Calibration system, camera module and 3D scanner

Abstract

This invention provides a calibration system, a camera module, and a 3D scanner, belonging to the field of photography. The system includes a camera module, a rotating stage, and at least one image display device. The camera module is located on the rotating stage and includes an open-loop motor. The at least one image display device is configured to orbit the rotating stage at intervals. The rotating stage is used to rotate the camera module to adjust the orientation of the camera module's lens relative to the at least one image display device, enabling focus calibration when the camera module's lens is in multiple target poses. Specifically, when the camera module is in one target pose, one image display device is located in the direction of the camera module's lens. Using the system provided by this invention, focus calibration of the camera module can be performed in different poses, which helps improve the accuracy of focus control.

Description

Technical Field

[0001] This utility model relates to the field of camera technology, and in particular to a calibration system, a camera module, and a 3D scanner. Background Technology

[0002] The camera is one of the key devices in a 3D scanner. During the 3D scanning process, it is usually necessary to keep the camera's intrinsic parameters constant, which means that the relative position between the lens and the image sensor in the camera module must be fixed to ensure the clarity of the camera image.

[0003] In camera modules, the relative position between the lens and the image sensor is controlled by a focusing motor. However, in 3D scanners, cameras are increasingly adopting open-loop motors as focusing motors, and the drive commands of these open-loop motors correspond to drive current values. Due to the influence of gravity or other environmental characteristics, the relative position between the lens and the image sensor changes when the 3D scanner is in different postures. Even with the same drive current, it may be impossible to drive the lens and image sensor to maintain the correct focusing distance through the focusing motor. Therefore, it is necessary to calibrate the drive current values ​​of the open-loop motor under different postures. Utility Model Content

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention exemplarily provides a calibration system, comprising:

[0006] A camera module, a rotating platform, and at least one image display device, wherein the camera module is located on the rotating platform, the camera module includes an open-loop motor, and the at least one image display device is configured to be spaced around the rotating platform.

[0007] The rotating platform is used to rotate the camera module to adjust the orientation of the camera module's lens relative to the at least one image display device, so that the camera module's lens is in multiple target poses for focus calibration, wherein when the camera module is in one of the target poses, an image display device is located in the direction of the camera module's lens.

[0008] The calibration system described above may optionally include:

[0009] A guide rail is fixedly connected to the rotating platform, and the camera module is slidably connected to the guide rail. When the camera module is in the target pose, the distance between the camera module and an image display device located in the lens direction is adjusted so that the camera module can be calibrated at multiple working distances.

[0010] The calibration system described above may optionally include:

[0011] case;

[0012] The rotating platform is located in the middle of the housing, and the at least one image display device is spaced apart on the inner wall of the housing and distributed in the rotation direction of the rotating platform.

[0013] Optionally, in the above-mentioned calibration system, the at least one image display device includes a first image display device, a second image display device, and a third image display device;

[0014] The first image display device is disposed on the inner wall directly above the inside of the housing;

[0015] The second image display device is disposed on the inner wall on the right side inside the housing;

[0016] The third image display device is located on the inner wall directly below the interior of the housing.

[0017] Optionally, in the above-mentioned calibration system, the at least one image display device includes a fourth image display device and a fifth image display device;

[0018] The fourth image display device is disposed on the inner wall directly above the inside of the housing;

[0019] The fifth image display device is located inside the shell, directly below it.

[0020] Optionally, the above-mentioned calibration system may include only one image display device among the at least one image display device;

[0021] The image display device is fixedly connected to the guide rail, and the position of the image display device corresponds to the lens direction of the camera module.

[0022] Alternatively, the image display device is a mountable device, and when the camera module is in the target pose, the image display device is mounted in the lens direction of the camera module.

[0023] Optionally, in the above calibration system, the open-loop motor is configured to be driven by input DAC commands, and a reset operation is performed on the open-loop motor before the next DAC command is input during the focus calibration process.

[0024] In the above-described calibration system, optionally, the plurality of target poses include a first pose, a second pose, and a third pose;

[0025] The first pose is one where the camera is facing vertically upwards;

[0026] The second pose is one where the camera is positioned horizontally to the right.

