CN204650606U - A kind of line-scan digital camera calibration facility of high ferro detection system - Google Patents

Abstract

The utility model discloses the line-scan digital camera calibration facility of a kind of high ferro inspection truck system, line-scan digital camera is installed on track checking car, and the side of track checking car is provided with scaling board, scaling board is provided with and demarcates band; Scaling board can move along close or away from track checking car direction, and the top of scaling board is provided with laser range finder, and track checking car is provided with telltale mark.Calibration facility structure of the present utility model is simple, and manufacturing process is simple, and cost is low; Scaling method of the present utility model is simple to operate, can carry out camera calibration fast and accurately; After demarcation of the present utility model, measuring accuracy can reach 1mm, ensure that the accuracy requirement of measurement result.

Description

A kind of line-scan digital camera calibration facility of high ferro detection system

Technical field

The utility model belongs to railway detection technique field, relates to a kind of line-scan digital camera calibration facility of high ferro detection system.

Background technology

Along with high speed development that is economic and society, transportation network is day by day flourishing.High-speed railway is as the important component part of transportation network, and also achieve abnormal swift and violent development, this makes how to ensure that the safety of high-speed railway becomes a very important problem.Present stage, high-speed railway detection technique is flourishing not enough, and traditional static detection method can not meet the standard-required of modern speed rail maintenance.Therefore, the detection of high-speed railway rail is completed in the urgent need to a kind of high precision, high efficiency dynamic detection system, to ensure the safety of high-speed railway.

Nowadays computer technology is constantly fast-developing, and photogrammetric technology is widely used in engineering.Binocular solid is photogrammetric is different from traditional contactless measurement as a kind of, the features such as it is accurate, quick and real-time that it has.Therefore binocular solid photogrammetric technology is applied to high-speed railway rail detection field, has boundless prospect to the detection of dynamic realizing high-speed railway rail.It is exactly the photogrammetric basis of binocular solid that the line-scan digital camera that the utility model is mentioned is demarcated, and only has and camera calibration accurately accurately could be measured CP III with it afterwards, and then carry out data processing work below.

Utility model content

In image measurement process and machine vision applications, for determining three-dimensional geometry position and its mutual relationship in the picture between corresponding point of certain point of space object surface, the geometric model of camera imaging must be set up, the demarcation of camera is exactly solve these geometric model parameters, to reach the object accurately measured.The utility model provides a kind of line-scan digital camera calibration facility to high ferro detection system and scaling method, and in order to realize this task, the utility model is achieved through the following technical solutions:

A line-scan digital camera calibration facility for high ferro inspection truck system, line-scan digital camera is installed on track checking car, and the side of track checking car is provided with scaling board, scaling board is provided with and demarcates band; Scaling board can move along close or away from track checking car direction, and the top of scaling board is provided with laser range finder, and track checking car is provided with telltale mark.

Further, described scaling board is T-shaped plate, and the bottom of scaling board is assemblied on a guide rail, and guide rails assembling is in the demarcation frame of pair of parallel setting; Described demarcation frame takes the shape of the letter U structure, demarcates between framves for two and is connected by semi-girder; Be symmetrically arranged with the installing plate with guide rail parallel at each demarcation top of the trellis, the both sides of each demarcation frame are provided with a tripod, and tripod top braces is bottom installing plate; Scaling board is provided with the micro-adjusting mechanism for adjusting tripod.

Further, described line-scan digital camera arranges two, is respectively First Line array camera and the second line-scan digital camera, and wherein First Line array camera is positioned at directly over the second line-scan digital camera, the position of telltale mark between First Line array camera and the second line-scan digital camera, telltale mark is cross telltale mark.

Further, the blackstreak that described demarcation is brought interval along its length to arrange and is parallel to each other marks and white stripes mark.

