CN103618891A - Objective evaluation method of stereo camera microspur convergence shooting quality - Google Patents

Abstract

The invention belongs to the technical field of stereo image acquisition, and relates to an objective evaluation method of stereo camera microspur convergence shooting quality. The objective evaluation method of stereo camera microspur convergence shooting quality comprises the steps of determining an evaluation scoring standard of stereo camera microspur shooting quality, selecting objective evaluation indexes of stereo camera microspur convergence shooting quality, building a corresponding relation between an objective evaluation index value range and an objective evaluation value of stereo image quality, using a stereo convergence camera to shoot a stereo image pair on the situation of microspur, extracting camera parameters in the process of stereo camera microspur convergence shooting according to the shot stereo image pair, calculating objective evaluation indexes of the stereo images, and obtaining the objective evaluation result of the shot stereo image pair. According to the stereo camera microspur convergence shooting quality objective evaluation method, the quality of the stereo images shot in a stereo camera microspur convergence mode can be effectively evaluated.

Description

A kind of stereoscopic camera microspur is assembled shooting quality method for objectively evaluating

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 to assemble shooting quality method for objectively evaluating, can effectively evaluate stereoscopic camera microspur and assemble the stereo image quality of taking, and can provide shooting criterion for stereoscopic shooting amateurs.Technical solution of the present invention is as follows:

Stereoscopic camera microspur is assembled a shooting quality method for objectively evaluating, comprises the following steps:

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

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

$p=f^{0.815}\arctan \left(\frac{d/2}{h}\right);$

3) set up the corresponding relation of the objective evaluation value M of objective evaluation index p value scope and stereo image quality, objective evaluation index p value is larger, and corresponding objective evaluation value M is less, and stereoscopic camera microshot quality is poorer:

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

5), according to captured stereo-picture pair, extract stereoscopic camera microspur and assemble camera shooting distance h, camera spacing d and the camera focus f while taking;

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

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

1), in, the evaluation standards of grading of the stereoscopic camera microshot quality of foundation are as follows:

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, shot type based on stereoscopic camera and the requirement to acquisition parameters, set up stereoscopic camera method for evaluating objective quality, stereoeffect and the picture quality of stereo-picture when the method can effectively be evaluated stereoscopic camera microspur and assemble to take, and provide 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 the three-dimensional camera schematic diagram of assembling;

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

Fig. 3 is that two stereoscopic cameras obtain the illustraton of model of image from different points of view;

Fig. 4 assembles 12 ° of theoretical schematic diagrames of camera;

Fig. 5 (a) and (b) be that 3dsMax takes stereo scene schematic diagram;

Fig. 6 (a) and (b) be that real stereoscopic camera is taken stereo scene figure;

Fig. 7 is subjective evaluation value Pearson correlation coefficient 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 assembles and takes the research of carrying out evaluation method for microspur, in conjunction with assembling the shooting feature of 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.In conjunction with microspur, assemble the basis of the restriction of the scene parameter of taking simultaneously, set up a kind of stereoscopic camera microspur and assembled shooting quality method for objectively evaluating.

For stereoscopic camera microspur, assemble and take, the present invention has set up microspur camera and has assembled shooting quality objective evaluation overall model, as shown in Figure 2.First, from stereo image pair, obtain the acquisition parameters of stereoscopic camera, parameter is input to and assembles camera shooting quality evaluation module, the evaluation index of existing convergence 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 stereoscopic camera microspur convergence shooting quality.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?calibration?and?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?with?a1D?object?under,Pattern?Recognition,45(10)(2012)3636-3647

Figure 3 shows that two stereoscopic cameras obtain the illustraton of model of image from different points of view, establish two cameras and be respectively C ₁and C ₂, 1 p in space, in two cameras, imaging is respectively p ₁(u ₁, v ₁) and p ₂(u ₂, v ₂), establish world coordinate system and C ₁camera coordinates system overlap, the world coordinate system of p and C ₁camera coordinates is p (x, y, z), and the camera coordinates of C2 is p (x ₂, y ₂, z ₂).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, mutual restricting relation between research stereoscopic camera microspur convergence acquisition parameters, sets up and comprises the desirable stereoscopic camera microspur convergence acquisition parameters model that relevant microspur is assembled acquisition parameters.

For assembling camera, one of the most frequently used criterion when 12 ° of theories are stereoscopic camera microshot, it requires camera baseline angle (in Fig. 4) to be controlled in 12 °.The present invention, by lot of experiment validation, finds that 12 ° is not a strict angle boundary, can not directly use 12 ° of theories to evaluate camera shooting quality.So the present invention, on 12 ° of theoretical bases, has carried out further analysis and research.

In order to obtain microspur, assemble the lower corresponding camera parameter setting criterion of shooting, the present invention utilizes 3dsMax that different camera spacing d is set in the situation that shooting distance h is certain, takes a series of stereo-pictures pair, changes h and repeats above experimentation; , experimental results demonstrate, the stereoeffect of camera focus f stereoscopic image also has a great impact meanwhile, changes f, repeats above experimentation, can obtain a series of stereo-pictures pair.Make α=arctan (d/2/h) (α is stereoscopic camera baseline angle), the quality of camera parameter stereoscopic image and the impact of stereoeffect while adopting subjective detection Experimental Research microshot.

In conjunction with above-mentioned analysis result, set up the relational expression of subjective assessment value and shooting distance h, camera spacing d, camera focus f, and selected it as evaluation index p

$p=\frac{\mathrm{\α}}{f^{-0.815}}=\frac{\arctan \left(\frac{d/2}{h}\right)}{f^{-0.815}}=f^{0.815}\arctan \left(\frac{d/2}{h}\right)$

The above analysis result, the present invention has set up stereoscopic camera microspur and has assembled shooting quality objective evaluation overall model, as shown in Figure 2, evaluates detailed rules and regulations as described in Table 1, wherein the M output objective evaluation value of evaluation model for this reason.

The corresponding relation of table 1 evaluation of estimate p scope and stereo image quality M

(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 stereoscopic camera microspur obtaining in step (2), assemble shooting quality objective evaluation model method 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 5 and Figure 6.The present invention assembles the contrast of shooting quality method for objectively evaluating and subjective evaluation method according to the stereoscopic camera microspur that step is set up before, adopt Pearson correlation coefficient (Pearson Correlation Coefficient, PCC) index to calculate the coefficient correlation (Fig. 7) of subjective evaluation value.Result shows, the model that the present invention proposes is very consistent with the impression of people's subjective vision, so this evaluation model can be effectively for the evaluation of stereoscopic camera microspur convergence shooting quality.

The objective evaluation model of foundation proposed by the invention has not only been realized the evaluation of stereoscopic camera microspur being assembled to shooting quality, but also can take for instructing stereoscopic camera microspur to assemble, 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. stereoscopic camera microspur is assembled a shooting quality method for objectively evaluating, comprises the following steps:

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

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

$p=f^{0.815}\arctan \left(\frac{d/2}{h}\right);$

3) set up the corresponding relation of the objective evaluation value M of objective evaluation index p value scope and stereo image quality, objective evaluation index p value is larger, and corresponding objective evaluation value M is less, and stereoscopic camera microshot quality is poorer:

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

5), according to captured stereo-picture pair, extract stereoscopic camera microspur and assemble camera shooting distance h, camera spacing d and the camera focus f while taking;

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

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

2. stereoscopic camera microspur according to claim 1 is assembled shooting quality method for objectively evaluating, it is characterized in that 1) in, the evaluation standards of grading of the stereoscopic camera microshot quality of foundation are as follows:

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