CN112634376B - Calibration method and device, calibration equipment and storage medium - Google Patents

Abstract

The calibration method comprises the steps of shooting a first calibration image of a calibration piece through a first sensor, shooting a second calibration image of the calibration piece through a second sensor, wherein the calibration piece is driven by a motion platform and comprises characteristic points; calculating a first calibration coordinate of the motion platform according to the first calibration image, and calculating a second calibration coordinate of the motion platform according to the second calibration image, wherein when the motion platform is positioned at the first calibration coordinate, the characteristic point is positioned at the center of a field of view of the first sensor, and when the motion platform is positioned at the second calibration coordinate, the characteristic point is positioned at the center of the field of view of the second sensor; and calibrating the position conversion relation between the first sensor and the second sensor according to the first calibration coordinate and the second calibration coordinate. The calibration method, the calibration device, the calibration equipment and the nonvolatile computer readable storage medium are simple in operation and are beneficial to improving the detection efficiency.

Description

Calibration method and device, calibration equipment and storage medium

Technical Field

The present application relates to the field of calibration technology, and in particular to a calibration method, a calibration device, a calibration equipment and a non-volatile computer-readable storage medium.

Background technique

At present, the realization of the scanning path of the measuring machine has always been the main link of the measuring machine programming. The current mainstream method in the industry is to manually control two different types of cameras (such as visible light cameras and depth cameras, etc.) to approach the object to be measured respectively, and take pictures after adjusting to the appropriate position, so as to realize the detection of the object to be measured by taking images. The operation is relatively cumbersome and the detection efficiency is low.

Summary of the invention

The present application provides a calibration method, a calibration apparatus, a calibration device and a non-volatile computer-readable storage medium.

The calibration method of the embodiment of the present application includes photographing a first calibration image of a calibration part through a first sensor, and photographing a second calibration image of the calibration part through a second sensor, wherein the calibration part is driven by a motion platform, and the calibration part includes feature points; calculating a first calibration coordinate of the motion platform according to the first calibration image, and calculating a second calibration coordinate of the motion platform according to the second calibration image, wherein when the motion platform is at the first calibration coordinate, the feature point is located at the center of the field of view of the first sensor, and when the motion platform is at the second calibration coordinate, the feature point is located at the center of the field of view of the second sensor; and calibrating the position conversion relationship between the first sensor and the second sensor according to the first calibration coordinate and the second calibration coordinate.

The calibration device of the embodiment of the present application includes a shooting module, a first calculation module and a calibration module. The shooting module is used to shoot a first calibration image of a calibration part through a first sensor, and shoot a second calibration image of the calibration part through a second sensor, wherein the calibration part is driven by a motion platform, and the calibration part includes feature points; the first calculation module is used to calculate the first calibration coordinates of the motion platform according to the first calibration image, and calculate the second calibration coordinates of the motion platform according to the second calibration image, wherein when the motion platform is at the first calibration coordinates, the feature points are located at the center of the field of view of the first sensor, and when the motion platform is at the second calibration coordinates, the feature points are located at the center of the field of view of the second sensor; the calibration module is used to calibrate the position conversion relationship between the first sensor and the second sensor according to the first calibration coordinates and the second calibration coordinates.

The calibration device of the embodiment of the present application includes a first sensor, a second sensor, a motion platform and a processor. The first sensor is used to capture a first calibration image of the calibration part; the second sensor is used to capture a second calibration image of the calibration part; the motion platform is used to carry the calibration part; the processor is used to calculate the first calibration coordinates of the motion platform based on the first calibration image, and calculate the second calibration coordinates of the motion platform based on the second calibration image, wherein when the motion platform is at the first calibration coordinates, the feature point is located at the center of the field of view of the first sensor, and when the motion platform is at the second calibration coordinates, the feature point is located at the center of the field of view of the second sensor; and the position conversion relationship between the first sensor and the second sensor is calibrated according to the first calibration coordinates and the second calibration coordinates.

A non-volatile computer-readable storage medium storing a computer program in an embodiment of the present application, when the computer program is executed by one or more processors, enables the processor to execute the calibration method. The calibration method includes photographing a first calibration image of a calibration member through a first sensor, photographing a second calibration image of the calibration member through a second sensor, wherein the calibration member is driven by a motion platform, and the calibration member includes feature points; calculating a first calibration coordinate of the motion platform according to the first calibration image, and calculating a second calibration coordinate of the motion platform according to the second calibration image, wherein when the motion platform is at the first calibration coordinate, the feature point is located at the center of the field of view of the first sensor, and when the motion platform is at the second calibration coordinate, the feature point is located at the center of the field of view of the second sensor; and calibrating the position conversion relationship between the first sensor and the second sensor according to the first calibration coordinate and the second calibration coordinate.

The calibration method, calibration device, calibration equipment and non-volatile computer-readable storage medium of the present application calculate the first calibration coordinates by photographing a first calibration image of the calibration part with a first sensor, and photographing a second calibration image of the calibration part with a second sensor. Since the first calibration coordinates and the second calibration coordinates correspond to the same feature point, the position conversion relationship between the first sensor and the second sensor can be calculated based on the first calibration coordinates and the second calibration coordinates. Therefore, in the subsequent detection process, it is only necessary to manually adjust one of the sensors to shoot, and the position of the other sensor when shooting can be automatically determined according to the position of the sensor when shooting and the calibrated position conversion relationship, so that there is no need to manually adjust both the first sensor and the second sensor, the operation is relatively simple, and it is beneficial to improve the detection efficiency.

Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a schematic flow chart of a calibration method according to certain embodiments of the present application;

FIG2 is a schematic diagram of a module of a calibration device according to some embodiments of the present application;

FIG3 is a schematic plan view of a calibration device according to some embodiments of the present application;

FIG4 is a schematic diagram of the principle of a calibration method according to some embodiments of the present application;

FIG5 is a schematic diagram of the principle of a calibration method in some embodiments of the present application;

FIG6 is a schematic flow chart of a calibration method according to certain embodiments of the present application;

FIG7 is a schematic diagram of a flow chart of a calibration method according to certain embodiments of the present application;

FIG8 is a schematic diagram of the principle of a calibration method according to some embodiments of the present application;

FIG9 is a schematic diagram of the principle of a calibration method according to some embodiments of the present application;

FIG10 is a schematic diagram of the principle of a calibration method in some embodiments of the present application; and

FIG. 11 is a connection diagram of a processor and a computer-readable storage medium in certain embodiments of the present application.

Detailed ways

The embodiments of the present application are further described below in conjunction with the accompanying drawings. The same or similar reference numerals in the accompanying drawings represent the same or similar elements or elements with the same or similar functions from beginning to end. In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the present application.

Please refer to Figures 1 to 3. The calibration method of the embodiment of the present application includes the following steps:

011: photographing a first calibration image of the calibration object 200 through the first sensor 20, and photographing a second calibration image of the calibration object 200 through the second sensor 40, wherein the calibration object 200 is driven by the motion platform 30, and the calibration object 200 includes feature points;

012: Calculate the first calibration coordinates of the motion platform 30 according to the first calibration image, and calculate the second calibration coordinates of the motion platform 30 according to the second calibration image, wherein when the motion platform 30 is at the first calibration coordinates, the feature point is located at the center of the field of view of the first sensor 20, and when the motion platform 30 is at the second calibration coordinates, the feature point is located at the center of the field of view of the second sensor 40;

013: Calibrate the position conversion relationship between the first sensor 20 and the second sensor 40 according to the first calibration coordinates and the second calibration coordinates.

The calibration device 10 of the embodiment of the present application includes a shooting module 11, a first calculation module 12, and a calibration module 13. The shooting module 11 is used to shoot a first calibration image of the calibration member 200 through the first sensor 20, and shoot a second calibration image of the calibration member 200 through the second sensor 40. The calibration member 200 is driven by the motion platform 30, and the calibration member 200 includes feature points; the first calculation module 12 is used to calculate the first calibration coordinates of the motion platform 30 according to the first calibration image, and calculate the second calibration coordinates of the motion platform 30 according to the second calibration image, wherein when the motion platform 30 is at the first calibration coordinates, the feature points are located at the center of the field of view of the first sensor 20, and when the motion platform 30 is at the second calibration coordinates, the feature points are located at the center of the field of view of the second sensor 40; the calibration module 13 is used to calibrate the position conversion relationship between the first sensor 20 and the second sensor 40 according to the first calibration coordinates and the second calibration coordinates. That is to say, step 011 can be implemented by the shooting module 11, step 012 can be performed by the first calculation module 12, and step 013 can be performed by the calibration module 13.

The calibration device 100 of the embodiment of the present application includes a first sensor 20, a second sensor 40, a motion platform 30 and a processor 50. The first sensor 20 is used to capture a first calibration image of the calibration piece 200. The second sensor 40 is used to capture a second calibration image. The calibration piece 200 is disposed on the motion platform 30, and the motion platform 30 drives the calibration piece 200 to move. The calibration piece 200 includes one or more feature points, and the feature points are specific parts of the calibration piece 200 that can be accurately identified through an image. For example, the calibration piece 200 includes one or more feature areas. If the feature area is circular, the feature point is the center of each feature area. If the feature area is rectangular, the feature point can be the intersection of the diagonal of each feature area or the vertex of the feature area. In this way, by identifying the feature area, the feature point can be determined quickly and accurately.

The processor 50 is connected to the first sensor 20, the second sensor 40 and the motion platform 30; the processor 50 is used to calculate the first calibration coordinates of the motion platform 30 according to the first calibration image, and calculate the second calibration coordinates of the motion platform 30 according to the second calibration image, wherein when the motion platform 30 is at the first calibration coordinates, the feature point is located at the center of the field of view of the first sensor 20, and when the motion platform 30 is at the second calibration coordinates, the feature point is located at the center of the field of view of the second sensor 40; and calibrate the position conversion relationship between the first sensor 20 and the second sensor 40 according to the first calibration coordinates and the second calibration coordinates. That is to say, step 011 can be executed by the first sensor 20, the second sensor 40 and the motion platform 30, and steps 012 and 013 can be executed by the processor 50.

Specifically, the calibration device 100 may be a measuring machine. It is understood that the specific form of the calibration device 100 is not limited to a measuring machine, and may also be any device having two cameras and requiring calibration.

