CN103596001A - Method for objectively evaluating quality of parallel macrophotography of stereo camera - Google Patents

Abstract

The invention belongs to the technical field of collection of stereo images and relates to a method for objectively evaluating the quality of parallel macrophotography of a stereo camera. The method comprises the steps that the evaluation and scoring standard of the quality of macrophotography of the stereo camera is determined; an objective evaluation index of the quality of parallel macrophotography of the stereo camera is selected; the corresponding relation between the range of the value of the objective evaluation index of the quality of parallel macrophotography of the stereo camera and the objective evaluation value of the quality of the stereo images is established; a stereo image pair is shot through the stereo parallel camera under the condition of macrophotography; according to the stereo image pair, the camera parameters generated when parallel macrophotography is conducted through the stereo camera are extracted; the objective evaluation index of the stereo images is calculated; and objective evaluation results of the shot stereo image pair are obtained. By the adoption of the method for objectively evaluating the quality of parallel macrophotography of the stereo camera, the quality of the stereo images shot in a parallel macrophotography mode through the stereo camera can be effectively evaluated.

Description

The parallel shooting quality method for objectively evaluating of a kind of stereoscopic camera microspur

Technical field

The invention belongs to three-dimensional image acquisition technical field, be specifically related to a kind of stereoscopic camera microshot assessment method for encoding quality.

Background technology

Development along with stereo technology, the treatment technology of three-dimensional (3D) image is ripe day by day, the stereopsis source of countries in the world is increasing, having met the hope that people thirst for seeing 3D image on screen. yet people are when watching some film source, there will be dizziness, feel sick and balance under degradation malaise symptoms, a lot of people are attributed to stereopsis treatment technology or Display Technique is not enough, therefore carry out the correlative study of stereopsis processing and Display Technique, and set up corresponding evaluation theory system.But these appraisement systems still can not solve all malaise symptoms that occur while watching completely, because current evaluation theory is all that before and after processing for stereopsis, the comparing result of feature extraction carries out subjective evaluation, researchers think that the stereopsis obtaining is the desirable of standard, ignored stereopsis source in shooting process because parameter arranges the undesirable situation that causes film source poor effect. based on above reason, a lot of researchers are launching correlative study work aspect the evaluation of stereoscopic camera shooting quality.

In addition, because people are when watching the natural scene of different distance, area-of-interest is different, and the information that human eye obtains is also different, can shot type be divided into microspur, low coverage and long distance according to stereoscopic camera shooting distance difference thus.Researchers take and only come that to do relevant research stereoscopic camera according to shooting distance, and have pointed out that some are applicable to the shooting criterion of stereoscopic camera.But under the tangible specific precondition of above-mentioned achievement in research great majority, for part camera parameter, analyze and study, do not propose an extensively stereoscopic camera shooting quality evaluation criterion that generally acknowledge, that comprehensively comprise camera parameter and scene parameter.

Summary of the invention

Technical problem to be solved by this invention is: provide a kind of stereoscopic camera microspur parallel shooting quality method for objectively evaluating, can effectively evaluate the stereo image quality of the parallel shooting of stereoscopic camera microspur, and can provide shooting criterion for stereoscopic shooting amateurs.Technical solution of the present invention is as follows:

The parallel shooting quality method for objectively evaluating of microspur, comprises the following steps:

1) establishing subjective assessment value is MOS, determines the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur;

2) establishing shooting distance is that h, camera spacing are that d, camera focus are f, chooses the objective evaluation index k of the parallel shooting quality of stereoscopic camera microspur:

$k=\frac{d}{h^{0.49}}\·\exp {\left(\frac{f-94.643}{101.475}\right)}^2$

3) set up the corresponding relation of the objective evaluation value K of objective evaluation index k value scope and stereo image quality, objective evaluation index k value is larger, and corresponding objective evaluation value K is less, and the parallel shooting quality of stereoscopic camera microspur is poorer:

4) utilize three-dimensional parallel camera to take stereo-picture pair in microspur situation;

5), according to captured stereo-picture pair, extract camera shooting distance h, camera spacing d and camera focus f when stereoscopic camera microspur is parallel to be taken;

6) calculate the objective evaluation index k of stereo-picture, stereoscopic camera is carried out to objective evaluation, obtain the right objective evaluation value K of described stereo-picture;

7) objective evaluation value K and subjective assessment value MOS are compared, obtain the right objective evaluation result of captured stereo-picture.

