TWI734451B - Calibration equipment and correction method of oral scanner - Google Patents

Abstract

A calibration equipment and a correction method of oral scanner is provided. The calibration equipment includes a base, a processing device, a calibration plate, a multi-axis device, and a fixed seat. The multi-axis device is disposed on the base and connected to the calibration plate. The processing device is configured to control the multi-axis device, so that the calibration plate is capable of moving along the X axis, the Y axis, the Z axis, or rotating around the Y axis. The calibration plate has a black and white checkerboard pattern. The fixed seat is configured to fix an oral scanner. The processing device is configured to controlling the multi-axis device to operate, so that the calibration plate is located at a plurality of different predetermined positions. The processing device controls the oral scanner to project a structured light to the calibration plate and captures an image of the calibration plate to generate a plurality of images to be corrected. The processing device is capable of correcting the stereoscopic imaging procedure of the oral scanner based on the images to be corrected.

Description

Calibration equipment and calibration method of oral scanner

The invention relates to a calibration device and a calibration method of an oral scanner, in particular to a calibration device for image correction of an oral scanner, and an oral scanner that uses the correction device to correct images of the oral scanner method.

An oral scanner is a device used to scan teeth to present a 3D stereo image of the tooth on the screen. The relevant dentist will use the 3D image produced by the oral scanner to make a stereo dental model, etc. , The 3D stereo image generated by the oral scanner must be within a predetermined specification for the error of the actual tooth size.

The existing common calibration methods of oral scanners mostly use manual methods, so that the oral scanner and components with known dimensions are first set at predetermined coordinate positions in the space, and then the oral scanner scans the components with only known dimensions. , Finally, use the predetermined coordinate position, the size of the component of known size, and the image scanned by the oral scanner to perform image correction.

However, in practical applications, when the oral scanner and components of known dimensions are manually set at the predetermined coordinate positions, it may happen that the oral scanner and the components of known dimensions are not correctly set at the predetermined coordinate positions, and Cause the subsequent image correction to be incorrect.

The present invention discloses a calibration device and a calibration method of an oral scanner. It is mainly used to improve the manual method of manually setting the oral scanner and components of known dimensions at predetermined coordinate positions for scanning and image correction operations. The oral scanner or components with known dimensions are not correctly set at the predetermined coordinate positions, which leads to the problem of incorrect subsequent image correction.

One embodiment of the present invention discloses a calibration device for calibrating an oral scanner. The calibration device includes: a base, a processing device, a calibration plate, a multi-axis device, and a fixing seat. The processing device can execute a calibration procedure. The calibration board has a calibration surface, and the calibration surface has a black and white checkerboard pattern. The multi-axis device is arranged on the base, the multi-axis device is connected to the calibration plate, and the processing device is electrically connected to the multi-axis device. The processing device can control the action of the multi-axis device, so that the calibration board moves in an X-axis direction and a Y-axis direction. , Move in a Z-axis direction or rotate with a Z-axis as the center. The fixing seat is arranged on the base, and the fixing seat is arranged adjacent to the calibration plate. The fixing seat is used to fix an oral scanner; wherein the processing device can be electrically connected with an oral scanner, and the processing device can control the oral scanner to project a structured light ( Structured Light) to the correction surface, and the processing device can control the oral scanner to capture the black and white checkerboard pattern of the correction surface projected with structured light and correspondingly generate a to-be-corrected image; wherein, when the processing device executes the correction procedure, the processing device The control multi-axis device is actuated to move the calibration plate in at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction, and the processing device will control the multi-axis device to rotate a plurality of predetermined angles around the Y-axis to make The calibration plate is located at a plurality of different predetermined positions relative to the oral scanner, and the processing device will control the oral scanner to generate the image to be corrected when the calibration plate is located at each predetermined position, and the processing device will be based on the multiple images to be corrected A three-dimensional imaging procedure of the oral scanner is calibrated; wherein a processing unit of the oral scanner can execute the three-dimensional imaging procedure to integrate a plurality of images scanned by the oral scanner into a three-dimensional image.