A line-scan digital camera scaling method for high ferro detection system, comprises the following steps:

Step one, track checking car is travelled the position to smooth spaciousness, the side of setting up and being placed in First Line array camera and the second line-scan digital camera on track checking car will be demarcated, adjustment First Line array camera and the second line-scan digital camera camera lens towards, make the optical axis of two line-scan digital cameras be intersected in a bit, two line-scan digital cameras are connected with computing machine;

Step 2, mounting guide rail and scaling board, supported demarcation frame by four tripods, open laser range finder, and utilize level meter and micro-adjusting mechanism adjustment tripod, the luminous point that laser range finder is got overlaps with the telltale mark on track checking car; Make the inclined degree of scaling board be no more than 1 degree by adjustment, and ensure in the moving range of scaling board on guide rail, comprise all the time in the image of two line-scan digital cameras gathered in computing machine and can see demarcation band image that is complete or part;

Step 3, with the specifically labelled center of cross on track checking car for initial point, sets up target surface coordinate system, wherein with initial point towards the direction of track checking car for X-axis, initial point is Y-axis towards the direction on ground;

Step 4, in the moving range of scaling board on guide rail, choose multiple position, each position all obtains image information corresponding to this position according to following steps;

Step S40, measures demarcation and takes to outside car body, be i.e. the distance of X-direction;

Step S41, measures laser range finder and gets to luminous point on track checking car to cross telltale mark center distance in the Y-axis direction, be designated as C;

Step S42, is numbered to demarcating the mode that blackstreak marks according to from top to bottom, number order is ascending brought;

Step S43, two line-scan digital cameras all gather demarcates band image, finds out public blackstreak mark in two images, and on scaling board, these blackstreaks of correspondence is designated as marks for treatment;

Step S44, this distance, to the distance of marks for treatment upper edge on scaling board, is designated as B by the laser emission point measuring laser range finder;

Step S45, this position at least gathers 6 groups of images, and the sum comprising public blackstreak mark and white stripes mark in each group image will reach more than 13;

Step 5, filters out one group of image that sharpness is the highest in each position, calculate the coordinate figure X of center pixel in target surface coordinate system of marks for treatment corresponding to this group image ₀and Y ₀, and the coordinate figure a of center pixel in the pixel coordinate system of this image of marks for treatment in the image that gathers of First Line array camera, the second line-scan digital camera ₁and a ₂, concrete steps are as follows:

Step S50, coordinate figure X ₀be the distance recorded in step S40;

Step S51, coordinate figure Y ₀for wherein d ₁for the width that each blackstreak marks, d ₂for the width that each white stripes marks, i is the numbering of blackstreak mark;

Step S52, utilizes HALCON software in the image of First Line array camera, the second line-scan digital camera collection, obtain the pixel coordinate value of the center pixel of marks for treatment, by do not photograph or the coordinate figure of the center pixel of taking incomplete marks for treatment be designated as 0;

Step 6, the matching of parameter

Step S60, by X corresponding for each public blackstreak mark of each position shooting in step 5 ₀, Y ₀, a ₁and a ₂be designated as one group of data, obtain each group data of each position, if a in a certain group of data ₁or a ₂be zero, then delete this group data, then by all data copy in txt file;

Step S61, sets name variable X in software 1stopt ₀, Y ₀, a ₁and a ₂, add X ₀, Y ₀value, wherein X ₀, Y ₀value be value in step S50, S51, the data in the txt file of step S60 are added in software;

Step S62, select wheat quart method to carry out iterative computation, convergence judge index is 1.00E-10, arrange greatest iteration number be 1000, in real time output domination number be 20; Choice criteria (LM)+general Global Optimization Method pattern, arranging repeat number is 30, and controlling number of iterations is 20, and convergence judges that number of iterations is 15, is respectively X ₀and Y ₀carry out matching, related coefficient will reach more than 0.99999, obtains corresponding fitting parameter;

Step S62, according to fitting parameter, determines the corresponding relation of the constrained input of two line-scan digital cameras, completes line-scan digital camera calibration process.

The utility model compared with prior art has following technical characterstic:

(1) calibration facility structure of the present utility model is simple, and manufacturing process is simple, and cost is low;

(2) scaling method of the present utility model is simple to operate, can carry out camera calibration fast and accurately;

(3) after demarcation of the present utility model, measuring accuracy can reach 1mm, ensure that the accuracy requirement of measurement result.

