TWI849657B - Six degrees of freedom aligning equipment and calibration thereof - Google Patents

Abstract

A six degrees of freedom aligning equipment includes an optical probe assembly and a correction module. The optical probe assembly includes a low-distortion image probe and a ranging probe arranged adjacent to each other. The calibration module is electrically connected to the optical probe assembly and a motion platform, and the motion platform is movably arranged within the field of view of each probe of the optical probe assembly. The calibration module is used to calculate the error of six degrees of freedom between each probe and the precision six-axis platform through a calibration with calibration patterns configured on the precision six-axis platform and each probe of the optical probe assembly respectively, adjusts the pose of the precision six-axis platform to the corrected pose corresponding to each probe, and save six degrees of freedom coordinate parameters corresponding the corrected pose.

Description

Six-degree-of-freedom alignment device and correction method thereof

The present invention relates to a six-degree-of-freedom alignment device and a calibration method thereof, and more particularly to a six-degree-of-freedom alignment device and a calibration method thereof for assembling electronic products.

With the advancement of industry and the increasing precision requirements for electronic product assembly, many electronic product assembly processes have introduced six-degree-of-freedom alignment equipment to align the various components that make up the electronic product before assembling them. Specifically, the six-degree-of-freedom alignment equipment is an optical-mechanical device that includes an optical probe assembly, which is mainly used to adjust the posture of the aforementioned components to the correct posture (including position and rotation).

Since the alignment results of the 6-DOF alignment equipment will affect the assembly quality and even the functions of electronic products, it is most important to ensure that the alignment results of the 6-DOF alignment equipment are error-free. In other words, if the alignment results of the 6-DOF alignment equipment have errors, in addition to the poor assembly quality of the electronic product, it is more likely to cause the electronic product's functions to not operate normally.

In order to solve the problems of the prior art, the present invention provides a six-degree-of-freedom alignment device, including a six-degree-of-freedom alignment device, including an optical probe group and a correction module. The optical probe group includes a low-distortion image probe and a ranging probe arranged adjacent to each other. The correction module is electrically connected to the optical probe group and the motion platform, and the motion platform can be movably arranged within the field of view of each probe in the optical probe group. The correction module is used to calculate the six-degree-of-freedom error between each probe and the motion platform through a correction sheet with a plurality of correction patterns arranged on the motion platform and each probe in the optical probe group, and adjust the posture of the motion platform to a corrected posture corresponding to each probe according to the six-degree-of-freedom error, and store the six-degree-of-freedom coordinate parameters corresponding to the corrected posture.

On the basis of the above-mentioned necessary technical means, an auxiliary technical means derived from the present invention is that the six-degree-of-freedom error between the low-distortion image probe and the motion platform includes a first x-axis translation error, a first y-axis translation error, a first x-axis rotation error, a first y-axis rotation error, a first z-axis rotation error and a first z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a first x-axis translational degree-of-freedom coordinate value, a first y-axis translational degree-of-freedom coordinate value, a first z-axis translational degree-of-freedom coordinate value, a first x-axis rotational degree-of-freedom coordinate value, a first y-axis rotational degree-of-freedom coordinate value and a first z-axis rotational degree-of-freedom coordinate value.

In one embodiment, the six-degree-of-freedom error between the ranging probe and the motion platform includes a second x-axis translation error, a second y-axis translation error, a second x-axis rotation error, a second y-axis rotation error, and a second z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a second x-axis translational degree of freedom coordinate value, a second y-axis translational degree of freedom coordinate value, a second z-axis translational degree of freedom coordinate value, a second x-axis rotational degree of freedom coordinate value, and a second y-axis rotational degree of freedom coordinate value.

In one embodiment, the calibration pattern includes a cross calibration pattern, a checkerboard calibration pattern, a solid circle calibration pattern, and a total reflection surface calibration pattern, wherein the first z-axis rotation error and the third z-axis translation error are calculated through the cross calibration pattern and the corresponding probe; the first x-axis rotation error, the first y-axis rotation error, and the first z-axis focus error are calculated through the checkerboard calibration pattern and the corresponding The first x-axis translation error, the first y-axis translation error, the second x-axis translation error, the second y-axis translation error, the third x-axis translation error and the third y-axis translation error are calculated through the solid circle calibration pattern and the corresponding probe; and the second x-axis rotation error and the second y-axis rotation error are calculated through the total reflection surface calibration pattern and the corresponding probe.

In one embodiment, the optical probe group further includes a light collimating probe, which is arranged adjacent to the low-distortion image probe and the ranging probe, and the six-degree-of-freedom errors between the light collimating probe and the motion platform include a third x-axis translation error, a third y-axis translation error, a third x-axis rotation error, a third y-axis rotation error, a third z-axis rotation error, and a third z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a third x-axis translational degree of freedom coordinate value, a third y-axis translational degree of freedom coordinate value, a third z-axis translational degree of freedom coordinate value, a third x-axis rotational degree of freedom coordinate value, a third y-axis rotational degree of freedom coordinate value, and a third z-axis rotational degree of freedom coordinate value.

In one embodiment, the fourth z-axis focus error is calculated through a checkerboard correction pattern and a corresponding probe; the fourth x-axis translation error and the fourth y-axis translation error are calculated through a solid circle correction pattern and a corresponding probe; and the fourth x-axis rotation error, the fourth y-axis rotation error and the fourth z-axis rotation error are calculated through a total reflection surface correction pattern and a corresponding probe.

In one embodiment, a positioning device is provided, wherein a motion platform is used to carry a correction plate, and a correction module is used to calculate a fourth x-axis translation error, a fourth y-axis translation error, and a fourth z-axis translation error between the correction plate and the motion platform through the correction plate and a low-distortion image probe, and adjust the posture of the motion platform to a corrected posture according to the fourth x-axis translation error, the fourth y-axis translation error, and the fourth z-axis translation error, and store the fourth x-axis translation degree of freedom coordinate value, the fourth y-axis translation degree of freedom coordinate value, and the fourth z-axis translation degree of freedom coordinate value corresponding to the corrected posture.

The present invention is to solve the problems of the prior art and provides a calibration method for the aforementioned six-degree-of-freedom alignment device, comprising the following steps: S111, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the low-distortion image probe and is photographed into an image; S112, the calibration module calculates the six-degree-of-freedom error between the low-distortion image probe and the motion platform according to the calibration pattern in the image; S113, the calibration module adjusts the posture of the motion platform to a calibrated posture corresponding to the low-distortion image probe according to the six-degree-of-freedom error in step S112; S114, the calibration module stores the six-degree-of-freedom error in step S112; The six-axis free coordinate parameters corresponding to the corrected posture in step S113; S115, the correction module moves the motion platform so that the correction pattern of the correction sheet appears within the field of view of the ranging probe and performs sensing to generate sensing information; S116, the correction module calculates the six-degree-of-freedom error between the ranging probe and the motion platform according to the sensing information; S117, the correction module adjusts the posture of the motion platform to the corrected posture corresponding to the ranging probe according to the six-degree-of-freedom error in step S116; and S118, the correction module stores the six-axis free coordinate parameters corresponding to the corrected posture in step S117.

In one embodiment, after step S118, the following steps are further included: S119, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the light collimating probe and captures an image; S120, the calibration module calculates the six-degree-of-freedom error between the light collimating probe and the motion platform according to the calibration pattern in the image; S121, the calibration module adjusts the posture of the motion platform to the calibrated posture corresponding to the light collimating probe according to the six-degree-of-freedom error in step S120; and S122, the calibration module stores the six-axis free coordinate parameters corresponding to the calibrated posture in step S121.

In one embodiment, between step S114 and step S115, the following steps are further included: S114a, the calibration module moves the motion platform so that the calibration pattern of the calibration sheet appears within the field of view of the low-distortion image probe and is photographed into an image; S114b, the calibration module calculates the six-degree-of-freedom error between the calibration sheet and the carrier according to the calibration pattern in the image; S114c, the calibration module adjusts the posture of the motion platform to a calibrated posture according to the six-degree-of-freedom error in step S114b; and S114d, the calibration module stores the six-axis free coordinate parameters corresponding to the calibrated posture in step S114c.

In summary, the six-degree-of-freedom alignment device and its correction method provided by the present invention can automatically calibrate the relative posture between each probe in the optical probe group and the motion platform through the correction module, the correction sheet with multiple correction patterns, and each probe in the optical probe group, so as to correct the relative posture between the two.

The specific implementation of the present invention will be described in more detail below in conjunction with schematic diagrams. The advantages and features of the present invention will become clearer based on the following description and the scope of the patent application. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to conveniently and clearly assist in explaining the embodiments of the present invention.

Please refer to Figure 1 and Figure 2. Figure 1 is a three-dimensional diagram of the six-degree-of-freedom alignment device, motion platform and calibration plate according to the present invention, and Figure 2 is a schematic diagram showing the calibration plate of the present invention. As shown in Figure 1, a six-degree-of-freedom alignment device 100 includes an optical probe set 110 and a calibration module 130.