The motion platform 30 includes an XY motion platform 31 and a Z motion platform 32, and the first sensor 20 and the second sensor 40 are arranged on the motion platform 30, specifically: the first sensor 20 and the second sensor 40 are arranged on the Z motion platform 32, wherein the XY motion platform 31 is used to control the movement of the calibration piece 200 along the horizontal plane, and change the relative position of the calibration piece 200 and the first sensor 20 and the second sensor 40 in the horizontal plane, and the Z motion platform 32 is used to control the movement of the first sensor 20 and the second sensor 40 in the direction perpendicular to the horizontal plane. In this way, the three-dimensional position of the first sensor 20 and the second sensor 40 relative to the calibration piece 200 (that is, the relative position in the horizontal plane and the relative position in the direction perpendicular to the horizontal plane) is realized through the cooperation of the XY motion platform 31 and the Z motion platform 32.

It is understandable that the motion platform 30 is not limited to the above structure, and only needs to be able to change the three-dimensional position of the first sensor 20 and the second sensor 40 relative to the calibration piece 200.

For example, the Z motion platform 32 is arranged on the XY motion platform 31, and the first sensor 20 and the second sensor 40 are arranged on the Z motion platform 32. At this time, the movement of the XY motion platform 31 can drive the Z motion platform 32 to move in the horizontal plane, and the XY motion platform 31 cooperates with the Z motion platform 32 to change the three-dimensional position of the first sensor 20 and the second sensor 40 relative to the calibration object 200;

For another example, the calibration piece 200 is set on the Z motion platform 32. At this time, the movement of the XY motion platform 31 can drive the Z motion platform 32 to move in the horizontal plane. The XY motion platform 31 cooperates with the Z motion platform 32 to change the three-dimensional position of the calibration piece 200 relative to the first sensor 20 and the second sensor 40.

The first sensor 20 and the second sensor 40 may both be two-dimensional imaging sensors, such as the first sensor 20 is a visible light camera and the second sensor 40 is a depth camera; or, the first sensor 20 is a depth camera and the second sensor 40 is a visible light camera; or, one of the first sensor 20 and the second sensor 40 is a two-dimensional imaging sensor and the other is a distance sensor, such as the first sensor 20 is a visible light camera and the second sensor 40 is a distance sensor. In this case, the information collected by the second sensor 40 on the calibration piece 200 is: the distance sensor generates a depth image by collecting the depth of different positions of the calibration piece 200; or, the first sensor 20 is a distance sensor and the second sensor 40 is a visible light camera. In this case, the first calibration image captured by the first sensor 20 is: the distance sensor generates a depth image by collecting the depth of different positions of the calibration piece 200; or, the first sensor 20 is a depth camera and the second sensor 40 is a distance sensor; or, the first sensor 20 is a distance sensor and the second sensor 40 is a depth sensor, etc. In this embodiment, the first sensor 20 is a visible light camera and the second sensor 40 is a distance sensor. The second sensor 40 may perform distance measurement by spectral confocal method.

During calibration, the processor 50 controls the motion platform 30 to move, so as to drive the first sensor 20 to move, so that the calibration piece 200 is located within the depth of field range and the field of view range of the first sensor 20, wherein the depth of field range of the first sensor 20 is preset, and therefore, the motion platform 30 can determine the distance between the Z motion platform 32 and the calibration piece 200 in the vertical and horizontal plane directions according to the preset depth of field range, thereby realizing the adjustment of the Z motion platform 32. For example, the Z motion platform 32 is adjusted so that the calibration piece 200 is located at the midpoint of the depth of field range of the first sensor 20. If the depth of field range is 5 cm to 10 cm, the distance between the calibration piece 200 and the first sensor 20 is 7.5 cm. In order to ensure that the characteristic point of the calibration surface 210 of the calibration piece 200 is accurately located at the midpoint of the depth of field range, the distance between the Z motion platform 32 and the calibration surface 210 of the calibration piece 200 in the vertical horizontal plane direction can be further determined according to the preset thickness of the calibration piece 200, so that the calibration surface 210 (i.e., the characteristic point) is accurately located at the midpoint of the depth of field range.

After the calibration piece 200 is located within the depth of field of the first sensor 20, in order to accurately capture the entire calibration piece 200, the processor 50 can detect whether the calibration piece 200 is completely within the field of view according to the image captured by the first sensor 20. When the calibration piece 200 is large, part of the calibration piece 200 may be outside the field of view. At this time, the XY motion platform 31 can be adjusted first to make the calibration piece 200 completely within the field of view. After adjusting the XY motion platform 31 for multiple times, if part of the calibration piece 200 is still outside the field of view, the distance between the Z motion platform 32 and the calibration surface 210 can be increased to ensure that the calibration surface 210 is within the depth of field and the calibration piece 200 is completely within the field of view. Thus, the first calibration image of the entire calibration piece 200 is clearly captured. Of course, the first calibration area can be determined according to the position of the feature point. The first calibration area can be a part of the calibration surface 210 and only needs to include the feature point. Taking a first calibration image of the first calibration area including the feature point can also realize subsequent calibration, so there is no need to take a picture of the entire calibration part 200, and the first calibration area can be more easily located within the field of view of the first sensor 20.

