CN103398660B - For obtaining the structured light vision sensor parameter calibration method of weld bead height information - Google Patents

Abstract

The present invention is for obtaining the structured light vision sensor parameter calibration method of weld bead height information, relate to non-dedicated in the measurement of particular variables, it is a kind of Constructed Lighting Vision System parameter calibration method based on wedge shape target, utilize and demarcate parameters obtained, two dimensional image is processed to the side-play amount obtaining structured light, weld bead height information can be calculated, and then the three-dimensional coordinate of laser band and weld seam intersection point on target can be calculated, concrete steps comprise: the first step, identify horizontal departure; Second step, identifies vertical direction deviation; 3rd step, carries out Constructed Lighting Vision System parameter calibration with video camera; 4th step, the acquisition of weld bead height information.The calibration process of the inventive method does not relate to extensive matrixing, and calculated amount is less, there is not the occlusion issue of target, there is not the difficult problem not converging to globally optimal solution solving in constrained nonlinear equation and occur yet.

Description

For obtaining the structured light vision sensor parameter calibration method of weld bead height information

Technical field

Technical scheme of the present invention relates to non-dedicated in the measurement of particular variables, specifically for obtaining the structured light vision sensor parameter calibration method of weld bead height information.

Background technology

The demarcation of vision system is a major issue in robot vision, the image that vision system gathers, the image coordinate location of every bit and space object surface certain a bit between one-to-one relationship need the imaging model of vision system to decide, and the parameters of imaging model needs to be determined by the demarcation of vision system, therefore the demarcation of vision system is the key realizing changing from two-dimensional image information to three-dimensional environment information.In the calibration process of vision system, the acquisition of three-dimensional height information is a more thorny difficult problem always.

Structured light vision detection method has the advantages such as wide range, noncontact, Large visual angle and system flexibility are good, is in recent years widely used in industrial environment especially welding field.The calibration of camera of video camera and the structural parameters calibration of line structured light vision sensor are mainly comprised to the demarcation of the parameter of structured light vision sensor.Intrinsic parameters of the camera mainly refers to geometry and the optical characteristics of video camera inside, as optical centre, focal length, position etc., the structural parameters of sensor refer to the transformation relation between image coordinate system and three-dimensional camera coordinate system, the object that sensor parameters is demarcated makes, by two dimensional image coordinate Reconstruction of three-dimensional world coordinates, to realize three-dimensional measurement.

At welding technology field, traditional structured light vision sensor parameter calibration method, surface of the work is projected by structure light or linear structure light, weld bead height information is calculated (see " Wu Lin, Chen Shanben, intelligentized welding technology; 210th ~ 211 pages; 215th ~ 217 pages, Beijing: National Defense Industry Press, 1999 years " by triangulation method; See " Xu De, Tan Min, Li Yuan, robot vision Measurement & Control, the 133rd page, Beijing: National Defense Industry Press, 2008 years ").Calibrated and calculated process is based upon on laser instrument and the lucky basis crossing lens optical center of surface level intersection point, but in practical operation, we are difficult to the optical centre shaft position of determining video camera, are difficult to Accurate Calibration when using especially at the scene.Therefore, above-mentioned triangulation method needs to improve perfect further for actual conditions.

CN03142658.1 discloses " a kind of structured light vision sensor scaling method based on plane target ", the method mainly adopts the two dimensional surface target being distributed with black bars that can move freely to demarcate structured light vision sensor, using the summit of black bars as unique point in calibration process, the demarcation having come intrinsic parameters of the camera by utilizing the conversion between the image coordinate system of unique point and world coordinate system, the method relates to extensive matrixing, calculate complexity of deriving, need high-precision two-dimensional plane target, target difficulty of processing is large, and there is the problem of mutually blocking.

CN200710121397.X discloses " a kind of method for standardizing structural parameter of structure optical vision sensor ", the method is mainly by the plane target having multiple nonlinear characteristic point, by the position of repeatedly plane of motion target, obtain each mobile after a four or more nonlinear characteristic point coordinate on target image, and under transforming to camera coordinate system and then simulate high order ternary structural light equation.The method calibration process complex steps can affect precision, and coordinate transform and fit procedure complexity.

CN200910089307.2 reports " the structured light vision sensor scaling method based on one dimension target ", the method utilizes at least three unique points with known spatial constraint of one dimension target, in conjunction with perspective projection equation, calculate the video camera system coordinate of unique point according to the length constraint of unique point and direction constrain and carry out matching and obtain optic plane equations.The method needs to solve the constrained nonlinear equation of tool, and introduce nonlinear optimization, method is more numerous, and speed is slow, to Initial value choice and noise ratio more responsive, and can not ensure that parameter converges to global optimum.

Summary of the invention

Technical matters to be solved by this invention is: be provided for the structured light vision sensor parameter calibration method obtaining weld bead height information, it is a kind of Constructed Lighting Vision System parameter calibration method based on wedge shape target, weld bead height parameter in target is accurately measured in advance, the three-dimensional coordinate of laser band and weld seam intersection point on target can be calculated thus, in calibration process, still can the parameter of accurate Fast Calibration vision system when the optical centre shaft position of uncertain video camera, and calibration process does not relate to extensive matrixing, calculated amount is less, there is not the occlusion issue of target, there is not the difficult problem not converging to globally optimal solution solving in constrained nonlinear equation and occur yet.