The optical probe assembly 110 includes a low-distortion imaging probe 111, a distance measuring probe 112, a light collimating probe 113, and a housing 114, wherein the low-distortion imaging probe 111, the distance measuring probe 112, and the light collimating probe 113 are disposed adjacent to each other, and the housing 114 is used to accommodate and fix the low-distortion imaging probe 111, the distance measuring probe 112, and the light collimating probe 113. It should be noted that the relative positions of the low-distortion imaging probe 111, the distance measuring probe 112, and the light collimating probe 113 are merely illustrative and are not limited thereto.

The low-distortion image probe 111 can be used to capture 2D images, the distance measuring probe 112 can be used to measure the energy of a single point, and the light collimating probe 113 can be used to capture 2D images. In this embodiment, the low-distortion image probe 111 can be a face camera with an object telecentric lens or a binocular telecentric lens, the distance measuring probe 112 can be a color confocal probe or an IR interferometric distance measuring probe, and the light collimating probe 113 can be an autocollimator, but the present invention is not limited thereto.

The calibration module 130 is electrically connected to the optical probe assembly 110 and the motion platform 300. The motion platform 300 can be movably disposed within the field of view of each probe 111-113 in the optical probe assembly 110. Specifically, the motion platform 300 can be used to carry an object, and can drive the carried object to perform translation and rotation in at least one degree of freedom among the six degrees of freedom. When the posture of the motion platform 300 is to be calibrated using each probe 111-113 in the optical probe assembly 110, the motion platform 300 must be moved to the field of view of each probe 111-131 in the optical probe assembly 110, respectively, to perform the subsequent calibration process. In this embodiment, the motion platform 300 may be a six-axis motion platform, such as a Hexapod; in other embodiments, the motion platform 300 may also be a two-axis motion platform or a three-axis motion platform, but is not limited thereto. For ease of explanation, the following motion platform 300 will be taken as an example of a six-axis motion platform.

The calibration module 130 is used to calculate the six-degree-of-freedom error between each probe 111-113 and the motion platform 300 through the calibration sheet 200 with multiple calibration patterns disposed on the motion platform 300 and each probe 111-113 in the optical probe set 110, and adjust the posture of the motion platform 300 to the calibrated posture corresponding to each probe 111-113 according to the six-degree-of-freedom error, and store the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture.

Specifically, the calibration module 130 is electrically connected to the low-distortion image probe 111, the distance measuring probe 112, and the light collimating probe 113 of the optical probe set 110, so as to control the movements of the low-distortion image probe 111, the distance measuring probe 112, and the light collimating probe 113, respectively. The calibration module 130 is electrically connected to the motor (not shown) inside the motion platform 300, so as to control the motion platform 300 to perform translation and rotation of at least one of the six degrees of freedom. In this embodiment, the calibration module 130 may be an electronic device with processing, control, and storage functions, such as a computer, but is not limited thereto.

Next, the calibration sheet 200 is described. As shown in FIG. 2 , the calibration pattern of the calibration sheet 200 includes a cross calibration pattern 210, a checkerboard calibration pattern 220, a solid circle calibration pattern 230, and a total reflection surface calibration pattern 240.

Specifically, the center of the cross correction pattern 210 overlaps with the center of the correction sheet 200, and the longitudinal line segments and the transverse line segments of the cross correction pattern 210 extend from the center to divide the correction sheet 200 into an upper left area AUL, a lower left area ALL, an upper right area AUR, and a lower right area ALR. The checkerboard correction pattern 220 is disposed in the upper left area AUL of the correction sheet 200, wherein the checkerboard correction pattern 200 includes a first square pattern 221 and a second square pattern 222, and the two are arranged in a checkerboard shape, and the reflectivity of the two differs by at least ten times. The solid circle correction pattern 230 is disposed in the lower right area ALR of the correction sheet 200, wherein the solid circle correction pattern 230 includes an outer circle pattern 231 and a solid circle pattern 232, wherein the outer circle pattern 231 surrounds the solid circle pattern 232, and the reflectivity of the two differs by at least ten times. The total reflection surface correction pattern 240 can be the lower left area ALL or the upper right area AUR of the correction sheet 200, wherein the reflectivity of the total reflection surface correction pattern 240 is close to 100%.

In this embodiment, the calibration sheet 200 may be a quartz mask sheet, and each calibration pattern 210-240 on the calibration sheet 200 is formed by a reflective material coated on the quartz mask sheet. Specifically, the portion coated with the reflective material may be defined as a light reflection area that reflects most of the incident light, such as the total reflection surface calibration pattern 240 of the calibration sheet 200, the second square pattern 222 of the checkerboard calibration pattern 200, the solid circle pattern 232 of the solid circle calibration pattern 230, and the total reflection surface calibration pattern 240; and the portion not coated with the reflective material may be defined as a light transmission area that transmits most of the incident light, such as the cross calibration pattern 210, the first square pattern 221 of the checkerboard calibration pattern 200, and the outer circle pattern 231 of the solid circle calibration pattern 230. For ease of explanation and understanding, the portion coated with the reflective material is indicated in gray, and the portion not coated with the reflective material is indicated in white.

It should be noted that the configuration (including quantity and position) of the cross correction pattern 210, checkerboard correction pattern 220, solid circle correction pattern 230 and total reflection surface correction pattern 240 of the correction sheet 200 will be designed differently according to different correction requirements and is not limited to the configuration shown in FIG. 2 .

After explaining the six-degree-of-freedom alignment device 100, the correction plate 200 and the motion platform 300 of the present invention, it can be further explained how to calibrate the six-degree-of-freedom alignment device 100 through the correction plate 200, especially to calibrate the relative posture between each probe 111~131 in the optical probe group 110 and the motion platform 300, so as to calibrate the relative posture between the two to be correct.

The method for calibrating the relative posture between each probe 111~131 in the optical probe group 110 and the motion platform 300 is generally to first calculate the six-degree-of-freedom error between each probe 111~131 in the optical probe group 110 and the motion platform 300 through the correction sheet 200, and then adjust the posture of the motion platform 300 to the posture corresponding to each probe 111~113 after compensating the six-degree-of-freedom error. Finally, the six-degree-of-freedom coordinate parameters of the corresponding posture are stored to complete the calibration.

Please refer to Figure 1 and Figures 3A to 3C. Figures 3A to 3C are flowcharts showing the calibration method of the present invention. In order to facilitate the description of the relative relationship between the six-degree-of-freedom alignment device 100, the calibration sheet 200 and the motion platform 300, the concept of six degrees of freedom needs to be introduced. The six degrees of freedom refer to the degrees of freedom of an object moving in three-dimensional space. Taking the three-dimensional Cartesian coordinate system shown in Figure 1 as an example, it includes the degree of freedom x for translation in the x-axis direction (abbreviated as the x-axis translational degree of freedom), the degree of freedom y for translation in the y-axis direction (abbreviated as the y-axis translational degree of freedom), the degree of freedom z for translation in the z-axis direction (abbreviated as the z-axis translational degree of freedom), the degree of freedom θx for rotation around the x-axis (abbreviated as the x-axis rotational degree of freedom), the degree of freedom θy for rotation around the y-axis (abbreviated as the y-axis rotational degree of freedom), and the degree of freedom θz for rotation around the z-axis (abbreviated as the z-axis rotational degree of freedom).

Thus, in the space shown in FIG. 1 , the postures of the optical probe assembly 110, the correction plate 200 and the motion platform 300 of the six-degree-of-freedom alignment device 100 can be defined by six degrees of freedom and expressed by coordinates. Taking the motion platform 300 as an example, its six-degree-of-freedom coordinate parameters include x-axis translational freedom x ₀ , y-axis translational freedom y ₀ , z-axis translational freedom z ₀ , x-axis rotational freedom θx ₀ , y-axis rotational freedom θy ₀ and z-axis rotational freedom θz ₀ , and the corresponding posture can be expressed as coordinates (x ₀ , y ₀ , z ₀ , θx ₀ , θy ₀ , θz _{0 ). For ease of explanation and understanding, the initial posture of the motion platform is set to (0, 0, 0, 0, 0, 0} ) below.

Returning to FIG. 3A and FIG. 3B , it is a calibration method for the six-degree-of-freedom alignment device 100, including steps S111 to S122, wherein steps S111 to S114 are calibrations of the relative posture between the low-distortion imaging probe 111 and the motion platform 300, steps S115 to S118 are calibrations of the relative posture between the ranging probe 112 and the motion platform 300, and steps S119 to S122 are calibrations of the relative posture between the light collimation probe 113 and the motion platform 300. It should be particularly noted that, when performing the aforementioned calibration, in order to calibrate the relative postures between the low-distortion image probe 111, the distance measuring probe 112, and the light collimating probe 113 and the motion platform 300 to be correct, the method may be to adjust the posture of at least one of the low-distortion image probe 111, the distance measuring probe 112, the light collimating probe 113, and the motion platform 300. For ease of explanation, in this embodiment, the postures of the low-distortion image probe 111, the distance measuring probe 112, and the light collimating probe 113 and the motion platform 300 will not be changed, but the posture of the motion platform 300 is adjusted.

The following refers to steps S111 to S114 to illustrate the calibration of the relative posture between the low-distortion image probe 111 and the motion platform 300.