[0027] The third pose is the pose where the camera is facing vertically downwards.

[0028] Secondly, this utility model provides an exemplary camera module, which uses the calibration system described above for focus calibration.

[0029] Thirdly, this utility model provides an exemplary 3D scanner, including the camera module described above.

[0030] A calibration system based on the above-described embodiment of the present invention includes: a camera module, a rotating platform, and at least one image display device. The camera module is located on the rotating platform and includes an open-loop motor. The at least one image display device is configured to be spaced around the rotating platform. The rotating platform is used to rotate the camera module to adjust the orientation of the camera module's lens relative to the at least one image display device, enabling focus calibration when the camera module's lens is in multiple target poses. Specifically, when the camera module is in one target pose, one image display device is located in the direction of the camera module's lens. Using the calibration system provided by this embodiment, the pose of the camera module to be calibrated can be adjusted using the rotating platform, enabling focus calibration of the camera module under different poses. The system provided by this utility model embodiment can complete the focus calibration of the camera module under different poses, thereby obtaining the open-loop motor calibration drive current value corresponding to multiple poses. Based on the open-loop motor calibration drive current value, the drive current value corresponding to other different poses can be obtained by interpolation. During the shooting process of the camera in a spatial environment, the drive current value matched to the current pose can be determined based on the open-loop motor calibration drive current value or the interpolated drive current value obtained by interpolation. This drives the open-loop motor to control the distance between the lens and the image sensor in the camera module, thereby performing focus control and improving the accuracy of focus control. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 A schematic diagram of the structure of a calibration system provided in an embodiment of this utility model;

[0033] Figure 2 Another structural schematic diagram of a calibration system provided in this embodiment of the present utility model;

[0034] Figure 3 Example diagram of an engineering drawing of a calibration system provided for an embodiment of this utility model;

[0035] Figure 4 Another structural schematic diagram of a calibration system provided in this embodiment of the present utility model;

[0036] Figure 5 A calibration image provided for an embodiment of this utility model. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0038] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] It should be noted that in this application, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0040] 3D scanners can be used to scan objects to obtain scanned data representing those objects. For example, a 3D scanner can be a handheld scanner that a user can hold and scan an object at a free distance and angle; a 3D scanner can be a fixed scanner fixed in physical space that moves / rotates the object; or a 3D scanner can be a portable scanner mounted on a mobile vehicle, such as a vehicle. It should be understood that this document does not impose any limitations on the specific form of the 3D scanner, as long as it can satisfy the requirement of scanning an object and obtaining object data.

[0041] Exemplarily, a 3D scanner may also include a projector for projecting light / patterns, such as a multispectral laser generator, a speckle generator, or other suitable pattern generator. To capture light reflected from an object or patterns overlaid on the object, the 3D scanner may also include one or more cameras, or a camera array of multiple cameras. In some examples, the one or more cameras may include a combination of one or more monochrome cameras or one or more color cameras.

[0042] It is understandable that a black and white camera can be configured to primarily acquire point cloud data related to the object in order to reconstruct the object's 3D model, while a color camera can be configured to primarily acquire texture information related to the object and apply the texture to the reconstructed 3D model through texturing. Typically, it is required that the intrinsic parameters of the color camera do not change during the texturing process, that is, the lens of the color camera is fixed relative to the image sensor.

[0043] In exemplary 3D scanning scenarios, such as when the distance between the 3D scanner and the object is fixed, the 3D scanner's camera typically maintains fixed intrinsic parameters to ensure image quality. However, the 3D scanner needs to capture images of the object from different angles. The camera module will then assume different postures, and the lens will also be in different equilibrium positions due to the influence of gravity under these different postures. In other words, the driving force required to maintain fixed intrinsic parameters varies depending on the posture. For cameras using closed-loop motors, the DAC (Digital-to-Analog Conversion) command corresponds to displacement, meaning that closed-loop motors can relatively easily meet the requirement of constant camera intrinsic parameters. However, for open-loop motors, the DAC command corresponds to the drive current value. Due to the influence of gravity, the same drive current results in different drive strokes for the camera module in different postures. This causes the camera lens to be unable to remain fixed relative to the image sensor, effectively changing the camera's intrinsic parameters and leading to texture mapping failure.

