Reflectivity compensation method, compensation device and tof camera of tof camera

Abstract

The present application relates to a kind of reflectivity compensation method, compensation device and TOF camera of TOF camera, the compensation method includes: receiving the original depth data of TOF camera based on the reflection signal acquisition of measured object;Reflectivity compensation is carried out to original depth data based on predetermined compensation reference point, and the compensated depth data for obtaining the distance information of measured object is obtained;Wherein, compensation reference point is based on the data obtained from the fitting function processing of each group of test depth data of TOF camera pre-acquisition multiple sets of test depth data;Test depth data includes: the depth data of TOF camera based on the reflection signal acquisition of the reflection object of two or more reflectivity at the same test distance.The compensation method of the present application suppresses the difference between the depth data of measured object of different reflectivity in the original depth data collected by TOF camera, and then reduces the ranging error caused by measured object of different reflectivity to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of TOF technology, and more particularly to a reflectivity compensation method, compensation device, and TOF camera for a TOF camera. Background Technology

[0002] Time-of-flight (TOF) cameras are a type of depth camera. Compared to traditional cameras, TOF cameras can measure depth, thus enabling more accurate perception of the surrounding environment. This capability makes TOF cameras promising for applications in many scenarios, including robot navigation, motion-sensing games, industrial inspection, autonomous driving, and 3D imaging.

[0003] One of the key performance indicators of a Time-of-Flight (TOF) camera is its ranging accuracy. One of the significant factors affecting this accuracy is the reflectivity of the object. The TOF camera works by actively emitting modulated light onto the object being measured, then receiving the reflected light. It calculates the time difference or phase difference between the emitted and reflected light to obtain depth data, which is then further converted to determine the distance. When the reflectivity of the object varies, the TOF camera receives different reflected light from objects with different reflectivities at the same distance. This results in different depth data for objects at the same distance, leading to different distances and consequently, ranging errors, thus reducing the TOF camera's ranging accuracy. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a reflectivity compensation method, compensation device and TOF camera for TOF camera, which reduces the ranging error caused by the different reflectivity of the measured object in the existing TOF camera.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, embodiments of the present invention provide a reflectivity compensation method for a TOF camera, comprising:

[0009] Receive raw depth data acquired by a TOF camera based on the reflected signals of the object being measured;

[0010] Based on a predetermined compensation reference point, reflectivity compensation is performed on the original depth data to obtain compensated depth data. The compensated depth data is used by the TOF camera to acquire distance information of the measured object.

[0011] The compensation reference point is based on multiple sets of test depth data pre-collected by the TOF camera, and the data used to compensate for reflectivity is obtained by processing each set of test depth data according to the fitting function; the test depth data includes: depth data collected by the TOF camera based on the reflection signals of reflective objects belonging to two or more reflectivities at the same test distance.

[0012] Optionally, before receiving the raw depth data acquired by the TOF camera based on the reflection signal of the object being measured, the method further includes:

[0013] Acquire multiple sets of test depth data pre-collected by a TOF camera at multiple test distances; each set of test depth data includes: test depth data of at least two reflecting objects collected at the same test distance; wherein, the reflectivity of each reflecting object is different; and,

[0014] Obtain the fitting function for each set of test depth data, and calculate the compensation benchmark point based on the fitting function.

[0015] Optionally, the reflective object includes a first reflective object and a second reflective object;

[0016] Each set of test depth data includes: the depth and intensity values ​​of the first reflecting object and the second reflecting object acquired by the TOF camera at the same test distance.

[0017] Optionally, the fitting function for each set of test depth data is obtained based on a calculation process, which includes:

[0018] For the i-th test depth data, i is a positive integer not less than 2.

[0019] Substituting the depth and intensity values ​​corresponding to the first reflecting object into formula (1), we obtain the first coordinate in the Cartesian coordinate system.

[0020] Substituting the depth and intensity values ​​corresponding to the second reflecting object into formula (1), we obtain the second coordinates in the Cartesian coordinate system.

[0021] Will pass The equation of the straight line between the two points is used as the fitting function for this set of test depth data;

[0022] Wherein, formula (1) is,

[0023]

[0024] In formula (1), amp i Phase represents the intensity value corresponding to the reflecting object.i This represents the depth value corresponding to the reflecting object, and f represents the range of depth values ​​in the depth data of the TOF camera.