The present invention solves this technical problem adopted technical scheme: for obtaining the structured light vision sensor parameter calibration method of weld bead height information, and be a kind of Constructed Lighting Vision System parameter calibration method based on wedge shape target, step is:

Described wedge shape target adopts triangle wedge, used major equipment has the scrambler in video camera, laser instrument, motion, one of them acute angle is 20 ° ~ 60 ° triangle wedge, weldment, electronics wedge shape vernier scale and servomotor, relate generally to camera lens in described video camera;

The first step, identifies horizontal departure

Video camera moved the distance of 5mm ~ 25mm along the direction that structure light belt is parallel and survey record by controlling servomotor, then the pixel value of the movement in the vertical direction of weld seam in two dimensional image is calculated, and then the actual range size calculated representated by each pixel, the Proportional coefficient K between pixel value and actual distance value can be obtained;

Second step, identifies vertical direction deviation

2-I step, is placed on below video camera by triangle wedge, guarantees that laser tape is just beaten in triangle wedge edge;

2-II step, moves forward distance y by triangle wedge _x1the structure light belt that laser instrument produces can move up by the hypotenuse along with the movement of triangle wedge along triangle wedge, until the height A C=10mm making this structure light belt rise on surface level stops, structure light belt is △ y in the distance as movement in plane ₁, the scrambler in moving process in motion can record the distance y that triangle wedge moves forward _x1, process in two dimensional image and the distance △ y of interrecord structure light belt movement in picture plane ₁;

2-III step, repeats the operating process of 2-II step, just continues triangle wedge to move forward distance y again _x2, until make structure light belt rise to apart from the height A on surface level ' and C '=20mm place stopping, now structure light belt is △ y in the distance as movement in plane ₂, the scrambler in moving process in motion can record the distance y that triangle wedge moves forward _x2, process in two dimensional image and the distance △ y of interrecord structure light belt movement in picture plane ₂;

3rd step, carries out Constructed Lighting Vision System parameter calibration with video camera

The position mark of the surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-I step operating process is made D, the position mark of surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-II step operating process is made D1, the position mark of surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-III step operating process is made D2, then the distance between D and D1 is y _x1, the distance between D1 and D2 is y _x2,

If the line laser that laser instrument sends is A with the hypotenuse intersection point of triangle wedge of the triangle wedge position being arranged in the operating process of 2-II step, camera lens center is designated as O, the extended line of camera lens center O and A hands over the surface level of height 0mm in a B, make the vertical line of A to the surface level of height 0mm, hand over surface level in a C, then 3 composition △ ABC; Make the vertical line of camera lens central point O to the surface level of height 0mm, hand over surface level in an O ', then 3 O, B, O ' form triangle △ OBO ', and the distance between note AC is h ₁,

Obtain according to △ ABC ∽ △ OBO ' is similar:

$\frac{h_1}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{BC}}{{\mathrm{BO}}^{\′}}---\left(1\right)$

If the line laser that laser instrument sends is A ' with the hypotenuse intersection point of triangle wedge of position of the triangle wedge being arranged in the operating process of 2-III step, the extended line of camera lens center O and A ' hands over the surface level of height 0mm in a B ', make the vertical line of A ' to the surface level of height 0mm, hand over surface level in a C ', then 3 composition △ A ' B ' C '; Make camera lens 1 central point O and hand over surface level and some O ' to the vertical line of the surface level of height 0mm, then 3 O, B ', O ' form triangle △ OB ' O '.Distance between note A ' C ' is h ₂.

Obtain according to △ A ' B ' C ' ∽ △ OB ' O ' is similar:

$\frac{h_2}{{\mathrm{OO}}^{\′}}=\frac{B^{\′}{C}^{\′}}{B^{\′}{O}^{\′}}---\left(2\right)$

Filters center axle and vertical direction angle are designated as θ, note BD=y ₁, B ' B=y ₂,

Then BC=y ₁-(y _x1-h ₁/ tan θ), B ' C '=y ₁+ y ₂-(y _x1+ y _x2-h ₁/ tan α), the distance OO ' of note optical center O to highly 0mm is the distance of H, 2-I step intermediate cam shape wedge sharp-angled apex D to camera optics central shaft OO ' is Y, i.e. OO '=H, DO '=Y, can obtain BO '=Y+y ₁, B ' O '=Y+y ₁+ y ₂, bring (1) into and can obtain with (2):

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.---\left(3\right)$

Wherein h ₁=10mm, h ₂=20mm, α=20 ° ~ 60 °, known quantity is brought into, can obtain:

The value of parameter H, Y can be obtained by (4) formula, in addition, can be obtained by geometric relationship in figure:

y _x1-AC/tanα＝AC*tanθ

That is:

$\tan \mathrm{\θ}=\frac{y_{x1}-\mathrm{AC}/\tan \mathrm{\α}}{\mathrm{AC}}---\left(5\right)$

Known h ₁=AC=10mm, α=20 ° ~ 60 ° of substitutions (5),

Namely tan θ can be calculated by above formula.

So far, carry out Constructed Lighting Vision System parameter calibration with video camera and complete, obtain the numerical value of parameter K, H, Y, tan θ respectively;

4th step, the acquisition of weld bead height information

In weld joint tracking situation, what measure is the weld bead height information of weld seam and structure light belt point of intersection, the weldment will measuring weld bead height information moves, until the weld seam solder joint place will measuring weld bead height is crossing with structure light belt, note intersection point is M, the extended line making OM hands over 0mm plane in a N, and the distance of note N point and 2-I step intermediate cam shape wedge sharp-angled apex D is y ₃=ND, visible y ₃be structure light belt and the intersection point M of weld seam solder joint and the horizontal range of 2-I step intermediate cam shape wedge sharp-angled apex D that will measure weld bead height, as the vertical line of M point to 0mm plane, the point that hangs down is for P, and note point M is h with the distance of some P ₃=MP,

Obtain according to △ MNP ∽ △ ONO ' is similar:

$\frac{\mathrm{MP}}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{NP}}{{\mathrm{NO}}^{\′}}$

Be:

$\frac{h_3}{H}=\frac{y_3-\tan \mathrm{\θ}*h_3}{y_3+Y}---\left(6\right)$

That is: $h_3=\frac{y_3*H}{y_3+Y+\tan \mathrm{\θ}*H}=f\left(y_3\right)---\left(7\right)$

H can be seen by above formula ₃about y ₃function,

Weld seam is moved along vertical stratification light belt direction, until structure light belt is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 ' between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, then △ y3=△ y3 '-Y/K, namely obtains the size of side-play amount △ y3.Then the size of y3 is y3=K* △ y3, the elevation of water of setting welding initial point is 0mm, when the deviation of in the vertical direction to be deposited by video camera relative to weld seam, the laser stripe in image will be caused to be moved in the lateral direction, now weld seam does not move, when image generation so changes, by image procossing record weld seam and structure light belt intersection point shift offset △ y3, and then learn y3=K* △ y3, the deviation that welding gun exists with actual welds in vertical direction can be identified in conjunction with (7) formula, so far, obtain weld seam and structure light belt point of intersection weld bead height information, achieve the reconstruct of three-dimensional camera coordinate.