One of the embodiments of the present invention discloses a calibration method for an oral scanner, which is suitable for a calibration device. The calibration device includes a base, a calibration plate, a multi-axis device, and a processing device. The calibration plate has a calibration surface. There is a black and white checkerboard pattern on the front. The multi-axis device is arranged on the base. The multi-axis device is connected to the calibration board. The processing device is electrically connected to the multi-axis device. The processing device can control the action of the multi-axis device so that the calibration board is A movement in the X-axis direction, a movement in the Y-axis direction, a movement in the Z-axis direction or rotation around a Y-axis. Scanning machine, oral scanning machine The calibration method includes: a position adjustment step: using a processing device to control the action of the multi-axis device, so that a structured light (Structured Light) emitted by the oral scanner fixed on the fixed seat is projected onto the black and white checkerboard pattern of the calibration surface Above; a pattern capture step: use the processing device to control the multi-axis device to rotate the calibration plate along the Y axis for multiple predetermined angles, and control the oral scanner to project structured light on the calibration plate after each rotation of the calibration plate by a predetermined angle , And make the oral scanner capture the black and white checkerboard pattern of the correction surface projected with structured light and correspondingly generate an image to be corrected; an image calculation step: using the processing device, according to the predetermined angle of each rotation of the correction plate, The multiple images to be corrected generated by the oral scanner, the size of the correction plate, the coordinate position of the correction plate and the coordinate position of the oral scanner, calculate the focal length of a lens, a focal point, and a lens distortion of the oral scanner (lens distortion) 1. A relative translation amount and a relative rotation amount, based on which a reprojection error value of the oral scanner is calculated; a software calibration step of the oral scanner: according to the reprojection error value, a three-dimensional image of the oral scanner The imaging procedure is corrected; wherein a processing unit of the oral scanner can execute a stereo imaging procedure to integrate a plurality of images scanned by the oral scanner into a stereo image.

In summary, the calibration equipment and the calibration method of the oral scanner of the present invention, through the design of the multi-axis device and the fixed seat, can allow the user to correctly set the oral scanner and the calibration board at the predetermined coordinate position, so as to Improve the accuracy of image correction.

In order to further understand the features and technical content of the present invention, please refer to the following detailed descriptions and drawings about the present invention, but these descriptions and drawings are only used to illustrate the present invention, and do not make any claims about the protection scope of the present invention. limit.

100: Calibration equipment

1: base

2: Processing device

3: Calibration board

31: Correction surface

311: Black and White Checkerboard Pattern

4: Multi-axis device

41: The first linear slide assembly

411: First Track

412: The first slider

42: The second linear slide assembly

421: Second Track

422: second slider

43: The third linear slide assembly

431: The Third Track

432: third slider

44: Rotating component

45: Correction plate fixing seat

5: fixed seat

6: Rotating device

7: auxiliary device

P: Oral scanner

P1: Image to be corrected

P2: The first image to be corrected

P3: The second image to be corrected

P4: The third image to be corrected

Fig. 1 and Fig. 2 respectively show schematic diagrams of different viewing angles of the calibration device of the present invention.

Fig. 3 shows a block diagram of the calibration device and the oral scanner of the present invention.

Fig. 4 shows a schematic diagram of the calibration device of the present invention provided with an oral scanner.

Fig. 5 shows a top view of the calibration device of the present invention provided with an oral scanner.

6 and 7 respectively show schematic diagrams of the calibration device of the present invention provided with an oral scanner and the calibration plate rotated by a predetermined angle in different directions.

Figures 8 to 10 respectively show schematic diagrams of images to be calibrated generated by the oral scanner scanning calibration plates at different positions.

FIG. 11 shows a schematic flowchart of the calibration method of the present invention.

In the following description, if it is pointed out, please refer to the specific drawing or as shown in the specific drawing, it is only used to emphasize that in the subsequent description, most of the related content appears in the specific drawing. However, it is not limited that only the specific drawings can be referred to in this subsequent description.

Please refer to FIG. 1 and FIG. 2 together, which respectively show schematic diagrams of different viewing angles of the calibration device 100 of the present invention. The calibration device 100 is used to calibrate an oral scanner P so that the 3D stereo image generated by the oral scanner P after scanning a tooth meets the allowable error amount.