First, the correction of the x-axis translational degree of freedom and the y-axis translational degree of freedom in the posture of the motion platform 300 relative to the low-distortion image probe 111 is described.

In step S111, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the low-distortion image probe and is captured as an image. Please also refer to FIG. 1 and FIG. 4, FIG. 4 is a schematic diagram showing an image including a solid circle calibration pattern captured by the low-distortion image probe of the present invention. Specifically, as shown in FIG. 1 and FIG. 4, the calibration module 130 moves the motion platform 300 so that the solid circle calibration pattern 230 of the calibration film 200 appears within the field of view of the low-distortion image probe 111, and the calibration module 130 then controls the low-distortion image probe 111 to capture and generate an image IM including the solid circle calibration pattern 230.

In step S112, the calibration module calculates the six-degree-of-freedom error between the low-distortion image probe and the motion platform according to the solid circle calibration pattern in the image. Specifically, as shown in FIG. 4, the calibration module 130 identifies the position of the center C1 of the solid circle pattern 232 of the solid circle calibration pattern 230 through image recognition technology; and then calculates the error between the position of the center C1 and the position of the field of view center CF of the low-distortion image probe 111 in the image IM in the x-axis direction and the y-axis direction through image processing technology, that is, the error in the x-axis direction is the first x-axis translation error ∆x ₁ , and the error in the y-axis direction is the first y-axis translation error ∆y ₁ .

In step S113, the calibration module adjusts the posture of the motion platform to a calibrated posture corresponding to the low-distortion image probe according to the six-degree-of-freedom error of step S112. Specifically, the calibration module 130 can adjust the posture of the motion platform 300 from the initial posture (0,0,0,0,0,0,0) to a calibrated posture (x ₁ ,y ₁ ,0,0,0,0) corresponding to the low-distortion image probe 111 according to the first x-axis translation error ∆x ₁ and the first y- _axis translation error ∆y 1. At this time, within the field of view of the low-distortion image probe 111, the center C1 of the solid circle pattern 232 of the solid circle calibration pattern 230 will overlap with the field of view center CF of the low-distortion image probe 111.

In step S114, the correction module 130 stores _the six-degree-of-freedom coordinate parameters corresponding to the posture in step S113. Specifically, the correction module 130 stores the first x-axis translational degree-of-freedom coordinate value _x1 and the first y-axis translational degree-of-freedom coordinate value _y1 in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture ( _x1 , y1, 0,0,0,0).

Thereby, the x-axis translational freedom and the y-axis translational freedom of the motion platform 300 are calibrated relative to the low-distortion image probe 111 .

Next, the correction of the x-axis rotational freedom, the y-axis rotational freedom, and the z-axis translational freedom in the posture of the motion platform 300 relative to the low-distortion image probe 111 is described.

Returning to step S111, please refer to FIG. 1, FIG. 5A and FIG. 5B simultaneously. FIG. 5A is a schematic diagram showing an image including a checkerboard correction pattern captured by the low-distortion image probe of the present invention, and FIG. 5B is a schematic diagram showing the spatial frequency response (Spatial Frequency Response, SFR) of the four corner areas and the middle area of the image including the checkerboard correction pattern during height scanning of the present invention.

Specifically, the correction module 130 first moves the motion platform 300 so that the checkerboard correction pattern 220 of the correction film 200 appears within the field of view of the low-distortion image probe 111; then, the correction module 130 controls the motion platform 300 to drive the checkerboard correction pattern 220 to move along the z-axis direction, and at the same time, the correction module 130 controls the low-distortion image probe 110 to continuously shoot multiple images IM of the checkerboard correction pattern 220 of the correction film 200 at different z values, one of which is shown in Figure 5A.

Referring to step S112, specifically, the correction module 130 can calculate the spatial frequency response values (hereinafter referred to as SFR values) of the first area A1, the second area A2, the fourth area A3, the third area A4 and the middle area A5 of the checkerboard correction pattern 220 at different z values, and respectively generate the corresponding spatial frequency response graphs shown in FIG. 5B, wherein the horizontal axis represents the z value and the vertical axis represents the SFR value. It should be particularly noted that the SFR value is proportional to the image clarity, that is, when the SFR value is the largest, the image clarity is the highest, indicating that the corresponding area of the checkerboard correction pattern 220 at this time is located at the focal plane of the low-distortion image probe 111.

As shown in Figure 5B, the spatial frequency response diagrams of the first area A1, the second area A2, the third area A3, the fourth area A4 and the fifth area A5 are located at the upper left corner, the lower left corner, the upper right corner, the lower right corner and the middle, respectively. From the aforementioned spatial frequency response diagrams, it can be seen that the first area A1, the second area A2, the third area A3, the fourth area A4 and the fifth area A5 have the largest SFR value when the z value is the first focus height Z1, the second focus height Z2, the third focus height Z3, the fourth focus height Z4 and the fifth focus height Z5, respectively.

The first x-axis rotation error △θ x ₁ and the first y-axis rotation error △θ y ₁ can be further calculated through the first focusing height Z1, the second focusing height Z2, the third focusing height Z3 and the fourth focusing height Z4, and the first z-axis focusing error can be further calculated through the first focusing height Z5. The specific calculation method is as follows:

First, the calculation of the first x-axis rotation error △θ x ₁ and the first y-axis rotation error ∆θ y ₁ is explained.

When the first focus height Z1, the second focus height Z2, the third focus height Z3 and the fourth focus height Z4 are equal, the calibration sheet 200 having the checkerboard calibration pattern 220 is not tilted relative to the low-distortion image probe 110; when the first focus height Z1, the second focus height Z2, the third focus height Z3 and the fourth focus height Z4 are different, the calibration sheet 200 having the checkerboard calibration pattern 220 is tilted relative to the low-distortion image probe 110. At this time, the checkerboard calibration pattern 220 can be used in combination with trigonometric function formulas to calculate the tilt error between the motion platform 300 carrying the calibration sheet 200 and the low-distortion image probe 110 on the xy plane, including the first x-axis rotation error ∆θx ₁ and the first y-axis rotation error ∆θy ₁ .

Furthermore, the schematic diagram of the first x-axis rotation error ∆θx ₁ is located in the middle of the spatial frequency response diagram of the first area A1 and the spatial frequency response diagram of the third area A3 in FIG. 5B. When the first focus height Z1 corresponding to the first area A1 and the third focus height Z3 corresponding to the third area A3 are different, the first x-axis rotation error ∆θx ₁ can be calculated by using the difference between the two (i.e., Z3-Z1) and the distance W1 between the first area A1 and the third area A3 in combination with the trigonometric function formula.

Similarly, the schematic diagram of the first y-axis rotation error ∆θy ₁ is located in the middle of the spatial frequency response diagram of the first area A1 and the spatial frequency response diagram of the second area A2 in Figure 5B. When the first focus height Z1 corresponding to the first area A1 and the second focus height Z2 corresponding to the second area A2 are different, the first y-axis rotation error ∆θy ₁ can be calculated by using the difference (Z2-Z1) between the two and the distance W2 between the first area A1 and the second area A2 in combination with trigonometric formulas.

Next, the calculation of the first z-axis focus error ∆z ₁ is explained.

Please refer to the spatial frequency diagram of the middle area A5 in FIG. 5B again. The initial z value of the middle area A5 is the initial height Z0, and the corresponding SFR value is not the maximum, indicating that the middle area A5 at the initial height Z0 is not located in the focal plane of the low-distortion imaging probe 111. As the Z value of the middle area A5 is moved from the initial height Z0 to the fifth focusing height Z5, the corresponding SFR value is the maximum, indicating that the middle area A5 at the fifth focusing height Z5 is located in the focal plane of the low-distortion imaging probe 111, which is also the desired correction result. Therefore, the difference between the initial height Z0 and the fifth focusing height Z5 can be used to calculate the first z-axis focusing error ∆z ₁ .

Thereby, the first x-axis rotation error ∆θx ₁ , the first y-axis rotation error ∆θy ₁ , and the first z-axis focus error ∆z ₁ are all calculated.

Referring to step S113, specifically, the calibration module 130 may adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x 1 , y ₁ , 0, 0 _{, 0} ) to the calibrated posture (x ₁ , y ₁ , z 1 , θx ₁ , θy ₁ , 0) corresponding to the low-distortion image probe 111 according to the first x-axis rotation error ∆θx ₁ , the first y- _axis rotation error ∆θy ₁ , and the first z-axis focus error ∆z 1. At this time, the plane of the calibration sheet 200 will overlap with the focal plane of the low-distortion image probe 111.

Referring to step S114, specifically, the correction module 130 stores _the first x-axis rotational degree of freedom coordinate value θx1 _, the first y-axis rotational degree of freedom coordinate value _θy1 , and the first z-axis translational degree of freedom coordinate value z1 in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture ( _x1 , _y1 , _z1 , θx1, _θy1 , ₀₎ .

Thereby, the correction of the x-axis rotational freedom, the y-axis rotational freedom and the z-axis translational freedom in the posture of the motion platform 300 is completed relative to the low-distortion image probe 111.

Finally, the correction of the z-axis rotational degree of freedom in the posture of the motion platform 300 relative to the low-distortion image probe 111 is described.