Wherein, the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur are as following table:

The present invention's advantage is compared with prior art: the present invention utilizes double vision point stereo-picture to extracting inner parameter, external parameter and the scene parameter of stereoscopic camera, by subjective detection test stereoscopic image to making subjective assessment, feature based on the parallel shooting of stereoscopic camera microspur and the requirement to acquisition parameters, set up stereoscopic camera method for evaluating objective quality, the method can be evaluated stereoeffect and the picture quality of stereo-picture when stereoscopic camera microspur is parallel to be taken effectively, and provides corresponding shooting criterion for the amateur of stereoscopic shooting.

Accompanying drawing explanation

By describing embodiments of the present invention in detail with reference to accompanying drawing, above feature and advantage of the present invention will be easy to become obviously for those skilled in the art, wherein:

Fig. 1 is three-dimensional parallel camera schematic diagram;

Fig. 2 is the parallel shooting quality objective evaluation of stereoscopic camera microspur model;

Fig. 3 (a) and (b) be that 3dsMax takes stereo scene schematic diagram;

Fig. 4 (a) and (b) be that real stereoscopic camera is taken stereo scene figure;

Fig. 5 is subjective evaluation value correlation schematic diagram;

Embodiment

Now will with reference to accompanying drawing, embodiments of the present invention be described in further detail hereinafter.Yet, can specifically implement the present invention and the present invention should be interpreted as being limited to execution mode set forth herein by different forms.More precisely, it is comprehensive and complete in order to expose that these execution modes are provided, and will to those skilled in the art, pass on idea of the present invention all sidedly.

The present invention only for microspur parallel shooting carry out the research of evaluation method, in conjunction with the shooting feature of parallel camera (as Fig. 1) and existing shooting criterion, probe into and expanded the impact of a plurality of stereoscopic camera acquisition parameters on picture quality, and having set up corresponding model.While, in conjunction with the basis of the restriction of the scene parameter of the parallel shooting of microspur, has been set up the parallel shooting quality method for objectively evaluating of a kind of stereoscopic camera microspur.

For the parallel shooting of stereoscopic camera microspur, the present invention has set up the parallel shooting quality objective evaluation of microspur camera overall model, as shown in Figure 2.First, from stereo image pair, obtain the acquisition parameters of stereoscopic camera, parameter is input to parallel camera shooting quality evaluation module, the evaluation index of existing parallel camera evaluation theory and the present invention's proposition is combined, and output integrated objective evaluation value, by the contrast of this objective evaluation value and subjective assessment value, can learn that the method for objectively evaluating that the present invention proposes is applicable to the evaluation to the parallel shooting quality of stereoscopic camera microspur.Concrete implementation step is as follows:

(1) from stereogram image source, obtain stereoscopic camera acquisition parameters

What stereoscopic camera parameter extraction was got the bid earnest method is mainly to set up transformational relation model between world coordinate system, camera coordinates system and image coordinate system.The method that has multiple extracting parameter in prior art, the present invention adopts vanishing point method to extract shooting distance h, camera spacing d, camera focus f.The specific implementation of method can be referring to two pieces of documents below:

[1]E.Guillou,D.Meneveaux,E.Maisel,and?K.Bouatouch,Using?vanishing?points?for?camera?calibrationand?coarse3D?reconstruction?from?a?single?image,Visual?Computer,16(7)(2000)396-410

[2]JA.de?Franca,MR.Stemmer,MBD.Franca,A?new?robust?algorithmic?for?multi-camera?calibration?witha1D?object?under,Pattern?Recognition,45(10)(2012)3636-3647

The present invention samples by hyperspace, and analytic method is set up Mathematical Modeling and two steps of optimal estimation parameter model are extracted stereoscopic camera inside and outside parameter, and the area-of-interest exacting method of combining image visual stimulus, and extracts scene parameter with this.The method adopts interactively mode, top-down information is converted to the different weighted values of input picture low-level image feature, simultaneously in conjunction with Itti-Koch model and Stentiford model, realizes the area-of-interest exacting method of combining image visual stimulus.

(2) the present invention is based on forefathers to part camera parameter and the research of stereoeffect relation, according to achievement in research and conclusions such as Percival comfort zone, A Enshacikaya stereo formula and Bercovitz formula, in conjunction with human eye corresponding circle of sensation, by subjectivity, survey experiment, between the parallel acquisition parameters of research stereoscopic camera microspur, mutual restricting relation, sets up the parallel acquisition parameters model of desirable stereoscopic camera microspur that comprises the relevant parallel acquisition parameters of microspur.