The above-mentioned structured light vision sensor parameter calibration method for obtaining weld bead height information, institute's laser instrument is laser line generator.

The above-mentioned structured light vision sensor parameter calibration method for obtaining weld bead height information, described triangle wedge, one of them acute angle is 30 °.

The above-mentioned structured light vision sensor parameter calibration method for obtaining weld bead height information, wherein involved equipment is by commercially available.

The invention has the beneficial effects as follows:

The outstanding substantive distinguishing features of the inventive method is: the inventive method is a kind of Constructed Lighting Vision System parameter calibration method based on wedge shape target, utilize and demarcate parameters obtained, two dimensional image is processed to the side-play amount obtaining structured light, weld bead height information can be calculated, and then the three-dimensional coordinate of laser band and weld seam intersection point on target can be calculated.

The marked improvement of the inventive method is:

(1) there is certain difficulty when obtaining weld bead height information in monocular vision, binocular vision needs the information to two video cameras obtain to merge when obtaining weld bead height information, calculated amount is large, influential system real-time, this present situation of algorithms to improve proposed by the invention, not only avoid the matrixing loaded down with trivial details when obtaining weld bead height information, it also avoid coarse problem when determining camera optics cental axial position, greatly save and demarcated and computing time, significantly improved the real-time of system.

(2) in structured light vision sensor parameter calibration process, still can the parameter of accurate Fast Calibration vision system when the optical centre shaft position of uncertain video camera, and calibration process does not relate to extensive matrixing, calculated amount is less, there is not the occlusion issue of target, there is not the difficult problem not converging to globally optimal solution solving in constrained nonlinear equation and occur yet.

(3) the inventive method avoids on the one hand and sets up complicated camera imaging model, enhances the precision of camera calibration, robustness and adaptability on the other hand.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the present invention is further described.

Fig. 1 (a) is total schematic diagram of the inventive method calibration process intermediate cam shape wedge change in location.

Fig. 1 (b) carries out identifying the schematic diagram of intermediate cam shape wedge position to vertical direction deviation for demarcating 2-I step in the inventive method.

Fig. 1 (c) carries out identifying the schematic diagram of triangle wedge position to vertical direction deviation for demarcating 2-II step in the inventive method.

Fig. 1 (d) repeats the schematic diagram of the triangle wedge position of the operating process of 2-II step for demarcating in the inventive method during 2-III step identifies vertical direction deviation.

The schematic diagram of Fig. 1 (e) for utilizing calibration result butt-welding fitting to carry out weld bead height acquisition of information in the inventive method.

There is the variation relation schematic diagram of deviation and image thereof in the horizontal direction for video camera in the inventive method and weld seam in Fig. 2 (a).

There is the variation relation schematic diagram of deviation and image thereof for video camera in the inventive method and weld seam in the vertical direction in Fig. 2 (b).

Fig. 3 is the test findings data fitting result curve figure of the inventive method.

In figure, 1. camera lens, 2. laser instrument, the position of the triangle wedge in the 2-I step operating process during 3-1. second step identifies vertical direction deviation, the position of the triangle wedge in the 2-II step operating process during 3-2. second step identifies vertical direction deviation, the position of the triangle wedge in the 2-III step operating process during 3-3. second step identifies vertical direction deviation, 4. weldment, 5. video camera, 6. laser stripe, 7. weld seam.

Embodiment

Fig. 1 (a) illustrated embodiment indicates the changing condition of the position of the inventive method calibration process intermediate cam shape wedge.Camera lens 1 is denoted in figure, laser instrument 2, second step is to the position 3-1 of the 2-I step operating process intermediate cam shape wedge that vertical direction deviation identifies, second step carries out to vertical direction deviation the position 3-2 identifying intermediate cam shape wedge, and the 3rd step carries out to vertical direction deviation the position 3-3 identifying intermediate cam shape wedge, the acute angle of triangle wedge is α, the position that the sharp-angled apex of the triangle wedge of the position 3-1 of the triangle wedge in the 2-I step operating process in being identified vertical direction deviation by second step is in surface level 0mm is denoted as D, D point is designated as Y to the distance of the optical centre axle OO ' of camera lens 1, the position that the sharp-angled apex of the triangle wedge of the position 3-2 of the triangle wedge in the operating process of 2-II step is in surface level 0mm is denoted as D1, the position that the sharp-angled apex of the triangle wedge of the position 3-2 of the triangle wedge in the operating process of 2-III step is in surface level 0mm is denoted as D2, the distance that triangle wedge moves forward is y _x1time structured light distance △ y of movement in picture plane ₁, the distance that triangle wedge moves forward is y _x2time structured light distance △ y of movement in picture plane ₂the hypotenuse intersection point of the triangle wedge during position 3-2 of the triangle wedge in the 2-II step operating process during line laser and second step identify vertical direction deviation is A, the extended line of the line OA of camera lens 1 center O and A hands over the surface level of height 0mm in a B, making A hands over surface level in a C to the vertical line of the surface level of height 0mm, then 3 composition △ ABC, making camera lens 1 central point O hands over surface level in an O ' to the vertical line of the surface level of height 0mm, then 3 O, B, O ' form triangle △ OBO ', line laser is A ' with being arranged in second step to the hypotenuse intersection point of the triangle wedge of the position 3-3 of the triangle wedge of the 2-III step operating process that vertical direction deviation identifies, the extended line of camera lens 1 center O and A ' hands over the surface level of height 0mm in a B ', make the vertical line of A ' to the surface level of height 0mm, hand over surface level in a C ', then 3 composition △ A ' B ' C ', BD=y ₁, B ' B=y ₂.

For the ease of clearly demonstrating, this figure is decomposed into following Fig. 1 (b), Fig. 1 (c) and Fig. 1 (d).