The calibration equipment 100 includes: a base 1, a processing device 2, a calibration board 3, a multi-axis device 4 and a fixing base 5. The processing device 2 can execute a calibration procedure. The processing device 2 may be, for example, various computer equipment, servers, etc., which are not limited herein. The calibration board 3 has a calibration surface 31 with a black and white checkerboard pattern 311 on the calibration surface 31. Regarding the size of the black and white checkerboard pattern 311 on the calibration surface 31 and the number of black and white squares it contains, it can be based on the relevant parameters of the oral scanner P (as shown in Figure 3) (for example, oral scanning) The angle between the projection device and the imaging device in the camera P is changed.

In practical applications, in order for the oral scanner P to better capture the black and white checkerboard pattern 311 on the calibration surface 31, the calibration plate 3 can be made of a material with low reflectivity. For example, the calibration plate 3 can It is a ceramic plate. In this way, when the oral scanner P projects structured light on the correction surface 31, the oral scanner P will not easily capture an overexposed image.

The multi-axis device 4 is arranged on the base 1, the multi-axis device 4 is connected to the calibration plate 3, and the processing device 2 is electrically connected to the multi-axis device 4. Axis direction movement, a Y axis direction movement, a Z axis direction movement or a Y axis as the center rotation. In practical applications, the multi-axis device 4 may include three linear slide assemblies and a rotary assembly 44. The three linear slide assemblies are defined as a first linear slide assembly 41 and a second linear slide assembly. 42 and a third linear slide assembly 43. The first linear slide assembly 41 includes a first track 411 and a first slider 412. The first slider 412 is disposed on the first track 411 and the first slider 412 can be along the Y axis direction relative to the first track 411 move. The second linear slide assembly 42 includes a second track 421 and a second slider 422. The second slider 422 is disposed on the second track 421 and the second slider 422 can move in the X-axis direction relative to the second track 421 . The third linear slide assembly 43 includes a third rail 431 and a third slider 432. The third slider 432 is disposed on the third rail 431 and the third slider 432 can move in the Z-axis direction relative to the third rail 431 .

The first rail 411 is fixed to the base 1, the second rail 421 is fixed to the first sliding block 412, the third rail 431 is fixed to the second sliding block 422, the rotating assembly 44 is fixed to the third sliding block 432, and the rotating assembly 44 and the correction The boards 3 are connected. Regarding the connection between the first linear slide assembly 41, the second linear slide assembly 42, and the third linear slide assembly 43, and the movement direction of each slider relative to the slide rail to which it is connected, all can be based on Changes in demand are not limited to the above description. Therefore, the processing device 2 can control the first linear slide assembly 41, the second linear slide assembly 42 or the third linear slide assembly 43 to actuate, so that the correction plate 3 moves along Y Axis direction, X-axis direction, or Z-axis direction movement.

The rotating assembly 44 can be controlled by the processing device 2 to rotate clockwise or counterclockwise with the Y axis as the center, and the rotating assembly 44 is connected to the correction plate 3, and the processing device 2 can control the rotation assembly 44 to act so as to make the correction plate 3. Rotate clockwise or counterclockwise with the Y axis as the center. In practical applications, the rotating assembly 44 is controlled by the processing device 2, and the single minimum rotation degree can be 0.1 degrees. In order to make the correction plate 3 rotate to a predetermined position more accurately. Of course, the single minimum degree of rotation of the rotating assembly 44 can be changed according to requirements, and the range can be 0.1 degrees to 60 degrees, and is not limited to 0.1 degrees.

The multi-axis device 4 may also include a correction plate fixing base 45, which is connected to the rotating assembly 44, and the correction plate fixing base 45 can follow the three linear slide assemblies and the rotating assembly 44 along the X axis and Y axis. Axis, Z-axis movement or Y-axis as the center rotation. The correction plate 3 is detachably fixed in the correction plate fixing seat 45. Through the design of the calibration board fixing seat 45, the user can replace the calibration board 3 with a new calibration board 3 when the black and white checkerboard pattern 311 of the calibration board 3 is worn out, or the user can change the calibration board 3 according to the different size and appearance of the oral scanner P , And replace the calibration board 3 with the black and white checkerboard pattern 311 of the corresponding size.