[0025] Optionally, the compensation reference point is obtained based on a pre-processing procedure, which includes:

[0026] Based on the multiple sets of test depth data pre-collected by the TOF camera, calculate the point (x0, y0) in the Cartesian coordinate system that satisfies formulas (2) to (4), and use this point as the reference compensation point;

[0027] Formulas (2) to (4) are respectively:

[0028]

[0029]

[0030]

[0031] Where (x,y) represents the coordinates of any point in the Cartesian coordinate system, and d represents the distance between any point in the Cartesian coordinate system and the equation of the line.

[0032] Optionally, the reflectivity compensation of the original depth data includes:

[0033] Obtain the original depth value ori_phase and the original intensity value ori_amp from the original depth data;

[0034] Substituting ori_phase and ori_amp into formula (1), we obtain the original coordinates (x) in the Cartesian coordinate system. o ,y o ),

[0035] Based on the original coordinates (x) o ,y o ) and the reference compensation point (x0, y0), according to formula (5) to obtain the compensated depth value phasecomp and the compensated intensity value ampcomp, and output phasecomp and ampcomp as the compensated depth data;

[0036] The formula (5) is:

[0037]

[0038] In formula (5), phasecomp represents the compensated depth value, ampcomp represents the compensated intensity value, atan2() represents the arctangent operation, and f represents the range of depth values ​​in the depth data of the TOF camera.

[0039] Optionally, the reflectivity of the first reflective object is 80% to 100%, and the reflectivity of the second reflective object is 40% to 60%.

[0040] Secondly, embodiments of the present invention provide a compensation device, which compensates the original depth data collected by the TOF camera based on the reflectivity compensation method of the TOF camera described in the first aspect, in order to reduce the ranging error caused by the measured object with different reflectivity.

[0041] Optionally, the compensation device includes:

[0042] The compensation reference point calculation module is used to calculate the compensation reference point based on the test depth data pre-acquired by the TOF camera.

[0043] The compensation module is used to perform reflectivity compensation on the raw depth data acquired by the TOF camera based on the compensation reference point.

[0044] Thirdly, embodiments of the present invention provide a TOF camera, the TOF camera including the compensation device described in the second aspect.

[0045] (III) Beneficial Effects

[0046] The compensation method proposed in this invention is based on multiple sets of test depth data pre-collected by a TOF camera at multiple test distances. A fitting function is obtained for each set of test depth data. Based on the fitting function, the point with the smallest sum of distances to all fitting functions is calculated as a compensation reference point. Based on the compensation reference point, the difference in depth data between measured objects with different reflectivities in the original depth data collected by the TOF camera is suppressed, thereby reducing the ranging error caused by measured objects with different reflectivities to a certain extent. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating a reflectivity compensation method for a TOF camera provided in this embodiment.

[0048] Figure 2 This is a schematic diagram showing the position of the test depth data in the Cartesian coordinate system in the embodiment;

[0049] Figure 3 This is a schematic diagram of the linear equation corresponding to the test depth data in the embodiment;

[0050] Figure 4 This is a schematic diagram illustrating the correspondence between the raw depth value and distance directly obtained by the TOF camera in HDR mode in the embodiment.

[0051] Figure 5This is a schematic diagram illustrating the correspondence between the depth value and the distance after compensation based on the compensation reference point for the original depth value obtained by the TOF camera in HDR mode in the embodiment.

[0052] Figure 6 This is a schematic diagram showing the comparison relationship between diff1 and diff2 in the embodiment;

[0053] Figure 7 A schematic diagram of the structure of a compensation device provided in an embodiment;

[0054] Figure 8 This is a schematic diagram of the structure of a TOF camera provided for an embodiment. Detailed Implementation

[0055] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0057] Example 1

[0058] This embodiment provides a reflectivity compensation method for a TOF camera, such as... Figure 1 As shown, the compensation method includes:

[0059] Receive raw depth data acquired by a TOF camera based on the reflected signals of the object being measured.

[0060] Based on a predetermined compensation reference point, reflectivity compensation is performed on the original depth data to obtain compensated depth data. The compensated depth data is used by the TOF camera to acquire distance information of the measured object.

[0061] The compensation reference point is based on multiple sets of test depth data pre-collected by the TOF camera, and the data used to compensate for reflectivity is obtained by processing the fitting function of each set of test depth data; the test depth data includes: depth data collected by the TOF camera based on the reflection signals of reflective objects belonging to two or more reflectivities at the same test distance.