Fig. 1 (b) illustrated embodiment shows, in the 2-I step operating process that vertical direction deviation is identified, first triangle wedge to be placed on below camera lens 1 i.e. second step vertical direction deviation is identified in the operating process of 2-I step in the position 3-1 of triangle wedge, guarantee that the laser tape of laser instrument 2 is just beaten in triangle wedge edge, the position that the sharp-angled apex of triangle wedge is in surface level 0mm is denoted as D, camera lens 1 center is O, camera lens 1 central point O hands over the intersection point of surface level to be O ' to the vertical line of the surface level of height 0mm, the acute angle of triangle wedge is α, laser instrument 2 central shaft and vertical direction angle are θ.

Fig. 1 (c) illustrated embodiment shows, laser instrument 2 central shaft and vertical direction angle are θ, the acute angle of triangle wedge is α, the position that the sharp-angled apex of the triangle wedge of the position 3-1 of the triangle wedge in the 2-I step operating process in being identified vertical direction deviation by second step is in surface level 0mm is denoted as D, the position that the sharp-angled apex of the triangle wedge of the position 3-2 of the triangle wedge in the operating process of 2-II step is in surface level 0mm is denoted as D1, and the distance that triangle wedge moves forward is y _x1time structured light distance △ y of movement in picture plane ₁.In the 2-II step operating process that vertical direction deviation is identified, line laser is A with being arranged in the hypotenuse intersection point of second step to the triangle wedge of the position 3-2 of the triangle wedge of the 2-II step operating process that vertical direction deviation identifies, the extended line of the line OA of camera lens 1 center O and A hands over the surface level of height 0mm in a B, make A and meet at a C to vertical line and the surface level of the surface level of height 0mm, then 3 form △ ABC; Making camera lens 1 central point O hands over surface level in an O ' to the vertical line of the surface level of height 0mm, then 3 O, B, O ' form triangle △ OBO '.Obtain according to △ ABC ∽ △ OBO ' is similar:

$\frac{h_1}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{BC}}{{\mathrm{BO}}^{\′}}---\left(1\right)$

Wherein, h ₁for the distance between AC.

Fig. 1 (d) illustrated embodiment shows, laser instrument 2 central shaft and vertical direction angle are θ, the acute angle of triangle wedge is α, the position that the sharp-angled apex of the triangle wedge of the position 3-1 of the triangle wedge in the 2-I step operating process in being identified vertical direction deviation by second step is in surface level 0mm is denoted as D, the position that the sharp-angled apex of the triangle wedge of the position 3-2 of the triangle wedge in the operating process of 2-III step is in surface level 0mm is denoted as D2, and the distance that triangle wedge moves forward is y _x2time structured light distance △ y of movement in picture plane ₂.In the 2-III step operating process that vertical direction deviation is identified, line laser is A ' with being arranged in second step to the hypotenuse intersection point of the triangle wedge of the position 3-3 of the triangle wedge of the 2-III step operating process that vertical direction deviation identifies, the extended line of camera lens 1 center O and A ' hands over the surface level of height 0mm in a B ', make the vertical line of A ' to the surface level of height 0mm, hand over surface level in a C ', then 3 composition △ A ' B ' C '; Make camera lens 1 central point O and hand over surface level and some O ' to the vertical line of the surface level of height 0mm, then 3 O, B ', O ' form triangle △ OB ' O '.Obtain according to △ A ' B ' C ' ∽ △ OB ' O ' is similar:

$\frac{h_2}{{\mathrm{OO}}^{\′}}=\frac{B^{\′}{C}^{\′}}{B^{\′}{O}^{\′}}---\left(2\right)$

Wherein, h ₂for the distance between A ' C '.

BD=y ₁, B ' B=y ₂, then BC=y ₁-(y _x1-h ₁/ tan θ), B ' C '=y ₁+ y ₂-(y _x1+ y _x2-h ₁/ tan α).Suppose that camera lens 1 center O is H to the distance OO ' of height 0mm, first step intermediate cam shape calibrating block 3 sharp-angled apex is Y to the distance of camera optics central shaft, then OO '=H, BO '=Y+y ₁, B ' O '=Y+y ₁+ y ₂, bring (1) into and can obtain with (2):

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.---\left(3\right)$

Wherein h ₁=10mm, h ₂=20mm, α=20 ° ~ 60 °, known quantity is brought into, can obtain:

The value of parameter H, Y can be obtained by (4) formula, in addition, can be obtained by geometric relationship in figure:

y _x1-AC/tanα＝AC*tanθ

That is:

$\tan \mathrm{\θ}=\frac{y_{x1}-\mathrm{AC}/\tan \mathrm{\α}}{\mathrm{AC}}---\left(5\right)$

Known h ₁=AC=10mm, α=20 ° ~ 60 ° of substitutions (5),

Namely tan θ can be calculated by above formula.

So far, camera parameters has been demarcated, and obtains the size of parameter K, H, Y, tan θ respectively.

In Fig. 1 (e), camera lens 1 center is O, and camera lens 1 central point O hands over the intersection point of surface level to be O ' to the vertical line of the surface level of height 0mm, and laser instrument 2 central shaft and vertical direction angle are θ.

Fig. 1 (e) illustrated embodiment shows, in weld joint tracking situation, what measure is the weld bead height information of weld seam and structure light belt point of intersection, the weldment 4 will measuring weld bead height information moves, until the weld seam solder joint place will measuring weld bead height is crossing with structure light belt, note intersection point is M, and the extended line making OM hands over 0mm plane in a N, and the distance of note N point and 2-I step intermediate cam shape wedge sharp-angled apex D is y ₃=ND, visible y ₃be structure light belt and the intersection point M of weld seam solder joint and the horizontal range of 2-I step intermediate cam shape wedge sharp-angled apex D that will measure weld bead height, as the vertical line of M point to 0mm plane, the point that hangs down is for P, and note point M is h with the distance of some P ₃=MP,

Obtain according to △ MNP ∽ △ ONO ' is similar:

$\frac{\mathrm{MP}}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{NP}}{{\mathrm{NO}}^{\′}}$

Be:

$\frac{h_3}{H}=\frac{y_3-\tan \mathrm{\θ}*h_3}{y_3+Y}---\left(6\right)$

That is: $h_3=\frac{y_3*H}{y_3+Y+\tan \mathrm{\θ}*H}=f\left(y_3\right)---\left(7\right)$

H can be seen by above formula ₃about y ₃function.