Accompanying drawing explanation

Fig. 1 is the structural representation of the utility model calibration facility;

Fig. 2 is the side view of track checking car;

Fig. 3 is the front elevation of track checking car;

Fig. 4 is the Computing Principle schematic diagram of coordinate system and line-scan digital camera part;

Fig. 5 is the schematic diagram measuring target surface;

Fig. 6 is the schematic diagram demarcating band;

Fig. 7 is the schematic diagram (Fig. 6 is horizontal rear) of pixel center;

Fig. 8 is the utility model iterative algorithm setting parameter figure;

Number in the figure represents: 1-demarcate frame, 2-guide rail, 3-scaling board, 4-tripod, 5-laser range finder, 6-micro-adjusting mechanism, 7-installing plate, 8-semi-girder, 9-First Line array camera, 10-telltale mark, the 11-the second line-scan digital camera, 12-track checking car, 13-demarcate band.

Embodiment

The utility model proposes a kind of line-scan digital camera calibration facility and scaling method of high ferro detection system, wherein the structure of calibration facility is as shown in Figure 1:

A line-scan digital camera calibration facility for high ferro inspection truck system, line-scan digital camera is installed on track checking car 12, and the side of track checking car 12 is provided with scaling board 3, scaling board 3 is provided with and demarcates band 13; Scaling board 3 can move along close or away from track checking car 12 direction, and the top of scaling board 3 is provided with laser range finder 5, track checking car 12 is provided with telltale mark 10.

As depicted in figs. 1 and 2.Line-scan digital camera is distributed in the both sides of track checking car 12, and every side arranges a camera in the vertical direction respectively.For the demarcation of camera, scaling board 3 is utilized to complete.Scaling board 3 is provided with and demarcates band 13, utilize the image on line-scan digital camera collection demarcation band 13, the calibration process of camera can be completed by scaling method of the present utility model.Because timing signal needs to demarcate band 13 apart from image information during track checking car 12 diverse location by line-scan digital camera collection, to complete calibration process, therefore in this programme, scaling board 3 can move along close or away from track checking car 12 direction.Laser range finder 5 for adjusting the position of scaling board 3 in calibration process, and measures the distance between scaling board 3 and track checking car 12.Telltale mark 10 is then coordinate with laser range finder 5, completes position fixing process, and telltale mark 10 also can be assisted as setting up target surface coordinate system simultaneously, is the reference frame of camera calibration process.

As the preferred structure of one, in this programme, scaling board 3 is T-shaped plate, and the bottom of scaling board 3 is assemblied on a guide rail 2, and guide rail 2 is installed in the demarcation frame 1 of pair of parallel setting; Described demarcation frame 1 takes the shape of the letter U structure, demarcates between framves 1 for two and is connected by semi-girder 8; Be symmetrically arranged with the installing plate 7 parallel with guide rail 2 at each demarcation frame 1 top, the both sides of each demarcation frame 1 are provided with the tripod 4 of, and tripod 4 top braces is bottom installing plate 7; Scaling board 3 is provided with the micro-adjusting mechanism 6 for adjusting tripod.

As shown in the figure, demarcating frame 1 is the supporting mechanism of whole calibration facility, demarcates frame 1 and takes the shape of the letter U, and demarcates framves 1 for two and is consolidated by semi-girder 8, is used for bearing guide rail 2.Guide rail 2 is installed on two and demarcates the recess of frame 1 inside, and due to the setting of semi-girder 8, makes scaling board 3 structure of T-shaped to slide on guide rail 2 easily and can not offset.Laser range finder 5 is arranged on the top of scaling board 3 in the present embodiment.Installing plate 7 demarcates the load position on frame 1, is used for and tripod 4 cooperation installation.Due to the difference of geomorphological environment, in order to ensure that scaling board 3 can be in same level all the time under difference demarcation condition, multiple tripod 4 is selected jointly to assist the position of adjustment installing plate 7.In this programme, four installing plate 7 bottoms arrange a tripod 4 respectively, and tripod 4 energy stable support, in each position, utilize micro-adjusting mechanism 6 to adjust the height of tripod 4, and external level meter coordinates, and can adjust the position of scaling board 3 quickly and easily.This calibration facility can demarcate the line-scan digital camera of track checking car 12 both sides respectively, and when demarcating the line-scan digital camera on the left of track checking car 12, the moving range of scaling board 3 on guide rail 2 is 1 ~ 2.2m, and when demarcating right-hand line array camera, scaling board 3 moving range is 5.8 ~ 6.8m.