After taking the first calibration image, the processor 50 controls the motion platform 30 to move again to drive the second sensor 40 to move, so that the calibration piece 200 is located within the depth of field and field of view of the second sensor 40, wherein the depth of field of the second sensor 40 is preset. Therefore, the motion platform 30 can determine the distance between the Z motion platform 32 and the calibration piece 200 in the vertical and horizontal plane directions according to the preset depth of field range, thereby realizing the adjustment of the Z motion platform 32, for example, adjusting the Z motion platform 32 so that the calibration piece 200 is located at the midpoint of the depth of field of the second sensor 40. If the depth of field range is 5 cm to 10 cm, the distance between the calibration piece 200 and the second sensor 40 is 7.5 cm. In order to make the feature point of the calibration surface 210 of the calibration piece 200 accurately located at the midpoint of the depth of field range, the distance between the Z motion platform 32 and the calibration surface 210 of the calibration piece 200 in the vertical horizontal plane direction can be further determined according to the thickness of the calibration piece 200, so that the calibration surface 210 (i.e., the feature point) is accurately located at the midpoint of the depth of field range.

After the calibration object 200 is located within the depth of field of the second sensor 40, in order to accurately capture the entire calibration object 200, the processor 50 can detect whether the calibration object 200 is completely within the field of view according to the image captured by the second sensor 40. When the calibration object 200 is large, part of the calibration object 200 may be outside the field of view. At this time, the XY motion platform 31 can be adjusted first to make the calibration object 200 completely within the field of view. After adjusting the XY motion platform 31 for multiple times, if part of the calibration object 200 is still outside the field of view, the distance between the Z motion platform 32 and the calibration surface 210 can be appropriately increased to ensure that the calibration surface 210 is within the depth of field and the calibration object 200 is completely within the field of view. Thus, the second calibration image of the entire calibration object 200 is clearly captured. Of course, the second calibration area can be determined according to the position of the feature point. The second calibration area can be a part of the calibration surface 210 and only needs to include the feature point. It can be understood that in order to make the first calibration image and the second calibration image both include the same feature point, the first calibration area and the second calibration area also need to include the same feature point. Shooting the second calibration image of the second calibration area including the feature point can also realize subsequent calibration, so there is no need to shoot the entire calibration part 200, and the second calibration area can be more easily located within the field of view of the second sensor 40.

After clearly photographing the first calibration image and the second calibration image, the processor 50 calculates the first calibration coordinates of the motion platform 30 according to the first calibration image, and calculates the second calibration coordinates of the motion platform 30 according to the second calibration image.

Specifically, the processor 50 obtains the first initial coordinate of the motion platform 30 when shooting the first calibration image. The first initial coordinate corresponds to a pixel in the first calibration image. For example, the pixel is generally the center pixel of the first calibration image. At this time, the first sensor 20 is aligned with the portion of the calibration piece 200 corresponding to the center pixel (that is, the portion of the calibration piece 200 is located at the center of the field of view of the first sensor 20). Of course, the pixel can also be any pixel in the first calibration image. This embodiment is described by assuming that the first initial coordinate corresponds to the center pixel of the first calibration image.

Since there is a corresponding relationship between the first initial coordinate and the center pixel, that is, there is a corresponding relationship between the image coordinate system of the first calibration image and the physical coordinate system of the motion platform 30, the first calibration coordinate corresponding to the feature point can be calculated based on the corresponding relationship, the difference between the image coordinates of the feature point and the image coordinates of the center pixel, and the actual physical size corresponding to each pixel in the first calibration image.

It can be understood that the coordinates of the motion platform 30 in the physical coordinate system are (X, Y, Z), X and Y represent the relative position of the XY motion platform 31 in the horizontal plane and the coordinate origin, and Z represents the relative position of the Z motion platform 32 in the vertical horizontal plane direction and the coordinate origin. Among them, the coordinate origin can be arbitrarily selected to facilitate the subsequent calculation of the coordinates. For example, in the initial state, the position where the center of the calibration piece 200 is located is the coordinate origin.

Since the first calibration image is taken at the same Z coordinate, the Z coordinates of the motion platform 30 corresponding to all pixels of the first calibration image are the same and are all at the same depth of field where clear imaging can be achieved. The first sensor 20 can be aligned with the feature point (i.e., the feature point is located at the center of the field of view of the first sensor 20) by simply changing the X and Y coordinates of the motion platform 30 so that the coordinates of the motion platform 30 are the first calibration coordinates. Therefore, the difference between the first calibration coordinates and the first initial coordinates is only in X and Y.

For example, the size of the first calibration image P1 shown in FIG4 is 100 pixels * 100 pixels, wherein the image coordinates of the center pixel are (50, 50), and the first initial coordinates of the motion platform 30 are (2, 3, 5), and the unit is millimeter (mm). The actual physical size of the first calibration image P1 is 0.1 mm, and the actual physical size of 0.1 mm means that each pixel in the first calibration image P1 corresponds to a rectangular area with a length and width of 0.1 mm in the physical coordinate system. If the first calibration image P1 includes 9 feature areas, the feature point Q may occupy one pixel in the first calibration image P1, such as the pixel corresponding to the center of the feature area at the center of the first calibration image P1; the image coordinates of the feature point Q are (48, 51), then the first calibration coordinates corresponding to the feature point Q are (2-(50-48)*0.1, 3-(50-51)*0.1, 5), that is, (1.8, 2.1, 5). Therefore, according to the difference in image coordinates between the feature point Q and the center pixel and the actual physical size, the coordinate difference between the first calibration coordinate and the first initial coordinate corresponding to the feature point Q can be determined (such as the difference in X coordinate is 0.2 and the difference in Y coordinate is -0.1 in the above example), thereby calculating the first calibration coordinate based on the first initial coordinate and the coordinate difference.