Weld seam is moved along vertical stratification light belt direction, until structure light belt is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 ' between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, △ y3=△ y3 '-Y/K, namely obtains the size of side-play amount △ y3.For y1, in fig. l (a), the side-play amount obtained by image procossing is △ y1, then the size of y1 is K* △ y1.In like manner known, y3=K* △ y3, as long as therefore obtain by image procossing the value that side-play amount △ y3 can obtain y3, and then can calculate the weld bead height information h of this point ₃.The elevation of water of setting welding initial point is 0mm, when the deviation of in the vertical direction to be deposited by video camera relative to weld seam, the laser stripe in image will be caused to be moved in the lateral direction, now weld seam does not move, image produces when so changing, and can identify in conjunction with above-mentioned scaling method the deviation that welding gun exists with actual welds in vertical direction.So far, weld seam and structure light belt point of intersection weld bead height information is obtained.

Fig. 2 (a) illustrated embodiment shows, and the position relationship of weldment 4 and video camera 5 is for shown in (1) in Fig. 2 (a), and weld image is for shown in (2) in Fig. 2 (a).When video camera 5 deposits deviation in the horizontal direction relative to weld seam 7, will cause the weld seam 7 in its image that the movement of position as shown in phantom in FIG. occurs at above-below direction, now laser stripe 6 does not move.

Fig. 2 (b) illustrated embodiment shows, and the position relationship of weldment 4 and video camera 5 is for shown in (1) in Fig. 2 (b), and weld image is for shown in (2) in Fig. 2 (b).When video camera 5 deposits the deviation of in the vertical direction relative to weld seam 7, will cause the laser stripe 6 in image that the movement of position as shown in phantom in FIG. occurs at left and right directions, now weld seam 7 does not move.

Embodiment 1

In the present embodiment, wedge shape target adopts an acute angle to be the triangle wedge of 30 °, used major equipment has the scrambler in video camera, laser instrument, motion, one of them acute angle is 30 ° triangle wedge, weldment, electronics wedge shape vernier scale and servomotor, relate generally to camera lens in described video camera;

The first step, carries out horizontal departure identification

By control motor, video camera is moved the distance of 10mm along the direction that structure light belt is parallel, then the pixel value of the movement in the vertical direction of weld seam in two dimensional image is calculated, and then the actual range size calculated representated by each pixel, the Proportional coefficient K between pixel value and actual value can be obtained, K=83;

Second step, identifies vertical direction deviation

2-I step, as above-mentioned Fig. 1 (b) illustrated embodiment operates, is placed on below video camera by triangle wedge, guarantees that laser tape is just beaten in triangle wedge edge; The position that the sharp-angled apex of triangle wedge is in surface level 0mm is denoted as D,

2-II step, as above-mentioned Fig. 1 (c) illustrated embodiment carries out operating and calculating, wherein triangle wedge moves forward y _x1, the height A C=10mm place that structure light belt is risen on surface level stops, and the scrambler record triangle wedge in motion moves forward distance y _x1=20.118mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₁=0.0291mm;

2-III step, repeats the operating process of 2-II step, just continues triangle wedge to move forward distance y again _x2, structure light belt is risen to apart from the height A on surface level ' and C '=20mm place stopping, the scrambler record triangle wedge in motion moves forward distance y _x2=20.118mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₂=0.03497mm;

3rd step, carries out Constructed Lighting Vision System parameter calibration with video camera

As the description of above-mentioned Fig. 1 (d) illustrated embodiment, obtain:

$\frac{h_1}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{BC}}{{\mathrm{BO}}^{\′}}---\left(1\right)$

$\frac{h_2}{{\mathrm{OO}}^{\′}}=\frac{B^{\′}{C}^{\′}}{B^{\′}{O}^{\′}}---\left(2\right)$

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.---\left(3\right)$

According to (3) formula, wherein,

h ₁=AC=10mm,h ₂=A’C’=20mm，

Known y again ₁=K* △ y ₁=83*0.0291=2.4153, y ₂=K* △ y ₂=83*0.03497=2.9024;

Substitution known quantity obtains

Calculate H=120.1, Y=-6.8379

By obtain tan θ=0.2787

So far, carry out Constructed Lighting Vision System parameter calibration with video camera and complete, obtain parameter K respectively, the numerical value of H, Y, tan θ is: K=83, H=120.1, tan θ=0.2787, Y=-6.8379, wherein negative sign does not represent size, only represents directional information.

4th step, the acquisition of weld bead height information

In weld joint tracking situation, what measure is the weld bead height information of weld seam and structure light belt point of intersection, the weldment 4 will measuring weld bead height information moves, until the weld seam solder joint place will measuring weld bead height is crossing with structure light belt, note intersection point is M, the extended line making OM hands over 0mm plane in a N, and the distance of note N point and 2-I step intermediate cam shape wedge sharp-angled apex D is y ₃=ND, visible y ₃be structure light belt and the intersection point M of weld seam solder joint and the horizontal range of 2-I step intermediate cam shape wedge sharp-angled apex D that will measure weld bead height, as the vertical line of M point to 0mm plane, the point that hangs down is for P, and note point M is h with the distance of some P ₃=MP,

Obtain according to △ MNP ∽ △ ONO ' is similar:

$\frac{\mathrm{MP}}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{NP}}{{\mathrm{NO}}^{\′}}$

Be:

$\frac{h_3}{H}=\frac{y_3-\tan \mathrm{\θ}*h_3}{y_3+Y}---\left(6\right)$

That is: $h_3=\frac{y_3*H}{y_3+Y+\tan \mathrm{\θ}*H}=f\left(y_3\right)---\left(7\right)$

Weld seam is moved along vertical stratification light belt direction, until structure light belt is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 '=-0.05168mm between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, according to △ y3=△ y3 '-Y/K=-0.05168-(-6.8379)/83=0.0307mm, side-play amount △ y3 can be tried to achieve, and then y3=K* △ y3=83*0.0307=2.5481 can be obtained.Above-mentioned negative sign does not all represent size, only represents directional information.