[0044] Therefore, it is necessary to perform focus calibration on the camera module of a camera, such as a color camera, under different postures (or shooting poses), that is, to calibrate the drive current value of the open-loop motor required to keep the lens and image sensor relatively fixed under different postures at the same shooting distance.

[0045] This utility model provides a calibration system, the structural schematic diagram of which is shown below. Figure 1 As shown, it should be noted that Figure 1 The illustration shows an example of a system configured with multiple image display devices. In a specific implementation, the system may also be configured with only a single image display device. In the case of deploying only a single image display device, the image display device may be an assemblable device or a device that can rotate with the camera module.

[0046] The system provided in this embodiment of the utility model includes:

[0047] The camera module 101, the rotating platform 102, and at least one image display device 103 are provided. The camera module 101 is located on the rotating platform 102. The camera module 101 includes an open-loop motor. The at least one image display device 103 is configured to be spaced around the rotating platform 102.

[0048] The rotating platform 102 is used to rotate the camera module 101 to adjust the orientation of the lens of the camera module 101 relative to the at least one image display device 103, so that the lens of the camera module 101 is in multiple target poses for focus calibration. When the camera module 101 is in one of the target poses, an image display device 103 is located in the direction of the lens of the camera module 101.

[0049] The calibration system provided in this embodiment of the invention can be used to calibrate the focus of a camera module in a 3D scanner, such as a color camera. The focusing motor of the camera module in this embodiment is an open-loop motor, and the DAC command of the open-loop motor corresponds to the drive current value. Using the system provided in this embodiment, the camera module can be adjusted to a corresponding pose, allowing it to capture a calibration image displayed on an image display device in the lens direction. During the capture process, the drive current value of the open-loop motor can be continuously adjusted to obtain images captured by the camera module under different drive current values. A focusing algorithm (e.g., gradient method) is used to calculate the drive current value corresponding to the maximum sharpness, thereby obtaining the calibration current value of the open-loop motor corresponding to the camera module in the corresponding pose. The specific structure of the system provided in this embodiment of the invention will be described below.

[0050] The system provided in this embodiment of the utility model includes a rotating platform, a camera module, and at least one image display device. The camera module is fixedly mounted on the rotating platform, which is positioned to rotate clockwise or counterclockwise in a vertical plane. The rotation axis of the rotating platform (e.g., Figure 1 The dashed dot at the center of the rotary table (shown in the diagram) is perpendicular to the direction of gravity (i.e., vertically downward). The rotary table can be used to rotate the camera module, thereby adjusting the lens orientation of the camera module in the vertical plane. In practical applications, the posture of the camera module to be calibrated can be selected as needed, i.e., various target poses can be set, and the rotation range of the rotary table should be sufficient to adjust the camera module to each target pose. The target pose can be measured by the angle between the lens orientation and the vertically upward direction.

[0051] In the system provided by this embodiment of the invention, at least one image display device can be configured as needed to display pre-configured calibration images. The image display device can be any object capable of displaying images, such as a monitor or printed material. The pattern of the calibration image can be selected according to actual needs; for example, existing conventional calibration images, such as a checkerboard pattern, can be selected, or a custom calibration pattern can be designed without affecting the functionality of this embodiment. The number of image display devices can be selected based on the number of target poses and the installation method of the image display devices, ensuring that when the camera module is in each target pose, a corresponding image display device exists in the lens direction to capture the calibration image. It is understood that if multiple image display devices are configured, each image display device can correspond one-to-one with each target pose; when the camera module is in a certain target pose, the image display device corresponding to that target pose is in the lens direction. For example… Figure 1 The illustrated structure shows an example of deploying three image display devices, each positioned directly above, to the right of, and below the camera module, respectively. This allows for calibration of the camera module's lens orientation (up, down, and right). If only a single image display device is configured, it will be aligned with the lens orientation regardless of the camera module's target pose. For example, if the image display devices are fixed in position, a corresponding device can be positioned in the direction corresponding to each target pose. Figure 1 The architecture shown features an image display device positioned vertically upwards, vertically downwards, and horizontally to the right. If the image display devices are installed in a movable manner, only a single device needs to be installed, allowing it to adjust to the position of the camera module and be aligned with the camera lens. For example, the image display device could rotate with the camera module, or it could be detached and mounted in different locations.

