries, preferably lithium ion batteries. In this example, the camera is connected to a conventional telephone line via a socket 103 and the camera includes an appropriate modem for communicating via this analogue channel. Alternatively, communication may be achieved over a digital connection, such as ISDN, or communication may be achieved using mobile technology, such as GSM technology operating in data transmission mode.

The camera includes an input lens and light sensitive circuitry, such as charge couple device circuitry for producing input video images. In addition, the camera includes compression circuitry for compressing the input video images to produce compressed output images. In the preferred embodiment, the video images are compressed in accordance with the JPEG recommendations. The camera also includes a modem or similar device for supplying the compressed output data to the network. In this way, the camera is configured to receive data requests from the viewing station and to transmit output image frame data in response to these requests. In the example shown in Figure 1, the camera has been set up to view a chemical experiment, shown generally at 121. An experimenter is waiting for a particular reaction to complete, whereafter the experimenter may return to the experiment and continue with the next stage of the process. Thus, the video camera has been set up to monitor an appropriate portion of the experiment such that the experimenter may view images from the camera via a remote viewing station. In particular, any personal computer or similar equipped with a modem and a telephone line may, temporarily, provide an appropriate viewing station, as described with respect to Figure 6 onwards. The camera 101 is mounted on a tripod 123 and the tripod may include motors for adjusting various positions, such as camera height, tilt and pan. In addition, motors may be included for adjusting a zoom control of the camera itself and each of these motors may be controlled remotely from the remote viewing station. The camera 101 is connected to a conventional telephone socket

103 that in turn provides communication via the public switched telephone network. In order for a remote viewer, in this case the experimenter, to receive pictures from the camera 101 , the experimenter is merely required to dial the telephone number associated with the socket 103 whereafter, after following appropriate security provisions, images are supplied from the camera 101 to the viewing station. The brightness and sharpness of the CCD capturing unit, along with any other available parameters, may also be controlled remotely.

It should be emphasised, that the camera 101 in the preferred embodiment is not using internet technology in order to achieve this. By dedicating the communication channel, in this case a PSTN, optimum use is made of the available bandwidth in order to obtain optimised image quality at the viewing station.

An overview of the environment in which cameras of the type shown in Figure 1 are operated is illustrated in Figure 2. In this example, a first camera 201 is connected to the PSTN 202, along with a second camera 203 that is also connected to the PSTN 202, both by conventional telephone links.

Similar connections to the PSTN are made by a first personal computer station 205 and a second computer station 206.

By being connected to a conventional telephone line, the first video camera 201 has a first telephone number associated with it whereas the second video camera 202 has a second telephone number associated with it. Thus, each camera may be contacted over the PSTN 202 by dialling the appropriate telephone number.

Thus, at station 205 it is possible to dial the first telephone number in order to receive images from camera 201. In addition, it is possible to dial the second telephone number in order to obtain different images from camera 203. Likewise, station 206 may receive images from camera 201 or at station 206 it is possible to receive images from camera 203.

In the preferred embodiment, executable instructions for the viewing station are retained on a portable data carrying medium such as a floppy disk. In this way, it is possible for the experimenter to retain the floppy disk and then use it in order to view images from an appropriate location. Thus, in this way, the experimenter may be working from a large office block having many computers each connected to an outside telephone line. In accordance with the preferred embodiment, there is no need to install specific instructions at these computers. The experimenter merely loads the floppy disk into a computer and is then in a position, after satisfying security provisions, in order to receive and view images from the remote camera. In this way, surveillance has been achieved using relatively inexpensive equipment at the viewing end and the ability to view images from the camera becomes extremely easy given that they can be viewed from any machine that has an appropriate connection. In this way, the experimenter may maintain a watch on his experiment with minimal further disruption to other activities until a particular event has occurred.

The example given herein in terms of an experimenter viewing an experiment is merely one of many examples to which the camera could be used. For example, the camera could be mounted in a more secure position and used for security purposes. A camera could be permanently mounted at a particular location or could be secured temporarily while particular activities are taking place. A viewer could install several cameras, each with their respective telephone line allowing several views of a location to be received or allowing several locations to be viewed.

Operations performed within the environment shown in Figure 2 are illustrated in Figure 3. The position of the camera is illustrated generally at 301 and the position of a viewing station is shown generally at 302. Initially, at the viewing station 302, software is loaded, as indicated by process 303. This then results in the telephone number of camera 101 being dialled as indicated by arrow 304. At the camera, a power-up procedures is initiated, as illustrated by process 305, resulting in a request 306 for a password being transmitted back to the viewing station. At the viewing station a password 307 is generated and returned back to the camera. This is then acknowledged (308) whereupon at the viewing station an enabling process 309 is initiated.