The fixing base 5 is arranged on the base 1, and the fixing base 5 is arranged adjacent to the calibration plate 3, and the fixing base 5 is used to fix an oral scanner P. In practical applications, the calibration device 100 may also include a rotating device 6 and an auxiliary device 7. The rotating device 6 is connected to the fixing base 5, and the rotating device 6 can be operated to rotate the fixing base 5 along the Z axis. The auxiliary device 7 is fixed to the base 1, and the fixing base 5 is connected with the auxiliary device 7. The auxiliary device 7 can be operated to move the fixing base 5 in at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. Through the design of the rotating device 6 and the auxiliary device 7, the user can adjust the coordinate position of the oral scanner P relative to the calibration plate 3 according to requirements. In practical applications, the rotating device 6 and the auxiliary device 7 may be manual devices or electric devices electrically connected to the processing device 2, for example.

Please refer to FIGS. 3 to 5 together. FIG. 4 shows a schematic diagram of the calibration device of the present invention equipped with an oral scanner, and FIG. 5 shows a top view of the calibration device of the present invention equipped with an oral scanner. After the oral scanner P is fixed on the fixing base 5, the oral scanner P can be electrically connected to the processing device 2 in a wired or wireless manner, and the processing device 2 can control the operation of the oral scanner P to enable the oral scanner P A structured light (Structured Light) is projected to the correction surface 31, and the processing device 2 can control the oral scanner P to capture the black and white checkerboard pattern 311 projected with the structured light, and make the oral scanner P correspondingly generate a to-be-corrected Image P1. Among them, the structured light projected by the oral scanner P to the calibration plate 3 covers the entire calibration surface 31. In practical applications, the structure of the oral scanner P projected to the correction plate 3 The light may be a black and white stripe pattern, a black and white checker pattern, a color stripe pattern, or a color checker pattern formed on the calibration surface 31, and the oral scanner P captures the calibration of the calibration plate 3. When the front side 31 is used, the black and white checkerboard pattern 311 on the correction surface 31 and the pattern projected by the oral scanner P onto the correction surface 31 are captured at the same time.

When the processing device 2 executes the calibration program, the processing device 2 will control the multi-axis device 4 to move so that the calibration plate 3 moves in at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction, and the processing device 2 will control The multi-axis device 4 rotates a plurality of predetermined angles with the Y axis as the center, so that the calibration plate 3 is located at a plurality of different predetermined positions relative to the oral scanner P, and the processing device 2 will control the oral scanner P to be positioned on the calibration plate 3 At each predetermined position, an image P1 to be corrected is generated correspondingly, and the processing device 2 will correct a stereo imaging procedure of the oral scanner P according to the plurality of images P1 to be corrected; wherein, a processing unit of the oral scanner P can execute The three-dimensional imaging program integrates multiple images scanned by the oral scanner P into a three-dimensional image. It should be noted that the correction plate 3 can also be rotated around the X axis, but it is not limited to this.

Please refer to Figures 6 to 10 together. Figures 6 and 7 respectively show schematic diagrams after the calibration plate is rotated by a predetermined angle. Figures 8 to 10 show the corresponding oral scanners in the state of Figures 5 to 7 respectively. Schematic diagram of the generated image to be corrected. In a specific implementation of the calibration device 100 of the present invention, for example, the oral scanner P may be set on the fixed seat 5, and the oral scanner P is correspondingly located directly above the calibration plate 3, and the calibration surface 31 of the calibration plate 3 is substantially parallel. On the ground (as shown in FIG. 5), the processing device 2 is used to control the oral scanner P to project structured light to the calibration plate 3, and to capture an image from the calibration plate 3 to generate a first image as shown in FIG. The image P2 to be corrected; then, the processing device 2 activates the control rotating component 44 to rotate the calibration plate 3 clockwise with the Y axis as the center by a predetermined angle, and causes the oral scanner P to project structured light on the calibration plate 3, and It performs image structure to generate a second image to be corrected P3; then, the processing device 2 can control the rotation component 44 to act, so that the correction plate 3 rotates counterclockwise with the Y axis as the center, and the oral scanner P corrects the correction. The board 3 projects structured light and performs image capture on it to generate a third image P4 to be corrected.