Researchers [3,4,5] find 1/30 theory, i.e. the ratio of camera spacing and shooting distance (dh), variation can affect stereo image quality.In addition the present invention finds that by great many of experiments camera focus f also has considerable influence to stereoscopic camera shooting quality.Comprehensive experimental result, the stereo image quality evaluation index k while setting up camera focus f=50mm of analyzing ₁

$k_1=\frac{d}{h^{\frac{1}{2.05}}}=\frac{d}{h^{0.49}}$

Change f, get respectively f=85mm, f=135mm, f=200mm repeats above experimentation, utilizes MATLAB matching to obtain comprehensive evaluation index relational expression k

$k=\frac{d}{h^{0.49}}\·\exp {\left(\frac{f-94.643}{101.475}\right)}^2$

Therefore, the present invention combines the impact of camera shooting distance h, camera spacing d, camera focus f stereoscopic image quality and analyzes, and sets up parallel camera microshot quality evaluation module.The above analysis result, the present invention has set up the parallel shooting quality objective evaluation of stereoscopic camera microspur overall model, as shown in Figure 2, evaluates detailed rules and regulations as described in Table 1, wherein the K output objective evaluation value of evaluation model for this reason.

The corresponding relation of table 1 evaluation of estimate k scope and stereo image quality K

[3] Chen Enyan, Lu Shuwen. three-dimensional imaging principle, shooting and reproduction summary [J]. television engineering, 2010,3:25-30.

[4]Bercovitz?Formulae?for?Sereo?Base[EB/OL]．

http://nzphoto.tripod.com/stereo/3dtake/fbercowitz.htm,2012-3-19

[5]Mendiburu?B.3D?movie?making:stereoscopic?digital?cinema?from?script?to?screen[J].Taylor&Francis?US,2009.

(3), because objective evaluation model proposed by the invention is set up on a large amount of subjective experiments basis, therefore, the present invention will carry out subjective experiment according to current general Pyatyi evaluation criterion (table 2).And the output of the objective evaluation model method of subjective assessment result and the present invention's proposition is contrasted, with this, verify exploitativeness of the present invention.

Table 2 stereoscopic camera microshot quality evaluation standards of grading

In order to verify the present invention, utilize different cameral in same position, to obtain the picture of Same Scene, and same camera obtain the picture of Same Scene under different apertures, then according to step (1), obtain the acquisition parameters of stereoscopic camera.According to the parallel shooting quality objective evaluation of the stereoscopic camera microspur model method obtaining in step (2), the stereo-picture in the image library of laboratory is carried out to objective evaluation, a kind of shooting stereo images scene wherein as shown in Figure 3 and Figure 4.The present invention is according to the parallel shooting quality method for objectively evaluating of stereoscopic camera microspur of step foundation before and the contrast of subjective evaluation method, as shown in Figure 5.Result shows, the model that the present invention proposes experiences very consistent with people's subjective vision, so this evaluation model can be effectively for the parallel shooting quality evaluation of stereoscopic camera microspur.

The objective evaluation model of foundation proposed by the invention has not only been realized the evaluation to the parallel shooting quality of stereoscopic camera microspur, but also can be for instructing the parallel shooting of stereoscopic camera microspur, for amateur provides a foundation that acquisition parameters is rationally set.

The content not being described in detail in specification of the present invention belongs to the known prior art of professional and technical personnel in the field.

Claims (2)

1. the parallel shooting quality method for objectively evaluating of stereoscopic camera microspur, comprises the following steps:

1) establishing subjective assessment value is MOS, determines the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur;

2) establishing shooting distance is that h, camera spacing are that d, camera focus are f, chooses the objective evaluation index k of the parallel shooting quality of stereoscopic camera microspur:

$k=\frac{d}{h^{0.49}}\·\exp {\left(\frac{f-94.643}{101.475}\right)}^2$

3) set up the corresponding relation of the objective evaluation value K of objective evaluation index k value scope and stereo image quality, objective evaluation index k value is larger, and corresponding objective evaluation value K is less, and the parallel shooting quality of stereoscopic camera microspur is poorer:

4) utilize three-dimensional parallel camera to take stereo-picture pair in microspur situation;

5), according to captured stereo-picture pair, extract camera shooting distance h, camera spacing d and camera focus f when stereoscopic camera microspur is parallel to be taken;

6) calculate the objective evaluation index k of stereo-picture, stereoscopic camera is carried out to objective evaluation, obtain the right objective evaluation value K of described stereo-picture;

7) objective evaluation value K and subjective assessment value MOS are compared, obtain the right objective evaluation result of captured stereo-picture.

2. the parallel shooting quality method for objectively evaluating of stereoscopic camera microspur according to claim 1, is characterized in that, the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur are as following table:

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