At this point, the camera should be in a position to transmit image frames and the viewing station should be in a position to receive and process the image frames. The process is initiated by the viewing station issuing a request for an image 310 whereupon a compressed image is then sent 311 to the viewing station. At the viewing station the compressed image is buffered 312 whereafter a further request 313 is made resulting in a further image 314 being returned. Consequently, this process of requesting an image and the compressed image being returned continues until the process is closed down. Video camera 101 is detailed in Figure 4. The camera includes a lens 401 configured to focus an image upon a light sensitive device, such as a charge couple device (CCD). CCD 402 is scanned by a video circuit 403 that in turn provides a video signal to a compression circuit. Compressed image frames are supplied to a modem 405 that is in turn connectable to a socket 103 via a twisted pair connection 406.

A micro-controller, such as a PIC processor 407 controls the operation of devices 403 to 405 and said devices, along with the micro- controller, receive power from a power supply unit 408, connected to mains socket 102 by a mains supply lead 409.

The micro-controller 407 includes an electrically erasable programmable memory device 410. This stores operations performed by the micro-controller and a user name and a password that are specified by a user the first time the camera is used. Thereafter, access to the camera is only possible from a remote station if at the remote station the correct password is identified.

Operations performed by the PIC micro-controller 507 are detailed in Figure 5. When not operational, the camera is placed into a low power consumption mode (sleep mode) and is then powered-up upon receiving a telephone call from a remote station. Upon receiving a telephone call, detected on line 406 by modem 405, modem 405 answers the call and supplies an interrupt to the micro-controller 407 over interrupt line 411. Upon receiving an interrupt the micro-controller powers-up the system at step 502. This results in the video circuit 403 being placed in a condition allowing it to produce video images, placed as compression circuit 404 in a condition to compress said images and places modem 405 in a condition to supply image data to the telephone 406. At step 503 the micro-controller issues a message to modem 405 over line 412 in the form of a token that is interpreted by the instructions being executed by the remote station to the effect that the remote station is required to answer a password.

At step 504 a password is received from the remote station and at step 505 a question is asked as to whether the password is correct. In order to answer this question, the camera compares the password received at step 504 with the password stored in non-volatile memory 410. If the password received at step 504 is considered to be correct, the video camera is enabled at step 506. Alternatively, if the password is not correct the video camera is disconnected at step 509, thereby freeing-up the telephone line. In alternative embodiments the video camera may ask for the password to be supplied again (possibly several times) if the password is identified as being incorrect before a disconnection occurs. Such an approach may be considered desirable because in the preferred embodiment the instructions executed by the remote station do not include provision for passwords to be retained therefore on each connection a user must manually identify the password to the system. Consequently, there is a possibility that errors could be introduced at this stage.

In an alternative configuration a password is asked for more than once from different dialogue boxes before a connection is allowed.

If for whatever reason a malfunction occurs at the camera, at the remote station or within the telecommunications network connecting the two together, it is desirable for both parties to disconnect so that a new connection may be re-established by the making of a fresh telephone call. Consequently, procedures are included for each party to reaffirm to the other party that it is operational. Consequently, if such a reassurance is not received, the party will disconnect and await reconnection.

In the embodiment shown in Figure 5, the remote station periodically requests an image frame to be supplied over the communication channel. If such a request has not been made over a pre-specified period of time, the question asked at step 507 is answered in the negative and a disconnection occurs. In alternative embodiments separate procedures could be invoked in order to achieve this.

When a frame request is received, the question asked at step 507 is answered in the affirmative and a frame of compressed image data is supplied from compression circuit 404 to modem 405 whereupon the data is modulated by the modem 405 and applied to the transmission line 406.

In a preferred embodiment, devices 401 to 403 may be embodied in a single device such as an Omnivision 7620. Preferably, the compression circuit 404 is a Zoran Zr36060. Micro-controller 407 is implemented as a PIC 16F877 and the modem may be a Multitech MT5634SMI 56K device.

Viewing station 205 is detailed in Figure 6. The experimenter has requested use of a conventional PC workstation that is normally used by someone else. A main computer system 601 includes a modem connected to a telephone line via a socket 602. Input devices are provided in the form of a keyboard 603 and a mouse 604. Similarly, output images are supplied to a visual display unit 605.

