CN210466473U

CN210466473U - Calibration device and calibration equipment of TOF camera

Info

Publication number: CN210466473U
Application number: CN201921451159.XU
Authority: CN
Inventors: 王振兴; 曾海
Original assignee: Shenzhen Orbbec Co Ltd
Current assignee: Orbbec Inc
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2020-05-05
Anticipated expiration: 2029-08-30

Abstract

The utility model provides a calibration device and calibration equipment of TOF camera, this calibration device has following part: the guide rail comprises a plurality of supporting frames which are arranged at intervals and used for supporting the TOF camera; the calibration plates are slidably mounted on the vertical support slide rails, each calibration plate at least comprises a calibration surface, and the distance between each calibration surface and the TOF camera corresponding to the calibration surface is different from that between each calibration surface and the TOF camera corresponding to the calibration surface; the mechanical arm operates the TOF camera to be calibrated and is used for placing the TOF camera to be calibrated on the support frame or taking the TOF camera out of the support frame; the controller is connected with the guide rail and the TOF camera and used for sending a first group of time sequence control signals to control the guide rail to carry the TOF camera to move along the guide rail, and sending a second group of time sequence control signals to the TOF camera to control the plurality of TOF cameras to work simultaneously or alternately to measure the distance value between the TOF cameras and the corresponding calibration plate. The technical scheme of the utility model calibration efficiency and the rate of accuracy that can effectively improve the TOF camera.

Description

Calibration device and calibration equipment of TOF camera

Technical Field

The utility model belongs to the technical field of the camera, especially, relate to a calibration equipment and calibration equipment of TOF camera.

Background

TOF (Time-of-Flight) is a technique for measuring the Time of Flight of light to achieve accurate distance measurement by utilizing the characteristic that the propagation speed of light in the air is constant. The TOF camera is a camera apparatus that converts the distance of a photographed object by calculating a light ray emission reflection time difference or a phase difference to generate depth information. Moreover, since the TOF camera can simultaneously acquire a grayscale image and a distance image, it has been gradually applied to the system fields of gesture control, 3D modeling, automotive radar, and robot vision. However, due to the presence of systematic errors and random errors, the measurement results and measurement accuracy of the TOF camera are affected by many factors, i.e., measurement errors, such as the internal and external environments of the camera system. In order to obtain higher accuracy distance information, depth value calibration of the TOF camera is often required. However, the conventional calibration device can only calibrate one TOF camera at a time, and needs to continuously move the calibration plate to different distances for calibrating for multiple times, so that the calibration efficiency is low, and the calibration result is not accurate enough.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome above-mentioned prior art not enough, provide a calibration device of TOF camera, its calibration efficiency and the lower problem of rate of accuracy that aim at solving current TOF camera.

The utility model provides a calibration device of TOF camera, include:

the guide rail comprises a plurality of supporting frames which are arranged at intervals, and the supporting frames are used for supporting the TOF camera to be calibrated;

the calibration plates are slidably mounted on the vertical support slide rail, each calibration plate at least comprises a calibration surface, and the distance between each calibration surface and the TOF camera corresponding to the calibration surface is different from that between each calibration surface and the TOF camera corresponding to the calibration surface;

the mechanical arm is used for operating the TOF camera to be calibrated and is used for placing the TOF camera to be calibrated on the support frame or taking the TOF camera out of the support frame;

and the controller is connected with the guide rail and the TOF camera and used for sending a first group of time sequence control signals to control the guide rail to carry the TOF camera to move along the guide rail and sending a second group of time sequence control signals to the TOF camera to control the TOF cameras to work simultaneously or alternatively to measure the distance value between the TOF camera and the corresponding calibration plate.

Optionally, the calibration device of the TOF camera further includes a jig assembly disposed on the guide rail, the jig assembly is electrically connected to the guide rail through a wire, and a central slip ring for arranging the wire is disposed at the center of the guide rail.

Optionally, the calibration device of TOF camera still includes lock cylinder and opens the cylinder, the lock cylinder be used for with treat the calibration TOF camera with the closely lock of tool subassembly is in order to guarantee to treat the calibration the depth of parallelism of TOF camera, it is used for with to open the cylinder TOF camera with the separation of tool subassembly.

Optionally, the guide rail is annularly arranged, and the calibration surface is parallel to the plane of the guide rail.