After the processing device 2 obtains the first image to be corrected P2, the second image to be corrected P3, and the third image to be corrected P4, the processing device 2 can cooperate with the calibration plate 3 and the oral scanner in FIGS. 5, 6 and 7 Related parameters known to P, such as the coordinates of the calibration plate 3 in space, the coordinates of the oral scanner P in space, the vertical distance between the calibration plate 3 and the oral scanner P, the rotation angle of the calibration plate 3, etc., are calculated A lens focal length, a focal point, a lens distortion, a relative translation, and a relative rotation of the oral scanner P. Finally, the processing device 2 can be calculated based on The lens focal length (focal length), focus (focal point), lens distortion (lens distortion), relative translation amount and relative rotation amount, compared with the actual parameters of the oral scanner P, according to the correction of the oral scanner P The said stereo imaging program. In particular, in practical applications, in order to effectively calibrate the oral scanner P, the processing device 2 may control the oral scanner P to sequentially capture images of calibration plates 3 located at more than 10 different predetermined positions.

Please refer to FIG. 11, which shows a schematic flowchart of the calibration method of the oral scanner of the present invention. The calibration method of the oral scanner of the present invention is suitable for the aforementioned calibration equipment. The calibration method of the oral scanner includes: a position adjustment step S1: using a processing device to control the action of the multi-axis device, so that the oral scanner fixed on the fixed seat A structured light (Structured Light) is emitted corresponding to the black and white checkerboard pattern projected on the calibration surface; a pattern capture step S2: the processing device is used to control the multi-axis device to rotate the calibration board along the Y axis for a number of predetermined Angle, and control the oral scanner to project structured light on the calibration plate after each rotation of the calibration plate by a predetermined angle, and make the oral scanner capture the black and white checkerboard pattern projected with the structured light to correspondingly generate a to-be-corrected image; An image calculation step S3: using the processing device, according to the predetermined angle of each rotation of the calibration plate, a plurality of images to be calibrated generated by the oral scanner, the size of the calibration plate, the coordinate position of the calibration plate and the coordinate position of the oral scanner, Calculate a lens focal length (focal length), a focal point (focal point), a lens distortion (lens distortion), A relative translation amount and a relative rotation amount are used to calculate a reprojection error value of the oral scanner; a software calibration of the oral scanner. Step S4: According to the reprojection error value, a stereo image of the oral scanner is calculated. The imaging procedure is calibrated; wherein a processing unit of the oral scanner can execute a stereo imaging procedure to integrate a plurality of images scanned by the oral scanner into a stereo image.

In practical applications, after the oral scanner software calibration step S4, it may also include a verification step: a verification member with a predetermined size is set on the calibration plate, and the oral scanner scans the verification member to obtain the oral scan A three-dimensional image generated by the machine through a three-dimensional imaging program; the processing device is used to compare the three-dimensional image and the verification component to calculate a corresponding re-projection error value; if the processing device determines that the re-projection error value is higher than 0.05 mm (mm ), for example, the processing device sends out a prompt message to remind the user that the oral scanner still needs to be calibrated again. In contrast, if the processing device determines that the reprojection error value is less than 0.05 millimeters (mm), the processing device may send another prompt message to remind the user that the oral scanner has been calibrated. It should be noted that the error value setting range can be 0.01 millimeters (mm) to 100 millimeters (mm), but it is not limited to this.

In practical applications, in the aforementioned pattern capturing step S2, the processing device 2 may control the action of the multi-axis device 4 so that the calibration plate 3 moves along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction, and The processing device 2 also controls the multi-axis device 4 to rotate a plurality of predetermined angles with the Y axis as the center, so that the calibration plate 3 is located at 10 or more different predetermined positions relative to the oral scanner P, thereby enabling the oral scanner P to Correspondingly, more than 10 images P1 to be corrected are generated. In other words, in the aforementioned pattern capturing step S2, the processing device 2 can control the action of the multi-axis device 4 so that the calibration plate 3 is relatively The oral scanner P moves along the X-axis, Y-axis, and Z-axis directions, and rotates around the Y-axis, so that the oral scanner P correspondingly captures the black and white chessboards on the calibration plate 3 at different positions According to the grid pattern, a plurality of images to be corrected P1 are generated.

