CN104077768B

CN104077768B - Method and device for calibrating fish-eye lens radial distortion

Info

Publication number: CN104077768B
Application number: CN201410244246.3A
Authority: CN
Inventors: 杜歆; 方奎; 朱云芳
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2014-06-04
Filing date: 2014-06-04
Publication date: 2017-04-19
Anticipated expiration: 2034-06-04
Also published as: CN104077768A

Abstract

The embodiment of the invention discloses a method and device for calibrating fish-eye lens radial distortion. The method includes the following steps of obtaining a calibration image comprising at least two sets of space parallel straight lines; conducting fitting processing on circle center collinear arc sets mapped by each set of space parallel straight lines in the at least two sets of space parallel straight lines on a distortion image; generating a distortion calibration model according to a fitting processing result. The accuracy of calibrating results of the distortion calibration model can be improved.

Description

A kind of scaling method and caliberating device of fish eye lens radial distortion

Technical field

The present invention relates to electronic technology field, more particularly to a kind of scaling method and demarcation dress of fish eye lens radial distortion Put.

Background technology

With continually developing and perfect for electronics technology, camera, mobile phone etc. possess photograph, camera function terminal device Jing is widely applied in daily life, and in order to increase the manifestation mode of shooting image, user would generally use one The camera lens of a little special-effects, for example：Fish eye lens, shifting lens shaft, Macro Lens are first-class, increased the effect and kind of image taking Class.

Fish eye lens is a kind of extreme wide-angle lens, for make camera lens reach maximum Camera angle, its front lens it is straight Footpath is protruded in parabolical to camera lens is anterior, and fish-eye visual angle makes every effort to reach or beyond the scope to be seen of human eye.Therefore, There is very big difference in the scene of the real world in fish eye lens and people's eye.However, the image captured by fish eye lens is deposited In polytype distortion, wherein radial distortion is considered as the principal element for affecting picture quality, due to traditional radial direction it is abnormal The calibration process of change is only limitted to be fitted the circular arc of single line correspondences to obtain distortion parameter, to generate distortion peg model, causes The calibration result accuracy rate of the distortion peg model is low, it is impossible to solve the problems, such as fish eye lens radial distortion well.

The content of the invention

The embodiment of the present invention provides a kind of scaling method and caliberating device of fish eye lens radial distortion, can improve distortion The accuracy rate of the calibration result of peg model.

In order to solve above-mentioned technical problem, embodiment of the present invention first aspect provides a kind of fish eye lens radial distortion Scaling method, it may include：

Obtain the uncalibrated image comprising at least two groups of space parallel lines；

The center of circle that each group of space parallel lines at least two groups space parallel lines is mapped on fault image Conllinear circular arc group is fitted process；

Distortion peg model is generated according to process of fitting treatment result.

Based in a first aspect, in the first feasible embodiment of first aspect, at least two groups spaces are parallel Arbitrary group of space parallel lines is mapped as the conllinear circular arc group in center of circle, the arbitrary group of space on fault image in straight line There is a corresponding circular arc in the conllinear circular arc group in the center of circle that arbitrary straight line maps on fault image in parallel lines.

Based on first aspect or first aspect the first feasible embodiment, second in first aspect is feasible It is described that each group of space parallel lines at least two groups space parallel lines is mapped on fault image in embodiment The conllinear circular arc group in the center of circle be fitted process, including：

Using default nonlinear optimization algorithm, each group of space is parallel at least two groups space parallel lines described in calculating The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle that straight line maps on fault image；

Calculated using the common parameter and the proportionality coefficient and obtain process of fitting treatment result, the process of fitting treatment result bag The parametrization for including every circular arc in the conllinear circular arc group in each described center of circle is represented and the conllinear circular arc group correspondence in each described center of circle Two common intersections；

Wherein, the common parameter includes that the middle point coordinates of line and the midpoint are to institute between described two common intersections State the vector of arbitrary intersection point in two common intersections, the proportionality coefficient includes justifying per bar in the conllinear circular arc group in each described center of circle The corresponding predetermined coefficient of arc.

Second feasible embodiment based on first aspect, in the third feasible embodiment of first aspect In, described using default nonlinear optimization algorithm, each group of space is parallel at least two groups space parallel lines described in calculating The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle that straight line maps on fault image, including：

The circle that each group of space parallel lines maps on fault image at least two groups space parallel lines described in obtaining The corresponding square distance minimization equation of the conllinear circular arc group of the heart；

The square distance minimization equation is calculated using default nonlinear optimization algorithm, is obtained described in each The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle.

Second feasible embodiment based on first aspect, in the 4th kind of feasible embodiment of first aspect In, it is described that distortion peg model is generated according to process of fitting treatment result, including：

Center of distortion point coordinates and distortion parameter are obtained according to process of fitting treatment result；

Distortion peg model is generated using the center of distortion point coordinates and the distortion parameter.

The 4th kind of feasible embodiment based on first aspect, in the 5th kind of feasible embodiment of first aspect In, it is described that center of distortion point coordinates and distortion parameter are obtained according to process of fitting treatment result, including：

Obtain the linear equation of corresponding two common intersections of the conllinear circular arc group in each center of circle, and by all linear equations Intersecting point coordinate is defined as center of distortion point coordinates；

Represented according to the parametrization of arbitrary circular arc in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle, obtained Distortion parameter.

Based on first aspect the third feasible embodiment, in the 6th kind of feasible embodiment of first aspect In, the square distance minimization equation is：

Wherein, m represents the number of the point of i-th circular arc of fitting, | Q_i,jo_i| represent the point Q on i-th circular arc_i,jWith the center of circle o_iThe distance between, r_iThe radius of i-th circular arc is represented, n represents the bar number of circular arc in the conllinear circular arc group in center of circle, (p_x, p_y) Represent the coordinate of the midpoint P points of line between described two common intersection M points and N points, (t_x, t_y) represent the P points to the M points Or the vector of N points, (k₁…k_n) represent n bar circular arcs in every circular arc proportionality coefficient；

The default nonlinear optimization algorithm is LM (Leven-Marquardt) algorithm.

