A module error calibration method and device

Abstract

The present invention provides a module error calibration method and device, the method comprising: using a standard module, a plurality of optical attenuation sheets with different transmittances and a preset distance error threshold to determine a target calibration distance and a target optical attenuation sheet; based on the target calibration distance and the target optical attenuation sheet, error calibration is performed on a module to be measured, wherein the module to be measured has the same model as the standard module; thus, when the target calibration distance is determined using the optical attenuation sheet and the standard module, the intensity of a photon pulse received by the module can be weakened, thereby delaying the moment when the SPAD is triggered by the returned photon pulse, so that the determined target calibration distance will be smaller than the traditional calibration distance, thereby simultaneously reducing the size of the plane to be measured and reducing the calibration cost; and when error calibration is performed on multiple modules in the mass production stage, the size of the plane to be measured can be adjusted to meet the calibration requirements of the production line, thereby improving the calibration efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of sensor error correction, and in particular to a module error calibration method and device. Background Art

[0002] The principle of direct measurement of time of flight (dTOF) is to directly calculate the depth of the object by emitting a light pulse to the object and measuring the time interval between the reflected and emitted light pulses.

[0003] The core device of dTOF sensor for calculating pulse time is single photon avalanche diode (SPAD). When SPAD is triggered by the returning photon pulse, it will remain closed for a period of time to receive new photon triggers, so that the captured electrons have enough time to be released again without causing avalanche again. This period of time is called the dead time between two detection states of SPAD. Therefore, if the reflected pulse is too strong, it will cause errors in the calculation of pulse flight time. The closer to the reflecting surface, the greater the error will be. However, when it exceeds a certain distance, it will not be affected by the dead time.

[0004] Based on this, the dTOF module needs to be calibrated before it is put into normal use, and the distance error calibration item is one of the calibration items of dTOF. If the distance error is to be calibrated, the influence of SPAD dead time must be eliminated first. The existing technology generally calibrates at a sufficiently far distance, which will cause the size of the plane to be measured to be very large, resulting in a high calibration cost; and in the actual mass production process, if the size of the plane to be measured is very large, it may not meet the calibration requirements of the production line, resulting in the inability to calibrate the module error, affecting the calibration efficiency. Summary of the invention

[0005] In response to the problems existing in the prior art, an embodiment of the present invention provides a module error calibration method and device to solve or partially solve the problem that when performing error calibration on the dTOF module in the prior art, the size of the plane to be measured is very large, which leads to high calibration costs; and in the actual mass production process, if the size of the plane to be measured is very large, it may not meet the calibration requirements of the production line, resulting in the inability to calibrate the module error, affecting the calibration efficiency.

[0006] A first aspect of the present invention provides a module error calibration method, the method comprising:

[0007] Determine the target calibration distance and the target optical attenuation sheet by using a standard module, a plurality of optical attenuation sheets with different light transmittances, and a preset distance error threshold;

[0008] The error of the module to be measured is calibrated based on the target calibration distance and the target optical attenuation sheet, and the model of the module to be measured is the same as that of the standard module.

[0009] In the above scheme, a target calibration distance and a target optical attenuation sheet are determined by using a standard module, a plurality of optical attenuation sheets with different light transmittances, and a preset distance error threshold, including:

[0010] Determine the center area of ​​the plane to be measured and the reference distance; the reference distance is the distance corresponding to the need to load the optical attenuation sheet to the receiving end of the standard module;

[0011] Taking the reference distance as a reference, gradually reducing the actual distance between the standard module and the central area based on a preset step size;

[0012] At a position corresponding to any actual distance, controlling a standard module loaded with a current optical attenuation sheet to emit a light pulse to the plane to be measured, obtaining a measured distance and an actual distance between the standard module and the central area; and determining a first distance error based on the measured distance and the actual distance;

[0013] If the first distance error is greater than a preset error threshold, the current optical attenuation sheet is replaced with a next optical attenuation sheet, and the actual distance between the standard module and the central area is gradually shortened with the preset step length until a preset test condition is met; the transmittance of the next optical attenuation sheet is less than the transmittance of the current optical attenuation sheet;

[0014] The distance corresponding to the test condition is determined as the target calibration distance, and the optical attenuation sheet corresponding to the test condition is determined as the target optical attenuation sheet.