Similarly, when calculating the second calibration coordinates, the processor 50 obtains the second initial coordinates of the motion platform 30 when the second calibration image is captured. The second initial coordinates correspond to a pixel in the second calibration image. For example, the pixel is generally the center pixel of the second calibration image. At this time, the second sensor 40 is aligned with the portion of the calibration member 200 corresponding to the center pixel (that is, the portion of the calibration member 200 is located at the center of the field of view of the second sensor 40). Of course, the pixel can also be any pixel in the second calibration image. This embodiment is described by assuming that the second initial coordinate corresponds to the center pixel of the second calibration image.

Since there is a corresponding relationship between the second initial coordinate and the center pixel, that is, there is a corresponding relationship between the image coordinate system of the second calibration image and the physical coordinate system of the motion platform 30, the second calibration coordinate corresponding to the feature point can be calculated based on the corresponding relationship, the difference between the image coordinates of the feature point and the image coordinates of the center pixel, and the actual physical size corresponding to each pixel in the second calibration image.

Since the second calibration image is taken at the same Z coordinate, the Z coordinates of the motion platform 30 corresponding to all pixels are the same and are all at the same depth of field where clear imaging can be achieved. The second sensor 40 can be aligned with the feature point (i.e., the feature point is located at the center of the field of view of the first sensor 20) by simply changing the X and Y coordinates of the motion platform 30 so that the coordinates of the motion platform 30 are the second calibration coordinates. Therefore, the difference between the second calibration coordinates and the second initial coordinates is only in X and Y.

For example, the size of the second calibration image P2 shown in FIG5 is 60 pixels * 60 pixels, wherein the image coordinates of the center pixel are (30, 30), and the second initial coordinates of the motion platform 30 are (10, 11, 15), in millimeters (mm). The actual physical size of the second calibration image P2 is 0.1 mm. If the second calibration image P2 includes 9 feature areas, the feature point Q may occupy one pixel in the second calibration image P2, such as the pixel corresponding to the center of the feature area at the center of the first calibration image P2; if the image coordinates of the feature point Q are (25, 25), then the second calibration coordinates corresponding to the feature point Q are (10-(30-25)*0.1, 11-(30-25)*0.1, 15), i.e. (9.5, 10.5, 15). Therefore, based on the difference in image coordinates between the feature point Q and the center pixel and the actual physical size, the coordinate difference between the second calibration coordinate and the second initial coordinate corresponding to the feature point Q can be determined (such as the difference in the X coordinate in the above example is 0.5, and the difference in the Y coordinate is 0.5), thereby calculating the second calibration coordinate based on the second initial coordinate and the coordinate difference.

The processor 50 can calibrate the position conversion relationship between the first sensor 20 and the second sensor 40 according to the first calibration coordinates and the second calibration coordinates. For example, the coordinate difference between the first calibration coordinates and the second calibration coordinates can be used as the position conversion relationship between the first sensor 20 and the second sensor 40. When the first coordinate when the first sensor 20 (second sensor 40) takes the image of the test piece 400 is subsequently determined, the second coordinate when the second sensor 40 (first sensor 20) takes the image of the test piece 400 can be calculated according to the coordinate difference. For example, according to the first calibration coordinates (1.8, 2.1, 5) and the second calibration coordinates (9.5, 10.5, 15), the X coordinate difference can be calculated to be 7.7, the Y coordinate difference can be 8.4, and the Z coordinate difference can be 10. If the first coordinate is (3, 5, 7), the second coordinate is (10.7, 13.4, 17), so that the coordinate of the motion platform 30 when one of the sensors takes the test piece 400 and the coordinate difference can be quickly calculated.

It can be understood that the calibration device 100 can also include more sensors, such as a third sensor, a fourth sensor, etc., and the calibration of all sensors can be completed by only calculating the position conversion relationship between any two sensors in sequence according to the above-mentioned calibration method for the first sensor 20 and the second sensor 40. Therefore, in subsequent inspections, it is only necessary to manually adjust one of the sensors to accurately photograph the part to be tested 400. According to the coordinates and position conversion relationship of the motion platform 30 corresponding to the sensor, the coordinates of the motion platform 30 corresponding to the other multiple sensors can be determined, thereby achieving accurate photography of the part to be tested 400 by the other multiple sensors.

The calibration method, calibration device 10, calibration equipment 100 and non-volatile computer-readable storage medium 300 of the present application calculate the first calibration coordinates by photographing the first calibration image of the calibration part 200 by the first sensor 20, and photographing the second calibration image of the calibration part 200 by the second sensor 40. Since the first calibration coordinates and the second calibration coordinates correspond to the same feature point, the position conversion relationship between the first sensor 20 and the second sensor 40 can be calculated according to the first calibration coordinates and the second calibration coordinates. Therefore, in the subsequent detection process, it is only necessary to manually adjust one of the sensors to shoot, and the position of the other sensor when shooting can be automatically determined according to the position of the sensor when shooting and the calibrated position conversion relationship, so that there is no need to manually adjust the first sensor 20 and the second sensor 40. The operation is relatively simple, which is conducive to improving the detection efficiency.