[0052] In practical applications, various support devices such as racks can be used to fix rotating tables, image display devices, and other equipment in their respective positions.

[0053] By applying the system provided in this embodiment of the utility model, the camera module can be positioned in each target pose for focusing calibration through the adjustment of the rotary table. Through calibration, the open-loop motor drive current value of the camera module corresponding to different target poses can be obtained.

[0054] The calibration system provided by this embodiment includes: a camera module, a rotating platform, and at least one image display device. The camera module is located on the rotating platform and includes an open-loop motor. The at least one image display device is configured to orbit the rotating platform at intervals. The rotating platform is used to rotate the camera module to adjust the orientation of the camera module's lens relative to the at least one image display device, enabling focus calibration when the camera module's lens is in multiple target poses. Specifically, when the camera module is in one target pose, one image display device is located in the direction of the camera module's lens. By applying the calibration system provided by this embodiment, the pose of the camera module to be calibrated can be adjusted using the rotating platform, enabling focus calibration of the camera module under different poses. The system provided by this utility model embodiment can complete the focus calibration of the camera module under different poses, thereby obtaining the open-loop motor calibration drive current value corresponding to multiple poses. Based on the open-loop motor calibration drive current value, the drive current value corresponding to other different poses can be obtained by interpolation. During the camera shooting process, the drive current value matched to the current pose can be determined based on the open-loop motor calibration drive current value or the drive current value obtained by interpolation, thereby performing focus control, which is beneficial to improving the accuracy of focus control.

[0055] exist Figure 1 Based on the calibration system shown, this embodiment of the present invention provides another calibration system, which further includes:

[0056] A guide rail is fixedly connected to the rotating platform, and the camera module is slidably connected to the guide rail. When the camera module is in the target pose, the distance between the camera module and an image display device located in the lens direction is adjusted so that the camera module can be calibrated at multiple working distances.

[0057] The structural schematic diagram of the calibration system provided in this embodiment of the utility model is shown below. Figure 2 As shown, the calibration system includes: a camera module 201, a rotating stage 202, a guide rail 203, and an image display device 204. It should be noted that... Figure 2 The structure shown is only one embodiment of using multiple image display devices and is not intended to limit the number or deployment location of image display devices.

[0058] In the system provided by this embodiment of the invention, the guide rail is fixedly connected to the rotary table. Rotation of the rotary table causes the guide rail to rotate, and the camera module rotates accordingly. The camera module can be fixed to the guide rail by a clamp, forming a sliding connection with the guide rail. Based on this sliding connection, the camera module can move along the guide rail, thereby adjusting its position in that direction, i.e., adjusting the distance (or shooting distance) between the camera module and the corresponding image display device. This determines the appropriate focal length at which the camera module can maintain good shooting results and the corresponding drive current value of the open-loop motor that adjusts the camera module to that appropriate focal length. When the camera module is adjusted to the desired position, it can be fixed to the guide rail using a locking device (e.g., a buckle, a clip, or any other suitable fixing device).

[0059] In the system provided by this embodiment, the guide rail can be used to adjust the distance between the camera module and the image display device in the direction of its lens. When the camera module is in a certain target pose, it can slide along the guide rail to change the distance between the camera module and the image display device in the direction of its lens, adjusting the distance between the camera module and the corresponding image display device to a preset working distance. After the calibration of the current working distance in the current pose is completed, the distance between the camera module and the image display device can be adjusted to another preset working distance, allowing the camera module to perform focus calibration at different working distances. Calibrating the camera module at the working distance can obtain the focal length corresponding to the scene with better shooting effect and the drive current value corresponding to the open-loop motor.

[0060] Based on the calibration system provided in this embodiment, during the focus calibration process, the distance between the camera module and the image display device in the corresponding pose can be adjusted by the guide rail. This allows for focus calibration of the camera module at different working distances, thus enabling focus calibration of the camera module at different poses and working distances. This provides multiple sets of open-loop motor calibration drive current values ​​corresponding to different poses and working distances, which helps to further improve the accuracy of focus control.