[0015] In the above solution, the determining of the reference distance includes:

[0016] Taking the initial distance as the standard, based on the stepwise reduction of the actual distance between the standard module and the plane to be measured; the initial distance is greater than the reference distance;

[0017] At a position corresponding to any actual distance, controlling the standard module to emit a light pulse to the plane to be measured, and sequentially acquiring a measured distance and an actual distance between the standard module and the central area;

[0018] determining a third distance error based on the measured distance and the actual distance;

[0019] If it is determined that the third distance error is greater than the error threshold, the third distance corresponding to the distance greater than the error threshold is determined as the reference distance.

[0020] In the above solution, the error calibration of the module to be measured based on the target calibration distance and the target optical attenuation sheet includes:

[0021] Mounting the target optical attenuation sheet on the receiving end of the module to be tested;

[0022] When the distance between the module to be measured and the plane to be measured is the target calibration distance, controlling the module to be measured to emit a light pulse to the plane to be measured, and obtaining the current distance measured by the module to be measured;

[0023] The difference between the current distance and the target calibration distance is calibrated as an error value.

[0024] In the above solution, after the error calibration of the module to be measured based on the target calibration distance and the target optical attenuation sheet, the method further includes:

[0025] Remove the target optical attenuation sheet loaded on the receiving end of the module to be tested;

[0026] When the actual distance between the module to be measured and the plane to be measured is the initial distance, determining the measurement error of the module to be measured;

[0027] The target calibration distance and the target optical attenuation sheet are verified based on the measurement error and the error threshold.

[0028] In the above solution, the verification of the target calibration distance and the target optical attenuation sheet based on the measurement error and the error threshold includes:

[0029] If it is determined that the measurement error is less than the error threshold, it is determined that the target calibration distance is suitable for the target optical attenuation sheet.

[0030] In the above solution, determining the measurement error of the module to be measured includes:

[0031] Obtaining a measurement distance measured by the module to be measured at an initial distance;

[0032] The measurement error of the module to be measured is determined based on the difference between the measured distance and the initial distance.

[0033] A second aspect of the present invention provides a module error calibration system, the system comprising: a plane to be measured, a standard module, and a plurality of optical attenuation sheets with different light transmittances; wherein:

[0034] The receiving end of the standard module can be installed with an optical attenuation sheet of any transmittance;

[0035] The plane to be measured is located at one side of the standard module, and there is a preset distance between the plane to be measured and the standard module.

[0036] In the above solution, the system further comprises: a module to be tested;

[0037] When the target calibration distance and the target optical attenuation sheet are determined by using the standard module, the standard module is removed; the distance between the module to be measured and the plane to be measured is the target calibration distance, and the receiving end of the module to be measured is installed with the target optical attenuation sheet.

[0038] In the above solution, the central area of ​​the plane to be measured is the area that can be covered by the field of view angle of the standard module.

[0039] The present invention provides a module error calibration method and device, the method comprising: using a standard module, a plurality of optical attenuation sheets with different transmittances and a preset distance error threshold to determine a target calibration distance and a target optical attenuation sheet; based on the target calibration distance and the target optical attenuation sheet, error calibration is performed on a module to be measured, wherein the module to be measured has the same model as the standard module; thus, when the target calibration distance is determined using the optical attenuation sheet and the standard module, the intensity of a photon pulse received by the module can be weakened, thereby delaying the moment when the SPAD is triggered by the returned photon pulse, so that the determined target calibration distance will be smaller than the traditional calibration distance, thereby simultaneously reducing the size of the plane to be measured and reducing the calibration cost; and when error calibration is performed on multiple modules in the mass production stage, the size of the plane to be measured can be adjusted to meet the calibration requirements of the production line, thereby improving the calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings.