Please refer to FIG. 2 , FIG. 3 and FIG. 6 , in some embodiments, step 013 includes:

0131: Calculate the coordinate difference between the first calibration coordinate and the second calibration coordinate; and

0132: Establish a calibration function between the first sensor 20 and the second sensor 40 according to the coordinate difference.

In some embodiments, the calibration module 13 is further configured to establish a calibration function between the first sensor 20 and the second sensor 40 according to the coordinate difference. That is, step 131 and step 132 may be performed by the calibration module 13.

In some embodiments, the processor 50 is further configured to establish a calibration function between the first sensor 20 and the second sensor 40 according to the coordinate difference. That is, step 0131 and step 0132 may be executed by the processor 50.

Specifically, when calibrating the position conversion relationship between the first sensor 20 and the second sensor 40, the processor 50 may first calculate the coordinate difference between the first calibration coordinate and the second calibration coordinate, and then establish a calibration function between the first sensor 20 and the second sensor 40 according to the coordinate difference. For example, the coordinates of the first sensor 20 are (X1, Y1, Z1) and the coordinates of the second sensor 40 are (X2, Y2, Z2). According to the first calibration coordinate and the second calibration coordinate, the X coordinate difference is 8, the Y coordinate difference is 8, and the Z coordinate difference is 10. Then the calibration function is X2=X1+7.7; Y2=Y1+8.4; Z2=Z1+10.

In subsequent testing, it is only necessary to determine the coordinates of the motion platform 30 when the first sensor 20 (second sensor 40) clearly photographs the test piece 400, and the coordinates of the motion platform 30 when the second sensor 40 (first sensor 20) photographs the test piece 400 can be quickly calculated according to the calibration function.

Referring to FIG. 2 , FIG. 3 and FIG. 7 , in certain embodiments, the calibration method further includes:

014: Calculate the second coordinate set of the motion platform 30 when the second sensor 40 collects information of the test piece 400 according to the calibration function and the first coordinate set of the motion platform 30 when the first sensor 20 photographs the test piece 400.

In some embodiments, the calibration device 10 further includes a second calculation module 14. The second calculation module is used to calculate a second coordinate set of the motion platform 30 when the second sensor 40 collects information of the test piece 400 according to the calibration function and the first coordinate set of the motion platform 30 when the first sensor 20 photographs the test piece 400. That is, step 014 can be performed by the second calculation module 14.

In some embodiments, the processor 50 is further configured to calculate a second coordinate set of the motion platform 30 when the second sensor 40 collects information of the test piece 400 based on the calibration function and the first coordinate set of the motion platform 30 when the first sensor 20 photographs the test piece 400. That is, step 014 can be executed by the processor 50.

Specifically, during the detection process, the fields of view of the first sensor 20 and the second sensor 40 are generally different. For example, when the first sensor 20 is a visible light camera and the second sensor 40 is a distance sensor, the field of view of the second sensor 40 is smaller. For example, the second sensor 40 only collects local information of the device under test 400 corresponding to one pixel each time. Therefore, after the first sensor 20 captures the first image of the device under test 400, in order for the second sensor 400 to collect information of all parts of the device under test 400, the processor 50 first needs to obtain the image coordinates of all pixels under test of the device under test 400 in the first image, each pixel under test corresponding to a part of the device under test 400, and then the coordinates of the motion platform 30 corresponding to the image coordinates of all pixels under test can be calculated according to the third initial coordinates of the motion platform 30 when the first sensor 20 captures the first image and the coordinates of the corresponding central pixel, wherein the coordinates of the motion platform 30 corresponding to the image coordinates of the pixels under test refer to the coordinates of the motion platform 30 (hereinafter referred to as the first coordinates) when the part of the device under test 400 corresponding to the pixels under test is located at the center of the field of view of the first sensor 20.

The processor 50 can obtain a first coordinate set based on all the first coordinates, and the first coordinate set includes all the first coordinates; then, based on the calibration function and the first coordinate set, the second coordinate corresponding to each first coordinate in the second coordinate set can be obtained, thereby obtaining the second coordinate set.

For example, as shown in FIG8 , the image coordinates of the central pixel of the first image P3 are (50,50), the actual physical size is 0.1 mm, the device under test 400 is a rectangle, and the image area corresponding to the device under test 400 is a rectangular area corresponding to the image coordinates (10,10) to (80,70). When capturing the first image, the third initial coordinates of the motion platform 30 are (15, 15, 23). The processor 50 calculates the coordinates of the motion platform 30 corresponding to all pixels in the pixel area corresponding to the device under test 400 according to the third initial coordinates, the image coordinates of the central pixel, and the pixel area corresponding to the device under test 400, i.e., (15-(50-10)*0.1, 15-(50-10)*0.1, 23) to (15-(50-80)*0.1, 15-(50-70)*0.1, 23). In other words, the first coordinate set is (11, 11, 23) to (18, 17, 23). Then, according to the first coordinate set and the calibration function, the second coordinate set corresponding to the second sensor 40 is calculated to be (18.7, 19.4, 33) to (25.7, 25.4, 33).