This programme is got the bid the line-scan digital camera determined on the left of track checking car 12, line-scan digital camera arranges two, be respectively First Line array camera 9 and the second line-scan digital camera 11, wherein First Line array camera 9 is positioned at directly over the second line-scan digital camera 11, the position of telltale mark 10 between First Line array camera 9 and the second line-scan digital camera 11, telltale mark 10 is cross telltale mark 10.Cross telltale mark 10 will be conducive to the foundation of coordinate system, can effectively match with laser range finder 5 simultaneously.

About the scaling board 3 used in this programme, scaling board 3 is provided with near the side of track checking car 12 and demarcates band 13, demarcating band 13 is be made up of chequered with black and white hash mark, and interval arranges the blackstreak mark and white stripes mark that are parallel to each other along its length.Blackstreak mark and white stripes mark are follow-up bases of carrying out image processing process.

Calibration principle:

With reference to accompanying drawing 2, Fig. 3, to demarcate the linear array CCD camera on the left of track checking car in this example.Wherein First Line array camera is upper, the second line-scan digital camera under, two line-scan digital cameras are laid in the plane perpendicular to track checking car travel direction, and the optical axis of two line-scan digital cameras is uneven, but are intersected in a bit, see Fig. 4.The visual angle of lower two line-scan digital cameras is two fan-shaped visual fields, and these two mutual crossovers in fan-shaped visual field, and this intersectional region is the common field range of two cameras, namely measures target surface, with reference to accompanying drawing 5.Set up the target surface coordinate system be made up of the measurement target surface of two line-scan digital cameras, coordinate origin O is arranged on the cross specifically labelled right-angled intersection point place on track checking car car body outer surface, wherein X-axis is the direction perpendicular to track checking car outside surface principle track checking car, and Y-axis is vertically point to the direction on ground.As shown in Figure 4, in figure, each alphabetical implication is as follows:

A (x _a, y _a), B (x _b, y _b): the coordinate of First Line array camera, the second line-scan digital camera focus;

F _a, f _b: the focal length of First Line array camera, the second line-scan digital camera;

α _a, α _b: the optical axis of First Line array camera, the second line-scan digital camera relative to the angle of Y-axis, and has 0 ° of < α _a, α _b<90 °;

: measure the image space coordinate of any point P on First Line array camera, the second line-scan digital camera in target surface;

: the picture centre of First Line array camera, the second line-scan digital camera;

(when the image space of P point is above the O of camera image center, corresponding Δ 1 or the value of Δ 2 are just to the deviation of Δ 1, the Δ 2:P point image space on upper and lower two line-scan digital cameras and the picture centre of corresponding camera; When below, be negative);

First Line array camera can be calculated by geometric relationship, the coordinate of picture centre O (i.e. the imaging point of line-scan digital camera optical axis) of the second line-scan digital camera is respectively:

$O_A=(x_{O_A},y_{O_A})=(x_A-f_A\cos {\mathrm{\&alpha;}}_A,y_A+f_A\sin {\mathrm{\&alpha;}}_A)---\left(1\right)$

$O_B=(x_{O_B},y_{O_B})=(x_B-f_B\cos {\mathrm{\&alpha;}}_B,y_B+f_B\sin {\mathrm{\&alpha;}}_B)---\left(2\right)$

According to the image space P of any point P (x, y) on First Line array camera, the second line-scan digital camera in the known measurement target surface of image-forming principle _a, P _bstraight line L _a, L _brespectively with the intersection point of the imaging surface of two line-scan digital cameras, imaging point P can be calculated by geometric relationship _a, P _bcoordinate be respectively:

$P_A(x_{P_A},y_{P_A})=(x_A-f_A\cos {\mathrm{\&alpha;}}_A+\mathrm{\&Delta;}A\cos {\mathrm{\&alpha;}}_A,y_A+f_A\sin {\mathrm{\&alpha;}}_A+\mathrm{\&Delta;}A\cos {\mathrm{\&alpha;}}_A)---\left(3\right)$

$P_B(x_{P_B},y_{P_B})=(x_B-f_B\cos {\mathrm{\&alpha;}}_B+\mathrm{\&Delta;}B\cos {\mathrm{\&alpha;}}_B,y_B+f_B\sin {\mathrm{\&alpha;}}_B+\mathrm{\&Delta;}B\cos {\mathrm{\&alpha;}}_B)---\left(4\right)$

If straight line L _a, L _bslope be k respectively _a, k _b, then:

$k_A=\frac{y_{P_A}-y_A}{x_{P_A}-x_A}=\frac{f_A\sin {\mathrm{\&alpha;}}_A+\mathrm{\&Delta;}A\sin {\mathrm{\&alpha;}}_A}{-f_A\cos {\mathrm{\&alpha;}}_A+\mathrm{\&Delta;}A\cos {\mathrm{\&alpha;}}_A}---\left(5\right)$

$k_B=\frac{y_{P_B}-y_B}{x_{P_B}-x_B}=\frac{f_B\sin {\mathrm{\&alpha;}}_B+\mathrm{\&Delta;}B\sin {\mathrm{\&alpha;}}_B}{-f_B\cos {\mathrm{\&alpha;}}_B+\mathrm{\&Delta;}B\cos {\mathrm{\&alpha;}}_B}---\left(6\right)$

Then straight line L can be drawn again by point slope form formula of equation of straight line _a, L _bequation be:

y-y _A＝k _A(x-x _A) (7)

y-y _B＝k _B(x-x _B) (8)

Simultaneous (7) (8) formula, can solve straight line L _a, L _bthe coordinate (x, y) of intersection point P:

$x=\frac{k_B{x}_B-y_B-k_A{x}_A+y_A}{k_B-k_A}---\left(9\right)$

$y=\frac{k_A{k}_B(x_B-x_A)+k_B{y}_A-k_A{y}_B)}{k_B-k_A}---\left(10\right)$

(5), (6) formula substitutes into (9), (10) formula derives the function F that can draw about x, y _xand F _y:

x＝F _x(x _A,y _A,x _B,y _B,f _A,f _B,Δ1,Δ2,α _A,α _B) (11)

y＝F _x(x _A,y _A,x _B,y _B,f _A,f _B,Δ1,Δ2,α _A,α _B) (12)

After two line-scan digital cameras installations are fixed, so focal distance f of two line-scan digital cameras _aand f _b, two line-scan digital cameras optical axis relative to the angle α of Y-axis _a, α _b, the focus coordinate A (x in a coordinate system of two line-scan digital cameras _a, y _a), B (x _b, y _b) all no longer change, the x namely in formula along with the fixing of installation _a, y _a, x _b, y _b, f _a, f _b, α _a, α _bfor state constant, can obtain after formula (11) (12) are simplified:

$x=\frac{c_0\mathrm{\&Delta;}1\mathrm{\&Delta;}2+c_1\mathrm{\&Delta;}1+c_2\mathrm{\&Delta;}2+c_3}{c_4\mathrm{\&Delta;}1\mathrm{\&Delta;}2+c_5\mathrm{\&Delta;}1+c_6\mathrm{\&Delta;}2+c_7}+c_8---\left(13\right)$

$y=\frac{c_9\mathrm{\&Delta;}1\mathrm{\&Delta;}2+c_{10}\mathrm{\&Delta;}1+c_{11}\mathrm{\&Delta;}2+c_{12}}{c_{13}\mathrm{\&Delta;}1\mathrm{\&Delta;}2+c_{14}\mathrm{\&Delta;}1+c_{15}\mathrm{\&Delta;}2+c_{16}}+c_{17}--\left(14\right)$

C in formula _i(i=0,1 ..., 17) and be Δ 1, the polynomial coefficient of Δ 2.These state constants only decide the corresponding relation of input quantity and output quantity in camera measuring system.3 is known with reference to the accompanying drawings, function F _xand F _yin parameter Δ 1, Δ 2 can change in the change of measuring position in target surface along with measured target point, namely the coordinate of measured target P point is only relevant with the change of Δ 1, Δ 2, so Δ 1, Δ 2 are input quantities of camera measuring system, and the coordinate of P point (x, y) be unique output quantity, according to above analysis, measuring principle is simply expressed as: according to the image space of P point at upper and lower line-scan digital camera, by formula (13) (14), the coordinate of P point in measurement target surface can be calculated.