[0041] In the attached picture:

[0042] Figure 1 A schematic diagram of a module error calibration method flow chart according to an embodiment of the present invention is shown;

[0043] Figure 2 A schematic diagram of the module error calibration principle according to an embodiment of the prior art is shown;

[0044] Figure 3 A schematic diagram of the module error calibration principle according to an embodiment of the present invention is shown;

[0045] Figure 4 A schematic diagram of the structure of a module error calibration system according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0046] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0047] The embodiment of the present invention provides a module error calibration method, such as Figure 1 As shown, the method comprises the following steps:

[0048] S110, determining a target calibration distance and a target optical attenuation sheet using a standard module, a plurality of optical attenuation sheets with different light transmittances, and a preset distance error threshold;

[0049] This embodiment mainly weakens the influence of the SPAD dead time by weakening the intensity of the photon pulse received by the receiving end of the dTOF module, thereby shortening the calibration distance.

[0050] In one embodiment, a target calibration distance and a target optical attenuation sheet are determined using a standard module, a plurality of optical attenuation sheets with different light transmittances, and a preset distance error threshold, including:

[0051] Determine the center area of ​​the plane to be measured and the reference distance; the reference distance is the distance corresponding to the need to load the optical attenuation sheet to the receiving end of the standard module;

[0052] Based on the reference distance, the actual distance between the standard module and the central area is gradually reduced based on the preset step length;

[0053] At a position corresponding to any actual distance, controlling a standard module loaded with a first optical attenuation sheet to emit a light pulse to the plane to be measured, obtaining a measured distance and an actual distance between the standard module and the central area; and determining a first distance error based on the measured distance and the actual distance;

[0054] If the first distance error is greater than a preset error threshold, the first optical attenuation sheet is replaced with a second optical attenuation sheet, and the second distance error is re-determined; the transmittance of the second optical attenuation sheet is less than the transmittance of the second optical attenuation sheet;

[0055] The distance corresponding to the second distance error being less than or equal to the error threshold is determined as the target calibration distance, and the second optical attenuation sheet is determined as the target optical attenuation sheet.

[0056] In one implementation, determining a reference distance includes:

[0057] Taking the initial distance as the standard, the actual distance between the standard module and the plane to be measured is gradually reduced; the initial distance is greater than the reference distance;

[0058] At any position corresponding to the actual distance, the standard module is controlled to emit a light pulse to the plane to be measured, and the measured distance and the actual distance between the standard module and the central area are obtained in turn;

[0059] determining a third distance error based on the measured distance and the actual distance;

[0060] If it is determined that the third distance error is greater than the error threshold, the third distance corresponding to the distance greater than the error threshold is determined as the reference distance.

[0061] Specifically, if the initial distance is too far (eg, 2 m), loading an optical attenuation sheet at the receiving end of the standard module will affect the calibration accuracy. Therefore, this embodiment needs to first determine the reference distance corresponding to the need to load the optical attenuation sheet.

[0062] It is worth noting that in order to avoid the influence of the accuracy of the module itself, a standard module is used in this embodiment. The standard module is a module whose parameters have been calibrated and is in a standard state.

[0063] First, determine the center area of ​​the plane to be measured; generally speaking, when the distance between the module and the plane to be measured is the initial distance, the area covered by the field of view of the module receiving end on the plane to be measured is the center area. Figure 2 If the field of view angle fov is 60 degrees and the calibration distance D is 1500mm, then the central area is the area covered by the 60-degree field of view angle.

[0064] Then, taking the initial distance as the reference, the distance between the module and the plane to be measured is gradually shortened with a preset step length (e.g., 5 cm each time). At each position, the corresponding third distance error is determined according to the actual distance and the measured distance of the module. If the third distance error is greater than a preset error threshold (e.g., 1%), the actual distance corresponding to this time is used as the reference distance.