According to (7) formula $h_3=\frac{y_3*H}{y_3+Y+\tan \mathrm{\θ}*H},$

Weld bead height can be obtained

$h_3=\frac{2.5481*120.1}{2.5481+(-6.8379)+0.2787*120.1}=10.50\mathrm{mm}$

Use electronics wedge shape vernier scale butt welded seam true altitude to carry out measurement and obtain weld bead height for 10.45mm.

The two-dimensional coordinate (181,130.5) at weld seam solder joint place to be measured can be determined by the product of two dimensional image coordinate and ratio K, achieve the reconstruct (181,130.5,10.50) of weld seam three-dimensional camera coordinate.

Embodiment 2

Moved along vertical stratification light direction by video camera except by controlling motor, triangle wedge moves forward and makes structure light belt rise to h on surface level ₁the At The Height of=AC=5mm stops, distance y _x1the distance △ y of=10.079mm and structured light movement in picture plane ₁=0.01424mm; Triangle wedge moves forward and makes structure light belt rise to h on surface level ₂the At The Height of=A ' C '=15mm stops, distance y _x2the distance △ y of=20.157mm and structured light movement in picture plane ₂=0.0325mm; In addition, other are with embodiment 1,

Camera calibration result is K=82.8, H=121.3, tan θ=0.2826, Y=-6.8612, and negative sign does not represent size herein, only represents directional information.

Weld seam is moved along vertical stratification light direction, until structured light is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 '=-0.05176mm between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, according to △ y3=△ y3 '-Y/K=-0.05176-(-6.8612)/82.8=0.0311mm, can side-play amount be tried to achieve, and then y3=K* △ y3=82.8*0.0311=2.5751 can be obtained.Above-mentioned negative sign does not all represent size, only represents directional information.

According to (7) formula weld bead height can be obtained

$h_3=\frac{2.5751*121.3}{2.5751+(-6.8612)+0.2826*121.3}=10.31\mathrm{mm}$

Use electronics wedge shape vernier scale butt welded seam true altitude to carry out measurement and obtain weld bead height for 10.31mm.

The two-dimensional coordinate (181.5,130.2) at weld seam solder joint place to be measured can be determined by the product of two dimensional image coordinate and ratio K, achieve the reconstruct (181.5,130.2,10.31) of weld seam three-dimensional camera coordinate.

Embodiment 3

Except by controlling motor, video camera is moved 15mm along the direction that structure light belt is parallel, triangle wedge moves forward and makes structure light belt rise to h on surface level ₁the At The Height of=AC=15mm stops, distance y _x1the distance △ y of=28.737mm and structured light movement in picture plane ₁=0.02594; Triangle wedge moves forward and makes structure light belt rise to h on surface level ₂the At The Height of=A ' C '=25mm stops, distance y _x2the distance △ y of=21.443mm and structured light movement in picture plane ₂=0.05701mm; In addition, other are with embodiment 1,

Camera calibration result is K=83.1, H=119.8, tan θ=0.2741, Y=-6.8856, and negative sign does not represent size herein, only represents directional information.

Weld seam is moved along vertical stratification light direction, until structured light is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 '=-0.05316mm between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, according to △ y3=△ y3 '-Y/K=-0.05316-(-6.8856)/83.1=0.0297mm, can side-play amount be tried to achieve, and then y3=K* △ y3=83.1*0.0297=2.4681 can be obtained.Above-mentioned negative sign does not all represent size, only represents directional information.

According to (7) formula weld bead height can be obtained

$h_3=\frac{2.4681*119.8}{2.4681+(-6.8856)+0.2741*119.8}=10.40\mathrm{mm}$

Use electronics wedge shape vernier scale butt welded seam true altitude to carry out measurement and obtain weld bead height for 10.45mm.

Can determine that the two-dimensional coordinate (181.2,130.2) at weld seam solder joint place to be measured achieves the reconstruct (181.2,130.3,10.40) of weld seam three-dimensional camera coordinate by the product of two dimensional image coordinate and ratio K.

Embodiment 4

Except the triangle wedge shape target used adopts an acute angle to be the triangle wedge of 20 °; In addition, other, with embodiment 1, obtain Different Results as follows in calibration process:

Carry out in horizontal departure identification step in the first step, by control motor, video camera is moved the distance of 10mm along the direction that structure light belt is parallel, then the pixel value of the movement in the vertical direction of weld seam in two dimensional image is calculated, and then the actual range size calculated representated by each pixel, the Proportional coefficient K between pixel value and actual value can be obtained, K=83.2;

Carry out in identification step at second step to vertical direction deviation, in 2-II step, wherein triangle wedge moves forward y _x1, the height A C=10mm place that structure light belt is risen on surface level stops, and the scrambler record triangle wedge in motion moves forward distance y _x1=30.306mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₁=0.0297mm; In 2-III step, repeat the operating process of 2-II step, just continue triangle wedge to move forward distance y again _x2, structure light belt is risen to apart from the height A on surface level ' and C '=20mm place stopping, the scrambler record triangle wedge in motion moves forward distance y _x2=30.403mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₂=0.0369mm;

Carry out in Constructed Lighting Vision System parameter calibration process at the 3rd step video camera,

By formula (3)

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.$

Wherein,

h ₁=AC=10mm,h ₂=A’C’=20mm，α=20°

Known y again ₁=K* △ y ₁=83.2*0.0297=2.4680, y ₂=K* △ y ₂=83.2*0.0369=3.0729;

Substitution known quantity obtains

Calculate H=121.1, Y=-6.8643

By obtain tan θ=0.2831

So far, carry out Constructed Lighting Vision System parameter calibration with video camera and complete, obtain parameter K respectively, the numerical value of H, Y, tan θ is: K=83.2, H=121.1, tan θ=0.2831, Y=-6.8643, wherein negative sign does not represent size, only represents directional information.

In the obtaining step of the 4th step weld bead height information, weld seam is moved along vertical stratification light direction, until structured light is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 '=-0.05221mm between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, according to △ y3=△ y3 '-Y/K=-0.05221-(-6.8643)/83.2=0.0303mm, can side-play amount be tried to achieve, and then y3=K* △ y3=83.2*0.0303=2.5210 can be obtained.Above-mentioned negative sign does not all represent size, only represents directional information.