Because the pixel coordinate position in the image that the image space of measured target P point on line-scan digital camera collects relative to range deviation and the some P point of optical axis image space is directly proportional relative to the deviation of picture centre, remember that the pixel coordinate of P point in two linear array camera images is respectively a ₁, a ₂adopt in the camera measuring system of this example resolution be 4096 line-scan digital camera, and focal length, inclination angle, focal position are all state constants, then the pixel coordinate position in the image that collects at upper and lower two line-scan digital cameras of P point is respectively (2048-a relative to the deviation of image center location ₁) and (2048-a ₂) individual pixel, i.e. (2048-a ₁)/Δ 1=g ₁, (2048-a ₂)/Δ 2=g ₂, wherein g ₁, g ₂for constant, then formula (13) (14) can be rewritten as:

$x=\frac{c_0(2048-a_1)(2048-a_2)+c_1(2048-a_1)+c_2(2048-a_2)+c_3}{c_4(2048-a_1)(2048-a_2)+c_5(2048-a_1)+c_6(2048-a_2)+c_7}+c_8---\left(15\right)$

$y=\frac{c_9(2048-a_1)(2048-a_2)+c_{10}(2048-a_1)+c_{11}(2048-a_2)+c_{12}}{c_{13}(2048-a_1)(2048-a_2)+c_{14}(2048-a_1)+c_{15}(2048-a_2)+c_{16}}+c_{17}---\left(16\right)$

C in formula _i(i=0,1 ..., 17) and be (2048-a ₁), (2048-a ₂) polynomial coefficient, these polynomial coefficients represent the corresponding relation in camera measuring system between output quantity and input quantity, and this corresponding relation is constant all the time in this stational system, at this moment polynomial coefficient c in solution formula _i(i=0,1 ..., 17) just become and solve a Nonlinear System of Equations.In this stational system, as long as the image space of known point P respectively in upper and lower linear array CCD image, just can obtain the coordinate (x, y) at surving coordinate system mid point P.

For camera measuring system, as all coefficient c _itime known, taken the photo of same object by First Line array camera, the second line-scan digital camera, calculate the pixel coordinate a of this object in two linear array camera images ₁, a ₂, just can pass through formula (15) (16) and calculate the coordinate of this object in target surface coordinate system.Carrying out demarcation to twin-line array camera is exactly solve above coefficient c _ithe i.e. P point coordinate (timing signal measurement) of diverse location in known measurement target surface, and the pixel coordinate position of each P point in upper and lower linear array camera image (line-scan digital camera take pictures acquisition), utilize wheat quart method to carry out iterative computation and draw all coefficients in formula (15) (16).The corresponding relation in this stational system between output quantity and input quantity can be solved like this, and do not need concrete these coefficients that solves, avoid the complicated calculations process solving parameters, the impact that the error simultaneously decreasing error in complicated calculations process and camera measuring system self structure is brought.

Scaling method:

A kind of line-scan digital camera scaling method, comprises the following steps:

Step one, travels the position to smooth spaciousness by track checking car, will demarcate the side of setting up and being placed in First Line array camera and the second line-scan digital camera on track checking car, ensures to demarcate steadily fixing of frame; Such as, need in this example to demarcate line-scan digital camera on the left of track checking car, so demarcation frame is arranged in the left side of track checking car; Adjustment First Line array camera and the second line-scan digital camera camera lens towards, ensure that the demarcation band on scaling board can be distributed in the field range of First Line array camera, the second line-scan digital camera, even if the optical axis of two line-scan digital cameras is intersected in a bit, two line-scan digital cameras are connected with computing machine; The control program of high ferro detection system is housed in computing machine, and image processing software.