The 5th kind of feasible embodiment based on first aspect, in the 7th kind of feasible embodiment of first aspect In, it is assumed that the parametrization of arbitrary circular arc is expressed as in the conllinear circular arc group in the arbitrary center of circleIt is described Center of distortion point coordinates is (x_d0, y_d0), then the distortion parameter is：

Wherein, A, B and C are the parameter in the parametrization expression of arbitrary circular arc.

The 7th kind of feasible embodiment based on first aspect, in the 8th kind of feasible embodiment of first aspect In, the distortion peg model is：

Wherein, b=(x_d, y_d) be fault image coordinate points, a=(x_u, y_u) it is image coordinate after distortion correction Point, r_dFor b and the Euclidean distance of center of distortion point coordinates.

Embodiment of the present invention second aspect provides a kind of caliberating device of fish eye lens radial distortion, it may include：

Uncalibrated image acquisition module, for obtaining the uncalibrated image comprising at least two groups of space parallel lines；

Circular fitting module, for distorting to each group of space parallel lines at least two groups space parallel lines The conllinear circular arc group in the center of circle mapped on image is fitted process；

Model generation module, for generating distortion peg model according to process of fitting treatment result.

Based on second aspect, in the first feasible embodiment of second aspect, at least two groups spaces are parallel Arbitrary group of space parallel lines is mapped as the conllinear circular arc group in center of circle, the arbitrary group of space on fault image in straight line There is a corresponding circular arc in the conllinear circular arc group in the center of circle that arbitrary straight line maps on fault image in parallel lines.

Based on second aspect or second aspect the first feasible embodiment, second in second aspect is feasible In embodiment, the circular fitting module includes：

Parameter coefficient calculation unit, for using default nonlinear optimization algorithm, at least two groups spaces described in calculating to be put down The common parameter of the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image and ratio system in row straight line Number；

As a result acquiring unit, for calculating using the common parameter and the proportionality coefficient process of fitting treatment result is obtained, The process of fitting treatment result include the parametrization of every circular arc in the conllinear circular arc group in each described center of circle represent and each described in Corresponding two common intersections of the conllinear circular arc group in the center of circle；

Second feasible embodiment based on second aspect, in the third feasible embodiment of second aspect In, the parameter coefficient calculation unit includes：

Equation obtains subelement, for obtaining at least two groups space parallel lines in each group of space parallel lines exist The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle mapped on fault image；

Parameter coefficient obtain subelement, for using default nonlinear optimization algorithm to the square distance minimization side Cheng Jinhang is calculated, and obtains the common parameter and proportionality coefficient of the conllinear circular arc group in each described center of circle.

Second feasible embodiment based on second aspect, in the 4th kind of feasible embodiment of second aspect In, the model generation module includes：

Coordinate parameters acquiring unit, for obtaining center of distortion point coordinates and distortion parameter according to process of fitting treatment result；

Model signal generating unit, for generating distortion calibration mold using the center of distortion point coordinates and the distortion parameter Type.

The 4th kind of feasible embodiment based on second aspect, in the 5th kind of feasible embodiment of second aspect In, the coordinate parameters acquiring unit includes：

Coordinate obtains subelement, for obtaining the straight line side of corresponding two common intersections of the conllinear circular arc group in each center of circle Journey, and the intersecting point coordinate of all linear equations is defined as into center of distortion point coordinates；

Parameter acquiring subelement, for according to arbitrary circle in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle The parametrization of arc represents, obtains distortion parameter.

Based on second aspect the third feasible embodiment, in the 6th kind of feasible embodiment of second aspect In, the square distance minimization equation is：

The default nonlinear optimization algorithm is LM algorithms.

The 5th kind of feasible embodiment based on second aspect, in the 7th kind of feasible embodiment of second aspect In, it is assumed that the parametrization of arbitrary circular arc is expressed as in the conllinear circular arc group in the arbitrary center of circleIt is described Center of distortion point coordinates is (x_d0, y_d0), then the distortion parameter is：

The 7th kind of feasible embodiment based on second aspect, in the 8th kind of feasible embodiment of second aspect In, the distortion peg model is：

In embodiments of the present invention, by obtain comprising at least two groups of space parallel lines uncalibrated image, to it is described extremely The conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image in few two groups of space parallel lines is intended Conjunction is processed, and generates distortion peg model according to process of fitting treatment result.By adopting at least two groups space parallel lines, Yi Jifen The other conllinear circular arc group in the center of circle that each group of space parallel lines at least two groups space parallel lines is mapped on fault image Process is fitted, the accuracy rate of the calibration result of distortion peg model is improve；By using the conllinear property in the center of circle so that mark Determine result to be still able to keep robustness in the case where there is larger noise.

Description of the drawings

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing The accompanying drawing to be used needed for having technology description is briefly described, it should be apparent that, drawings in the following description are only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with Other accompanying drawings are obtained according to these accompanying drawings.