Optionally, the TOF camera has a motion section moving on the guide rail and a calibration position stationary relative to the guide rail, and in the calibration position, an optical axis of light emitted by the TOF camera coincides with a calibration center of the calibration surface corresponding to the position.

The utility model discloses still provide a calibration equipment of TOF camera, include:

calibration means for a TOF camera as described above;

the calibration device of the TOF camera is arranged inside the rack;

and the material stacking device is arranged on one side of the rack and used for placing the TOF camera.

Optionally, the rack includes a rack body and a mounting partition plate, the rack body is divided into an upper rack with an upper mounting cavity and a lower rack with a lower mounting cavity by the mounting partition plate, the calibration device of the TOF camera is arranged in the upper mounting cavity, the guide rail is fixedly arranged on the mounting partition plate, and the vertical support slide rail is mounted on the inner wall surface of the upper mounting cavity; the controller is arranged in the lower mounting cavity.

Optionally, the robotic arm is mounted on the mounting plate between the material stacking apparatus and the guide rail.

Optionally, the material stacking device comprises a material feeding box for placing the TOF camera to be calibrated, a calibration failure box for placing the TOF camera which fails to be calibrated, and a calibration completion box for placing the TOF camera which completes calibration.

Optionally, the inner wall surface of the upper mounting cavity is coated with a coating for reducing light reflectivity.

Controller

Based on this structural design, the utility model discloses an among the technical scheme, owing to the interval is provided with a plurality of TOF cameras on annular guide rail, be equipped with a plurality of calibration boards above the guide rail, and the calibration face of each calibration board and the TOF camera that corresponds rather than the position between all different, so when the calibration, just only need the controller to send first group time sequence control signal to order about TOF camera along the guide rail removal with the control guide rail, then the controller resends second group time sequence control signal, just can control a plurality of TOF cameras simultaneously or work in turn and measure its and the distance value of the calibration board that corresponds. In other words, the utility model discloses a set up a plurality of calibration boards, then the guide rail carries a plurality of TOF camera motion, make every calibration board all have at least one to wait to mark TOF camera and carry out distance measurement to it, like this, compare in the calibration method of present common TOF camera, this TOF camera's calibration equipment need not remove the calibration board at the in-process of demarcation, only need send first group time sequence control signal control guide rail through the controller and rotate the round, just can make the TOF camera of waiting to mark measure its and the distance value of different calibration boards, and realize demarcating a plurality of TOF cameras, thereby can improve TOF camera demarcation's efficiency and accuracy greatly.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a calibration apparatus of a TOF camera according to a first embodiment of the present invention;

fig. 2 is a schematic structural diagram of a calibration apparatus of a TOF camera according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of a calibration apparatus of a TOF camera according to a third embodiment of the present invention;

fig. 4 is a schematic structural diagram of a calibration apparatus of a TOF camera according to a fourth embodiment of the present invention;

fig. 5 is a schematic structural diagram of a calibration apparatus of a TOF camera according to a fifth embodiment of the present invention;

fig. 6 is a flowchart of a calibration method of a TOF camera according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a calibration apparatus of a TOF camera including a calibration apparatus of the TOF camera according to an embodiment of the present invention;

fig. 8 is a top view of a calibration apparatus of a TOF camera provided by an embodiment of the present invention;

fig. 9 is a flowchart of a calibration method of a TOF camera using a calibration apparatus of the TOF camera according to an embodiment of the present invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Guide rail	200	Calibration board
300	TOF camera	210	Calibration surface
				410	Calibration tube	420	Shading ring
430	Light-proof shell	110	First guide rail
				120	Second guide rail	10	Rack
12	Lower frame	11	Upper frame
				13	Mounting partition	20	Material stacking device
21	Feeding box	22	Calibration failure box
				23	Calibration completion box	500	Support slide rail
30	Mechanical arm	600	Jig assembly
				40	Central slip ring	51	Buckling cylinder
52	Opening cylinder

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It should be noted that the terms of left, right, upper and lower directions in the embodiments of the present invention are only relative concepts or are referred to the normal use state of the product, and should not be considered as limiting.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner" and "outer" indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

An embodiment of the utility model provides a calibration device and calibration equipment of TOF camera.