Returning to step S111, please refer to FIG. 1 and FIG. 6 at the same time. FIG. 6 is a schematic diagram showing three images containing cross correction patterns at different positions taken by the low-distortion imaging probe of the present invention.

Specifically, as shown in FIG. 6 , the calibration module 130 moves the motion platform 300 so that the cross calibration pattern 210 of the calibration film 200 appears within the field of view of the low-distortion image probe 111; then, the calibration module 130 controls the motion platform 300 so that the cross calibration pattern 210 is first located at the first position L1 within the field of view, then moves along the positive direction of the positive y-axis to the second position L2, and finally moves along the negative direction of the x-axis to the third position L3. When the cross calibration pattern 210 is located at the first position L1, the second position L2, and the third position L3, the calibration module 130 controls the low-distortion image probe 111 to capture it as images IM1, IM2, and IM3, respectively.

Referring to step S112, specifically, the correction module 130 can calculate the first z-axis rotation error ∆θz 1 according to the difference in x-coordinates, y-coordinates and the distance between the cross correction pattern 210 of the image IM1 and the cross correction pattern 210 of the image IM2, and according to the difference in x-coordinates, y-coordinates and the distance between the cross correction pattern 210 of the image IM2 and the cross correction pattern ₂₁₀ of the image IM3.

Referring to step S113, specifically, the calibration module 130 may adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₁ , y ₁ , z ₁ , θx ₁ , θy ₁ , 0) to the calibrated posture (x ₁ , y ₁ , z ₁ , θx ₁ , θy ₁ , θz ₁ ) corresponding to the low-distortion image probe 111 according to the first z-axis rotation error ∆θz _1. At this time, the x/y axis of the motion platform 300 is parallel to the x/y axis of the low-distortion image probe 111.

Referring to step S114, specifically, the calibration module 130 stores the first z-axis rotational degree _of freedom coordinate value θz ₁ among the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture (x ₁ , y ₁ , z 1 , θx ₁ , θy ₁ , θz ₁ ).

Thereby, the z-axis rotational freedom of the motion platform 300 is corrected relative to the low-distortion image probe 111 .

From the above, it can be seen that through the calibration of the low-distortion image probe 111 and the calibration pattern on the calibration sheet 200, the posture of the motion platform 300 has been adjusted from the initial posture (0,0,0,0,0,0) to the calibrated posture (x ₁ ,y ₁ ,z ₁ ,θx ₁ ,θy ₁ ,θz ₁ ), thereby completing the calibration between the low-distortion image probe 111 and the motion platform 300.

The following refers to steps S115 to S118 to illustrate the calibration of the relative posture between the low-distortion image probe 111 and the motion platform 300.

First, the correction of the x-axis rotational degree of freedom and the y-axis rotational degree of freedom in the posture of the motion platform 300 relative to the ranging probe 112 is described.

In step S115, the calibration module moves the motion platform so that the calibration pattern of the calibration sheet appears within the field of view of the ranging probe and performs sensing to generate sensing information. Please refer to FIG. 1, FIG. 7A and FIG. 7B at the same time. FIG. 7A is a schematic diagram showing the posture of the motion platform and the calibration sheet of the present invention after sensing along the x-axis direction by the ranging probe, and FIG. 7B is a schematic diagram showing the posture of the motion platform and the calibration sheet of the present invention after sensing along the y-axis direction by the ranging probe.

Specifically, the calibration module 130 first moves the motion platform 300 so that the total reflection surface calibration pattern 240 of the calibration sheet 200 appears within the field of view of the ranging probe 112; then, the calibration module 130 controls the motion platform 300 to drive the total reflection surface calibration pattern 240 to move along the y-axis direction, and at the same time, the ranging probe 112 senses the first point P1 and the second point P2 of the total reflection surface calibration pattern 240, thereby obtaining sensing information of the first point P1 and the second point P2, respectively, wherein the sensing information of the first point P1 is the coordinate (y ₂₁ , z ₂₁ ), and the sensing information of the second point P2 is the coordinate (y ₂₂ , z ₂₂ ).

Next, the correction module 130 controls the motion platform 300 to drive the total reflection surface correction pattern 240 to move along the x-axis direction. At the same time, the ranging probe 112 senses the third point P3 and the fourth point P4 of the total reflection surface correction pattern 240, thereby obtaining the sensing information of the third point P3 and the fourth point P4 respectively, wherein the sensing information of the third point P3 is the coordinates (x ₂₃ , z ₂₃ ), and the sensing information of the fourth point P4 is the coordinates (x ₂₄ , z ₂₄ ).

In step S116, the calibration module calculates the six-degree-of-freedom error between the ranging probe and the motion platform according to the sensing information. Specifically, the calibration module 130 can calculate the second x-axis rotation error ∆θx 2 between the motion platform 300 and the ranging probe 112 according to the coordinates (y ₂₁ , z ₂₁ ) of the first point P1 and the coordinates (y ₂₂ , z ₂₂ ) of the second point P2 in combination with trigonometric formulas. In addition, the calibration module 130 can calculate the second y-axis rotation error ∆θy ₂ between the motion platform 300 and the ranging probe 112 according to the coordinates (x ₂₃ , z ₂₃ ) of the third point P3 and the coordinates (x ₂₄ , z ₂₄ ) of the fourth point _P4 in combination with trigonometric formulas.

In step S117, the calibration module adjusts the posture of the motion platform to the calibrated posture corresponding to the ranging probe according to the six-degree-of-freedom error in step S116. Specifically, the calibration module 130 can adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₁ , y ₁ , z ₁ , θx ₁ , θy ₁ , _{θz 1} ) to the calibrated posture (x ₁ , y ₁ , z ₁ , θx ₂ , θy ₂ , θz 1 ) corresponding to the ranging probe 112 according to the second x-axis rotation error ∆θx ₂ and the second y-axis rotation error ∆θy _2. At this time, the plane of the calibration sheet 200 is parallel to the xy plane of the ranging probe 112.

In step S118, the correction module 130 stores the six- _axis free coordinate parameters corresponding to the corrected posture in step S117. Specifically, the correction module 130 stores the second x _- axis rotational degree of freedom coordinate value _θx2 and the second y-axis rotational degree of freedom coordinate value _θy2 in the six-degree-of-freedom coordinate parameters _{corresponding} to the corrected posture ( _x1 , _y1 , z1, θx2, θy2, _θz1 ).

Thereby, the correction of the x-axis rotational degree of freedom and the y-axis rotational degree of freedom in the posture of the motion platform 300 relative to the ranging probe 112 is completed.

Next, the correction of the z-axis translational degree of freedom in the posture of the motion platform 300 relative to the ranging probe 112 is described.

Returning to step S115, please also refer to FIG. 8, which is a schematic diagram showing the use of a ranging probe to find the second z-axis focusing error of the present invention.

Specifically, as shown in FIG. 8 , since the working point of the ranging probe 112 is the fifth point P5, the sensing information of the fifth point P5 in the z-axis direction is known, that is, the coordinate is (z ₂₅ ); then, the calibration module 130 controls the ranging probe 112 to sense the sixth point P6 of the total reflection surface calibration pattern 240, and thereby obtains the sensing information of the sixth point P6 in the z-axis direction, that is, the coordinate is (z ₂₆ ).

Referring to step S116, specifically, the calibration module 130 may subtract the coordinates (z ₂₅ ) of the fifth point P5 from the coordinates (z ₂₆ ) of the sixth point P6 to calculate the second z-axis focusing error ∆z ₂ between the ranging probes 112 of the motion platform 300 in the z-axis direction.

Referring to step S117, specifically, the calibration module 130 may adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₁ , y ₁ , z ₁ , θx ₁ , θy ₁ , θz ₁ ) to the calibrated posture (x ₁ , y ₁ , z ₂ , θx ₂ , θy ₂ , θz ₁ ) corresponding to the ranging probe 112 according to the second z-axis focus error ∆z2. At this time, the plane of the calibration sheet 200 overlaps with the focal plane of the ranging probe 112.

Referring to step S118, the calibration module 130 stores the second z-axis translational degree of freedom coordinate value z ₂ in the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture ( _{x 1} , y ₁ , z 2 , θx ₂ , θy ₂ , θz ₁ ).

Thereby, the z-axis translational degree of freedom of the motion platform 300 relative to the ranging probe 112 is corrected.

Next, the correction of the x-axis translational degree of freedom and the y-axis translational degree of freedom in the posture of the motion platform 300 relative to the ranging probe 112 is described.

Returning to step S115, please also refer to FIG. 9, which is a schematic diagram showing the use of the ranging probe and the solid circle correction pattern of the present invention to find the second x-axis translation error and the second y-axis translation error.

Specifically, the calibration module 130 first moves the motion platform 300 so that the measuring point of the ranging probe 112 scans from the first starting point B10 along the first straight line scanning path SPL1 in the same direction as the x-axis, and then scans from the second starting point B20 along the second straight line scanning path SPL2 in the opposite direction of the x-axis, and finally scans from the third starting point B30 along the third straight line scanning path SPL3 in the same direction as the x-axis.