[0061] Based on the system provided in the above embodiments, the calibration system provided in this utility model embodiment further includes:

[0062] case;

[0063] The rotating platform is located in the middle of the housing, and the at least one image display device is spaced apart on the inner wall of the housing and distributed in the rotation direction of the rotating platform.

[0064] The system provided in this embodiment of the utility model includes a housing, a rotating platform, a guide rail (if any), a camera module, and various image display devices. These can be deployed inside the housing using appropriate support devices (e.g., brackets), fitting, snap-fitting, snap-fitting, or other suitable connection / fixing methods. Each image display device can be mounted on the inner wall of the housing, while the rotating platform is located in the center of the housing, specifically on a vertical inner wall, or via appropriate support devices. Each image display device is positioned along the rotation direction of the rotating platform, or the rotating platform can be understood as being positioned in the direction each image display device faces. When the camera module is adjusted to a target pose by rotating the platform, one image display device is positioned in the lens direction of the camera module.

[0065] In the system provided by this embodiment of the invention, the housing can be a chassis structure or other device structures. For example, the housing can be a chassis with five closed sides and one open side. The rotary table can be deployed against the inner wall of the back of the chassis. In the vertical direction, the rotary table can be deployed in the middle of the chassis, while the image display devices can be deployed on the remaining inner walls of the chassis. If the number of image display devices is the same as the number of target poses, then each image display device can be fixedly installed on the inner wall corresponding to its corresponding target position. If the number of image display devices is less than the number of target poses, then each image display device can adopt an assemblable design, allowing the image display devices to be assembled in the required positions.

[0066] Based on the system provided in this embodiment, the camera module calibration process can be performed inside the housing, eliminating interference from the external environment and improving calibration accuracy. Secondly, the image display devices are mounted on the inner wall of the housing, maximizing the distance between the camera module and the image display devices within the housing, thus expanding the working distance range of the camera module and meeting different working distance calibration requirements. Furthermore, the image display devices are fixed to the inner wall of the housing, providing stable support and reducing interference to components such as the rotary table and guide rails, thereby improving system stability.

[0067] Based on the system provided in the above embodiments, the system provided in this utility model embodiment includes a first image display device, a second image display device, and a third image display device;

[0068] The first image display device is disposed on the inner wall directly above the inside of the housing;

[0069] The second image display device is disposed on the inner wall on the right side inside the housing;

[0070] The third image display device is located on the inner wall directly below the interior of the housing.

[0071] The system provided in this embodiment of the present invention includes a first image display device, a second image display device, and a third image display device. The first image display device is vertically upward corresponding to the lens direction, meaning it is located directly above the camera module. In this embodiment, the first image display device is mounted on the inner wall of the housing, directly above the camera module, using a bracket or other components. The second image display device is horizontally to the right corresponding to the lens direction, meaning it is located directly to the right of the camera module. In this embodiment, the second image display device is mounted on the inner wall of the housing, directly to the right, using a bracket or other components. The third image display device is vertically downward corresponding to the lens direction, meaning it is located directly below the camera module. In this embodiment, the third image display device is mounted on the inner wall of the housing, directly below the camera module, using a bracket or other components. Based on the above image display device settings, the camera module can be calibrated for focus in three target poses: 0°, 90°, and 180° (with the vertical upward direction as 0°), and the open-loop motor calibration drive current value in these three poses can be obtained. The drive current value in all other angles can be accurately interpolated.

[0072] To better illustrate the system provided in the embodiments of this utility model, Figure 3 An example of an engineering drawing of a calibration system is shown, wherein the system includes a camera module 301, a rotary table 302, a guide rail 303, a first image display device 304, a second image display device 305, a third image display device 306, and a housing 307.

[0073] The system provided by this utility model embodiment can meet the calibration requirements of the camera module in three poses: vertically upward, horizontally to the right, and vertically downward. Based on the calibration data of these three poses, the driving current value within the corresponding angle range can be effectively interpolated, which helps to improve the accuracy of the driving current value calculation.