The processor 50 can move the scanning path of the motion platform 30 according to the second coordinate set. For example, the motion platform 30 scans one by one according to the second coordinate set, and each time it moves to a second coordinate, the second sensor 40 collects the local depth of the piece to be tested 400 corresponding to the second coordinate; then the local depth collection of the piece to be tested 400 corresponding to all the second coordinates is completed in turn to generate a depth image of the entire piece to be tested 400; in order to reduce the length of the motion path to improve the shooting efficiency, the motion platform 30 can control the second sensor 40 to scan row by row or column by column according to the second coordinate set.

It can be understood that sometimes only a specific area of the test piece 400 needs to be detected. At this time, the processor 50 can first obtain the first coordinate set of the test area, and then calculate the second coordinate set corresponding to the first coordinate set of the test area, thereby controlling the second sensor 40 to complete the information collection of all parts of the test area.

Please refer to Figure 3. In some embodiments, the processor 50 is also used to obtain detection attributes; the motion platform 30 moves along the scanning path, and the second sensor 40 is used to collect information of the test piece 400; the processor 50 is also used to output the detection result based on the detection attributes and the information collected by the second sensor 40.

Specifically, when the scanning path is determined, the motion platform 30 cooperates with the second sensor 40 to start collecting information of the test piece 400 along the scanning path. The processor 50 can obtain the detection attributes that need to be detected in advance, such as flatness, roundness, height difference, etc. The detection attributes can be determined according to user input or according to the type of the test piece 400. Different types of test pieces 400 generally have different attributes that need to be detected.

At this time, the motion platform 30 starts to move along the scanning path S, which may include multiple shooting nodes. As shown in FIG9 , when the second sensor 40 only collects information (such as depth information) of a portion of the DUT 400 corresponding to one pixel each time, each second coordinate is used as a shooting node, and the motion platform 30 collects information each time it moves to a shooting node; as shown in FIG10 , when the second sensor 40 can collect information of multiple parts of the DUT 400 each time, the DUT 400 can be divided into multiple motion regions M, each motion region M includes multiple parts of the DUT 400, and then the second coordinates corresponding to the parts at the center of all the motion regions M are sequentially connected to obtain the scanning path S, so that the second sensor 40 can obtain the depth of multiple parts of the DUT 400 each time, which can improve the acquisition efficiency of the depth image of the DUT 400. Among them, the second coordinate corresponding to the part at the center of the motion region M is a shooting node, thereby reducing the number of acquisitions (the number of acquisitions in FIG10 is 1/9 of the number of acquisitions in FIG9 ), which is conducive to improving the detection efficiency.

Please refer to FIG9 . In one example, the device under test 400 is a rectangle, corresponding to 9*9 pixels under test in the first image (i.e., corresponding to 9*9 parts of the device under test 400 ), the second coordinate set includes 9*9 second coordinates. When the second sensor 40 acquires the depth of only one part of the device under test 400 each time, the scanning path S is as shown in FIG9 , and the second coordinates corresponding to each pixel under test are sequentially connected to form the scanning path S. When the second sensor 40 acquires the depth of multiple parts of the device under test 400 (e.g., 3*3) each time, the scanning path S is as shown in FIG10 , and the 9*9 device under test 400 can be divided into 9 motion regions M (i.e., the size of one motion region M is equal to the number of parts of the device under test 400 acquired by the second sensor 40 ), and then the second coordinates corresponding to the part at the center of each motion region M are sequentially connected to generate the scanning path S.

After the motion platform 30 has completed moving along the scanning path S, the second sensor 40 has completed collecting all local information of the calibration component 200, and the processor 50 detects the collected information according to the detection attribute, thereby outputting an output result corresponding to the detection attribute.

For example, if the detection attribute is flatness, the second sensor 40 collects the depth information of each part, and the flatness can be determined according to the difference in depth of different parts. Then the processor 50 outputs the flatness information as the detection result.

Please refer to Figure 11, one or more non-volatile computer-readable storage media 300 storing a computer program 302 in an embodiment of the present application, when the computer program 302 is executed by one or more processors 50, the processor 50 can execute the calibration method of any of the above embodiments.

For example, referring to FIG. 1 to FIG. 3 , when the computer program 302 is executed by one or more processors 50, the processor 50 performs the following steps:

011: photographing a first calibration image of the calibration object 200 through the first sensor 20, and photographing a second calibration image of the calibration object 200 through the second sensor 40, wherein the calibration object 200 is driven by the motion platform 30, and the calibration object 200 includes feature points;

012: Calculate the first calibration coordinates of the motion platform 30 according to the first calibration image, and calculate the second calibration coordinates of the motion platform 30 according to the second calibration image, wherein when the motion platform 30 is at the first calibration coordinates, the feature point is located at the center of the field of view of the first sensor 20, and when the motion platform 30 is at the second calibration coordinates, the feature point is located at the center of the field of view of the second sensor 40;

013: Calibrate the position conversion relationship between the first sensor 20 and the second sensor 40 according to the first calibration coordinates and the second calibration coordinates.