Referring to fig. 1 to 5, in various embodiments of the present invention, the calibration apparatus of the TOF camera includes a calibration device of the TOF camera. The calibration device of the TOF camera comprises at least one guide rail 100, a plurality of calibration plates 200, a mechanical arm 30 and a controller, wherein the guide rail 100, the calibration plates 200, the mechanical arm 30 and the controller are annularly arranged; the calibration plates 200 are slidably mounted on the vertical support slide rail 500, each calibration plate 200 at least comprises one calibration surface 210, the distance between each calibration surface 210 and the TOF camera 300 corresponding to the calibration surface is different, and the plane where the guide rail 100 is located is parallel to the calibration surface 210; the guideway 100 includes a plurality of support frames (not shown) arranged at intervals for supporting the TOF camera 300 to be calibrated; the robotic arm 30 operates the TOF camera 300 to be calibrated for placing the TOF camera 300 to be calibrated on or taking it out of the support; a controller (not shown) is coupled to both the guideway 100 and the TOF camera 300 for sending a first set of timing control signals to control the guideway 100 to carry the TOF camera 300 along the guideway 100 for movement, and a second set of timing control signals to the TOF camera 300 to control the plurality of TOF cameras 300 to operate simultaneously or alternately to measure their distance values from the corresponding calibration plate 200. In addition, the controller is further configured to calculate a compensation correction value according to the measured distance value and the actual distance value of the calibration board 200, and compensate the measured distance value according to the compensation correction value to obtain a calibration result.

It should be noted here that, in the technical solution of the present invention, the TOF camera 300 includes a light source emitting module and a photosensitive receiving module, and the light source emitting module includes a laser emitter. The light source emitting module is used for emitting light waves with a specific wave band, namely emitting light waves, the emitting light waves are reflected on the surface of the measured object and received by the photosensitive receiving module, and then the photosensitive receiving module calculates the depth information of the measured object according to the time difference or the phase difference between the emitting light waves and the receiving light waves. Therefore, in the calibration device of the TOF camera, it is important to select a light wave of a suitable wavelength band having a higher focusing power and a certain interference immunity in the external environment, and the laser can meet this requirement.

Based on this structural design, in the technical scheme of the utility model, owing to be provided with a plurality of TOF cameras 300 at the interval on annular guide rail 100, be equipped with a plurality of calibration boards 200 above guide rail 100, and calibration plane 210 and the guide rail 100 place plane of calibration board 200 are parallel, but the distance between calibration plane 210 of each calibration board 200 and the TOF camera 300 that corresponds with its position is all different, so when the calibration, just only need the controller to send first group time sequence control signal in order to control guide rail 100 to order about TOF camera 300 to move along guide rail 100, then the controller resends second group time sequence control signal, just can control a plurality of TOF cameras 300 and measure its and the distance value of corresponding calibration board 200 of work in turn simultaneously or. In other words, the utility model discloses a set up a plurality of calibration boards 200, then guide rail 100 carries a plurality of TOF camera 300 motion, make every calibration board 200 all have at least one to wait to mark TOF camera 300 and carry out distance measurement to it, like this, compare in the calibration method of present common TOF camera, this TOF camera's calibration equipment need not remove calibration board 200 at the in-process of demarcation, only need to send first group time sequence control signal control guide rail 100 through the controller and rotate the round, just can make the TOF camera 300 of waiting to mark measure its and different calibration board 200's distance value, and the realization is markd a plurality of TOF cameras 300, thereby can improve TOF camera 300 demarcation's efficiency and accuracy greatly. In addition, the controller can also control the TOF cameras 300 to be calibrated to be opened alternately by sending a second group of time sequence control signals, so that the TOF cameras 300 can be better matched with the guide rail 100 during calibration, the problem of multi-machine interference generated among the TOF cameras 300 during calibration can be solved, and the stability and the accuracy of camera calibration can be further improved.

It should be noted that, in order to facilitate the TOF camera 300 to rotate circularly on the guide rail 100, the guide rail 100 may be an arc-shaped ellipse or a circle, for example, as shown in fig. 1 to 5, the guide rail 100 is a circular track. However, the design is not limited thereto, and in other embodiments, the guide rail 100 may have other shapes, which is not limited herein.