[0074] Based on the calibration system provided in the above embodiments, this embodiment provides yet another calibration system. In the system provided by this utility model embodiment, the at least one image display device includes a fourth image display device and a fifth image display device.

[0075] The fourth image display device is disposed on the inner wall directly above the inside of the housing;

[0076] The fifth image display device is located inside the shell, directly below it.

[0077] The system provided in this embodiment of the invention includes a fourth image display device and a fifth image display device. The fourth image display device is vertically upward, corresponding to the lens direction, and is located directly above the camera module. The fifth image display device is vertically downward, corresponding to the lens direction, and is located directly below the camera module. In this embodiment, the fourth image display device is mounted on the inner wall directly above the camera module's interior using a bracket or other components, and the fifth image display device is mounted on the inner wall directly below the camera module's interior. Based on the above-mentioned image display device configuration, focusing calibration of the camera module can be achieved at 0° and 180° (with the vertically upward direction as 0°), obtaining the corresponding open-loop motor calibration drive current values. Based on these two open-loop motor calibration drive current values, interpolation can be performed on the drive current values ​​at all other angles.

[0078] The system provided by this utility model embodiment can meet the calibration requirements of the camera module in poses such as vertically upward and vertically downward in the lens direction. Based on the calibration data of these two poses, the driving current value in the corresponding angle range can be interpolated and calculated. The driving current value in all directions can be calculated with fewer image display devices.

[0079] Based on the calibration system provided in the above embodiments, this utility model provides yet another calibration system. In the system provided by this utility model, the at least one image display device includes only one image display device.

[0080] In one embodiment where only one image display device is provided, the image display device is fixedly connected to the guide rail, and the position of the image display device corresponds to the lens direction of the camera module.

[0081] In the system provided by this utility model embodiment, only a single image display device is provided. The image display device can be fixedly connected to the guide rail through components such as clamps. The image display device is located in the lens direction of the camera module. The image display device will rotate with the rotation of the guide rail. Therefore, when the camera module is in different positions, the image display device is always in the lens direction.

[0082] To better illustrate the system provided in the embodiments of this utility model, such as Figure 4The system, as shown, includes a camera module 401, a rotating platform 402, a guide rail 403, and an image display device 404. The solid circle in the center of the rotating platform represents the rotation axis. The camera module is mounted on the guide rail, and the image display device is located at the other end of the guide rail. The calibration image displayed by the image display device is opposite to the lens direction of the camera module. In this structure, when the rotating platform rotates, causing the guide rail to rotate, the camera module and the image display device will rotate synchronously, allowing the camera module to capture images directly facing the calibration image from different positions.

[0083] In another embodiment where only one image display device is provided, the image display device is an assemblable device, and when the camera module is in the target pose, the image display device is mounted in the lens direction of the camera module.

[0084] In the system provided by this embodiment of the invention, the image display device can be designed to be detached and assembled in different positions. When the camera module is in a corresponding target pose, the image display device can be assembled in the direction of the camera module's lens. For example, when the camera module is in a vertically upward pose, the image display device is assembled directly above the camera module; when the camera module is in a vertically downward pose, the image display device is assembled directly below the camera module.

[0085] Based on the system provided by this utility model embodiment, the calibration image display of the camera module in different poses can be realized based on a single image display device, which helps to reduce the number of system components.

[0086] Based on the calibration system provided in the above embodiments, in the system provided by this utility model embodiment, the open-loop motor is configured to be driven by input DAC commands, and a reset operation is performed on the open-loop motor before the next DAC command is input during the focusing calibration process.

[0087] In the system provided by this embodiment of the present invention, the open-loop motor in the camera module is configured to be driven by DAC (Digital-to-Analog Conversion) instructions. During the focusing calibration process, the open-loop motor will be driven based on the input DAC instructions. After completing the response to the current DAC instruction, before inputting the next DAC instruction, the open-loop motor will be reset by the zero-current DAC instruction to eliminate backlash error and ensure the accuracy of the motor's movement position under the drive of the next DAC instruction.

[0088] Based on the system provided in the above embodiments, the system provided in this utility model embodiment includes a first pose, a second pose, and a third pose.