During the scanning process, the ranging probe 112 is set to collect only the reflected light signal from the lower surface of the calibration sheet 200. Therefore, the reflected light signals collected by the ranging probe 112 under the first linear scanning path SPL1, the second linear scanning path SPL2, and the third linear scanning path SPL3f can correspond to the first signal intensity graph G1, the second signal intensity graph G2, and the third signal intensity graph G3. In addition, the measurement point positions of the ranging probe 112 are roughly divided into two types, namely, in the outer circle pattern 231 of the solid circle calibration pattern 230, and in the solid circle pattern 232 of the solid circle calibration pattern 230.

When the measuring point of the distance measuring probe 112 is located in the outer circle pattern 231 of the solid circle calibration pattern 230, since the outer circle pattern 231 is a portion of the calibration plate 200 that is not coated with a reflective material, most of the incident light can penetrate the upper and lower surfaces of the calibration plate 200 corresponding to the position of the outer circle pattern 231, and generate a small portion of reflected light signals on the upper and lower surfaces. Therefore, the distance measuring probe 112 will collect the reflected light signals generated by the lower surface of the calibration plate 200.

When the measuring point of the distance measuring probe 112 is located in the solid circle pattern 232 of the solid circle calibration pattern 230, since the solid circle pattern 232 belongs to the portion of the calibration plate 200 coated with a reflective material, most of the incident light will be reflected on the upper surface of the calibration plate 200 corresponding to the position of the solid circle pattern 232 and cannot penetrate to the lower surface, which also means that there is no reflected light signal on the lower surface of the calibration plate 200. Therefore, the distance measuring probe 112 does not collect the reflected light signal.

The operation details of the first straight scanning path SPL1, the second straight scanning path SPL2 and the third straight scanning path SPL3 are further described. In the first straight scanning path SPL1, the measuring point of the ranging probe 112 scans from the first starting point B10 along the first straight scanning path SPL1 and passes through the first intersection point B11.

The above scanning process can be divided into two stages according to the position of the measuring point of the ranging probe 112, namely, the first stage from the first starting point B10 to the first intersection point B11, and the second stage after the first intersection point B11. In the first stage from the first starting point B10 to the first intersection point B11, since the ranging probe 112 collects the reflected light signal generated by the lower surface of the calibration plate 200, the signal intensity of the reflected light signal collected by the ranging probe 112 at this time is the first signal intensity I1. After the first intersection point B11 of the second stage, the ranging probe 112 does not collect the reflected light signal, so the signal intensity of the reflected light signal collected by the ranging probe 112 at this time will gradually become zero.

Similarly, the operation details of the second linear scanning path SPL2 and the third linear scanning path SPL3 are similar to the operation details of the first linear scanning path SPL1, so they are not further described.

Referring to step S116, specifically, the calibration module 130 can draw a first signal strength map G1, a second signal strength map G2, and a third signal strength map G3 respectively according to the sensing information obtained from the first linear scanning path SPL1, the second linear scanning path SPL2, and the third linear scanning path SPL3, and then calculate the three coordinates of the first intersection point B11, the second intersection point B21, and the third point B31 on the xy plane respectively through the first distance D1, the second distance D2, and the third distance D3 of the first signal strength map G1, the second signal strength map G2, and the third signal strength map G3, and then calculate the coordinates of the center C1 of the solid circle pattern 232.

In detail, the calculation method of the coordinates of the first junction point B11 is first explained. From the first signal strength graph G1, it can be known that the position of the first starting point B10 in the x-axis direction can correspond to the x-coordinate value of the origin O of the first signal strength graph G1, and the position of the first junction point B11 in the x-axis direction can correspond to the x-coordinate value of the turning point TP of the first signal strength graph G1. When the coordinates of the first starting point B10 are known, by observing the first signal strength G1, it can be known that the distance difference between the turning point TP and the origin O in the x-axis direction is the first distance D1, and then the coordinates of the first junction point B11 can be calculated.

Then, the measuring point of the ranging probe 112 moves from the first junction point B11 to the second starting point B20. During the process, the position information of the ranging probe 112 is recorded. At this time, the coordinates of the second starting point B20 can be calculated by combining the known coordinates of the first junction point B11. The coordinates of the second junction point B21 can be calculated based on the coordinates of the second starting point B20. The calculation method can refer to the calculation method of the first junction point B11, which will not be described in detail here.

Finally, the measuring point of the ranging probe 112 moves from the second junction point B21 to the third starting point B30. During the process, the sensing position information of the ranging probe 112 is recorded. At this time, the coordinates of the third starting point B30 can be calculated by combining the known coordinates of the second junction point B21. The third junction point B31 can be calculated based on the coordinates of the third starting point B30. The calculation method can refer to the calculation method of the first junction point B11, which will not be described in detail here.

After the coordinates of the first intersection point B11, the second intersection point B21 and the third point B31 on the xy plane are calculated, the coordinates of the center C1 of the solid circle pattern 232 can be further calculated. Therefore, the calibration module 130 can calculate the second x-axis translation error ∆x ₂ and the second y-axis translation error ∆y ₂ between the motion platform 300 and the ranging probe 112 according to the coordinates of the center C1 of the solid circle pattern 232.

Referring to step S117, the calibration module 130 may adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₁ , y ₁ , z ₂ , θx ₂ , θy ₂ , θz ₁ ) to the calibrated posture (x ₂ , y ₂ , z 2 , θx 2 , θy ₂ , θz ₁ ) corresponding to the ranging probe 112 according to the second x-axis translation error ∆x ₂ and _the second y-axis translation error _{∆y 2.} At this time, the measurement point of the ranging probe 112 overlaps with the center C1 of the solid circle pattern 232 of the solid circle calibration pattern 230.

Referring to step S118, the calibration module 130 stores _the second x-axis _{translational degree} of freedom coordinate value _x2 and the second y-axis translational degree of freedom coordinate value _y2 in the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture ( _x2 , y2, z2, _θx2 , θy2, _θz1 ).

Thereby, the x-axis translational freedom and the y-axis translational freedom of the posture of the motion platform 300 relative to the ranging probe 112 are calibrated.

From the above, it can be seen that through the calibration of the ranging probe 112 and the calibration pattern on the calibration sheet 200, the posture of the motion platform 300 has been adjusted from the aforementioned calibrated posture (x ₁ , y ₁ , z1, θx ₁ , θy ₁ , θz ₁ ) to the calibrated posture (x ₂ , y ₂ , z ₂ , θx ₂ , θy ₂ , θz ₁ ), thereby completing the calibration between the ranging probe 112 and the motion platform 300.

The following refers to steps S119 to S122 to illustrate the calibration of the relative posture between the light collimating probe 113 and the motion platform 300.

First, the calibration of the x-axis rotational degree of freedom and the y-axis rotational degree of freedom in the posture of the motion platform 300 relative to the light collimation probe 113 is described.

In step S119, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the light collimation probe and is photographed as an image. Please also refer to FIG. 1 and FIG. 10, which is a schematic diagram showing an image including a cross camera target pattern and a cross light source target pattern photographed by the light collimation probe of the present invention.

Specifically, as shown in FIG. 10 , the correction module 130 moves the motion platform 300 so that the total reflection surface correction pattern 240 of the correction plate 200 appears within the field of view of the light collimating probe 113; then, the correction module 130 controls the light collimating probe 113 to project a cross light source target onto the total reflection surface correction pattern 240, and the light collimating probe 113 captures an image IM, wherein the image IM includes a cross camera target correction pattern PA1 marked by the light collimating probe 113, and a cross light source target correction pattern PA2 that reflects a cross light source from the total reflection surface correction pattern 240.

In step S120, the calibration module calculates the six-degree-of-freedom error between the light collimating probe and the motion platform according to the calibration pattern in the image.

Specifically, the calibration module 130 can calculate the third x-axis rotation error ∆θx ₃ and the third y-axis rotation error ∆θy ₃ between the optical collimation probe 113 and the motion platform 300 according to the cross camera target calibration pattern PA1 and the cross light source target calibration pattern PA2 in the image IM. Specifically, when the light collimating probe 113 is tilted relative to the motion platform 300 on the xy plane, the cross light source target calibration pattern PA2 in the image IM does not overlap with the cross camera target calibration pattern PA1, but has an x-axis direction error Δx ₃₀ and a y-axis direction error Δy ₃₀ in the x-axis direction and the y-axis direction respectively with the cross camera target calibration pattern PA1; in addition, since the x-axis direction error Δx ₃₀ and the y-axis direction error Δy ₃₀ have a corresponding relationship with the rotation error, the third x-axis rotation error Δθ _x3 and the third y-axis rotation error Δθy ₃ can be calculated through the x-axis direction error Δx ₃₀ and the y-axis direction error Δy ₃₀ . .

In step S121, the calibration module adjusts the posture of the _motion platform to the calibrated posture corresponding to the optical collimation probe according to the six-degree-of-freedom error of step S120. Specifically, the calibration module 130 can adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₂ , y 2 , z ₂ , θx ₂ , θy ₂ , θz ₁ ) to the calibrated posture (x ₂ , y ₂ , z ₂ , θx ₃ , θy ₃ , θz ₁ ) corresponding to the optical collimation probe 113 according to the third x-axis rotation error _∆θx 3 and the third y-axis rotation error ∆θy _3. At this time, the plane of the calibration sheet 200 is perpendicular to the optical axis of the optical collimation probe 113.