As will be illustrated below with reference to fig. 1, in a first embodiment, the TOF camera 300 has a motion section moving on the guideway 100 and a calibration position stationary with respect to the guideway 100, in which the TOF camera 300 has its light-exit optical axis perpendicular to the calibration plane 210 corresponding to the position. Specifically, in the present embodiment, eight TOF cameras 300 to be calibrated are arranged on each support frame of the circular guide rail 100, in a static state, that is, in a calibration time period, the calibration plane 210 of one calibration plate 200 is opposite to each TOF camera 300 to be calibrated in the light-emitting optical axis direction of each TOF camera 300 to be calibrated, and the distance from each calibration plane 210 to the TOF camera 300 to be calibrated is different, for example, the calibration distance may be specifically set to 300mm, 600mm, 900mm, 1200mm, 1500mm, 1800mm, 2100mm, 2400mm, and the like. Of course, in other embodiments, the number of TOF cameras 300 to be calibrated placed on the guide rail 100 may also be adaptively adjusted according to specific requirements, and each calibration distance may also be set according to actual requirements.

Further, in the present embodiment, at the calibration position, the light-emitting optical axis of the TOF camera 300 coincides with the calibration center of the calibration surface 210 corresponding to the calibration position. In this way, each time the TOF camera 300 moves step-by-step along with the guide rail 100 by a preset track length, the TOF camera can exactly correspond to a certain calibration plate 200, that is, each TOF camera 300 can respectively image at different distances after moving each time, and the relationship between the measured distance and the real distance is conveniently established, so that the technical purpose of correcting the measured distance and obtaining a more accurate depth map can be achieved. In addition, the calibration surface 210 of the calibration board 200 should be as smooth and smooth as possible, and in order to make the reflectivity of the surface of the calibration board 200 higher and more uniform, the calibration surface 210 is preferably white, and may be made of white matte paper.

Specifically, referring to fig. 1 to 5, in the first to fifth embodiments, the guide rail 100 is disposed in a circular ring shape, and the included angles formed by the connection lines between the two adjacent TOF cameras 300 and the circle centers of the guide rail 100 are equal, and the included angles are specifically but not limited to 45 degrees, so that when the guide rail 100 runs in a preset direction (clockwise or counterclockwise) under the control of the controller, the angle of each rotation is the same 45 degrees, so that the controller can easily control the rotation of the guide rail 100, and the rotation process is more accurate and stable. In addition, to ensure calibration efficiency, the rotational speed of the guide rail 100 is preferably greater than 2.5 r/min. However, the design is not limited thereto, and in other embodiments, the angle of each rotation of the guide rail 100 may also be different, and may be specifically set according to the shape of the guide rail 100 and the calibration time of each TOF camera 300 to be calibrated.

It will be appreciated that during the actual calibration process, if all the cameras are turned on, interference may occur between adjacent cameras, that is, one TOF camera 300 may receive not only the light emitted by the camera and reflected back through the calibration board 200, but also the light emitted by adjacent cameras, which may cause some errors in the measured distance value. Therefore, in order to avoid the problem of multi-camera interference, in addition to controlling the TOF camera 300 to work alternately or increasing the distance between the calibration plates 200 properly, a method of providing a light shielding device between the TOF camera 300 and the calibration plate 200 corresponding to the position may be further adopted. For example, in the third embodiment shown in fig. 3 and the fourth embodiment shown in fig. 4, the light shielding device is a calibration tube 410 having a hollow cavity, an axial extending direction of the calibration tube 410 is consistent with an optical axis of the light emitted from the TOF camera 300, the calibration plate 200 is disposed at one end of the calibration tube 410 away from the guide rail 100, and the optical signal emitted from the TOF camera 300 reaches the calibration plate 200 corresponding to the position through the hollow cavity. Here, in order to avoid the influence of ambient light on the optical signal emitted by the TOF camera 300 and reduce the influence of multipath effect on the inner sidewall of the hollow cavity of the calibration tube 410, it may be preferable to coat the inner wall surface of the hollow cavity with a coating layer to reduce the reflectivity, the coating layer is usually a black material, such as but not limited to a black polyvinyl chloride material, and the reflectivity should be less than 1.5%. Of course, in the fifth embodiment as shown in fig. 5, the light shielding device may also be replaced by a light shielding ring 420, and the light shielding ring 420 has an inner ring hole through which the light signal emitted by the TOF camera 300 can pass, that is, the light signal emitted by the TOF camera 300 to be calibrated can reach the calibration plate 200 through the inner ring hole which is hollow in the middle of the light shielding ring 420.

Similarly, to reduce the effect of ambient light on the light signals emitted by the TOF camera 300, the calibration apparatus further includes a light-proof housing 430 housing the guide rail 100, the calibration plate 200, and the TOF camera 300. The light-proof housing 430 may be coated with a coating to reduce light reflectivity, as may the inner sidewalls of the calibration tube 410.