[0089] The first pose is one where the camera is facing vertically upwards;

[0090] The second pose is one where the camera is positioned horizontally to the right.

[0091] The third pose is the pose where the camera is facing vertically downwards.

[0092] In the system provided by this embodiment of the utility model, each pre-set target pose includes at least three poses: a pose with the camera facing vertically upward, a pose with the camera facing horizontally to the right, and a pose with the camera facing vertically downward. Specifically, it can correspond to... Figure 3 The deployment of the image display device presented by the structure shown.

[0093] Based on the system provided by this utility model embodiment, the camera module can be focused and calibrated under the above three poses, and calibration data under these three poses can be obtained, which is beneficial for interpolation compensation of poses at other angles.

[0094] Based on the system provided in the above embodiments, in the system provided in this utility model embodiment, the image display device is a display.

[0095] In the system provided by this embodiment of the utility model, the image display device is a monitor, that is, the calibration image is displayed by projecting the calibration image on the monitor. The configuration of the monitor can be selected as needed, for example, a 27-inch monitor with a resolution of 2K and a refresh rate of 75Hz can be selected, or other monitor configurations can be selected as needed.

[0096] Based on the system provided in this embodiment of the present invention, the image display device is a display screen, which can flexibly replace the calibration image, thus helping to meet various needs for the calibration image.

[0097] Based on the system provided in the above embodiments, in the system provided by this utility model embodiment, the image display device includes a film and a uniform light panel.

[0098] In the system provided by this utility model embodiment, the image display device is a device composed of a film and a uniform light board. That is, a calibration image is customized on the film, and the film is illuminated by the uniform light board to realize the display of the calibration image.

[0099] Based on the system provided by this utility model, an image display device can be constructed based on film, which helps to reduce the complexity of the system structure and reduce equipment costs.

[0100] Based on the system provided in the above embodiments, in the system provided in this utility model embodiment, the calibration image displayed by the image display device is a black and white line pair pattern image.

[0101] In the system provided by this embodiment of the invention, a custom-designed black and white line pair pattern is used to set the calibration image. The black and white line pair pattern is a pattern formed by the interlacing of black and white lines. The calibration image provided by this embodiment of the invention can be as follows: Figure 5 As shown, it is specifically composed of pairs of black and white lines of different widths.

[0102] Based on the system provided in the above embodiments, in the system provided in this utility model embodiment, each of the working distances includes a near focal distance and a far focal distance; the near focal distance is 150 mm, and the far focal distance is 500 mm.

[0103] In the system provided by this embodiment of the invention, the preset working distances include 150 mm and 500 mm, which correspond to the near-focal distance and the far-focal distance in 3D scanning, respectively. That is, the system provided by this embodiment of the invention can move the camera module along the guide rail to make the distance between the camera module and the image display device in the lens direction 150 mm, at which focus calibration is performed. Furthermore, the distance between the camera module and the image display device in the lens direction can be adjusted to 500 mm by adjusting the guide rail, at which focus calibration is also performed.

[0104] Based on the system provided by this utility model embodiment, the camera module can be calibrated for focus when it is at near-focus and far-focus distances, respectively. This can obtain calibration data that matches the working distance of the 3D scanning scene, which is beneficial to improving the accuracy of focus control during 3D scanning.

[0105] To better illustrate the camera module calibration system provided in this embodiment of the present invention, based on the systems provided in the preceding embodiments, this embodiment of the present invention provides yet another camera module calibration system. A schematic diagram of the system provided in this embodiment of the present invention is shown below. Figure 2 As shown, the engineering drawings can be as follows: Figure 3 As shown, the calibration image displayed by the image display device can be as follows: Figure 5 As shown.

[0106] In the system provided by this embodiment of the utility model, image display devices are respectively arranged above, below, and to the right of the camera module. The image display devices are monitors. The position of the camera module can be adjusted by a rotating platform, so that the camera module can be calibrated for focus in three positions: vertically upward (0° angle with the vertical upward direction), horizontally to the right (90° angle with the vertical upward direction), and vertically downward (180° angle with the vertical upward direction). At the same time, in each position, the distance between the camera module and the image display device in the lens direction can be adjusted by a guide rail, so that the camera module can be calibrated for focus at two working distances: 500mm for telephoto and 150mm for near-focus.