[0062] It should be noted that the aforementioned reflected signal refers to the light signal emitted by the TOF camera, reflected by the object being measured, and then re-received by the TOF camera. Each set of the above depth data includes a depth value and an intensity value. The depth value corresponds to the phase difference information of the reflected signal, and the intensity value corresponds to the amplitude information of the reflected signal.

[0063] Specifically, the compensation reference point can be obtained based on a pre-measurement process before acquiring the raw depth data from the TOF camera. This pre-measurement process includes:

[0064] A001. Obtain multiple sets of test depth data pre-collected by the TOF camera at multiple test distances.

[0065] Each set of test depth data includes: test depth data of at least two reflective objects collected at the same test distance; wherein the reflectivity of each reflective object is different.

[0066] It should be noted that the test distance refers to the distance between the TOF camera and the reflecting object, which can be a calibration plate or calibration wall used for calibrating the TOF camera pair.

[0067] A002. Obtain the fitting function for each group of test depth data, and calculate the compensation benchmark point based on the fitting function.

[0068] The compensation reference point is the point whose sum of distances to all the fitted functions is the smallest.

[0069] It should be noted that the measurement process described above for obtaining the compensation reference point is performed for each pixel of the TOF camera; that is, each pixel of the TOF camera corresponds to a compensation reference point. In practical applications, the compensation reference points corresponding to each pixel of the TOF camera may be the same or different. Similarly, the process of performing reflectivity compensation on the raw depth data described above is also based on the reference compensation point corresponding to each pixel of the TOF camera and the raw depth data.

[0070] The compensation method proposed in this invention is based on multiple sets of test depth data pre-collected by a TOF camera at multiple test distances, obtaining a fitting function for each set of test depth data, calculating a compensation reference point based on the fitting function, and compensating the original depth data collected by the TOF camera based on the compensation reference point, thereby reducing the ranging error caused by the measured object with different reflectivity to a certain extent.

[0071] Example 2

[0072] The inventors discovered that by setting up two reflective objects during the preliminary measurement process, the correspondence between depth data and reflectivity can be obtained effectively, thus achieving a compensation reference point with a better compensation effect. As a preferred embodiment of Example 1, this example uses a first reflective object and a second reflective object to illustrate the steps of the above compensation method in detail.

[0073] This embodiment provides a reflectivity compensation method for a TOF camera, including:

[0074] S1. Acquire multiple sets of test depth data pre-collected by the TOF camera at multiple test distances.

[0075] Each set of test depth data includes: the depth and intensity values ​​of the first reflecting object and the second reflecting object acquired by the TOF camera at the same test distance.

[0076] Preferably, the reflectivity of the first reflective object is 80%–100%, and the reflectivity of the second reflective object is 40%–60%; more preferably, the reflectivity of the first reflective object is 90%, and the reflectivity of the second reflective object is 50%. Since the reflectivity of most objects is between 50% and 90%, the above-mentioned settings for the reflectivity of the first and second reflective objects can make the test depth data more representative.

[0077] More specifically, the first reflective object is a white wall with a reflectivity of 90%, and the second reflective object is a gray wall with a reflectivity of 50%.

[0078] S2. Obtain the fitting function for each group of test depth data, and calculate the compensation benchmark point based on the fitting function. The compensation benchmark point is the point with the smallest sum of distances to all the fitting functions.

[0079] The above S2 includes the following sub-steps:

[0080] S201. Obtain the fitting function corresponding to each group of test depth data.

[0081] Specifically, for the i-th test depth data, i is a positive integer not less than 2.

[0082] Substituting the depth and intensity values ​​corresponding to the first reflecting object into formula (1), we obtain the first coordinate in the Cartesian coordinate system. Substituting the depth and intensity values ​​corresponding to the second reflecting object into formula (1), we obtain the second coordinates in the Cartesian coordinate system. The representation of each set of test depth data in the Cartesian coordinate system is as follows: Figure 2As shown, the coordinates corresponding to the white wall are the first coordinates for each set of test depth data, and the coordinates corresponding to the gray wall are the second coordinates for each set of test depth data. Figure 2 It can be seen that all the first coordinates roughly form an irregular circle, and all the second coordinates roughly form an irregular circle.

[0083] Wherein, formula (1) is,

[0084]

[0085] In formula (1), in formula (1), amp i Phase represents the intensity value corresponding to the reflecting object. i This represents the depth value corresponding to the reflecting object, and f represents the range of depth values ​​in the depth data of the TOF camera.