Further, in the second embodiment shown in fig. 2 and the fourth embodiment shown in fig. 4, it is different from the first and third embodiments in that the guide rail 100 includes a first guide rail 110 and a second guide rail 120 provided at both sides of the calibration plate 200; wherein the calibration plate 200 has a first calibration face 210 facing the first rail 110 and a second calibration face 210 facing the second rail 120. The calibration principle of the calibration devices of the TOF camera in the two embodiments is the same as that of the other two embodiments, and is not described herein again. The controller can synchronously control the first guide rail 110 and the second guide rail 120, so that when the first guide rail 110 and the second guide rail 120 rotate for one turn at the same time, the UPH (units per hour) of the calibration device of the TOF camera can be doubled, and the calibration efficiency can be greatly improved.

Referring to fig. 7 and 8, in the technical solution of the present invention, on the basis of the structural design of the calibration apparatus of the TOF camera, the calibration apparatus of the TOF camera specifically includes a frame 10, the calibration apparatus as described above, and a material stacking apparatus 20. The rack 10 comprises a rack body and a mounting clapboard 13, wherein the rack body is divided into an upper rack 11 with an upper mounting cavity and a lower rack 12 with a lower mounting cavity by the mounting clapboard 13; the calibration device is arranged in the upper mounting cavity; the material stacking device 20 is arranged on one side of the rack 10 and used for placing the TOF camera 300; a controller (not shown) is disposed in the lower mounting cavity and connected to both the guide rail 100 and the TOF camera 300, and the controller is configured to send a first set of timing control signals to control the guide rail 100 to carry the TOF camera 300 along the guide rail 100 for movement, and send a second set of timing control signals to the TOF camera 300 to control the plurality of TOF cameras 300 to simultaneously or alternately operate to measure distance values between the plurality of TOF cameras 300 and the corresponding calibration plates 200.

Here, the calibration device of the TOF camera includes a calibration device of the TOF camera, and the specific structure of the calibration device of the TOF camera refers to the above embodiments, and since the calibration device of the TOF camera adopts all technical solutions of all the above embodiments, the calibration device of the TOF camera also has all beneficial effects brought by the technical solutions of the above embodiments, and details are not repeated here. The frame 10 is divided into an upper frame 11 and a lower frame 12, and the lower frame 12 is used for accommodating a controller and the like electrically connected with a calibration device of the TOF camera in the upper frame 11, so as to ensure that the front of the lower frame 12 is simple, thereby avoiding potential safety hazards caused by the fact that wires or parts and the like of the controller and the like are exposed outside. In addition, in order to avoid the influence of the ambient light on the calibration device of the TOF camera, it is preferable that the inner wall surface of the upper mounting cavity is coated with a coating for reducing the light reflectivity, for example, but not limited to, the inner side wall of the upper frame 11 is coated with a black material, for example, but not limited to, a black polyvinyl chloride material, so as to reduce the reflectivity and make the reflectivity less than 1.5%.

Specifically, as shown in fig. 7 and 8, in an embodiment, the supporting slide rails 500 extend in an up-down direction, each supporting slide rail 500 is slidably mounted with one calibration plate 200, and the plurality of supporting slide rails 500 are respectively mounted on left and right inner sidewalls of the upper frame 11 and are uniformly spaced on the same inner sidewall. Here, since the calibration plate 200 can slide in the up-and-down direction on the corresponding support slide rail 500, the controller can precisely control the up-and-down movement of the calibration plate 200 according to actual needs, thereby realizing that the distances between the calibration surface 210 on the calibration plate 200 and the TOF camera 300 corresponding to the position thereof are different.

Further, in one embodiment, the material stacking apparatus 20 includes a feeding box 21 for placing the TOF camera 300 to be calibrated, a calibration failure box 22 for placing the TOF camera 300 of which calibration fails, and a calibration completion box 23 for placing the TOF camera 300 of which calibration is completed. In the actual calibration process, the TOF camera 300 to be calibrated can be automatically sent to the feed box 21 by an agv (automated Guided vehicle) trolley, and then the TOF camera 300 to be calibrated can be taken out of the feed box 21 by the calibration device and calibrated; then, the TOF camera 300 that has failed to be calibrated is placed in the failed calibration box 22, and the TOF camera 300 that has completed to be calibrated is placed in the completed calibration box 23, so that subsequent operations can be performed on the TOF camera 300 that has undergone calibration.