Fig. 1 is a kind of schematic flow sheet of the scaling method of fish eye lens radial distortion provided in an embodiment of the present invention；

Fig. 2 is the schematic flow sheet of the scaling method of another kind of fish eye lens radial distortion provided in an embodiment of the present invention；

Fig. 3 is the schematic flow sheet of the scaling method of another fish eye lens radial distortion provided in an embodiment of the present invention；

Fig. 4 is example schematic of the conllinear circular arc group in the center of circle provided in an embodiment of the present invention on fault image；

Fig. 5 is a kind of structural representation of the caliberating device of fish eye lens radial distortion provided in an embodiment of the present invention；

Fig. 6 is the structural representation of circular fitting module provided in an embodiment of the present invention；

Fig. 7 is the structural representation of parameter coefficient calculation unit provided in an embodiment of the present invention；

Fig. 8 is the structural representation of model generation module provided in an embodiment of the present invention；

Fig. 9 is the structural representation of coordinate parameters acquiring unit provided in an embodiment of the present invention；

Figure 10 is the structural representation of the caliberating device of another kind of fish eye lens radial distortion provided in an embodiment of the present invention.

Specific embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than the embodiment of whole.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made Embodiment, belongs to the scope of protection of the invention.

Below in conjunction with accompanying drawing 1- accompanying drawings 4, the scaling method to fish eye lens radial distortion provided in an embodiment of the present invention Describe in detail.

Fig. 1 is referred to, is shown to embodiments provide a kind of flow process of the scaling method of fish eye lens radial distortion It is intended to.As shown in figure 1, the embodiment of the present invention the method comprising the steps of S101- steps S103.

S101, obtains the uncalibrated image comprising at least two groups of space parallel lines；

Specifically, the caliberating device of fish eye lens radial distortion is obtained using the uncalibrated image captured by fish eye lens, institute Stating uncalibrated image can be comprising at least two groups space parallel lines, and every group of space is parallel at least two groups space parallel lines Straight line includes some straight lines.

S102, maps each group of space parallel lines at least two groups space parallel lines on fault image The conllinear circular arc group in the center of circle is fitted process；

Specifically, the caliberating device can be parallel to each group of space at least two groups space parallel lines respectively Straight line is operated.The caliberating device is to the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image Process is fitted, further, the caliberating device adopts default nonlinear optimization algorithm, calculates each group of space The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle that parallel lines maps on fault image, the caliberating device is adopted The common parameter and the proportionality coefficient are calculated and obtain process of fitting treatment result, and the process of fitting treatment result includes each described circle The parametrization of every circular arc is represented and the corresponding two public friendships of the conllinear circular arc group in each described center of circle in the conllinear circular arc group of the heart Point.

Wherein, arbitrary group of space parallel lines is mapped as on fault image at least two groups space parallel lines The conllinear circular arc group in one center of circle, the center of circle that arbitrary straight line maps on fault image in the arbitrary group of space parallel lines is conllinear There is a corresponding circular arc in circular arc group.The common parameter includes the middle point coordinates of line between described two common intersections And the midpoint is to the vector of arbitrary intersection point in described two common intersections, the proportionality coefficient is common including each described center of circle The corresponding predetermined coefficient of every circular arc in line circular arc group.

S103, according to process of fitting treatment result distortion peg model is generated；

Specifically, the caliberating device according to the parametrization of every circular arc in the conllinear circular arc group in each described center of circle represent with And corresponding two common intersections of the conllinear circular arc group in each described center of circle obtain center of distortion point coordinates and distortion parameter, and adopt The center of distortion point coordinates and the distortion parameter generate distortion peg model.

Fig. 2 is referred to, to embodiments provide the flow process of the scaling method of another kind of fish eye lens radial distortion Schematic diagram.As shown in Fig. 2 the embodiment of the present invention the method comprising the steps of S201- steps S205.

S201, obtains the uncalibrated image comprising at least two groups of space parallel lines；

S202, using default nonlinear optimization algorithm, calculate described at least two groups space parallel lines each group it is empty Between the common parameter of the conllinear circular arc group in the center of circle that maps on fault image of parallel lines and proportionality coefficient；

S203, is calculated using the common parameter and the proportionality coefficient and obtains process of fitting treatment result, the process of fitting treatment As a result the parametrization for including every circular arc in the conllinear circular arc group in each described center of circle is represented and the conllinear circular arc in each described center of circle Corresponding two common intersections of group；

Specifically, the caliberating device of fish eye lens radial distortion can respectively at least two groups space parallel lines Each group of space parallel lines is operated.The caliberating device can adopt default nonlinear optimization algorithm, calculate each The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle that group space parallel lines maps on fault image, further, Each group of space parallel lines maps on fault image at least two groups space parallel lines described in the caliberating device acquisition The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle, and using default nonlinear optimization algorithm to described square Distance minimization equation is calculated, and obtains the common parameter and proportionality coefficient of the conllinear circular arc group in each described center of circle.

It is understood that there is respective common parameter and proportionality coefficient in the conllinear circular arc group in each center of circle.The mark Determining device can obtain the conllinear circular arc group corresponding two in each described center of circle according to the common parameter of the conllinear circular arc group in each center of circle Individual common intersection, according to the proportionality coefficient of the conllinear circular arc group in each center of circle every circular arc is obtained in the conllinear circular arc group in each center of circle Parametrization is represented.

S204, according to process of fitting treatment result center of distortion point coordinates and distortion parameter are obtained；

S205, using the center of distortion point coordinates and the distortion parameter distortion peg model is generated；

Specifically, the caliberating device obtains the straight line side of corresponding two common intersections of the conllinear circular arc group in each center of circle Journey, and the intersecting point coordinate of all linear equations is defined as into center of distortion point coordinates, the caliberating device is according in the distortion The parametrization of arbitrary circular arc is represented in the conllinear circular arc group of heart point coordinates and arbitrary center of circle, obtains distortion parameter.The caliberating device Distortion peg model can be generated according to point coordinates in the distortion and the distortion parameter.

Wherein, the step of the step of embodiment of the present invention S201 may refer to embodiment illustrated in fig. 1 S101, here is not carried out Repeat.