[0086] Will pass The equation of the straight line between the two points serves as the fitting function for this set of test depth data. The equation of the straight line can be expressed as:

[0087]

[0088] The linear equation corresponding to each set of test depth data is as follows: Figure 3 As shown in the figure, it can be seen that the linear equations corresponding to all the test depth data can basically intersect at a point close to the origin (0, 0).

[0089] S202. Calculate the compensation benchmark point based on the fitting function.

[0090] Specifically, calculate the point (x0, y0) in the Cartesian coordinate system that satisfies formulas (2) to (4), and use this point as the reference compensation point;

[0091] Formulas (2) to (4) are respectively:

[0092]

[0093]

[0094]

[0095] Where (x,y) represents the coordinates of any point in the Cartesian coordinate system, and d represents the distance between any point in the Cartesian coordinate system and the equation of the line.

[0096] More specifically, the above-mentioned reference compensation point (x0, y0) can be obtained by traversing the points in the Cartesian coordinate system using the grid method to find the point that best matches the formulas (2) to (4) as the reference compensation point; or by calculating the expressions for x0 and y0 based on the formulas (2) to (4) and the pre-derivation process, and then directly substituting the above-mentioned multiple sets of test depth data into the expressions for x0 and y0 to obtain the reference compensation point (x0, y0).

[0097] The above derivation process includes:

[0098] set up

[0099] Expanding formula (3) yields:

[0100]

[0101] Arrange equation (6) to get

[0102]

[0103] Equation (7) can be expressed as equation (8):

[0104] CX-DY=A(8),

[0105] Then we can obtain:

[0106]

[0107] Expanding formula (4) yields:

[0108]

[0109] Equation (9) can be expressed as equation (10):

[0110] EX-FY = B (10),

[0111] Then we can obtain:

[0112]

[0113] Solving equations (8) and (10) simultaneously yields the result.

[0114]

[0115] Substituting the expressions for A, B, C, D, E, and F into the right side of equation (11) yields the expressions for X and Y.

[0116] Based on the expressions for X and Y obtained from the above derivation process, the compensation reference point (x0, y0) can be obtained by substituting multiple sets of pre-collected test depth data into the expressions for X and Y.

[0117] S3. Based on the compensation reference point (x0, y0), compensate the raw depth data acquired in real time by the TOF camera.

[0118] Specifically, the original depth value ori_phase and the original intensity value ori_amp are obtained from the original depth data; ori_phase and ori_amp are substituted into formula (1) to obtain the original coordinates (x, y, y) in the Cartesian coordinate system. o ,y o Based on the original coordinates (x) o ,y o The compensation values ​​(x0, y0) and the reference compensation point (x0, y0) are used to obtain the compensated depth value phasecomp and the compensated intensity value ampcomp according to formula (5). The phasecomp and ampcomp are then output as the compensated depth data.

[0119] The formula (5) is:

[0120]

[0121] In formula (5), phasecomp represents the compensated depth value, ampcomp represents the compensated intensity value, atan2() represents the arctangent operation, and f represents the range of depth values ​​in the depth data of the TOF camera.

[0122] In one specific embodiment, the TOF camera employs high dynamic range and operates in HDR mode. By comparing the data characteristics of the original depth data and the compensated depth data, the beneficial effects of the compensation method provided in this embodiment are further illustrated.

[0123] In HDR mode, the odd-numbered and even-numbered rows of pixels in a TOF camera are controlled by different integration times. That is, HDR mode allows the TOF camera to acquire an image with two different integration times to increase dynamic range. In practical applications, the two sets of pixels are provided with the exact same light source modulation signal. Due to the different integration times, one set stops integrating earlier than the other. Therefore, the number of photons collected by the two sets of pixels is different. The integration times corresponding to these two sets of pixels are referred to as the high integration time and the low integration time, respectively.

[0124] Figure 4 The graph shows the correspondence between the raw depth value directly acquired by the TOF camera in HDR mode and the distance. It is clear that the raw depth values ​​of different reflective objects at the same test distance are different. Moreover, for the same reflective object, the difference in raw depth value is more obvious at the boundary between high and low integration values.