According to (7) formula weld bead height can be obtained

$h_3=\frac{2.5210*121.1}{2.5210+(-6.8643)+0.2831*121.1}=10.20\mathrm{mm}$

Use electronics wedge shape vernier scale butt welded seam true altitude to carry out measurement and obtain weld bead height for 10.43mm.

The two-dimensional coordinate (179.5,131.2) at weld seam solder joint place to be measured can be determined by the product of two dimensional image coordinate and ratio K, achieve the reconstruct (179.5,131.2,10.20) of weld seam three-dimensional camera coordinate.

Embodiment 5

Except the triangle wedge shape target used adopts an acute angle to be the triangle wedge of 60 °; In addition, other, with embodiment 1, obtain Different Results as follows in calibration process:

Carry out in horizontal departure identification step in the first step, by control motor, video camera is moved the distance of 10mm along the direction that structure light belt is parallel, then the pixel value of the movement in the vertical direction of weld seam in two dimensional image is calculated, and then the actual range size calculated representated by each pixel, the Proportional coefficient K between pixel value and actual value can be obtained, K=83.7;

Carry out in identification step at second step to vertical direction deviation, in 2-II step, wherein triangle wedge moves forward y _x1, the height A C=10mm place that structure light belt is risen on surface level stops, and the scrambler record triangle wedge in motion moves forward distance y _x1=8.5675mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₁=0.0289mm; In 2-III step, repeat the operating process of 2-II step, just continue triangle wedge to move forward distance y again _x2, structure light belt is risen to apart from the height A on surface level ' and C '=20mm place stopping, the scrambler record triangle wedge in motion moves forward distance y _x2=8.5694mm, processes and the distance △ y of interrecord structure light belt movement in picture plane in two dimensional image ₂=0.0348mm;

Carry out in Constructed Lighting Vision System parameter calibration process at the 3rd step video camera,

By formula (3)

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.$

Wherein,

h ₁=AC=10mm,h ₂=A’C’=20mm，α=60°

Known y again ₁=K* △ y ₁=83.7*0.0289=2.4204, y ₂=K* △ y ₂=83.7*0.0348=2.9108;

Substitution known quantity obtains

Calculate H=119.2, Y=-6.8731

By obtain tan θ=0.2794

So far, carry out Constructed Lighting Vision System parameter calibration with video camera and complete, obtain parameter K respectively, the numerical value of H, Y, tan θ is: K=83.7, H=119.2, tan θ=0.2794, Y=-6.8731, wherein negative sign does not represent size, only represents directional information.

In the obtaining step of the 4th step weld bead height information, weld seam is moved along vertical stratification light direction, until structured light is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 '=-0.05315mm between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, according to △ y3=△ y3 '-Y/K=-0.05315-(-6.8731)/83.7=0.0289mm, can side-play amount be tried to achieve, and then y3=K* △ y3=83.7*0.0289=2.4189 can be obtained.Above-mentioned negative sign does not all represent size, only represents directional information.

According to (7) formula weld bead height can be obtained

$h_3=\frac{2.4189*119.2}{2.4189+(-6.8731)+0.2794*119.2}=9.99\mathrm{mm}$

Use electronics wedge shape vernier scale butt welded seam true altitude to carry out measurement and obtain weld bead height for 10.23mm.

The two-dimensional coordinate (179.1,130.2) at weld seam solder joint place to be measured can be determined by the product of two dimensional image coordinate and ratio K, achieve the reconstruct (179.1,130.2,9.99) of weld seam three-dimensional camera coordinate.

In above-described embodiment, laser instrument used is laser line generator.

The weld seam choosing weldment diverse location height carries out test of many times, has carried out actual measurement, obtain weld bead height information in test with electronics wedge shape vernier scale butt welded seam altitudes.The weld seam three-dimensional coordinate information that actual welds three-dimensional coordinate information and demarcation obtain is carried out matching respectively, and fitting result curve is shown in Fig. 3.

Shown in Fig. 3, experimental result shows, the absolute error of X-direction in 0.5mm, height Z measure absolute error in 1mm, mean square deviation result is 0.707, and experiment shows, this arithmetic accuracy and stability higher, meet engineering precision demand.

Equipment involved in above-described embodiment is by commercially available.

Claims (3)

1. for obtaining the structured light vision sensor parameter calibration method of weld bead height information, it is characterized in that: be a kind of Constructed Lighting Vision System parameter calibration method based on wedge shape target, step is:

Described wedge shape target adopts triangle wedge, used major equipment has the scrambler in video camera, laser instrument, motion, one of them acute angle is 20 ° ~ 60 ° triangle wedge, weldment, electronics wedge shape vernier scale and servomotor, relate generally to camera lens in described video camera;

The first step, identifies horizontal departure

Video camera moved the distance of 5mm ~ 25mm along the direction that structure light belt is parallel and survey record by controlling servomotor, then the pixel value of the movement in the vertical direction of weld seam in two dimensional image is calculated, and then the actual range size calculated representated by each pixel, the Proportional coefficient K between pixel value and actual distance value can be obtained;

Second step, identifies vertical direction deviation

2-I step, is placed on below video camera by triangle wedge, guarantees that laser tape is just beaten in triangle wedge edge;

2-II step, moves forward distance y by triangle wedge _x1the structure light belt that laser instrument produces can move up by the hypotenuse along with the movement of triangle wedge along triangle wedge, until the height A C=10mm making this structure light belt rise on surface level stops, structure light belt is △ y in the distance as movement in plane ₁, the scrambler in moving process in motion can record the distance y that triangle wedge moves forward _x1, process in two dimensional image and the distance △ y of interrecord structure light belt movement in picture plane ₁;

2-III step, repeats the operating process of 2-II step, just continues triangle wedge to move forward distance y again _x2, until make structure light belt rise to apart from the height A on surface level ' the stopping of C'=20mm place, now structure light belt is △ y in the distance as movement in plane ₂, the scrambler in moving process in motion can record the distance y that triangle wedge moves forward _x2, process in two dimensional image and the distance △ y of interrecord structure light belt movement in picture plane ₂;

3rd step, carries out Constructed Lighting Vision System parameter calibration with video camera