Fig. 3 is referred to, to embodiments provide the flow process of the scaling method of another fish eye lens radial distortion Schematic diagram.As shown in figure 3, the methods described of the embodiment of the present invention may comprise steps of S301- steps S307.

S301, obtains the uncalibrated image comprising at least two groups of space parallel lines；

In embodiments of the present invention, the distortion peg model for being adopted can be expressed as (1) formula：

(1) in formula, b=(x_d, y_d) be fault image coordinate points, a=(x_u, y_u) it is that image after distortion correction is sat Punctuate, r_dFor b and the Euclidean distance of center of distortion point coordinates.Because the distortion peg model of traditional radial distortion is based on abnormal Become central point as picture centre it is assumed that solve to distortion parameter λ, to generate the distortion peg model, but logical In the case of often, center of distortion point is not on center of distortion point coordinates (x in picture centre, therefore the embodiment of the present invention_d0, y_d0) also serve as unknown parameter and solved.

In three dimensions, the arbitrary linear equation in each group of space parallel lines can be expressed as (2) formula：

(2) in formula, D=(dx, dy, dz) be unit direction vector, (x_i,y_i,z_i) be the straight line pass through some is three-dimensional Spatial point, t is a scale factor, for generating the difference on this straight line.From (2) formula, one group of space is parallel Straight line may be through different point (x_i,y_i,z_i), but necessarily there is identical unit direction vector D.

Under preferable perspective projection, this group of space parallel lines is mapped as one group of straight line on preferable fluoroscopy images, can To be expressed as (3) formula：

(3) in formula, f is the focal length of preferable perspective camera.As the three-dimensional point (x for passing through_i,y_i,z_i) it is different when, this group of space Parallel lines projects to formed straight line on preferable fluoroscopy images may be no longer parallel.

As t → ± ∞, the subpoint of the vanishing point on preferable fluoroscopy images of this group of space parallel lines is obtained, can be with It is expressed as (4) formula：

From (4) formula, under preferable perspective projection, this group of space parallel lines can be intersected on preferable fluoroscopy images Same point (being subpoint of the vanishing point of space parallel lines on preferable fluoroscopy images).

(1) formula is substituted into into (4) formula, and assumes that center of distortion is the origin of image, then can obtain (5) formula：

And (6) formula：

With (5) formula divided by (6) formula, obtain：

(7) formula represents that under the distortion peg model of traditional radial distortion a and b has identical slope, and they With image coordinate origin three point on a straight line.(7) formula is substituted into into (6) formula, (8) formula can be obtained：

This is one with regard to y_dQuadratic equation with one unknown, its discriminate be (9) formula：

Due to for radial distortion, there is λ ＜ 0, thus Δ is naturally larger than zero, and thus can obtain formula (8) necessarily has 2 realities Number solution.Knowable to deriving more than, under the distortion peg model of traditional radial distortion, the vanishing point of one group of space parallel lines exists 2 subpoints are had on fault image.Due to one group of space parallel lines be mapped under the model for a center of circle it is conllinear All of circular arc has 2 common intersections in circular arc group, therefore the conllinear circular arc group in the center of circle.

It should be noted that arbitrary group of space parallel lines is on fault image at least two groups space parallel lines The conllinear circular arc group in center of circle is mapped as, arbitrary straight line maps on fault image in the arbitrary group of space parallel lines There is a corresponding circular arc in the conllinear circular arc group in the center of circle.

S302, each group of space parallel lines maps on fault image at least two groups space parallel lines described in acquisition The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle；

Specifically, the caliberating device each group of space parallel lines at least two groups space parallel lines described in fitting During the conllinear circular arc group in the center of circle mapped on fault image, the caliberating device obtains the squared-distance of the conllinear circular arc group in the center of circle Minimize equation.

Please also refer to Fig. 4, show to embodiments provide citing of the conllinear circular arc group in the center of circle on fault image It is intended to.It is assumed that 2 common intersections are respectively M points and N points, it is assumed that the midpoint P of M, N point line is on fault image Coordinate be (p_x, p_y), P points are obtained to N points or the vector of M points, it is designated as to the vector of N points using P points in the embodiment of the present inventionIf the home position of i-th circular arc is o in the conllinear circular arc group in this center of circle_i, then point out from P and be dealt into o_iPoint The unit vector of directed line is represented by (10) formula：

(10) in formula,Represent and vectorPerpendicular vector, must meet Represent vectorMould.It follows that Po_i ^oThere are two groups of solutions, be respectivelyWith

One proportionality coefficient of settingThen center of circle o_i(11) formula can be expressed as：

Assume that the corresponding conllinear circle group of the conllinear circular arc group in the center of circle has n bar circular arcs, then the sum of known variables to be asked For (4+n), (4+n) in n indicate n proportionality coefficient (k₁…k_n), 4 are expressed as the common common parameter of n bar circular arcs, respectively It is the p for representing P points position_xAnd p_y, and represent vectorT_xAnd t_y。

For i-th circular arc in conllinear circle group, its radius is represented by (12) formula：

Then when the circular arc is fitted, it is desirable to which the equation of minimum is (13) formula：

(13) in formula, m represents the number of the point for being fitted the circular arc, | Q_i,jo_i| for the point Q on i-th circular arc_i,jWith circle Heart o_iThe distance between.

In the conllinear circular arc group in center of circle, the total n bars of such circular arc, therefore square distance minimization equation is (14) Formula：

S303, is calculated the square distance minimization equation using default nonlinear optimization algorithm, obtains each The common parameter and proportionality coefficient of the conllinear circular arc group in the individual center of circle；

Specifically, the default nonlinear optimization algorithm is preferably LM algorithms, and the caliberating device is using described default Nonlinear optimization algorithm the square distance minimization equation is calculated, obtain the conllinear circular arc group in each described center of circle Common parameter and proportionality coefficient.