[0065] At the reference distance, the current optical attenuation chip of any transmittance is loaded on the receiving end of the module, and then the actual distance between the standard module and the central area is gradually reduced based on the preset step length, taking the reference distance as the benchmark. At each position, the first distance error is determined according to the same method. If the first distance error is greater than the error threshold again, the next optical attenuation sheet with a lower transmittance is replaced, and the actual distance between the standard module and the central area is gradually shortened with the preset step length until the test conditions are met. The distance corresponding to the test conditions is determined as the target calibration distance, and the optical attenuation sheet corresponding to the test conditions is determined as the target optical attenuation sheet.

[0066] The test condition is that the distance between the module and the plane to be measured reaches the distance required for production line calibration, or the test condition is that the size of the plane to be measured meets the size required for production line calibration.

[0067] For example, when the test condition is that the distance between the module and the plane to be measured reaches the distance required for production line calibration, assuming that the distance required for production line calibration is 500mm, the distance error obtained at 498mm in the above determination process is less than the error threshold. At this time, 498mm can be used as the target calibration distance, and the optical attenuation chip loaded at 498mm can be used as the target attenuation chip.

[0068] S111, performing error calibration on a module to be measured based on the target calibration distance and the target optical attenuation sheet, wherein the module to be measured is of the same model as the standard module.

[0069] After the target calibration distance and target optical attenuation chip are determined, the error calibration of the module to be tested can be performed based on the target calibration distance and target optical attenuation chip. Since different types of modules use different receiving and transmitting ends, the calibration environment can only be ensured to be applicable to the module to be tested when the model of the module to be tested and the standard module are the same.

[0070] In one implementation, error calibration is performed on the module to be measured based on the target calibration distance and the target optical attenuation sheet, including:

[0071] Mount the target optical attenuation sheet on the receiving end of the module to be tested;

[0072] When the distance between the module to be measured and the plane to be measured is the target calibration distance, the module to be measured is controlled to emit a light pulse to the plane to be measured to obtain the current distance measured by the module to be measured;

[0073] The difference between the current distance and the target calibration distance is calibrated as the error value.

[0074] The error value is saved in a table as the subsequent error compensation value.

[0075] Furthermore, in order to ensure that the determined target calibration distance and the error value calibrated by the target optical attenuation sheet are accurate in a long-distance environment without an optical attenuation sheet, after performing error calibration on the module to be tested based on the target calibration distance and the target optical attenuation sheet, the method further includes:

[0076] Remove the target optical attenuation sheet installed on the receiving end of the module to be tested;

[0077] When the distance between the module to be measured and the plane to be measured is the initial distance, obtaining the measurement error of the module to be measured;

[0078] The target calibration distance and target optical attenuation sheet are verified based on the measurement error and error threshold.

[0079] Verify the target calibration distance and target optical attenuation sheet based on the measurement error and error threshold, including:

[0080] If it is determined that the measurement error is less than the error threshold, it is determined that the target calibration distance and the target optical attenuation sheet are appropriate;

[0081] If it is determined that the measurement error is greater than or equal to the error threshold, it is determined that the target calibration distance and the target optical attenuation sheet are not suitable, and the target calibration distance and the target optical attenuation sheet need to be re-determined.

[0082] In one implementation, determining the measurement error of the module to be measured includes:

[0083] Get the measured distance of the module to be tested at the initial distance;

[0084] The measurement error of the module to be measured is determined based on the difference between the measured distance and the initial distance.

[0085] For example, assuming that the initial distance is 1m and the measured distance is 0.99m, the difference between the measured distance and the initial distance is 10mm, and the measurement error is 10mm / 1m=1 / 100. Specifically, the target optical attenuation sheet is removed from the receiving end of the module to be measured, and then the distance between the module to be measured and the plane to be measured is adjusted to the initial distance, and the measurement error is determined according to the above method. If the measurement error is less than the error threshold, it is determined that the target calibration distance and the target optical attenuation sheet are appropriate.

[0086] If the measurement error is less than the error threshold, the standard module needs to be replaced with the module to be measured, and step S110 is repeated to re-determine the target calibration distance and the target optical attenuation sheet, which will not be described in detail here.