To further increase the degree of automation of the apparatus, as shown in figures 7 and 9, a robotic arm 30 is mounted on the mounting plate 13 and between the material stacking apparatus 20 and the guide rail 100, primarily for placing the TOF camera 300 to be calibrated on or removing it from the support frame. Here, the use of the mechanical arm 30 can avoid shaking when being held by a hand, thereby being beneficial to improving the calibration precision.

Further, referring to fig. 7 and 8, in an embodiment, the calibration apparatus further includes a jig assembly 600 disposed on the guide rail 100, the jig assembly 600 is electrically connected to the guide rail 100 through a wire, and a central slip ring 40 for guiding the wire is disposed on the mounting partition 13 at the center of the guide rail 100. Specifically, after the AGV cart automatically sends the TOF camera 300 to be calibrated to the magazine 21, the robot arm 30 automatically takes the TOF camera 300 to be calibrated out of the magazine 21 and places the TOF camera into the jig assembly 600. Here, jig assembly 600 is wired to rail 100 to provide electrical support for TOF camera 300, however, when rail 100 rotates with TOF camera 300, the wires are also correspondingly rotated, and to avoid tangling of the wires, the problem can be solved by providing a central slip ring 40 at the center of rail 100 for nesting the wires.

It should be particularly noted that, after the TOF camera 300 is placed on the jig assembly 600, the calibration apparatus of the TOF camera can detect the TOF camera 300, and firstly, detect whether the TOF camera 300 is well connected with the jig assembly 600, for example, whether there is a problem of poor contact; secondly, whether the TOF camera 300 is intact, for example, whether the transmitting module can normally transmit optical signals, whether the photosensitive receiving module can normally receive optical signals, and the like, is detected; once there is any one of the above problems, the TOF camera 300 skips the subsequent normal measurement steps, and merely moves with the rail 100 and is finally placed in the calibration failure box 22.

Further, in an embodiment, the calibration apparatus further includes a fastening cylinder 51 and an opening cylinder 52, and both the fastening cylinder 51 and the opening cylinder 52 are disposed on the guide rail 100 and located on both sides of the mechanical arm 30. Specifically, after the TOF camera 300 is placed in the jig assembly 600, the TOF camera 300 rotates to the fastening cylinder 51 along with the guide rail 100, and the fastening cylinder 51 is mainly used for fastening the TOF camera 300 to be calibrated with the jig assembly 600 tightly to ensure the parallelism of the TOF camera 300 to be calibrated, so as to avoid the occurrence of inaccurate calibration result caused by camera inclination; then, the TOF camera 300 will be rotated to various calibration positions to measure the distances between the TOF camera and different calibration plates 200, for example, various calibration distances may be set to 300mm, 450mm, 600mm, 750mm, 900mm, 1050mm, etc., these calibration distances are merely illustrative and not limiting, and in other embodiments, the calibration distances may be set according to actual requirements; after the TOF camera 300 has acquired all the calibration distances, the TOF camera 300 is rotated to the opening cylinder 52, and the opening cylinder 52 separates the TOF camera 300 from the jig assembly 600, so that the robot 30 can take out the calibrated TOF camera 300 from the jig assembly 600 and place the calibrated TOF camera 300 in the calibration complete box 23 in subsequent operations. In addition, since the distance between the calibration plate 200 and the TOF camera 300 can be dynamically changed, when the TOF camera 300 rotates one circle and acquires more different calibration distances, the calibration plate 200 can be moved, and the TOF camera 300 can also rotate along with the guide rail 100 again by skipping the opening of the air cylinder 52, so as to acquire different calibration distances again.

The following describes in detail a calibration method of a TOF camera according to the present technical solution, in which the calibration apparatus of the TOF camera is used to complete the calibration of the TOF camera 300. Referring to fig. 6, the calibration method of the TOF camera includes the following steps:

s100, mounting a plurality of calibration plates 200, wherein calibration surfaces 210 of the calibration plates 200 are parallel to a plane where the guide rail 100 is located;

s200, mounting a plurality of TOF cameras 300 on corresponding support frames one by one, wherein the distance between each calibration surface 210 and the TOF camera 300 corresponding to the calibration surface is different from each other;

in particular, in the calibration apparatus of the TOF camera, as shown in fig. 9, the step S200 may be changed to take out the TOF camera 300 in the material stacking apparatus 20 by using the robot arm 30 to be placed on the support frame on the guide rail 100.