S304, is calculated using the common parameter and the proportionality coefficient and obtains process of fitting treatment result, the process of fitting treatment As a result the parametrization for including every circular arc in the conllinear circular arc group in each described center of circle is represented and the conllinear circular arc in each described center of circle Corresponding two common intersections of group；

Specifically, there is respective common parameter and proportionality coefficient in the conllinear circular arc group in each center of circle.The caliberating device Can according to the common parameter of the conllinear circular arc group in each center of circle obtain the conllinear circular arc group in each described center of circle it is corresponding two it is public Intersection point, according to the proportionality coefficient of the conllinear circular arc group in each center of circle the parametrization of every circular arc in the conllinear circular arc group in each center of circle is obtained Represent.

S305, obtains the linear equation of corresponding two common intersections of the conllinear circular arc group in each center of circle, and by all straight lines The intersecting point coordinate of equation is defined as center of distortion point coordinates；

Specifically, what the caliberating device obtained that corresponding two common intersections of the conllinear circular arc group in each center of circle are constituted is straight Line equation, for example：M points and N points linear equation determined by fault image, it is right if space parallel lines there are W groups The conllinear circular arc group in the center of circle answered also has W, then can obtain W bar linear equations, and coordinate is found intersection to W bar linear equations, and will The intersecting point coordinate is defined as center of distortion point coordinates.For example：The intersecting point coordinate that W bar linear equations draw is (x_d0, y_d0), then will (x_d0, y_d0) it is defined as center of distortion point coordinates.

S306, according to the parametrization table of arbitrary circular arc in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle Show, obtain distortion parameter；

Specifically, it is assumed that the parametrization of arbitrary circular arc is expressed as in the conllinear circular arc group in arbitrary center of circle tried to achieveThe center of distortion point coordinates is (x_d0, y_d0), then the distortion parameter is：

S307, using the center of distortion point coordinates and the distortion parameter distortion peg model is generated；

Specifically, the caliberating device can determine r according to center of distortion point coordinates_dExpression way, it is assumed that in distortion Heart point coordinates is c, then expression way is：

r_d=︱ b-c ︱

The expression way and distortion parameter λ are substituted into into (1) formula, distortion peg model is generated.

In embodiments of the present invention, by obtain comprising at least two groups of space parallel lines uncalibrated image, to it is described extremely The conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image in few two groups of space parallel lines is intended Conjunction is processed, and generates distortion peg model according to process of fitting treatment result.By using at least two groups space parallel lines, right respectively The conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image at least two groups space parallel lines is carried out Process of fitting treatment, and center of distortion point coordinates is asked for again, improve the accuracy rate of the calibration result of distortion peg model；It is logical Cross using the conllinear property in the center of circle so that calibration result is still able to keep robustness in the case where there is larger noise.

Below in conjunction with accompanying drawing 5 and accompanying drawing 9, the caliberating device to fish eye lens radial distortion provided in an embodiment of the present invention Describe in detail.It should be noted that accompanying drawing 5 and the caliberating device shown in accompanying drawing 9, for performing Fig. 1-Fig. 4 institutes of the present invention The method for showing embodiment, for convenience of description, illustrate only the part related to the embodiment of the present invention, and particular technique details is not taken off Show, refer to the embodiment shown in Fig. 1-Fig. 4 of the present invention.

Fig. 5 is referred to, is shown to embodiments provide a kind of structure of the caliberating device of fish eye lens radial distortion It is intended to.As shown in figure 5, the caliberating device 1 of the embodiment of the present invention can include：Uncalibrated image acquisition module 11, circular arc is intended Matched moulds block 12 and model generation module 13.

Uncalibrated image acquisition module 11, for obtaining the uncalibrated image comprising at least two groups of space parallel lines；

In implementing, the uncalibrated image acquisition module 11 is obtained using the uncalibrated image captured by fish eye lens, institute Stating uncalibrated image can be comprising at least two groups space parallel lines, and every group of space is parallel at least two groups space parallel lines Straight line includes some straight lines.

And (6) formula：

With (5) formula divided by (6) formula, obtain：

Circular fitting module 12, for each group of space parallel lines at least two groups space parallel lines abnormal Become the conllinear circular arc group in the center of circle mapped on image and be fitted process；

In implementing, the circular fitting module 12 can respectively to each at least two groups space parallel lines Group space parallel lines is operated.The circular fitting module 12 maps each group of space parallel lines on fault image The conllinear circular arc group in the center of circle be fitted process, further, the circular fitting module 12 adopt default nonlinear optimization Algorithm, calculates the common parameter and ratio of the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image Example coefficient, the circular fitting module 12 is calculated using the common parameter and the proportionality coefficient and obtains process of fitting treatment result, The process of fitting treatment result include the parametrization of every circular arc in the conllinear circular arc group in each described center of circle represent and each described in Corresponding two common intersections of the conllinear circular arc group in the center of circle.

Specifically, please also refer to Fig. 6, to embodiments provide the structural representation of circular fitting module.Such as Shown in Fig. 6, the circular fitting module 12 can include：

Parameter coefficient calculation unit 121, for using default nonlinear optimization algorithm, at least two groups spaces described in calculating The common parameter and ratio of the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image in parallel lines Coefficient；

As a result acquiring unit 122, for calculating using the common parameter and the proportionality coefficient process of fitting treatment knot is obtained Really, the process of fitting treatment result includes that the parametrization of every circular arc in the conllinear circular arc group in each described center of circle is represented and each institute State corresponding two common intersections of the conllinear circular arc group in the center of circle；

In implementing, the parameter coefficient calculation unit 121 can respectively at least two groups space parallel lines In each group of space parallel lines operated.The parameter coefficient calculation unit 121 can adopt default nonlinear optimization Algorithm, calculates common parameter and the ratio system of the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image Number, further, the parameter coefficient calculation unit 121 obtains each group of space at least two groups space parallel lines and puts down The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle that row straight line maps on fault image, and using default non- Linear optimization algorithm is calculated the square distance minimization equation, obtains the public of the conllinear circular arc group in each described center of circle Parameter and proportionality coefficient.