[0087] This embodiment uses an optical attenuation sheet and a standard module to determine the target calibration distance, which can weaken the intensity of the photon pulse received by the module, thereby delaying the moment when the SPAD is triggered by the returned photon pulse. The determined target calibration distance will be smaller than the traditional calibration distance, so as to simultaneously reduce the size of the plane to be measured and reduce the calibration cost. When error calibration is performed on multiple modules in the mass production stage, the size of the plane to be measured can be adjusted to meet the calibration requirements of the production line, thereby improving the calibration efficiency.

[0088] For reference Figure 2 In the common calibration method, the transmitter 1 and the receiver 2 of the module to be measured are kept in normal state, the calibration distance D is 1500mm, and the length P of the plane 3 to be measured needs to be 1734mm. Figure 3 , the target attenuation optical chip 4 is loaded on the receiving end 2 of the module to be tested, the transmitting end 1 remains normal, the calibration distance D not affected by the dead time of SAPD can be reduced to 500mm, and the length P of the plane to be tested 3 is reduced to 578mm; compared with the existing technology, the size of the plane to be tested can be greatly reduced.

[0089] Based on the same inventive concept as the above-mentioned embodiment, this embodiment also provides a module error calibration system, such as Figure 4 As shown, the system includes: a plane to be measured 3, a standard module 5, and a plurality of optical attenuation sheets with different light transmittances;

[0090] The receiving end 2 of the standard module 5 can be installed with an optical attenuation sheet 6 of any light transmittance, and the transmitting end 1 is not blocked;

[0091] The plane to be measured 3 is located on one side of the standard module 5 , and there is a preset distance D between the plane to be measured 3 and the standard module 5 . The central area of ​​the plane to be measured 3 is the area that can be covered by the viewing angle of the standard module 5 .

[0092] The target calibration distance and the target optical attenuation sheet 4 can be determined by using the standard module 5, a plurality of optical attenuation sheets with different light transmittances and a preset distance error threshold. The specific implementation process can refer to the above method embodiment, which will not be described in detail here.

[0093] After the target calibration distance and the target optical attenuation sheet are determined by using the standard module 4, the standard module 4 is removed and the module to be tested 7 is placed; Figure 3 , the distance between the module to be measured 7 and the plane to be measured 3 is the target calibration distance, the plane to be measured 3 of the module to be measured is located on one side of the module to be measured 7, and the receiving end of the module to be measured 7 is installed with a target optical attenuation sheet 4. Then, the module to be measured 7 is calibrated for error, and the specific error calibration method can be implemented with reference to the above method, which will not be repeated here.

[0094] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0095] The present invention provides a module error calibration method and device, the method comprising: using a standard module, a plurality of optical attenuation sheets with different transmittances and a preset distance error threshold to determine a target calibration distance and a target optical attenuation sheet; based on the target calibration distance and the target optical attenuation sheet, error calibration is performed on a module to be measured, wherein the module to be measured has the same model as the standard module; thus, when the target calibration distance is determined using the optical attenuation sheet and the standard module, the intensity of a photon pulse received by the module can be weakened, thereby delaying the moment when the SPAD is triggered by the returned photon pulse, so that the determined target calibration distance will be smaller than the traditional calibration distance, thereby simultaneously reducing the size of the plane to be measured and reducing the calibration cost; and when error calibration is performed on multiple modules in the mass production stage, the size of the plane to be measured can be adjusted to meet the calibration requirements of the production line, thereby improving the calibration efficiency.

[0096] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the present invention described herein, and the description of the above specific languages ​​is for disclosing the best mode of the present invention.

[0097] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0098] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0099] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition they may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0100] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims below, any one of the claimed embodiments may be used in any combination.