In particular, the oral scanner that uses structured light to reconstruct three-dimensional images mainly uses a projection device (such as a laser light emitter) to project a predetermined pattern onto the surface of the tooth, and then uses an imaging device (such as a photosensitive coupling). CCD or complementary metal oxide semiconductor (CMOS), captures the tooth and a predetermined pattern projected on its surface to generate image information, and then calculates the coordinates of the tooth in space and the coordinates of the projection device in space based on the image information , The coordinates of the imaging device in the space and other information, combined with the principle of triangulation measurement method, to calculate and establish the three-dimensional contour of the tooth. Therefore, one of the important factors affecting whether the oral scanner P can establish the correct three-dimensional contour of the tooth is whether the oral scanner can correctly calculate the coordinates of the teeth in space and the coordinates of the projection device in space based on the image information. , The coordinates of the imaging device in space and other information.

The above-mentioned calibration method and calibration equipment of the present invention, through the design of a multi-axis device and a fixed seat, allow the user to set the oral scanner and the calibration board at predetermined coordinates, and then correctly calibrate the stereo imaging in the oral scanner The procedure, by this, enables the corrected oral scanner to correctly construct the corresponding three-dimensional image based on the image information captured by it.

The above descriptions are only the preferred and feasible embodiments of the present invention, which do not limit the scope of the present invention. Therefore, all equivalent technical changes made by using the description and drawings of the present invention are included in the protection scope of the present invention. .

100: Calibration equipment

1: base

3: Calibration board

31: Correction surface

311: Black and White Checkerboard Pattern

4: Multi-axis device

41: The first linear slide assembly

42: The second linear slide assembly

421: Second Track

422: second slider

43: The third linear slide assembly

431: The Third Track

432: third slider

44: Rotating component

45: Correction plate fixing seat

5: fixed seat

6: Rotating device

7: auxiliary device

Claims (10)