It is understood that there is respective common parameter and proportionality coefficient in the conllinear circular arc group in each center of circle.The knot Fruit acquiring unit 122 can obtain the conllinear circular arc group pair in each described center of circle according to the common parameter of the conllinear circular arc group in each center of circle Two common intersections answered, obtain in the conllinear circular arc group in each center of circle per bar according to the proportionality coefficient of the conllinear circular arc group in each center of circle The parametrization of circular arc is represented.

Specifically, please also refer to Fig. 7, to embodiments provide the structural representation of parameter coefficient calculation unit Figure.As shown in fig. 7, the parameter coefficient calculation unit 121 can include：

Equation obtains subelement 1211, for obtaining at least two groups space parallel lines in each group of space straight parallel The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle that line maps on fault image；

In implementing, it is each at least two groups space parallel lines described in fitting that the equation obtains subelement 1211 During the conllinear circular arc group in the center of circle that map on fault image of group space parallel lines, the equation obtains subelement 1211 and obtains this The square distance minimization equation of the conllinear circular arc group in the center of circle.

Parameter coefficient obtains subelement 1212, for minimum to the squared-distance using default nonlinear optimization algorithm Change equation to be calculated, obtain the common parameter and proportionality coefficient of the conllinear circular arc group in each described center of circle；

In implementing, the default nonlinear optimization algorithm is preferably LM algorithms, and it is single that the parameter coefficient obtains son Unit 1212 is calculated the square distance minimization equation using the default nonlinear optimization algorithm, obtains each institute State the common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle.

Model generation module 13, for generating distortion peg model according to process of fitting treatment result；

In implementing, ginseng of the model generation module 13 according to every circular arc in the conllinear circular arc group in each described center of circle Numberization is represented and corresponding two common intersections of the conllinear circular arc group in each described center of circle obtain center of distortion point coordinates and distortion Parameter, and distortion peg model is generated using the center of distortion point coordinates and the distortion parameter.

Specifically, please also refer to Fig. 8, to embodiments provide the structural representation of model generation module.Such as Shown in Fig. 8, the model generation module 13 can include：

Coordinate parameters acquiring unit 131, for obtaining center of distortion point coordinates and distortion parameter according to process of fitting treatment result；

In implementing, the coordinate parameters acquiring unit 131 obtains corresponding two public affairs of the conllinear circular arc group in each center of circle The linear equation of common intersection point, and the intersecting point coordinate of all linear equations is defined as into center of distortion point coordinates, the coordinate parameters Acquiring unit 131 represents according to the parametrization of arbitrary circular arc in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle, Obtain distortion parameter.

Specifically, please also refer to Fig. 9, to embodiments provide the structural representation of coordinate parameters acquiring unit Figure.As shown in figure 9, the coordinate parameters acquiring unit 131 can include：

Coordinate obtains subelement 1311, for obtaining the straight line of corresponding two common intersections of the conllinear circular arc group in each center of circle Equation, and the intersecting point coordinate of all linear equations is defined as into center of distortion point coordinates；

In implementing, the coordinate obtain subelement 1311 obtain the conllinear circular arc group in each center of circle it is corresponding two it is public The linear equation that intersection point is constituted, for example：M points and N points linear equation determined by fault image, if space parallel lines W groups are there are, then the conllinear circular arc group in the corresponding center of circle also has W, then can obtain W bar linear equations, and W bar linear equations are asked Intersecting point coordinate, and the intersecting point coordinate is defined as into center of distortion point coordinates.For example：The intersecting point coordinate that W bar linear equations draw is (x_d0, y_d0), then by (x_d0, y_d0) it is defined as center of distortion point coordinates.

Parameter acquiring subelement 1312, for appointing according in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle The parametrization of one circular arc represents, obtains distortion parameter；

In implementing, it is assumed that arbitrary circle in the conllinear circular arc group in arbitrary center of circle that the parameter acquiring subelement 1312 is obtained The parametrization of arc is expressed asThe center of distortion point coordinates is (x_d0, y_d0), then it is described abnormal Variable element is：

Model signal generating unit 132, demarcates for generating distortion using the center of distortion point coordinates and the distortion parameter Model；

In implementing, the model signal generating unit 132 can be according to point coordinates in the distortion and the distortion parameter Generate distortion peg model.

The model signal generating unit 132 can determine r according to center of distortion point coordinates_dExpression way, it is assumed that in distortion Heart point coordinates is c, then expression way is：

r_d=︱ b-c ︱

The expression way and distortion parameter λ are substituted into (1) formula by the model signal generating unit 132, are generated distortion and are demarcated Model.

Figure 10 is referred to, to embodiments provide the structure of the caliberating device of another kind of fish eye lens radial distortion Schematic diagram.As shown in Figure 10, the caliberating device 1000 can include：At least one processor 1001, such as CPU, Yong Hujie Mouth 1003, at least one network interface 1004, memory 1005, at least one communication bus 1002.Wherein, communication bus 1002 For realizing the connection communication between these components.Wherein, user interface 1003 can include display screen (Display), keyboard (Keyboard), optional user interface 1003 can also include wireline interface, the wave point of standard.Network interface 1004 is optional Can include standard wireline interface, wave point (such as WI-FI interfaces).Memory 1005 can be high-speed RAM memory, Can also be non-labile memory (non-volatile memory), for example, at least one magnetic disc store.Memory 1005 optionally can also be at least one storage device for being located remotely from aforementioned processor 1001.As shown in Figure 10, as one Can include in the memory 1005 of kind of computer-readable storage medium operating system, network communication module, Subscriber Interface Module SIM and Analysis program.