In order to operate the system, the experimenter inserts a floppy disk 606 within a floppy disk drive 607, from which executable instructions are read. The main computer system 601 is detailed in Figure 7. The system includes a central processing unit 701 , system memory 702, hard disk storage 703, video memory 704, a modem 705 and floppy disk reader 607. Operations performed by the system shown in Figure 7 are detailed in Figure 8.

At step 801 instructions are loaded from floppy disk 606. Alternatively, instructions may be held locally and loaded from disk storage 703.

After loading instructions at step 801 , internal modem 705 is configured so as to operate in accordance with the preferred protocols of the transmitting modem 405.

At step 803 security data is received from the user via manual operation of keyboard 603 The security data received at step 803 is then sent to the camera at step 804. A response is then received from the camera at step 805 and a question is asked at step 806 as to whether a valid connection has been achieved. If answered in the negative, control is returned to step 803 inviting the user to re-enter security data.

If a valid connection is established, resulting in the question asked at step 806 being answered in the affirmative, the system enters a wait state until a displayed start button is pressed at step 807.

After the start button has been pressed at step 807, the system enters an operational mode in which image frames are requested from the camera, received and processed.

At step 808 a request is made for an image to be sent of a specified size and quality. After a specified period of time a question is asked at step

809 as to whether an image is available and if answered in the negative the system is reset. The resetting ensures that the telephone line is cleared down, thereby allowing a new call to be established.

If the question asked at step 809 is answered in the affirmative, to the effect that image data is available, the image data is processed at step 801. After processing an image a question is asked at step 811 as to whether further processing is to continue. When answered in the affirmative, control is returned to step 808 and a request for a further image frame is made. Alternatively, if the question asked at step 811 is answered in the negative, a disconnection process is performed at step 812.

Process 803 for the receiving of security data results in a window being displayed on monitor 605, as illustrated in Figure 9. Window 901 displays a form in which three fields are to be entered. These fields consist of the user's name at 902, a password at 903 and the telephone number of the camera at 904. Having entered details in all of these fields 902 to 904, a user, by appropriate operation of mouse 604, operates a connect button 905. Alternatively, a user may operate a cancel button 906.

Process 803 is configured such that data cannot be sent to the camera at step 804 until all of the fields have been completed. Thus, in addition to the telephone number being called, a user must enter the correct user name and the correct password. User name details are stored by the executable procedures illustrated in Figure 8 and the password is stored by the camera at 410. Thus, having entered data in all three fields and operated the connect button, details of the password are sent to the camera at step 804.

Processors 810 for the processing of image data are detailed in Figure 10. At step 1001 the viewing station receives an indication of the size of the compressed frame to be transmitted by the camera. Each input frame supplied to compression circuit 404 has a specified size and therefore a predetermined data volume. The JPEG compression routine compresses the image data by procedures that take account of the redundancy within the data itself. Consequently, the size of an output frame will depend on several factors, including the complexity of the original input frame. Thus, if images are moving for example, the complexity of the images will change on a frame by frame basis. It is also possible to change the size of the input images that will in turn change the size of the resulting output data and to change the quality of the images. Quality is inversely related to the degree of data that is discarded during the compression process. Thus, with lower quality, the compression procedure becomes more lossy.

Having been informed as to the size of an incoming frame at step 1001 , an input buffer for the frame is established at step 1002. Thereafter, as the data is received, the data is written to the input buffer at step 1003.

After receiving a complete frame, the image frame is decompressed at step 1004 to reconstitute an image frame having a number of pixels that equals the number of pixels present in the original input image. However, due to the JPEG compression procedure, there will have been a degree of loss and degradation.

At step 1005, further processing of the image is performed, as required whereafter at step 1006 the image is written to an output buffer, that could be included as part of the video memory 704. Thus, the image held in the output buffer is then read at the output display frame rate so as to maintain a steady image on a display monitor such as monitor 605, which is then refreshed periodically when new image data is received.

The transmission channel through the PSTN 202 does convey instructions and elements of data used to control the operation of the systems. However, the amount of data used for these purposes is extremely small compared to the transmission of video data. In this way, the system is optimised for video data transmission so as to make optimum use of the available transmission bandwidth. In this way, the quality of images supplied through the telephone system is considerably higher than that available through conventional web camera techniques. However, it should be appreciated that the transmission of data through the PSTN does present the major real time constraint and other processes performed by this system, such as the decompression algorithm, take up relatively little time compared to the time required for a frame of compressed data to be transmitted.