For another example, referring to FIG. 2 , FIG. 3 , and FIG. 6 , when the computer program 302 is executed by one or more processors 50 , the processor 50 may further perform the following steps:

0131: Calculate the coordinate difference between the first calibration coordinate and the second calibration coordinate; and

0132: Establish a calibration function between the first sensor 20 and the second sensor 40 according to the coordinate difference.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations to the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims (6)

1. A calibration method, comprising:

shooting a first calibration image of a calibration piece through a first sensor, shooting a second calibration image of the calibration piece through a second sensor, wherein the calibration piece is driven by a motion platform and comprises characteristic points;

Calculating a first calibration coordinate according to a first initial coordinate of the motion platform, an image coordinate of a pixel corresponding to the first initial coordinate in the first calibration image and a pixel size of the first calibration image when the first calibration image is shot, wherein the feature point is positioned at the center of a view field of the first sensor when the motion platform is positioned at the first calibration coordinate;

Calculating a second calibration coordinate according to a second initial coordinate of the motion platform, an image coordinate of a pixel corresponding to the second initial coordinate in the second calibration image and a pixel size of the second calibration image when the second calibration image is shot, wherein the feature point is positioned at the center of a field of view of the second sensor when the motion platform is positioned at the second calibration coordinate;

calculating a coordinate difference value of the first calibration coordinate and the second calibration coordinate;

Establishing a calibration function between the first sensor and the second sensor according to the coordinate difference value;

according to the calibration function and the first coordinate set of the motion platform when the first sensor shoots the to-be-detected piece, calculating the second coordinate set of the motion platform when the second sensor collects the information of the to-be-detected piece; and

And determining a scanning path of the motion platform according to the second coordinate set.

2. The method of calibrating according to claim 1, wherein capturing a first calibration image of the calibration piece by the first sensor comprises:

Adjusting the motion platform so that the characteristic points are located in the depth of field range and the field of view range of the first sensor;

the shooting of the second calibration image of the calibration piece through the second sensor comprises the following steps:

And adjusting the motion platform so that the characteristic points are positioned in the depth of field range and the field of view range of the second sensor.

3. A calibration device, comprising:

the shooting module is used for shooting a first calibration image of the calibration piece through the first sensor, shooting a second calibration image of the calibration piece through the second sensor, wherein the calibration piece is driven by the motion platform and comprises characteristic points;

The first calculating module is used for calculating a first calibration coordinate according to a first initial coordinate of the moving platform, an image coordinate of a pixel corresponding to the first initial coordinate in the first calibration image and a pixel size of the first calibration image when the first calibration image is shot, wherein the characteristic point is positioned at the center of a view field of the first sensor when the moving platform is positioned at the first calibration coordinate; the method comprises the steps of shooting a first calibration image, calculating a first initial coordinate of a motion platform, an image coordinate of a pixel corresponding to the first initial coordinate in the first calibration image, and a pixel size of the first calibration image, wherein the feature point is positioned in the center of a field of view of a first sensor when the motion platform is positioned in the first calibration coordinate;

The difference value calculation module is used for calculating a coordinate difference value of the first calibration coordinate and the second calibration coordinate;

The calibration module is used for establishing a calibration function between the first sensor and the second sensor according to the coordinate difference value;

The second calculation module is used for calculating a second coordinate set of the moving platform when the second sensor collects information of the piece to be detected according to the calibration function and the first coordinate set of the moving platform when the first sensor shoots the piece to be detected;

And the determining module is used for determining the scanning path of the motion platform according to the second coordinate system.

4. A calibration apparatus, comprising:

the first sensor is used for shooting a first calibration image of the calibration piece;

the second sensor is used for shooting a second calibration image of the calibration piece;

the motion platform is used for driving the calibration piece; and

The processor is used for calculating a first calibration coordinate according to a first initial coordinate of the motion platform, an image coordinate of a pixel corresponding to the first initial coordinate in the first calibration image and a pixel size of the first calibration image when the first calibration image is shot, wherein a feature point is positioned at the center of a view field of the first sensor when the motion platform is positioned at the first calibration coordinate; calculating a second calibration coordinate according to a second initial coordinate of the motion platform, an image coordinate of a pixel corresponding to the second initial coordinate in the second calibration image and a pixel size of the second calibration image when the second calibration image is shot, wherein the feature point is positioned at the center of a field of view of the second sensor when the motion platform is positioned at the second calibration coordinate; calculating a coordinate difference value of the first calibration coordinate and the second calibration coordinate; establishing a calibration function between the first sensor and the second sensor according to the coordinate difference value; according to the calibration function and the first coordinate set of the motion platform when the first sensor shoots the to-be-detected piece, calculating the second coordinate set of the motion platform when the second sensor collects the information of the to-be-detected piece; and determining a scanning path of the motion platform according to the second coordinate system.

5. The calibration device of claim 4, wherein the motion platform is further configured to adjust the calibration member such that the feature point is within a depth of field and a field of view of the first sensor and/or the feature point is within a depth of field and a field of view of the second sensor.

6. A non-transitory computer readable storage medium storing a computer program which, when executed by one or more processors, causes the processors to perform the calibration method of any of claims 1 to 2.