In step S122, the correction module stores the six-axis free coordinate parameters corresponding to the corrected posture in step S121. Specifically, the correction module 130 stores the third x _- axis rotational degree of freedom coordinate value θx ₃ and the third y-axis rotational degree _of freedom coordinate value θy ₃ in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture ( _{x 2} , y ₂ , z 2 , θx 3 , θy ₃ , θz ₁ ).

Thereby, the x-axis rotational freedom and the y-axis rotational freedom of the motion platform 300 are calibrated relative to the light collimation probe 113 .

Next, the correction of the z-axis rotational freedom in the posture of the motion platform 300 relative to the light collimation probe 113 is described.

Returning to step 119, please refer to FIG. 1 and FIG. 11 at the same time. FIG. 11 is a schematic diagram showing three images taken by the light collimation probe of the present invention, which include cross light source target calibration patterns at different positions.

Specifically, as shown in FIG. 11 , the calibration module 130 moves the motion platform 300 so that the total reflection surface calibration pattern 240 of the calibration plate 200 appears within the field of view of the light collimating probe 113; then, the calibration module 130 controls the light collimating probe 113 to project a cross light source target onto the total reflection surface calibration pattern 240, so that the cross light source target calibration pattern PA2 also appears within the field of view of the light collimating probe 113 and moves. First, the cross light source target calibration pattern PA2 is located at the first position L1, then the calibration plate 200 is controlled to rotate around the x-axis so that the cross light source target calibration pattern PA2 moves to the second position L2, and then the calibration plate 200 is controlled to rotate around the y-axis so that the cross light source target calibration pattern PA2 moves to the third position L3.

When the cross light source target calibration pattern PA2 is located at the first position L1, the second position L2 and the third position L3 respectively, the calibration module 130 controls the low-distortion image probe 111 to capture it into images IM1, IM2 and IM3 respectively.

Referring to step S120, specifically, the calibration module 130 may calculate the third z-axis rotation error ∆θz 3 according to the difference in x-coordinates, the difference in y-coordinates, and the distance between the cross light source target calibration pattern PA2 of the image IM1 and the cross light source target calibration pattern PA2 of the image IM2, and according to the difference in x-coordinates, the difference in y-coordinates, and the distance between the cross light source target calibration pattern PA2 of the image IM2 and the cross calibration pattern ₂₁₀ of the image IM3.

Referring to step S121, specifically, the calibration module ₁₃₀ may adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x _{2 , y 2 , z 2 , θx 3 , θy 3 , θz 1 ) to the calibrated posture (x 2 , y 2 , z 2 , θx 3 , θy 3 , θz 3 ) corresponding} to the light collimation probe 113 according to the third z-axis rotation error ∆θz 3. At this time, the x/y axis of the motion platform 300 is parallel to the x/y axis of the light collimation probe 113.

Referring to step S122, specifically, the calibration module 130 stores the third x-axis rotational degree of freedom coordinate value θz ₃ of the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture (x ₂ , y ₂ , z ₂ , θx ₃ , θy ₃ , θz ₃ ).

Thereby, the z-axis rotational freedom of the motion platform 300 relative to the light collimation probe 113 is corrected.

Next, the correction of the z-axis translational freedom, the x-axis translational freedom, and the y-axis translational freedom in the posture of the motion platform 300 is explained relative to the light collimating probe 113. It should be particularly noted that the correction principle and execution method of the z-axis translational freedom, the x-axis translational freedom, and the y-axis translational freedom in the posture of the motion platform 300 are substantially the same for the light collimating probe 113 and the low-distortion imaging probe 111, the only difference being that the light collimating probe 113 needs to be equipped with an objective lens so that the checkerboard calibration pattern 220 can be imaged.

In other words, after the objective lens is installed on the light collimating probe 113, the correction principle and execution method of the z-axis translational freedom in the posture of the motion platform 300 are exactly the same as those of the low-distortion imaging probe 111, so the calculation details are not elaborated separately.

Thus, through steps S119 to S122, the calibration module 130 can calculate the third z-axis translation error ∆z ₃ , the third x-axis translation error ∆x ₃ , and the third y-axis translation error ∆y ₃ between the light collimating probe 113 and the motion platform 300 .

Next, the posture of the motion platform 300 is adjusted from the aforementioned calibrated posture (x ₂ , y ₂ , z 2 , θx 3 , θy ₃ , θz ₃ ) to the calibrated posture (x ₃ , y 3 , z ₃ , θx ₃ , θy ₃ , θz ₃ ) corresponding to the low-distortion probe 113 according to the third z-axis translation error ∆z _{3 , the third x-axis translation error ∆x 3 , and the third y-axis translation error ∆y 3 . At this time ,} the plane of the calibration sheet 200 overlaps with the focal plane of the light collimating probe 113 mounted with the objective lens, and the center of the camera target pattern of the light collimating probe 113 overlaps with the center C1 of the solid circle calibration pattern 232 .

Finally, the correction module 130 stores the third _z -axis translational degree of freedom coordinate value z3 _{, the} third x-axis translational degree of freedom coordinate value x3, and the third y-axis translational degree of freedom coordinate value _y3 in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture ( _x3 , _y3 , _z3 , θx3, θy3, _θz3 ).

Thereby, the z-axis translational freedom, the x-axis translational freedom, and the y-axis translational freedom of the motion platform 300 relative to the light collimation probe 113 are corrected.

From the above, it can be seen that through the correction of the light collimation probe 113 and the correction pattern on the correction plate 200, the posture of the motion platform 300 has been adjusted from the aforementioned corrected posture (x ₂ , y ₂ , z ₂ , θx ₃ , θy ₃ , θz ₁ ) to the corrected posture (x ₃ , y ₃ , z ₃ , θx ₃ , θy ₃ , θz ₃ ), thereby completing the correction between the light collimation probe 113 and the motion platform 300.

In the aforementioned embodiment, since there is no six-degree-of-freedom error between the motion platform 300 and the calibration piece 200 , there is no need to calibrate the six-degree-of-freedom error between the motion platform 300 and the calibration piece 200 .

However, in the following embodiments, since there is a six-degree-of-freedom error between the motion platform 300 and the calibration piece 200, the relative posture between the motion platform 300 and the calibration piece 200 can be corrected through the low-distortion image probe 111 and the calibration piece 200 to correct the relative posture between the two. It should be noted that when performing the six-degree-of-freedom error correction of the calibration piece 200, since the low-distortion image probe 111 will be used for correction, it is necessary to complete the correction items corresponding to the low-distortion image probe 111 before executing it, that is, the six-degree-of-freedom error correction of the calibration piece 200 can be executed after step S114 is completed.

First, the correction of the x-axis translational degree of freedom and the y-axis translational degree of freedom in the posture of the motion platform 300 relative to the correction sheet 200 is described.

As shown in FIG. 3C , in step S114a, the calibration module 130 moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the low-distortion image probe and is captured as an image. Please also refer to FIG. 1 and FIG. 12 , which is a schematic diagram showing that the motion platform drives the solid circle calibration pattern within the field of view of the low-distortion image probe of the present invention to rotate and scan around the z-axis with the origin of the motion platform on the xy plane as the center of the circle.

Specifically, the correction module 130 moves the motion platform 300 so that the solid circle pattern 232 of the solid circle correction pattern 230 of the correction film 200 appears at the center of the field of view of the low-distortion image probe 111; then, the origin C2 of the motion platform 300 on the xy plane is used as the center of the circle, and the solid circle pattern 232 of the solid circle correction pattern 230 is driven to scan around the origin C2 and along the arc scanning path SPA; at the same time, the correction module 130 controls the low-distortion image probe 110 to continuously shoot multiple images IM of the solid circle correction pattern 230 of the correction film 200 in position, one of the multiple images IM is shown in Figure 12.

In step S114b, the calibration module calculates the six-degree-of-freedom error between the calibration piece and the motion platform according to the calibration pattern in the image.

Specifically, since the centers C1 of the solid circle patterns 232 in the multiple images IM are all distributed on the arc scanning path SPA, the calibration module 130 can fit a circle with the center as the origin C2 according to the positions of the centers C1 of the solid circle patterns 232 in the multiple images IM3, and calculate the position of the origin C2 of the motion platform 300. Based on the known position of the center C1 of the solid circle pattern 232 as shown in FIG. 12, plus the calculated position of the origin C2 of the motion platform 300, the fourth x-axis translation error Δx4 and the fourth y-axis translation error _Δy4 can be calculated.

In step S114c, the calibration module adjusts the posture of the motion platform to the calibrated posture according to the six-degree-of-freedom error of step S114b. Specifically, the calibration module 130 can adjust the posture of the motion platform 300 from the aforementioned calibrated posture (x ₁ , y ₁ , z ₁ , θx 1 , θy ₁ , θz ₁ ) to the calibrated posture (x ₄ , y ₄ , z ₁ , θx ₁ , θy ₁ , θz ₁ ) according to the fourth x-axis translation error Δx4 _and the fourth y-axis translation error Δy _4. At this time, the origin of the motion platform 300 on the xy plane, the center C1 of the solid circle pattern 232, and the center of the field of view of the low-distortion image probe 111 overlap.