Step 2, mounting guide rail and scaling board, supported demarcation frame by four tripods, open laser range finder, utilize external level meter and micro-adjusting mechanism adjustment tripod, the luminous point that laser range finder is got overlaps with the specifically labelled cross searching point on track checking car; Make the inclined degree of scaling board be no more than 1 degree by adjustment, and ensure in the moving range of scaling board on guide rail, comprise all the time in the image of two line-scan digital cameras gathered in computing machine and can see demarcation band image that is complete or part; The line-scan digital camera of track checking car left and right sides, can demarcate respectively according to this method, and this programme provides the calibration process of left side line-scan digital camera.

Step 3, with the specifically labelled center of cross on track checking car for initial point, sets up target surface coordinate system; Wherein with initial point towards the direction of track checking car for X-axis, initial point is Y-axis towards the direction on ground; As shown in Figure 3;

Step 4, in the moving range of scaling board on guide rail, choose multiple position, choose 13 positions (comprise initial position and end position, more multiposition should be chosen in actual calibration process) each position in this example and all obtain image information corresponding to this position according to following steps;

Step S40, utilizes laser range finder to measure demarcation and takes to outside car body, be i.e. the distance of X-direction;

Step S41, measure laser range finder and get to luminous point on track checking car to cross telltale mark center distance in the Y-axis direction (namely the line of laser spots and right-angled intersection point is in the projected length of Y direction), be designated as C (when laser spots is above right-angled intersection point, C be on the occasion of; Otherwise C gets negative value);

Step S42, is numbered to demarcating the mode that blackstreak marks according to from top to bottom, number order is ascending brought; Demarcate the structure of band as shown in Figure 6, such as order from top to bottom, to blackstreak marker number 1 to 13;

Step S43, two line-scan digital cameras all gather demarcates band image, finds out public blackstreak mark in two images, and on scaling board, these blackstreaks of correspondence is designated as marks for treatment;

Being meant to here, on same position, First Line array camera with the second line-scan digital camera because visual angle is different, the image that the demarcation of shooting is brought may be different, such as, may only have the black telltale mark of 1 to No. 11 in the image of First Line array camera shooting, in the image of the second line-scan digital camera shooting, only have the blackstreak of 3 to No. 13 to mark.In the image of so now First Line array camera, by image direction from top to bottom, Article 1 blackstreak is labeled as the blackstreak mark that numbering is 1, and the last item blackstreak marker number is 11; In second line-scan digital camera, Article 1 blackstreak is labeled as the blackstreak mark that numbering is 3, and the last item blackstreak marker number is 13.Now get their common factor, namely public blackstreak mark, namely finds to demarcate and brings the blackstreak of numbering 3 to 11 to mark, and these blackstreaks mark is all designated as marks for treatment, is convenient to subsequent processes.

Step S44, this distance, to the distance of marks for treatment upper edge on scaling board, is designated as B by the laser emission point measuring laser range finder;

Step S45, this position at least gathers 6 groups of images, and the sum comprising public blackstreak mark and white stripes mark in each group image will reach more than 13; Here a picture group similarly is the two width images that finger two line-scan digital cameras are taken at same position;

Step S46, preserves the image collected, then moves the position of scaling board, repeat step above, carry out the collection of next location drawing picture.

Step 5, one group of image that sharpness is the highest is filtered out in each position, calculate the coordinate figure X of center pixel in target surface coordinate system of marks for treatment corresponding to this group image (marks for treatment may be multiple blackstreak mark, so needs to calculate respectively each blackstreak mark) ₀and Y ₀, and the coordinate figure a of center pixel in the pixel coordinate system of this image of marks for treatment in the image that gathers of First Line array camera, the second line-scan digital camera ₁and a ₂, the center pixel of marks for treatment here refers to, the pixel of marks for treatment center line, line as more shallow in blackstreak mark center place color in Fig. 7.