The position mark of the surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-I step operating process is made D, the position mark of surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-II step operating process is made D1, the position mark of surface level 0mm residing for the sharp-angled apex being arranged in the triangle wedge of the triangle wedge position of 2-III step operating process is made D2, then the distance between D and D1 is y _x1, the distance between D1 and D2 is y _x2,

If the line laser that laser instrument sends is A with the hypotenuse intersection point of triangle wedge of the triangle wedge position being arranged in the operating process of 2-II step, camera lens center is designated as O, the extended line of camera lens center O and A hands over the surface level of height 0mm in a B, make the vertical line of A to the surface level of height 0mm, hand over surface level in a C, then 3 composition △ ABC; Make the vertical line of camera lens central point O to the surface level of height 0mm, hand over surface level in an O ', then 3 O, B, O ' form triangle △ OBO ', and the distance between note AC is h ₁,

Obtain according to △ ABC ∽ △ OBO ' is similar:

$\frac{h_1}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{BC}}{{\mathrm{BO}}^{\′}}---\left(1\right)$

If the line laser that laser instrument sends is A' with the hypotenuse intersection point of triangle wedge of position of the triangle wedge being arranged in the operating process of 2-III step, the extended line of camera lens center O and A' hands over the surface level of height 0mm in a B', make the vertical line of A' to the surface level of height 0mm, hand over surface level in a C', then 3 composition △ A'B'C'; Make camera lens 1 central point O and hand over surface level and some O ', then O, B', O at 3 to the vertical line of the surface level of height 0mm ' form triangle △ OB'O ', the distance between note A'C' is h ₂,

Obtain according to △ A'B'C' ∽ △ OB'O ' is similar:

$\frac{h_2}{{\mathrm{OO}}^{\′}}=\frac{B^{\′}{C}^{\′}}{B^{\′}{O}^{\′}}---\left(2\right)$

Filters center axle and vertical direction angle are designated as θ, note BD=y ₁, B'B=y ₂,

Then BC=y ₁-(y _x1-h ₁/ tan θ), B'C'=y ₁+ y ₂-(y _x1+ y _x2-h ₁/ tan α), the distance OO' of note optical center O to highly 0mm is the distance of H, 2-I step intermediate cam shape wedge sharp-angled apex D to camera optics central shaft OO ' is Y, i.e. OO'=H, DO '=Y, can obtain BO'=Y+y ₁, B'O'=Y+y ₁+ y ₂, bring (1) into and can obtain with (2):

$\left\{\begin{array}{c}\frac{h_1}{H}=\frac{y_1-(y_{x1}-h_1/\tan \mathrm{\α})}{y_1+Y}\\ \frac{h_2}{H}=\frac{y_1+y_2-(y_{x1}+y_{x2}-h_2/\tan \mathrm{\α})}{y_1+y_2+Y}\end{array}\right.---\left(3\right)$

Wherein h ₁=10mm, h ₂=20mm, α=20 ° ~ 60 °, known quantity is brought into, can obtain:

The value of parameter H, Y can be obtained by (4) formula, in addition, can be obtained by geometric relationship in figure:

y _x1-AC/tanα＝AC*tanθ

That is:

$\tan \mathrm{\θ}=\frac{y_{x1}-\mathrm{AC}/\tan \mathrm{\α}}{\mathrm{AC}}---\left(5\right)$

Known h ₁=AC=10mm, α=20 ° ~ 60 ° of substitutions (5),

Namely tan θ can be calculated by above formula,

So far, carry out Constructed Lighting Vision System parameter calibration with video camera and complete, obtain the numerical value of parameter K, H, Y, tan θ respectively;

4th step, the acquisition of weld bead height information

In weld joint tracking situation, what measure is the weld bead height information of weld seam and structure light belt point of intersection, the weldment will measuring weld bead height information moves, until the weld seam solder joint place will measuring weld bead height is crossing with structure light belt, note intersection point is M, the extended line making OM hands over 0mm plane in a N, and the distance of note N point and 2-I step intermediate cam shape wedge sharp-angled apex D is y ₃=ND, visible y ₃be structure light belt and the intersection point M of weld seam solder joint and the horizontal range of 2-I step intermediate cam shape wedge sharp-angled apex D that will measure weld bead height, as the vertical line of M point to 0mm plane, the point that hangs down is for P, and note point M is h with the distance of some P ₃=MP,

Obtain according to △ MNP ∽ △ ONO ' is similar:

$\frac{\mathrm{MP}}{{\mathrm{OO}}^{\′}}=\frac{\mathrm{NP}}{{\mathrm{NO}}^{\′}}$

Be:

$\frac{h_3}{H}=\frac{y_3-\tan \mathrm{\θ}*h_3}{y_3+Y}---\left(6\right)$

That is: $h_3=\frac{y_3*H}{y_3+Y+\tan \mathrm{\θ}*H}=f\left(y_3\right)---\left(7\right)$

H can be seen by above formula ₃about y ₃function,

Weld seam is moved along vertical stratification light belt direction, until structure light belt is crossing with the solder joint place will measuring weld bead height, by the distance △ y3 ' between two dimensional image record weld seam and the optical centre axle OO ' of structure light belt point of intersection and camera lens, then △ y3=△ y3 '-Y/K, namely the size of side-play amount △ y3 is obtained, then the size of y3 is y3=K* △ y3, the elevation of water of setting welding initial point is 0mm, when the deviation of in the vertical direction to be deposited by video camera relative to weld seam, the laser stripe in image will be caused to be moved in the lateral direction, now weld seam does not move, when image generation so changes, by image procossing record weld seam and structure light belt intersection point shift offset △ y3, and then learn y3=K* △ y3, the deviation that welding gun exists with actual welds in vertical direction can be identified in conjunction with (7) formula, so far, obtain weld seam and structure light belt point of intersection weld bead height information, achieve the reconstruct of three-dimensional camera coordinate.

2., according to the said structured light vision sensor parameter calibration method for obtaining weld bead height information of claim 1, it is characterized in that: described laser instrument is laser line generator.

3., according to the said structured light vision sensor parameter calibration method for obtaining weld bead height information of claim 1, it is characterized in that: described triangle wedge, one of them acute angle is 30 °.