In step S114d, the correction module 130 stores _the six-axis free coordinate parameters corresponding to the corrected posture in step S114c. Specifically, the correction module 130 stores _the fourth x _- axis translational degree of freedom coordinate value x4 and the fourth y-axis translational degree of freedom coordinate value _y4 in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture ( _x4 , _y4 , z1, _θx1 , θy1, _θz1 ).

Thereby, the x-axis translational freedom and the y-axis translational freedom of the motion platform 300 are calibrated relative to the calibration sheet 200 .

Next, the correction of the z-axis translational degree of freedom in the posture of the motion platform 300 relative to the correction sheet 200 is described.

Return to step S114a, and please refer to Figure 1, Figure 13A and Figure 13B at the same time. Figure 13A is a schematic diagram showing the motion platform of the present invention driving the cross correction pattern to rotate around the y-axis with the origin of the motion platform as the center of the circle. Figure 13B is a schematic diagram showing the motion platform of the present invention driving the cross correction pattern to rotate around the y-axis with the origin of the motion platform as the center of the circle within the field of view of the low-distortion image probe.

Specifically, in order to highlight the error in the z-axis direction (ie, the fourth z-axis translation error Δz ₄ ) between the motion platform 300 and the calibration sheet 200 (especially the cross calibration pattern 210 ) for the convenience of subsequent description, FIG. 13A is presented. As shown in FIG. 13A, the calibration module 130 moves the motion platform 300 so that the cross calibration pattern 210 of the calibration sheet 200 appears within the field of view of the low-distortion imaging probe 111, and the upper surface of the cross calibration pattern 210 overlaps with the focal plane FP of the low-distortion imaging probe 111; then, please refer to the upper figure of FIG. 13B, the calibration module 130 controls the low-distortion imaging probe 111 to capture the cross calibration pattern 210 that appears within the field of view of the low-distortion imaging probe 111 into an image IM1, wherein the cross calibration pattern 210 The center C210 is located at the first position L1 of the image IM1; then, please refer to the lower figure of Figure 13B. The correction module 130 takes the origin C2 of the motion platform 300 on the xy plane as the center of the circle, controls the motion platform 300 to drive the cross correction pattern 210 around the origin C2 of the motion platform 300 and rotates around the y-axis direction by an angle α. The correction module 130 controls the low-distortion image probe 111 to capture it as an image IM2, wherein the center C210 of the cross correction pattern 210 is located at the second position L2 of the image IM2.

In step S114b, specifically, by analyzing the position difference of the center C210 of the cross correction pattern 210 in the image IM1 and the image IM2 in the x-axis direction shown in FIG. 13B , the distance a can be calculated; then, returning to FIG. 13A , when the distance a and the angle α are known, the correction module 130 can calculate the fourth z-axis translation error Δz ₄ =a/sin(α) based on the distance a and the angle α in combination with the trigonometric function formula.

In step S114c, specifically, the calibration module ₁₃₀ adjusts the posture of the motion platform 300 from the aforementioned calibrated posture (x ₄ , y ₄ , z ₁ , θx ₁ , θy ₁ , θz 1 ) to the calibrated posture (x ₄ , y 4 , z ₄ , θx ₁ , θy ₁ , θz ₁ ) according to the fourth z-axis translation error Δz _4. At this _time , the origin of the motion platform 300 on the xy plane overlaps with the focal plane of the low-distortion image probe 111.

In step S114d, specifically, the correction module 130 stores the fourth z-axis translational degree of freedom coordinate value z ₄ in the six-degree-of-freedom coordinate parameters corresponding to the corrected posture (x ₄ , y ₄ , z ₄ , θx ₁ , θy ₁ , θz ₁ ).

Thereby, the correction of the x-axis translational freedom, the y-axis translational freedom and the z-axis translational freedom in the posture of the motion platform 300 relative to the correction sheet 200 is completed.

From the above, it can be seen that when the six-degree-of-freedom error between the motion platform 300 and the calibration film is not taken into account, the posture of the motion platform 300 after correction is (x ₁ , y ₁ , z ₁ , θx ₁ , θy ₁ , θz ₁ ) relative to the low-distortion imaging probe 111; the posture of the motion platform 300 after correction is (x ₂ , y ₂ , z ₂ , θx ₂ , θy ₂ , θz ₁ ) relative to the ranging probe 112; and the posture of the motion platform 300 after correction is (x ₃ , y ₃ , z ₃ , θx ₃ , θy ₃ , θz ₃ ) relative to the light collimation probe 113.

In addition, when the six-degree-of-freedom error between the motion platform 300 and the calibration film is taken into account, the posture of the motion platform 300 after calibration is (x ₄ ,y ₄ ,z ₄ ,θx ₁ ,θy ₁ ,θz ₁ ) relative to the low-distortion imaging probe 111; the posture of the motion platform 300 after calibration is (x ₄ +x ₂ -x ₁ ,y ₄ +y ₂ -y ₁ ,z ₄ +z ₂ -z ₁ ,θx ₂ ,θy ₂ ,θz ₁ ) relative to the ranging probe 112; and the posture of the motion platform 300 after calibration is (x ₄ +x ₃ -x ₁ ,y ₄ +y ₃ -y ₁ ,z ₄ +z ₃ -z ₁ ,θx ₃ ,θy ₃ ,θz ₃ ).

In summary, the six-degree-of-freedom alignment device and its correction method provided by the present invention can automatically calibrate the relative posture between each probe in the optical probe group and the motion platform through the correction module, the correction sheet with multiple correction patterns, and each probe in the optical probe group, so as to correct the relative posture between the two.

The above detailed description of the preferred specific embodiments is intended to more clearly describe the features and spirit of the present invention, but is not intended to limit the scope of the present invention by the preferred specific embodiments disclosed above. On the contrary, the purpose is to cover various changes and arrangements with equivalents within the scope of the patent application for the present invention.

100: Six-degree-of-freedom alignment equipment 110: Optical probe set 111: Low-distortion image probe 112: Distance probe 113: Light collimation probe 114: Housing 130: Calibration module 200: Calibration sheet 210: Cross calibration pattern 220: Chessboard calibration pattern 221: First square pattern 222: Second square pattern 230: Solid circle calibration pattern 240: Total reflection surface calibration pattern 300: Motion platform A1: First area A2: Second area A3: Third area A4: Fourth area A5: Middle area ALL: Lower left area ALR: Lower right area AUL: Upper left area AUR: Upper right area B10: First starting point B11: First intersection point B20: Second starting point B21: Second intersection point B30: Third starting point B31: Third intersection point C1: Center of solid circle pattern C2: Origin of motion platform C210: Center of cross calibration pattern CF: Center of field of view D1: First distance D2: Second distance D3: Third distance FP: Focal plane G1: First signal intensity map G2: Second signal intensity map G3: Third signal intensity map IM, IM1, IM2, IM3: Image L1: First position L2: Second position L3: Third position P1: First point P2: Second point P3: Third point P4: Fourth point P5: Fifth point P6: Sixth point PA1: Cross camera target calibration pattern PA2: Cross light source target calibration pattern SPA: arc scanning path SPL1: first straight line scanning path SPL2: second straight line scanning path SPL3: third straight line scanning path TP: turning point W1: distance between the first area and the third area W2: distance between the first area and the second area Z1: first focus height Z2: second focus height Z3: third focus height Z4: fourth focus height Z5: fifth focus height a: distance α: angle x, y, z: degrees of freedom of translation θx, θy, θz: degrees of freedom of rotation S111~S122: steps

FIG. 1 is a stereoscopic diagram of the six-degree-of-freedom alignment device, motion platform, and calibration film according to the present invention. FIG. 2 is a schematic diagram showing the calibration film of the present invention. FIG. 3A to FIG. 3C are flowcharts showing the calibration method of the present invention. FIG. 4 is a schematic diagram showing an image including a solid circle calibration pattern captured by the low-distortion imaging probe of the present invention. FIG. 5A is a schematic diagram showing an image including a checkerboard calibration pattern captured by the low-distortion imaging probe of the present invention. FIG. 5B is a schematic diagram showing the spatial frequency response (SFR) of the four corner areas and the middle area of the image including the checkerboard calibration pattern during height scanning of the present invention. FIG. 6 is a schematic diagram showing three images including cross correction patterns at different positions taken by the low-distortion image probe of the present invention. FIG. 7A is a schematic diagram showing the posture of the motion platform and the correction plate of the present invention after being sensed by the ranging probe along the x-axis direction. FIG. 7B is a schematic diagram showing the posture of the motion platform and the correction plate of the present invention after being sensed by the ranging probe along the y-axis direction. FIG. 8 is a schematic diagram showing the present invention using the ranging probe to find the second z-axis focus error. FIG. 9 is a schematic diagram showing the present invention using the ranging probe and the solid circle correction pattern to find the second x-axis translation error and the second y-axis translation error. FIG. 10 is a schematic diagram showing an image including a cross camera target pattern and a cross light source target pattern taken by the light collimation probe of the present invention. FIG. 11 is a schematic diagram showing three images including cross light source target correction patterns at different positions taken by the light collimation probe of the present invention. FIG. 12 is a schematic diagram showing a solid circle correction pattern driven by the motion platform within the field of view of the low-distortion image probe of the present invention, which is rotated around the z-axis with the origin of the motion platform on the xy plane as the center of the circle. FIG. 13A is a schematic diagram showing a cross correction pattern driven by the motion platform of the present invention, which is rotated around the y-axis with the origin of the motion platform as the center of the circle. Figure 13B is a schematic diagram showing the present invention, in which the motion platform drives the cross correction pattern to rotate around the y-axis with the origin of the motion platform as the center within the field of view of the low-distortion image probe.