During the processing of image data, input video images received from camera 101 are displayed on monitor 605, as detailed in Figure 11. The received video image itself is displayed within a window 1101 and, typically, does not fill the whole of this window. Thus, in the example shown in Figure 11, the actual image occupies region 1102 within window 1101. Monitor 605 also displays various controls, that are operated in response to movement of mouse 604.

A region 1103 allows a capture quality be defined, that effectively defines the degree of compression. The first button defines a quality of fifty percent, a second defines a quality of thirty percent (a default value) and a third defines a quality of ten percent. Thus, the first button allows a high quality to be selected in which only fifty percent of the data is discarded. A second button allows a medium quality to be selected with seventy percent of the data being discarded and a third button allows a low quality to be selected with ninety percent of the data being discarded. Lowering quality increases the level of loss but reduces the amount of data which needs to be transmitted therefore over a period of time it is possible to transmit more frames. Thus, a high quality is selected if a low frame rate is tolerable but high definition is required. Similarly, low quality is selected if a higher frame rate is required at lower definition. A region 1104 allows an input image size to be selected. This represents the number of pixels processed by video circuit 403. A first button allows the large image size to be selected of three hundred and twenty by two hundred and forty pixels. A second button (the default) allows a medium size to be selected of one hundred and sixty by one hundred and twenty pixels. A third button allows a small image to be selected of eighty pixels by sixty pixels. A large image allows more detail to be seen within the picture but a small image will allow a higher frame rate to be achieved. Thus, like quality, there is a trade-off between image size and frame rate.

A soft slider 1105 allows an output display size to be selected. Increasing the output display size effectively magnifies and increases the size of region 1102, without actually increasing its data content. Thus, the degree of magnification performed by this process usually depends on a viewer's preference, although it may be adjusted to suit particular scenes or situations.

In an enhanced embodiment, seven image sizes are provided for ranging from 40w by 30h to 320w by 240h. Similarly ten levels of compression are provided for ranging from fifty percent to ninety five percent. This gives a user enhanced control over image quality and frame rate.

Soft buttons 1106 allow various types of filters to be selected. A first filter significantly increases contrast and therefore emphasises boundaries and in the extreme effectively performs an edge detection process. Such a procedure may be particularly attractive if image quality is low and a user is particularly interested in sudden movement.

The other buttons may be used to invoke various other filters, such as softening filters, sharpening filters, enhancement filters, embossing filters, a defocus filter and a blurring filter. The value of these filters will depend significantly on the type of image being viewed. In an enhanced embodiment it is possible to combine two filters, such as smoothness and edge detection, or smoothness and negation.

As shown in Figure 8, the loading of image frames does not start until a start button is pressed at step 807 and this start button is illustrated in Figure 11 at 1107.

A first display 1108 indicates the rate at which data is being received in terms of bytes per minute. A second display 1109 indicates the number of frames that have been received over a specified period. Thus, indicators 1108 and 1109 provide reassurance to a user to the effect that data is actually being received and updated, even if no changes are occurring in the image being viewed.

Procedures 812 for disconnecting the system are detailed in Figure

12. At step 1201 the system issues a command to the camera to the effect that a disconnection is to occur. Upon receiving this disconnection notice, the camera purges its compression circuit 404 of any data that may be held temporarily and then enters its sleeping state.

At step 1202 internal buffers at the viewing station are cleared such that no data received from the camera remains resident within the computer after a session has been completed. Such an approach provides a significant advantage over internet solutions in that there is no risk of buffered images remaining resident on the computer system.

At step 1203 modem and any other modified parameters are reset, thereby placing the computer system in a condition equivalent to that before floppy disk 606 was read.

The process is then closed down at step 1204 and if not already done so, the floppy disk 606 would be removed from the floppy disk drive.

In a first preferred embodiment, the minimal nature of the computer system is perceived as an advantage in that it may be produced at significantly lower cost compared to alternative solutions. In this way, it is possible to install surveillance apparatus in situations where existing technology would not prove commercially viable. Thus, for example a house could be monitored while residents are on holiday so as to provide them with reassurance to the effect that everything is well back at home. In the example given herein, an experimenter is allowed to monitor the progress of an experiment from remote locations thereby relieving the experimenter of the need to periodically check equipment etc. The solution is therefore seen as providing a platform to extent applications for surveillance equipment of this type.

