CN103596001B - 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

Along with the development of 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, meet the hope that people thirst for seeing 3D image on screen. but people are when watching some film source, there will be dizziness, feel sick and degradation malaise symptoms under balance, a lot of people is attributed to stereopsis treatment technology or Display Technique is not enough, therefore carry out the correlative study of stereopsis process and Display Technique, and set up corresponding evaluation theory system.But all malaise symptoms that these appraisement systems occur when still can not solve viewing completely, because current evaluation theory is all carry out subjective evaluation for the comparing result of feature extraction before and after stereopsis process, researchers think that the stereopsis obtained is the desirable of standard, have ignored stereopsis source and cause the situation of film source poor effect because optimum configurations is undesirable in shooting process. based on above reason, a lot of researcher expands correlative study work in 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, according to stereoscopic camera shooting distance difference, shot type can be divided into microspur, low coverage and long distance thus.Researchers only come that according to shooting distance to stereoscopic camera shooting and have done relevant research, and indicate 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, carry out analyzing and studying for part camera parameter, not the extensive stereoscopic camera shooting quality evaluation criterion that generally acknowledge, that comprehensively comprise camera parameter and scenario parameters of proposition one.

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, effectively can evaluate the stereo image quality of the parallel shooting of stereoscopic camera microspur, and shooting criterion can be provided for stereoscopic shooting amateurs.Technical solution of the present invention is as follows:

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

1) set subjective assessment value as MOS, determine the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur;

2) set shooting distance as h, camera spacing be d, camera focus is 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) three-dimensional parallel camera is utilized to take stereo pairs in microspur situation;

5) according to captured stereo pairs, camera shooting distance h, the camera spacing d and camera focus f when stereoscopic camera microspur is parallel to be taken is extracted;

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

7) objective evaluation value K and subjective assessment value MOS is compared, the objective evaluation result of the stereo pairs captured by acquisition.

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 pairs to extract the inner parameter of stereoscopic camera, external parameter and scenario parameters, by subjective detection test stereoscopic image to making subjective assessment, based on the feature of the parallel shooting of stereoscopic camera microspur and the requirement to acquisition parameters, set up stereoscopic camera method for evaluating objective quality, the stereoeffect of stereo-picture and picture quality when the method can evaluate the parallel shooting of stereoscopic camera microspur effectively, and take criterion accordingly for the amateur of stereoscopic shooting provides.

Accompanying drawing explanation

Describe embodiments of the present invention in detail by referring to accompanying drawing, above feature and advantage of the present invention will be easy to become obvious for those skilled in the art, wherein:

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

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

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

Fig. 4 (a) and (b) are real stereoscopic camera shooting stereo scene figure;

Fig. 5 is subjective evaluation value dependency diagram;

Embodiment

In further detail embodiments of the present invention are described hereinafter with reference to accompanying drawing now.But, specifically can implement the present invention by different forms and the present invention should be interpreted as be limited to execution mode set forth herein.More precisely, provide these execution modes to be comprehensive and complete in order to expose, and idea of the present invention will be passed on to those skilled in the art all sidedly.

The present invention only carries out the research of evaluation method for the parallel shooting of microspur, in conjunction with shooting feature and the existing shooting criterion of parallel camera (as Fig. 1), probe into and extend multiple stereoscopic camera acquisition parameters to the impact of picture quality, and establish corresponding model.Simultaneously in conjunction with the basis of the restriction of the scenario parameters of the parallel shooting of microspur, establish 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 establishes microspur camera parallel shooting quality objective evaluation overall model, as shown in Figure 2.First, the acquisition parameters of stereoscopic camera is obtained from stereo image pair, by parameters input to parallel camera shooting quality evaluation module, the evaluation index that existing parallel camera evaluation theory and the present invention propose is combined, and output integrated objective evaluation value, by the contrast of this objective evaluation value and subjective assessment value, can learn that 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) stereoscopic camera acquisition parameters is obtained from stereogram image source

Stereoscopic camera parameter extraction acceptance of the bid earnest method mainly at world coordinate system, set up transformational relation model between camera coordinates system and image coordinate system.Have the method for 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 see two sections 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 extracts stereoscopic camera inside and outside parameter by hyperspace sampling analytic method founding mathematical models and optimal estimation parameter model two steps, and the area-of-interest exacting method of combining image visual stimulus, and extract scenario parameters 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 detection 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 comprising the parallel acquisition parameters of relevant microspur.

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

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

Change f, get f=85mm respectively, f=135mm, f=200mm repeat above experimentation, utilize 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 camera shooting distance h, camera spacing d, the impact of camera focus f stereoscopic image quality is analyzed, and sets up parallel camera microshot quality assessment module.The above analysis result, the present invention establishes stereoscopic camera microspur parallel shooting quality objective evaluation overall model, as shown in Figure 2, evaluates detailed rules and regulations as described in Table 1, wherein the output objective evaluation value of K 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 experiment basis, therefore, the present invention carries out subjective experiment by according to Pyatyi evaluation criterion (table 2) general at present.And the output of objective evaluation model method subjective evaluation result and the present invention proposed contrasts, and verifies exploitativeness of the present invention with this.

Table 2 stereoscopic camera microshot quality evaluation standards of grading

In order to verify the present invention, utilize different cameral to obtain the picture of Same Scene in same position, and same camera obtain the picture of Same Scene under different aperture, then obtains the acquisition parameters of stereoscopic camera according to step (1).Stereoscopic camera microspur parallel shooting quality objective evaluation model method according to obtaining in step (2) carries out objective evaluation to the stereo-picture in the image library of laboratory, and a kind of shooting stereo images scene wherein as shown in Figure 3 and Figure 4.The stereoscopic camera microspur parallel shooting quality method for objectively evaluating of the present invention according to 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 the subjective vision of people, and therefore this evaluation model can effectively for the parallel shooting quality evaluation of stereoscopic camera microspur.

The objective evaluation model of foundation proposed by the invention not only achieves the evaluation to the parallel shooting quality of stereoscopic camera microspur, but also may be used for instructing the parallel shooting of stereoscopic camera microspur, for amateur provides the foundation that rationally arranges acquisition parameters.

The content be not 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) set subjective assessment value as MOS, determine the evaluation standards of grading of the parallel shooting quality of stereoscopic camera microspur;

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

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) three-dimensional parallel camera is utilized to take stereo pairs in microspur situation;

5) according to captured stereo pairs, camera shooting distance h, the camera spacing d and camera focus f when stereoscopic camera microspur is parallel to be taken is extracted;

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

7) objective evaluation value K and subjective assessment value MOS is compared, the objective evaluation result of the stereo pairs captured by acquisition.

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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