A calibration device for performing image calibration on an oral scanner. The calibration device includes: a base; a processing device capable of executing a calibration procedure; a calibration plate having a calibration surface, the calibration surface There is a black and white checkerboard pattern; a multi-axis device, which is arranged on the base, the multi-axis device is connected to the calibration plate, the processing device is electrically connected to the multi-axis device, and the processing device The multi-axis device can be controlled to move, so that the correction plate moves in an X-axis direction, a Y-axis direction, a Z-axis direction, or rotates with a Z-axis as the center; The base, and the fixing seat is arranged adjacent to the calibration plate, and the fixing seat is used to fix an oral scanner; wherein, the processing device can be electrically connected with an oral scanner, and the processing device can control all The oral scanner projects a structured light to the correction surface, and the processing device can control the oral scanner to capture the black and white checkerboard on the correction surface projected with the structured light Grid pattern and correspondingly generate a to-be-corrected image; wherein, when the processing device executes the correction program, the processing device will control the action of the multi-axis device so that the correction plate is moved along the X-axis direction and At least one of the Y-axis direction and the Z-axis direction is moved, and the processing device will control the multi-axis device to rotate a plurality of predetermined angles with the Y-axis as the center, so that the correction plate is relative to the The oral scanner is located at a plurality of different predetermined positions, and the processing device will control the oral scanner to generate the image to be corrected when the calibration plate is located at each of the predetermined positions, and the The processing device will perform a three-dimensional formation of the oral scanner according to the plurality of images to be corrected The image program is calibrated; wherein a processing unit of the oral scanner can execute the three-dimensional imaging program to integrate a plurality of images scanned by the oral scanner into a three-dimensional image. The calibration device according to claim 1, wherein the multi-axis device includes three linear slide components and a rotating component, and the three rotating components are defined as a first linear slide component and a second linear slide component. Linear slide rail assembly and a third linear slide rail assembly, a first rail of the first linear slide rail assembly is fixed to the base, and a second rail of the second linear slide rail assembly is fixed to the A first slider of the first linear slide assembly, a third track of the third linear slide assembly is fixed to a second slider of the second linear slide assembly, and the rotating assembly is fixed to A third sliding block of the third linear slide rail assembly, and the rotating assembly is connected with the correction plate. The calibration device according to claim 1, wherein the calibration device further includes a rotating device connected to the fixing base, and the rotating device can be operated to rotate the fixing base along the Z axis. The calibration device according to claim 1, wherein the calibration device further includes an auxiliary device, the auxiliary device is fixed to the base, the fixing base is connected to the auxiliary device, and the auxiliary device can be operated The fixed seat is moved along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. The correction device according to claim 1, wherein the correction plate is a ceramic plate. The correction device according to claim 1, wherein the structured light projected by the oral scanner to the correction plate will form a black and white striped pattern or a black and white checkerboard pattern corresponding to the correction surface . A calibration method for an oral scanner, which is suitable for a calibration device, which includes a base, a calibration plate, a multi-axis device, and a fixed seat And a processing device, the calibration board has a calibration surface, the calibration surface has a black and white checkerboard pattern, the multi-axis device is arranged on the base, and the multi-axis device is connected to the calibration board, The processing device is electrically connected to the multi-axis device, and the processing device can control the action of the multi-axis device so that the correction plate moves in an X-axis direction, a Y-axis direction, and a Z-axis direction. Or rotate with a Y axis as the center, the fixing seat is arranged on the base, and the fixing seat is arranged adjacent to the calibration plate, and the fixing seat is used to fix an oral scanning machine to be calibrated, and the oral scanning The calibration method of the machine includes: a position adjustment step: using the processing device to control the action of the multi-axis device, so that a structured light (Structured Light) emitted by the oral scanner fixed on the fixing base is projected To the black and white checkerboard pattern of the calibration surface; a pattern capturing step: use the processing device to control the multi-axis device so that the calibration plate rotates a plurality of predetermined angles along the Y axis , And control the oral scanner to project the structured light on the correction plate after each rotation of the correction plate by the predetermined angle, and make the oral scanner capture all the structured light projected The black and white checkerboard pattern of the correction surface corresponds to an image to be corrected; an image calculation step: using the processing device, according to the predetermined angle of each rotation of the correction plate, the oral scan A plurality of the images to be corrected, the size of the correction plate, the coordinate position of the correction plate and the coordinate position of the oral scanner generated by the machine, calculate a lens focal length, a focal point, and a focal point of the oral scanner. A lens distortion, a relative translation, and a relative rotation, based on which a reproiection error value of the oral scanner is calculated; a software calibration step of the oral scanner: according to the above Reprojection error value, right A stereo imaging procedure of the oral scanner is calibrated; wherein a processing unit of the oral scanner can execute the stereo imaging procedure to integrate a plurality of images scanned by the oral scanner into a stereo image. The calibration method of an oral scanner according to claim 7, wherein after the software calibration step of the oral scanner, it further includes a verification step: a verification member with a predetermined size is set on the calibration plate, and The oral scanner scans the verification component to obtain a three-dimensional image generated by the oral scanner through the three-dimensional imaging program; the processing device is used to compare the three-dimensional image and the verification component , To calculate the re-projection error value; if the processing device determines that the re-projection error value is higher than 0.01 mm, the processing device sends out a prompt message to remind the user that the oral scanner still needs to be calibrated again . The calibration method of an oral scanner according to claim 7, wherein the calibration plate is a ceramic plate, and the structured light projected by the oral scanner to the calibration plate will form black and white corresponding to the calibration surface. Alternate stripes pattern or black and white checkerboard pattern. The calibration method of the oral scanner according to claim 7, wherein, in the pattern capturing step, the processing device will control the action of the multi-axis device so that the calibration plate is along the X-axis direction , At least one of the Y-axis direction and the Z-axis direction is moved, and the processing device will control the multi-axis device to rotate a plurality of the predetermined angles with the Y-axis as the center to make the correction The board is located at a plurality of predetermined positions different from each other with respect to the oral scanner.

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