In enhanced systems, the camera could include an infrared light allowing the camera to view images without the presence of visible light. An alternative enhanced version may include a movement detector, similar to infrared detectors used for intruder alarms. Thus, in response to detecting movement, the camera could attempt to contact a user who would then be invited to view images being produced by the camera. Alternatively, a message could be sent to an automated computer system configured to record images when motion is detected.

In an enhanced system, the viewing station could be modified so as to make provision for images to be recorded in temporary files. An indication can be provided to show a user how much local storage is available for this purpose. It is also possible to vary the amount of storage allocated for this purpose.

In the example shown herein, the viewing station takes the form of a conventional personal computer. However, in alternative embodiments other platforms could be used such as computers or hand held devices etc. A plurality of cameras could be co-ordinated in a local radio environment employing appropriate multiplexing protocols, such as those defined by the blue tooth recommendations. In an enhanced embodiment, the camera may send a message by a pre-specified means to a pre-specified destination upon a pre-specified action taking place. The action could be as a result of movement being detected, possibly using infra red technology. Alternatively, a power low condition could be identified or a detection to the effect that access had been attempted using an incorrect password. Messages could be sent by SMS, fax, or pager etc. After a message has been sent, the processor is placed into sleep mode to prevent messages being continually sent.

The camera does not include any components that make an audible noise, therefore an intruder would not be made aware of a call being made to the camera in order to capture images.

Claims

1. A remote surveillance system comprising a video camera connected to a public communications network and a viewing station connected to said network, wherein said viewing station is configured to establish a call to said camera and to request compressed image frames; said video camera is configured to answer said call and to transmit compressed image frames; and said viewing station is configured to receive compressed frames from said camera and to decompress said frames to produce viewable images.

2. A remote surveillance system according to claim 1 , wherein said viewing station is configured to receive a telephone number of the video camera and a password before establishing a call to said camera.

3. A remote surveillance system according to claim 1 , wherein said viewing station is configured to request compressed image frames of a specified size and/or a specified quality.

4. A remote surveillance system according to claim 1 , wherein said viewing station is configured to display information relating to the amount of data received and/or the number of frames received from the video camera.

5. A remote surveillance system according to claim 1 , wherein said viewing station includes recording means configured to record images to a temporary file.

6. A remote surveillance system according to claim 1 , wherein said viewing station takes the form of a desktop personal computer, a lap top computer or a palm organiser.

7. A remote surveillance camera connectable to a public communications network for supplying video images to a remote viewing station, comprising input means for producing input video images; compression means for compressing said input video images to produce compressed output image data; communication means for receiving input signals from said network and for supplying said compressed output data to said network, wherein said communication means is configured to receive data requests and to transmit said output data in response to said requests.

8. A camera according to claim 7, including storage means configured to store an authentication code.

9. A camera according to claim 8, including means for recording said authentication code during a first operational use.

10. A camera according to claim 8, configured to enter a waiting or sleeping state until a telephone call is received from a remote viewing station.

11. A camera according to claim 7, including control means for controlling attributes of said camera in response to signals received from a viewing station.

12. A camera according to claim 7, including infrared detection means for detecting the presence of infrared emitters.

13. A camera according to claim 12, including means for generating an alert signal in response to an output being received from said infrared detection means.

14. A camera according to claim 7, including means for emitting infrared light.

15. A camera according to claim 7, wherein said public communications network is a public switched telephone network (PSTN) the integrated services digital network (ISDN) or a mobile telephone network.

16. A computer-readable medium having computer-readable instructions executable by a computer such that, when executing said instructions, a computer will perform the steps of establishing a call over a public network to a remote video camera, wherein said camera is configured to answer said call and to transmit compressed image frames; and to receive compressed frames from said video camera and to decompress said frames to produce viewable images.

17. A computer-readable medium having computer-readable instructions according to claim 16, such that when executing said instructions a computer will also perform the step of receiving a telephone number of the video camera and a password from the user before establishing a call to the camera.

18. A computer-readable medium having computer-readable instructions according to claim 16, such that when executing said instructions a computer will also perform the step of requesting compressed image frames of a specified size and/or a specified quality.

19. A computer-readable medium having computer-readable instructions according to claim 19, such that when executing said instructions a computer will also perform the step of displaying information relating to the amount of data received and/or the number of frames received from the video camera.

20. A computer-readable medium having computer-readable instructions according to claim 16, such that when executing said instructions a computer will issue commands for controlling attributes of the camera.