100: Six-degree-of-freedom alignment equipment 110: Optical probe set 111: Low-distortion image probe 112: Distance-measuring probe 113: Optical collimation probe 114: Housing 130: Calibration module 200: Calibration sheet 300: Motion platform x, y, z: Translational degrees of freedom θx, θy, θz: Rotational degrees of freedom

Claims (11)

A six-degree-of-freedom alignment device comprises: an optical probe set, comprising a low-distortion image probe and a distance measuring probe arranged adjacent to each other; and a calibration module, electrically connected to the optical probe set and a motion platform, and movably arranged within the field of view of each probe in the optical probe set, the calibration module is used to calculate a six-degree-of-freedom error between each probe and the motion platform through a calibration sheet having a plurality of calibration patterns arranged on the motion platform and each probe in the optical probe set, and adjust the posture of the motion platform to a calibrated posture corresponding to each probe according to the six-degree-of-freedom error, and store a six-degree-of-freedom coordinate parameter corresponding to the calibrated posture. A six-degree-of-freedom alignment device as described in claim 1, wherein the six-degree-of-freedom error between the low-distortion image probe and the motion platform includes a first x-axis translation error, a first y-axis translation error, a first x-axis rotation error, a first y-axis rotation error, a first z-axis rotation error and a first z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a first x-axis translational degree-of-freedom coordinate value, a first y-axis translational degree-of-freedom coordinate value, a first z-axis translational degree-of-freedom coordinate value, a first x-axis rotational degree-of-freedom coordinate value, a first y-axis rotational degree-of-freedom coordinate value and a first z-axis rotational degree-of-freedom coordinate value. The six-degree-of-freedom alignment device as described in claim 2, wherein the six-degree-of-freedom error between the ranging probe and the motion platform includes a second x-axis translation error, a second y-axis translation error, a second x-axis rotation error, a second y-axis rotation error, and a second z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a second x-axis translation freedom coordinate value, a second y-axis translation freedom coordinate value, a second z-axis translation freedom coordinate value, a second x-axis rotation freedom coordinate value, and a second y-axis rotation freedom coordinate value. The six-degree-of-freedom alignment device as described in claim 3, wherein the correction patterns include a cross correction pattern, a chessboard correction pattern, a solid circle correction pattern and a total reflection surface correction pattern, and the first z-axis rotation error and the third z-axis translation error are calculated through the cross correction pattern and the corresponding probe; the first x-axis rotation error, the first y-axis rotation error and the first z-axis focus error are calculated through the chessboard correction pattern. The first x-axis translation error, the first y-axis translation error, the second x-axis translation error, the second y-axis translation error, the third x-axis translation error and the third y-axis translation error are calculated through the solid circle correction pattern and the corresponding probe; and the second x-axis rotation error and the second y-axis rotation error are calculated through the total reflection surface correction pattern and the corresponding probe. The six-degree-of-freedom alignment device as described in claim 4, wherein the optical probe assembly further includes a light collimating probe, which is arranged adjacent to the low-distortion image probe and the ranging probe, and the six-degree-of-freedom error between the light collimating probe and the motion platform includes a third x-axis translation error, a third y-axis translation error, a third x-axis rotation error, a third y-axis rotation error, and a The third z-axis rotation error and the third z-axis focus error, and the corresponding six-degree-of-freedom coordinate parameters include a third x-axis translational degree-of-freedom coordinate value, a third y-axis translational degree-of-freedom coordinate value, a third z-axis translational degree-of-freedom coordinate value, a third x-axis rotational degree-of-freedom coordinate value, a third y-axis rotational degree-of-freedom coordinate value, and a third z-axis rotational degree-of-freedom coordinate value. The six-degree-of-freedom alignment device as described in claim 5, wherein: the third z-axis focus error is calculated through the checkerboard correction pattern and the corresponding probe; the third x-axis translation error and the third y-axis translation error are calculated through the solid circle correction pattern and the corresponding probe; and the third x-axis rotation error, the third y-axis rotation error and the third z-axis rotation error are calculated through the total reflection surface correction pattern and the corresponding probe. A six-degree-of-freedom alignment device as described in any one of claims 1 to 6, wherein the motion platform is used to carry the correction sheet, and the correction module is used to calculate a fourth x-axis translation error, a fourth y-axis translation error, and a fourth z-axis translation error between the correction sheet and the motion platform through the correction sheet and the low-distortion image probe, and adjust the posture of the motion platform to a corrected posture according to the fourth x-axis translation error, the fourth y-axis translation error, and the fourth z-axis translation error, and store a fourth x-axis translation freedom degree coordinate value, a fourth y-axis translation freedom degree coordinate value, and a fourth z-axis translation freedom degree coordinate value corresponding to the corrected posture. A calibration method for a six-degree-of-freedom alignment device as described in any one of claims 1 to 4, comprising the following steps: S111, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the low-distortion image probe and is photographed as an image; S112, the calibration module calculates the six-degree-of-freedom error between the low-distortion image probe and the motion platform according to the calibration pattern in the image; S113, the calibration module adjusts the posture of the motion platform to a calibrated posture corresponding to the low-distortion image probe according to the six-degree-of-freedom error in step S112; S114, the calibration module stores the six-degree-of-freedom error in step S112; 13, the six-axis free coordinate parameters corresponding to the corrected posture; S115, the correction module moves the motion platform so that the correction pattern of the correction sheet appears within the field of view of the ranging probe and performs sensing to generate sensing information; S116, the correction module calculates the six-degree-of-freedom error between the ranging probe and the motion platform according to the sensing information; S117, the correction module adjusts the posture of the motion platform to the corrected posture corresponding to the ranging probe according to the six-degree-of-freedom error in step S116; and S118, the correction module stores the six-axis free coordinate parameters corresponding to the corrected posture in step S117. The calibration method as described in claim 8 further includes the following steps between step S114 and step S115: S114a, the calibration module moves the motion platform so that the calibration pattern of the calibration sheet appears within the field of view of the low-distortion imaging probe and is captured as an image; S114b, the calibration module calculates the six-degree-of-freedom error between the calibration sheet and the carrier according to the calibration pattern in the image; S114c, the calibration module adjusts the posture of the motion platform to a calibrated posture according to the six-degree-of-freedom error in step S114b; and S114d, the calibration module stores the six-axis free coordinate parameters corresponding to the calibrated posture in step S114c. A calibration method for a six-degree-of-freedom alignment device as described in any one of claims 1 to 7, comprising the following steps: S111, the calibration module moves the motion platform so that the calibration pattern of the calibration film appears within the field of view of the low-distortion image probe and is photographed into an image; S112, the calibration module calculates the six-degree-of-freedom error between the low-distortion image probe and the motion platform according to the calibration pattern in the image; S113, the calibration module adjusts the posture of the motion platform to a calibrated posture corresponding to the low-distortion image probe according to the six-degree-of-freedom error in step S112; S114, the calibration module stores the six-axis free coordinate parameters corresponding to the calibrated posture in step S113; S115, the correction module moves the motion platform so that the correction pattern of the correction film appears within the field of view of the ranging probe and performs sensing to generate sensing information; S116, the correction module calculates the six-degree-of-freedom error between the ranging probe and the motion platform according to the sensing information; S117, the correction module adjusts the posture of the motion platform to the corrected posture corresponding to the ranging probe according to the six-degree-of-freedom error in step S116; S118, the correction module stores the six-axis free coordinate parameters corresponding to the corrected posture in step S117; S119, the correction module moves the motion platform so that the correction pattern of the correction film appears within the field of view of the light collimation probe and captures an image; S120, the calibration module calculates the six-degree-of-freedom error between the light collimating probe and the motion platform according to the calibration pattern in the image; S121, the calibration module adjusts the posture of the motion platform to the calibrated posture corresponding to the light collimating probe according to the six-degree-of-freedom error in step S120; and S122, the calibration module stores the six-axis free coordinate parameters corresponding to the calibrated posture in step S121. The calibration method as described in claim 10 further includes the following steps between step S114 and step S115: S114a, the calibration module moves the motion platform so that the calibration pattern of the calibration sheet appears within the field of view of the low-distortion imaging probe and is captured as an image; S114b, the calibration module calculates the six-degree-of-freedom error between the calibration sheet and the carrier according to the calibration pattern in the image; S114c, the calibration module adjusts the posture of the motion platform to a calibrated posture according to the six-degree-of-freedom error in step S114b; and S114d, the calibration module stores the six-degree-of-freedom coordinate parameters corresponding to the calibrated posture in step S114c.