[0125] Figure 5For TOF cameras in HDR mode, the relationship between the compensated depth value and distance is shown by comparing the original depth value acquired with the distance based on the compensation reference point. It is evident that the difference in compensated depth values ​​for different reflective objects at the same test distance is reduced. Furthermore, for the same reflective object at the boundary between high and low integral points, the difference in compensated depth values ​​is smaller than... Figure 6 It's shrunk.

[0126] In comparison with the above Figure 4 and Figure 5 It is understood that the compensation method provided in this embodiment of the invention can suppress the difference in depth data between measured objects with different reflectivities at the same distance in the original depth data acquired by the TOF camera. Furthermore, it can also reduce the depth value difference between high and low integration to a certain extent, thereby reducing the probability of layering phenomena occurring when switching between high and low integration, that is, suppressing the layering phenomenon in images acquired by the TOF camera in HDR mode.

[0127] On the other hand, when the test distance is the same, the compensation method provided by the embodiments of the present invention can effectively reduce the distance measurement error caused by the measured objects with different reflectivities. Based on the compensation process of the original depth data in step S3 above, the depth value error between the white wall and the gray wall can be compared according to the following formulas (12) to (13):

[0128] diff1=abs(phase1-phase2) (12)

[0129] diff2=abs(phasecomp1-phasecomp2) (13)

[0130] Where phase1 represents the original depth value of the white wall, phase2 represents the original depth value of the gray wall, abs() represents the absolute value operation, diff1 represents the difference between the original depth values ​​of the white wall and the gray wall; phasecomp1 represents the depth value of the white wall after compensation, phasecomp2 represents the depth value of the gray wall after compensation, and diff2 represents the difference between the depth values ​​of the compensated white wall and the gray wall.

[0131] The comparison relationship between diff1 and diff2 obtained in the actual test is as follows: Figure 6 As shown, from Figure 6 It is evident that at most test distances, diff2 is less than diff1. Therefore, the compensation method provided in this embodiment of the invention reduces the ranging error caused by objects with different reflectivities to a certain extent by suppressing the difference in depth value caused by the measured objects with different reflectivities at the same distance.

[0132] It needs to be explained that, Figure 6The curves of diff1 and diff2 have been processed by merging high and low integral values. That is, the depth value with high integral value is selected first. If the intensity of the high integral value is overexposed, the depth value with low integral value is selected for depth merging.

[0133] Example 3

[0134] This embodiment provides a compensation device that compensates the raw depth data collected by the TOF camera based on the reflectivity compensation method of the TOF camera provided in Embodiment 1 or 2, in order to reduce the ranging error caused by the measured object with different reflectivity.

[0135] like Figure 7 As shown, in a preferred embodiment of this invention, the compensation device 10 includes a compensation reference point calculation module 101 and a compensation module 102, as detailed below:

[0136] The compensation reference point calculation module 101 is used to calculate the compensation reference point based on the test depth data pre-acquired by the TOF camera. The compensation reference point is data used to compensate for reflectivity, obtained by processing multiple sets of test depth data pre-collected by the TOF camera according to a fitting function for each set of test depth data; each set of test depth data includes: depth data collected by the TOF camera based on the reflection signals of reflective objects belonging to two or more reflectivities at the same test distance.

[0137] The compensation module 102 is used to perform reflectivity compensation on the raw depth data acquired by the TOF camera based on the compensation reference point. The compensated depth data is used by the TOF camera to acquire distance information of the measured object.

[0138] Based on the technical effect of the compensation method in Embodiment 1 or 2, the compensation device provided in this embodiment can suppress the difference in depth data between measured objects with different reflectivities in the original depth data acquired by the TOF camera based on the compensation reference point calculation module and the compensation module, thereby reducing the ranging error caused by measured objects with different reflectivities to a certain extent.

[0139] like Figure 8 As shown, this embodiment of the invention also provides a TOF camera, including the aforementioned compensation device 10, and other modules for enabling the TOF camera to operate normally, such as a light emitting module 20, a light receiving module 30, and an image processing module 40, as detailed below:

[0140] The light emitting module 20 is used to emit modulated light.

[0141] The light receiving module 30 is used to receive modulated light reflected back from the object being measured and generate raw depth data.

[0142] The compensation device 10 is used to calculate a compensation reference point based on the test depth data pre-acquired by the TOF camera, and to compensate the original depth data based on the compensation reference point, and output the compensated depth data.

[0143] The image processing module 40 is used to process the compensated depth data to obtain an image containing distance information of the measured object.