S300, the controller sends a first group of time sequence control signals to the guide rail 100 to control the guide rail 100 to carry the TOF camera 300 to move along the guide rail 100, and the TOF camera 300 is in a non-calibration time period;

s400, when the TOF camera 300 runs to a preset calibration position, the guide rail 100 stops moving, and the TOF camera 300 is in a calibration time period;

and S500, in the calibration time period, the controller sends a second group of time sequence control signals to the TOF cameras 300 to control the TOF cameras 300 to work simultaneously or alternatively so as to measure the distance between the TOF cameras 300 and the corresponding calibration plates 200 and acquire measured distance values.

Further, in an embodiment, the controller is connected to the rail 100 by wire or wirelessly, the first group of timing control signals are pulse signals, and the step S300 includes the following sub-steps:

s310, the controller controls the guide rail 100 to carry the TOF camera 300 to perform stepping horizontal rotation by taking the central axis of the guide rail 100 as an axis;

s320, when the pulse is at a high level, the guide rail 100 rotates according to a preset direction (clockwise direction or anticlockwise direction), and the TOF camera 300 is in a non-calibration time period;

s330, when the pulse is at a low level, the guide rail 100 stops rotating, the TOF camera 300 is in a calibration time period, and a distance value between the TOF camera and the corresponding calibration plate 200 can be measured.

After the controller controls the guide rail 100 to rotate to the calibration position, that is, when the camera is in the calibration time period, the controller may send a second set of timing control signals to the TOF camera 300 to be calibrated to measure the distance value between the TOF camera 300 and the corresponding calibration plate 200. Specifically, the second group of timing control signals are pulse signals; when the pulse signal is at a high level, the TOF camera 300 is turned on and is in a working state, and when the pulse signal is at a low level, the TOF camera 300 is turned off and is in a non-working state; and the voltage state of the second group of timing control signals is opposite to that of the first group of timing control signals, namely when the first group of timing control signals is at a high level, the second group of timing control signals should be at a low level. Thus, the TOF camera 300 can be opened only in the calibration time period through two groups of time sequence control signals sent by the controller, so that the resource waste caused by opening the TOF camera 300 all the time can be avoided, the TOF camera 300 can start to measure the distance value after the guide rail 100 stops rotating, and the technical effect of improving the calibration stability and accuracy is achieved.

In one embodiment, the controller controls the TOF cameras 300 synchronously, for example, during a calibration period, the controller controls all TOF cameras 300 to be turned on, and during a non-calibration period, the controller controls all TOF cameras 300 to be turned off, so that after one rotation of the guideway 100, all TOF cameras 300 can measure all distance values relative to different calibration plates 200, thereby greatly improving the calibration efficiency. Of course, in other embodiments, the controller may also control each TOF camera 300 individually, and a worker may set whether a certain TOF camera 300 is turned on or off according to specific requirements.

In one embodiment, the controller controls one of the TOF cameras 300 to be turned on during the calibration period, and controls all TOF cameras 300 to be turned off during the non-calibration period. It is understood that the TOF camera 300 converts the distance of the object to be photographed by calculating the light ray emission and reflection time difference or phase difference, and therefore, if all the cameras are turned on, interference between adjacent cameras is likely to occur, i.e. the TOF camera 300 may receive not only the light ray emitted by the present camera and reflected by the calibration board 200, but also the light ray emitted by the adjacent cameras, which causes a certain error in the measured distance value. In the design, the cameras are alternately opened (for example, two adjacent cameras are selected, one of the two cameras is opened), one half of the TOF cameras 300 can be calibrated after the guide rail 100 rotates for one circle, and the other half of the TOF cameras 300 can be calibrated when the guide rail 100 rotates for the next circle, so that the problem of multi-camera interference generated when a plurality of TOF cameras 300 are calibrated can be solved, and the calibration stability and accuracy are further improved.

Here, the controller may be a host computer, such as a computer, which is connected to the guide rail 100 and the TOF camera 300 by a wire, such as a USB cable, or a wireless cable, or by a wireless network, so as to control the guide rail 100 and the TOF camera 300. In an embodiment, after step S500, the method further includes a step of how to obtain a final camera calibration result:

s600, transmitting the measured distance value measured in the step S500 to a controller;

s700, calculating and acquiring a compensation correction value by the controller according to the measured distance value and an actual distance value between the TOF camera 300 and the corresponding calibration plate 200;

and S800, compensating the measured distance value according to the compensation correction value to obtain a camera calibration result.