Concrete steps are as follows:

Step S50, coordinate figure X ₀be the distance recorded in step S40;

Step S51, coordinate figure Y ₀for wherein d ₁for the width that each blackstreak marks, d ₂for the width that each white stripes marks, i is the numbering of blackstreak mark; Such as, in this example, the width of blackstreak mark is 20mm, and that white is 50mm, then Y ₀for B+C+10+70 (i-1);

Step S52, utilizes HALCON software in the image of First Line array camera, the second line-scan digital camera collection, obtain the coordinate figure of the center pixel of marks for treatment, by do not photograph or the coordinate figure of the center pixel of taking incomplete marks for treatment be designated as 0; Here the coordinate figure of each marks for treatment should be obtained;

Step 6, the matching of parameter

Step S60, by X corresponding for each public blackstreak of each position in step 5 mark ₀, Y ₀, a ₁and a ₂be designated as one group of data, obtain each group data of each position, be entered into respectively in EXCEL software, then screen, if a in a certain group of data ₁or a ₂be zero, then delete this group data, then by all data copy in txt file; Namely each position may have multiple because public blackstreak marks, and so will there be multi-group data a position; These data of all positions are imported in software jointly and screens, to obtain data as much as possible.

Step S61, sets name variable X in software 1stopt ₀, Y ₀, a ₁and a ₂, add X ₀, Y ₀value, wherein X ₀, Y ₀value be value in step S50, S51, the data in the txt file of step S60 are added in software;

Step S62, select wheat quart method to carry out iterative computation, convergence judge index is 1.00E-10, arrange greatest iteration number be 1000, in real time output domination number be 20; Choice criteria (LM)+general Global Optimization Method pattern, arranging repeat number is 30, and controlling number of iterations is 20, and convergence judges that number of iterations is 15, is respectively X ₀and Y ₀carry out matching, related coefficient will reach more than 0.99999, obtains corresponding fitting parameter, software design patterns parameter reference accompanying drawing 8;

Step S62, according to fitting parameter, determines the corresponding relation of the constrained input of two line-scan digital cameras in high ferro detection system, completes the calibration process of line-scan digital camera.

To bring in formula (15) (16) with the above-mentioned fitting parameter result solved, carry out repeatedly the static measurement experiment of different distance, can obtain by analysis, the maximum error of each measurement is 1mm, measuring accuracy meets the demands substantially, so use the demarcation of this kind of method to line-scan digital camera to be suitable.

Claims (4)

1. the line-scan digital camera calibration facility of a high ferro inspection truck system, it is characterized in that, line-scan digital camera is installed on track checking car (12), the side of track checking car (12) is provided with scaling board (3), scaling board (3) is provided with and demarcates band (13); Scaling board (3) can move along close or away from track checking car (12) direction, the top of scaling board (3) is provided with laser range finder (5), track checking car (12) is provided with telltale mark (10).

2. the line-scan digital camera calibration facility of high ferro inspection truck system as claimed in claim 1, it is characterized in that, described scaling board (3) is T-shaped plate, the bottom of scaling board (3) is assemblied on a guide rail (2), and guide rail (2) is installed in the demarcation frame (1) of pair of parallel setting; Described demarcation frame (1) takes the shape of the letter U structure, demarcates between frame (1) for two and is connected by semi-girder (8); The installing plate (7) parallel with guide rail (2) is symmetrically arranged with at each demarcation frame (1) top, the both sides of each demarcation frame (1) are provided with a tripod (4), and tripod (4) top braces is in installing plate (7) bottom; Scaling board (3) is also provided with the micro-adjusting mechanism (6) for adjusting tripod (4).

3. the line-scan digital camera calibration facility of high ferro inspection truck system as claimed in claim 2, it is characterized in that, described line-scan digital camera arranges two, be respectively First Line array camera (9) and the second line-scan digital camera (11), wherein First Line array camera (9) is positioned at directly over the second line-scan digital camera (11), telltale mark (10) is positioned at the position between First Line array camera (9) and the second line-scan digital camera (11), and telltale mark (10) is cross telltale mark (10).

4. the line-scan digital camera calibration facility of high ferro inspection truck system as claimed in claim 1, is characterized in that, on described demarcation band (13), interval arranges the blackstreak mark and white stripes mark that are parallel to each other along its length.