[0144] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0145] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0146] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0147] It should be noted that any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In claims that enumerate several means, several of these means may be embodied by the same hardware. The use of the terms first, second, third, etc., is merely for convenience of expression and does not indicate any order. These terms can be understood as part of the component names.

[0148] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0149] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0150] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

Claims

1. A method for reflectivity compensation in a TOF camera, characterized in that, include: Receive raw depth data acquired by a TOF camera based on the reflected signals of the object being measured; Based on a predetermined compensation reference point, reflectivity compensation is performed on the original depth data to obtain compensated depth data. The compensated depth data is used by the TOF camera to acquire distance information of the measured object. The compensation reference point is based on multiple sets of test depth data pre-collected by the TOF camera, and the data used to compensate for reflectivity is obtained by processing each set of test depth data according to the fitting function of the test depth data; each set of test depth data includes: depth data collected by the TOF camera based on the reflection signals of reflective objects belonging to two or more reflectivities at the same test distance; Before receiving the raw depth data collected by the TOF camera based on the reflection signal of the object under test, the method further includes: acquiring multiple sets of test depth data pre-collected by the TOF camera at multiple test distances, acquiring a fitting function for each set of test depth data, and calculating the compensation reference point based on the fitting function. Specifically, based on multiple sets of test depth data pre-collected by the TOF camera, points in the Cartesian coordinate system that satisfy formulas (2) to (4) are calculated. This point will be used as the compensation benchmark point; Formulas (2) to (4) are respectively: （2） （3） （4） in, Represents the coordinates of any point in the Cartesian coordinate system, which will pass through... , The equation of the straight line between the two points is used as the fitting function for this set of test depth data; d represents the distance between any point in the Cartesian coordinate system and the equation of the straight line. , These are the coordinates of two reflective objects with different reflectivities in the Cartesian coordinate system used when obtaining the fitting function for each set of test depth data.

2. The compensation method according to claim 1, characterized in that, Each set of test depth data includes: test depth data of at least two reflective objects collected at the same test distance; wherein the reflectivity of each reflective object is different.

3. The compensation method according to claim 2, characterized in that, The reflective object includes a first reflective object and a second reflective object; Each set of test depth data includes: the depth and intensity values ​​of the first reflecting object and the second reflecting object acquired by the TOF camera at the same test distance.

4. The compensation method according to claim 3, characterized in that, The fitting function for each set of test depth data is obtained based on a calculation process, which includes: For the i-th test depth data, i is a positive integer not less than 2. Substituting the depth and intensity values ​​corresponding to the first reflecting object into formula (1), we obtain the first coordinate in the Cartesian coordinate system. ; Substituting the depth and intensity values ​​corresponding to the second reflecting object into formula (1), we obtain the second coordinates in the Cartesian coordinate system. ; Wherein, the formula (1) is, （1） In formula (1), This represents the intensity value corresponding to the reflecting object. This represents the depth value corresponding to the reflecting object, and f represents the range of depth values ​​in the depth data of the TOF camera.

5. The compensation method according to claim 1, characterized in that, The reflectivity compensation of the original depth data includes: Obtain the raw depth value from the raw depth data. and original strength value ; Will and Substituting into formula (1), we obtain the original coordinates in the Cartesian coordinate system. , Based on the original coordinates and benchmark compensation point The compensated depth value is obtained according to formula (5). and the compensated strength value ,Will and As the compensated depth data output; The formula (5) is: （5） In formula (5), This represents the compensated depth value. This represents the compensated intensity value, atan2() represents the arctangent operation, and f represents the range of depth values ​​in the depth data of the TOF camera.

6. The compensation method according to claim 3, characterized in that, The first reflective object has a reflectivity of 80% to 100%, and the second reflective object has a reflectivity of 40% to 60%.

7. A compensation device, characterized in that, The compensation device is based on the reflectivity compensation method of the TOF camera according to any one of claims 1 to 6, and compensates the original depth data collected by the TOF camera to reduce the ranging error caused by the measured object with different reflectivity.

8. The compensation device according to claim 7, characterized in that, The compensation device includes: The compensation reference point calculation module is used to calculate the compensation reference point based on the test depth data pre-acquired by the TOF camera. The compensation module is used to perform reflectivity compensation on the raw depth data acquired by the TOF camera based on the compensation reference point.

9. A TOF camera, characterized in that, The TOF camera includes the compensation device as described in claim 7 or 8.

Images