In addition, in an embodiment, the calibration method of the TOF camera further includes performing swing error calibration and fixed phase pattern noise calibration on the TOF camera 300. Specifically, however, due to the difference between the actual modulation waveform and the phase difference calculation model, different deviations may occur at different distances, and the deviations at the different distances are swing errors (wigglingerrors), so to improve the calibration accuracy, calibration needs to be performed at different distances to obtain various wiggling deviation values, that is, the calibration process of the measured distance values includes swing error calibration (wiggling calibration). In addition, due to differences in design and production processes, each pixel point of the sensor may be different in the manufacturing process, resulting in that each pixel point has an independent distance deviation, that is, each pixel has a different Fixed delay, that is, a Fixed Phase Pattern Noise (FPPN), so that in the calibration process of the TOF camera 300, a Fixed offset of each pixel point needs to be calibrated, that is, FPPN calibration is performed. Therefore, the calibration board 200 should include a calibration surface 210 with a size that can fully cover the field angle of the TOF camera 300 to be calibrated, so as to facilitate FPPN calibration. The two specific operation methods for calibration can be according to the common methods in the prior art, and are not described herein.

Finally, it should be noted that all or part of the functions of the various methods in the above embodiments may be implemented by hardware, or may be implemented by a computer program. When all or part of the functions of the above embodiments are implemented by way of a computer program, the program may be stored in a non-volatile computer-readable storage medium, which may include: a read only memory, a random access memory, a magnetic disk, an optical disk, a hard disk, etc., and the program is executed by a computer to realize the above functions. For example, the program may be stored in a memory of the device, and when the program in the memory is executed by the processor, all or part of the functions described above may be implemented. In addition, when the above-mentioned embodiments are implemented by computer programs, which are used to implement all or part of the functions of the present invention, the present invention is described in further detail with reference to the specific preferred embodiments, and it should not be construed that the present invention is limited to these descriptions.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modification, equivalent replacement or improvement made within the spirit and principle of the present invention should be included in the present invention.

Claims

1. A calibration apparatus of a TOF camera, comprising:

2. The calibration device of the TOF camera according to claim 1, further comprising a jig component disposed on the guide rail, wherein the jig component is electrically connected to the guide rail through a wire, and a central slip ring for arranging the wire is disposed at the center of the guide rail.

3. The TOF camera calibration device according to claim 2, further comprising a buckling cylinder for tightly buckling the TOF camera to be calibrated with the jig component to ensure parallelism of the TOF camera to be calibrated, and an opening cylinder for separating the TOF camera from the jig component.

4. The TOF camera calibration apparatus according to claim 1, wherein the guide rail is disposed in a ring shape, and the calibration surface is parallel to a plane of the guide rail.

5. Calibration arrangement for a TOF camera according to claim 1, wherein the TOF camera has a motion section moving on the guideway and a calibration position stationary relative to the guideway, in which calibration position the optical axis of the TOF camera coincides with the calibration center of the calibration plane at the corresponding position.

6. Calibration apparatus for a TOF camera, comprising:

calibration apparatus for a TOF camera according to any one of claims 1 to 5;

the calibration device of the TOF camera is arranged inside the rack;

7. The TOF camera calibration apparatus according to claim 6, wherein the frame includes a frame body and a mounting partition, the frame body is divided into an upper frame having an upper mounting cavity and a lower frame having a lower mounting cavity by the mounting partition, the calibration device of the TOF camera is disposed in the upper mounting cavity, the guide rail is fixedly disposed on the mounting partition, and the vertical support slide rail is mounted on an inner wall surface of the upper mounting cavity; the controller is arranged in the lower mounting cavity.

8. The TOF camera calibration apparatus according to claim 7 wherein the robotic arm is mounted on the mounting plate between the material stacking device and the guide rail.

9. The TOF camera calibration apparatus according to claim 6, wherein the material stacking apparatus includes a feeding box for placing the TOF camera to be calibrated, a calibration failure box for placing the TOF camera that fails calibration, and a calibration completion box for placing the TOF camera that completes calibration.

10. A calibration apparatus for a TOF camera according to claim 7 wherein an inner wall surface of the upper mounting chamber is coated with a coating to reduce light reflectivity.