The processor 1001 can be used for calling the Analysis program stored in memory 1005, and specifically perform with Lower step：

Described in a kind of feasible embodiment of the embodiment of the present invention arbitrary group at least two groups space parallel lines Space parallel lines is mapped as the conllinear circular arc group in center of circle on fault image, appoints in the arbitrary group of space parallel lines There is a corresponding circular arc in the conllinear circular arc group in the center of circle that one straight line maps on fault image.

In another kind of feasible embodiment of the embodiment of the present invention, the processor 1001 perform to it is described at least The conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image in two groups of space parallel lines is fitted During process, following steps are specifically performed：

In another feasible embodiment of the embodiment of the present invention, the processor 1001 is being performed using default Nonlinear optimization algorithm, each group of space parallel lines is shown in fault image at least two groups space parallel lines described in calculating When the common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle penetrated, following steps are specifically performed：

In another feasible embodiment of the embodiment of the present invention, the processor 1001 is being performed at according to fitting When reason result generates distortion peg model, following steps are specifically performed：

In another feasible embodiment of the embodiment of the present invention, the processor 1001 is being performed at according to fitting When reason result obtains center of distortion point coordinates and distortion parameter, following steps are specifically performed：

In another feasible embodiment of the embodiment of the present invention, the square distance minimization equation is：

The default nonlinear optimization algorithm is LM algorithms.

In another feasible embodiment of the embodiment of the present invention, it is assumed that arbitrary circle in the conllinear circular arc group in the arbitrary center of circle The parametrization of arc is expressed asThe center of distortion point coordinates is (x_d0, y_d0), then it is described abnormal Variable element is：

In another feasible embodiment of the embodiment of the present invention, the distortion peg model is：

Through the above description of the embodiments, those skilled in the art can be understood that the present invention can be with Realized with hardware, or firmware is realized, or combinations thereof mode is realizing.When implemented in software, can be by above-mentioned functions It is stored in computer-readable medium or is transmitted as one or more instructions on computer-readable medium or code.Meter Calculation machine computer-readable recording medium includes computer-readable storage medium and communication media, and wherein communication media includes being easy to from a place to another Any medium of individual place transmission computer program.Storage medium can be any usable medium that computer can be accessed.With As a example by this but it is not limited to：Computer-readable medium can include RAM, ROM or other optical disc storages, magnetic disk storage medium or Other magnetic storage apparatus or can be used in carrying or store the desired program code with instruction or data structure form simultaneously Can be by any other medium of computer access.In addition.Any connection can be appropriate become computer-readable medium.Example Such as, if software is to use coaxial cable, optical fiber cable, twisted-pair feeder, Digital Subscriber Line or such as infrared ray, radio and micro- The wireless technology of ripple etc is from website, server or other remote source transmission, then coaxial cable, optical fiber cable, multiple twin The wireless technology of line, Digital Subscriber Line or such as infrared ray, wireless and microwave etc be included in affiliated medium it is fixing in.Such as It is used in the present invention, disk (Disk) and dish (disc) include compression laser disc, laser disc, laser disc, Digital Versatile Disc, floppy disk and Blu-ray Disc, the replicate data of the usual magnetic of which disk, and dish is then with laser come optical replicate data.Above combination above also should When being included within the protection domain of computer-readable medium.

Above disclosed is only present pre-ferred embodiments, can not limit the right model of the present invention with this certainly Enclose, therefore the equivalent variations made according to the claims in the present invention, still belong to the scope that the present invention is covered.

Claims

1. a kind of scaling method of fish eye lens radial distortion, it is characterised in that include：

The center of circle mapped on fault image each group of space parallel lines at least two groups space parallel lines is conllinear Circular arc group is fitted process；

Distortion peg model is generated according to process of fitting treatment result；

Wherein, it is described that each group of space parallel lines at least two groups space parallel lines mapped on fault image The conllinear circular arc group in the center of circle is fitted process, including：

Using default nonlinear optimization algorithm, each group of space parallel lines at least two groups space parallel lines described in calculating The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle mapped on fault image；

Calculated using the common parameter and the proportionality coefficient and obtain process of fitting treatment result, the process of fitting treatment result includes each The parametrization of every circular arc is represented and the conllinear circular arc group corresponding two in each described center of circle in the conllinear circular arc group in the individual center of circle Individual common intersection；

Wherein, the common parameter includes that the middle point coordinates of line and the midpoint are to described two between described two common intersections The vector of arbitrary intersection point in individual common intersection, the proportionality coefficient includes every circular arc pair in the conllinear circular arc group in each described center of circle The predetermined coefficient answered.

2. method according to claim 1, it is characterised in that arbitrary group of space at least two groups space parallel lines Parallel lines is mapped as the conllinear circular arc group in center of circle on fault image, arbitrary straight in the arbitrary group of space parallel lines There is a corresponding circular arc in the conllinear circular arc group in the center of circle that line maps on fault image.

3. method according to claim 1, it is characterised in that described using default nonlinear optimization algorithm, calculates institute State at least two groups space parallel lines the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image Common parameter and proportionality coefficient, including：

Obtain at least two groups space parallel lines center of circle that each group of space parallel lines map on fault image common The corresponding square distance minimization equation of line circular arc group；

The square distance minimization equation is calculated using default nonlinear optimization algorithm, obtains each center of circle The common parameter and proportionality coefficient of conllinear circular arc group.