[0107] With the camera module in the corresponding pose and working distance, it captures the calibration image displayed on the monitor. By changing the drive current value of the open-loop motor, images under different driving states can be obtained. The drive current value corresponding to the position with the highest image clarity is obtained by using the gradient method. Thus, the calibration current value corresponding to the current working distance and current pose can be obtained. Based on the calibration current value under different working distances and poses, the instruction programming value of the open-loop motor can be configured to compensate for the real-time pose based on the calibration current value during the 3D scanning process. The drive current value corresponding to the real-time pose is calculated so that the open-loop motor can accurately control the distance between the camera module lens and the sensor.

[0108] This utility model embodiment also provides a camera module, which uses the calibration system described above for focus calibration.

[0109] This utility model embodiment provides a camera module, which is calibrated using the above-mentioned calibration system. During the use of the camera module, the driving current value matching the current pose of the camera module can be determined in real time based on the multi-pose calibration driving current value obtained from the calibration and the current value obtained by interpolation based on the calibration driving current value.

[0110] This utility model embodiment also provides a 3D scanner, including the camera module as described above.

[0111] This utility model embodiment provides a three-dimensional scanner, which is equipped with a camera module calibrated using the above-mentioned calibration system. During the three-dimensional scanning process, the corresponding drive current value can be matched in real time according to the posture of the camera module for drive control, so as to achieve accurate scanning under various postures.

[0112] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0113] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A calibration system, characterized in that, include: A camera module, a rotating platform, and at least one image display device, wherein the camera module is located on the rotating platform, the camera module includes an open-loop motor, and the at least one image display device is configured to be spaced around the rotating platform. The rotating platform is used to rotate the camera module to adjust the orientation of the camera module's lens relative to the at least one image display device, so that the camera module's lens is in multiple target poses for focus calibration, wherein when the camera module is in one of the target poses, an image display device is located in the direction of the camera module's lens.

2. The calibration system according to claim 1, characterized in that, Also includes: A guide rail is fixedly connected to the rotating platform, and the camera module is slidably connected to the guide rail. When the camera module is in the target pose, the distance between the camera module and an image display device located in the lens direction is adjusted so that the camera module can be calibrated at multiple working distances.

3. The calibration system according to claim 1, characterized in that, Also includes: case; The rotating platform is located in the middle of the housing, and the at least one image display device is spaced apart on the inner wall of the housing and distributed in the rotation direction of the rotating platform.

4. The calibration system according to claim 3, characterized in that, The at least one image display device includes a first image display device, a second image display device, and a third image display device; The first image display device is disposed on the inner wall directly above the inside of the housing; The second image display device is disposed on the inner wall on the right side inside the housing; The third image display device is located on the inner wall directly below the interior of the housing.

5. The calibration system according to claim 3, characterized in that, The at least one image display device includes a fourth image display device and a fifth image display device; The fourth image display device is disposed on the inner wall directly above the inside of the housing; The fifth image display device is located inside the shell, directly below it.

6. The calibration system according to claim 2, characterized in that, The at least one image display device includes only one image display device; The image display device is fixedly connected to the guide rail, and the position of the image display device corresponds to the lens direction of the camera module. Alternatively, the image display device is a mountable device, and when the camera module is in the target pose, the image display device is mounted in the lens direction of the camera module.

7. The calibration system according to claim 1, characterized in that, The open-loop motor is configured to be driven by input DAC commands, and a reset operation is performed on the open-loop motor before the next DAC command is input during the focus calibration process.

8. The calibration system according to claim 1, characterized in that, The multiple target poses include a first pose, a second pose, and a third pose; The first pose is one where the camera is facing vertically upwards; The second pose is one where the camera is positioned horizontally to the right. The third pose is the pose where the camera is facing vertically downwards.

9. A camera module, characterized in that, The camera module is calibrated for focus using the calibration system described in any one of claims 1-8.

10. A three-dimensional scanner, characterized in that, Includes the camera module as described in claim 9.

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