4. method according to claim 1, it is characterised in that described that distortion calibration mold is generated according to process of fitting treatment result Type, including：

5. method according to claim 4, it is characterised in that described center of distortion point is obtained according to process of fitting treatment result to sit Mark and distortion parameter, including：

Obtain the linear equation of corresponding two common intersections of the conllinear circular arc group in each center of circle, and by the intersection point of all linear equations Coordinate is defined as center of distortion point coordinates；

Represented according to the parametrization of arbitrary circular arc in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle, obtain distortion Parameter.

6. method according to claim 3, it is characterised in that the square distance minimization equation is：

\underset{\{\begin{matrix} p_{x}, p_{y}, t_{x}, t_{y} \\ k_{1} ... k_{n} \end{matrix}\}}{\arg \min} Σ_{i = 1}^{n} Σ_{j = 1}^{m} {[| Q_{i, j} o_{i} | - r_{i}]}^{2}

Wherein, m represents the number of the point of i-th circular arc of fitting, | Q_i,jo_i| represent the point Q on i-th circular arc_i,jWith center of circle o_iIt Between distance, r_iThe radius of i-th circular arc is represented, n represents the bar number of circular arc in the conllinear circular arc group in center of circle, (p_x, p_y) represent The coordinate of the midpoint P points of line, (t between described two common intersection M points and N points_x, t_y) represent the P points to the M points or N points Vector, (k₁…k_n) represent n bar circular arcs in every circular arc proportionality coefficient；

The default nonlinear optimization algorithm is LM (Leven-Marquardt) algorithm.

7. method according to claim 5, it is characterised in that assume the ginseng of arbitrary circular arc in the conllinear circular arc group in arbitrary center of circle Numberization is expressed asThe center of distortion point coordinates is (x_d0, y_d0), then the distortion parameter For：

λ = \frac{1}{x_{d 0}^{2} + y_{d 0}^{2} + {Ax}_{d 0} + {By}_{d 0} + C}

8. method according to claim 7, it is characterised in that the distortion peg model is：

a = \frac{b}{1 + {λr}_{d}^{2}}

Wherein, b=(x_d, y_d) be fault image coordinate points, a=(x_u, y_u) it is image coordinate point after distortion correction, r_dFor The Euclidean distance of b and center of distortion point coordinates.

9. a kind of caliberating device of fish eye lens radial distortion, it is characterised in that include：

Circular fitting module, for each group of space parallel lines at least two groups space parallel lines in fault image The conllinear circular arc group in the center of circle of upper mapping is fitted process；

Model generation module, for generating distortion peg model according to process of fitting treatment result；

Wherein, the circular fitting module includes：

Parameter coefficient calculation unit, for using default nonlinear optimization algorithm, at least two groups space straight parallels described in calculating The common parameter and proportionality coefficient of the conllinear circular arc group in the center of circle that each group of space parallel lines maps on fault image in line；

As a result acquiring unit, for calculating using the common parameter and the proportionality coefficient process of fitting treatment result is obtained, described Process of fitting treatment result includes that the parametrization of every circular arc in the conllinear circular arc group in each described center of circle is represented and each described center of circle Corresponding two common intersections of conllinear circular arc group；

10. caliberating device according to claim 9, it is characterised in that arbitrary at least two groups space parallel lines Group space parallel lines is mapped as the conllinear circular arc group in center of circle on fault image, in the arbitrary group of space parallel lines There is a corresponding circular arc in the conllinear circular arc group in the center of circle that arbitrary straight line maps on fault image.

11. caliberating devices according to claim 9, it is characterised in that the parameter coefficient calculation unit includes：

Equation obtains subelement, for obtaining at least two groups space parallel lines in each group of space parallel lines in distortion The corresponding square distance minimization equation of the conllinear circular arc group in the center of circle mapped on image；

Parameter coefficient obtains subelement, for being entered to the square distance minimization equation using default nonlinear optimization algorithm Row is calculated, and obtains the common parameter and proportionality coefficient of the conllinear circular arc group in each described center of circle.

12. caliberating devices according to claim 9, it is characterised in that the model generation module includes：

Model signal generating unit, for generating distortion peg model using the center of distortion point coordinates and the distortion parameter.

13. caliberating devices according to claim 12, it is characterised in that the coordinate parameters acquiring unit includes：

Coordinate obtains subelement, for obtaining the linear equation of corresponding two common intersections of the conllinear circular arc group in each center of circle, and The intersecting point coordinate of all linear equations is defined as into center of distortion point coordinates；

Parameter acquiring subelement, for according to arbitrary circular arc in the conllinear circular arc group of the center of distortion point coordinates and arbitrary center of circle Parametrization expression, obtains distortion parameter.

14. caliberating devices according to claim 11, it is characterised in that the square distance minimization equation is：

\underset{\{\begin{matrix} p_{x}, p_{y}, t_{x}, t_{y} \\ k_{1} ... k_{n} \end{matrix}\}}{\arg \min} Σ_{i = 1}^{n} Σ_{j = 1}^{m} {[| Q_{i, j} o_{i} | - r_{i}]}^{2}

The default nonlinear optimization algorithm is LM algorithms.

15. caliberating devices according to claim 13, it is characterised in that assume arbitrary circle in the conllinear circular arc group in arbitrary center of circle The parametrization of arc is expressed asThe center of distortion point coordinates is (x_d0, y_d0), then it is described abnormal Variable element is：

λ = \frac{1}{x_{d 0}^{2} + y_{d 0}^{2} + {Ax}_{d 0} + {By}_{d 0} + C}

16. caliberating devices according to claim 15, it is characterised in that the distortion peg model is：

a = \frac{b}{1 + {λr}_{d}^{2}}