[0101] The various component embodiments of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some or all components in a gateway, proxy server, or system according to an embodiment of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0102] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

[0103] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A module error calibration method, characterized in that: The method comprises: Determine the target calibration distance and the target optical attenuation sheet by using a standard module, a plurality of optical attenuation sheets with different light transmittances, and a preset distance error threshold; Based on the target calibration distance and the target optical attenuation sheet, the error of the module to be tested is calibrated, and the model of the module to be tested is the same as that of the standard module; wherein, The target calibration distance and the target optical attenuation sheet are determined by using a standard module, a plurality of optical attenuation sheets with different transmittances, and a preset distance error threshold, including: Determine the center area of ​​the plane to be measured and the reference distance; the reference distance is the distance corresponding to the need to load the optical attenuation sheet to the receiving end of the standard module; Taking the reference distance as a reference, gradually reducing the actual distance between the standard module and the central area based on a preset step size; At a position corresponding to any actual distance, controlling a standard module loaded with a current optical attenuation sheet to emit a light pulse to the plane to be measured, obtaining a measured distance and an actual distance between the standard module and the central area; and determining a first distance error based on the measured distance and the actual distance; If the first distance error is greater than a preset error threshold, the current optical attenuation sheet is replaced with a next optical attenuation sheet, and the actual distance between the standard module and the central area is gradually shortened with the preset step length until a preset test condition is met; the transmittance of the next optical attenuation sheet is less than the transmittance of the current optical attenuation sheet; The distance corresponding to the test condition is determined as the target calibration distance, and the optical attenuation sheet corresponding to the test condition is determined as the target optical attenuation sheet.

2. The method according to claim 1, characterized in that The determining of the reference distance comprises: Taking the initial distance as the standard, based on the stepwise reduction of the actual distance between the standard module and the plane to be measured; the initial distance is greater than the reference distance; At a position corresponding to any actual distance, controlling the standard module to emit a light pulse to the plane to be measured, and sequentially acquiring a measured distance and an actual distance between the standard module and the central area; determining a third distance error based on the measured distance and the actual distance; If it is determined that the third distance error is greater than the error threshold, the third distance corresponding to the distance greater than the error threshold is determined as the reference distance.

3. The method according to claim 1, characterized in that The error calibration of the module to be measured based on the target calibration distance and the target optical attenuation sheet includes: Mounting the target optical attenuation sheet on the receiving end of the module to be tested; When the distance between the module to be measured and the plane to be measured is the target calibration distance, controlling the module to be measured to emit a light pulse to the plane to be measured, and obtaining the current distance measured by the module to be measured; The difference between the current distance and the target calibration distance is calibrated as an error value.

4. The method according to claim 1, characterized in that After the error calibration of the module to be measured based on the target calibration distance and the target optical attenuation sheet, the method further includes: Remove the target optical attenuation sheet loaded on the receiving end of the module to be tested; When the actual distance between the module to be measured and the plane to be measured is the initial distance, determining the measurement error of the module to be measured; The target calibration distance and the target optical attenuation sheet are verified based on the measurement error and the error threshold.

5. The method according to claim 4, characterized in that The verifying the target calibration distance and the target optical attenuation sheet based on the measurement error and the error threshold includes: If it is determined that the measurement error is less than the error threshold, it is determined that the target calibration distance is suitable for the target optical attenuation sheet.

6. The method according to claim 4, characterized in that The determining the measurement error of the module to be measured includes: Obtaining a measurement distance measured by the module to be measured at an initial distance; The measurement error of the module to be measured is determined based on the difference between the measured distance and the initial distance.

7. A module error calibration system, characterized in that: The system comprises: a plane to be measured, a standard module, and a plurality of optical attenuation sheets with different light transmittances; wherein, The receiving end of the standard module can be installed with an optical attenuation sheet of any transmittance; The plane to be measured is located at one side of the standard module, and there is a preset distance between the plane to be measured and the standard module; The target calibration distance and the target optical attenuation sheet are determined by using a standard module, a plurality of optical attenuation sheets with different transmittances, and a preset distance error threshold, including: Determine the center area of ​​the plane to be measured and the reference distance; the reference distance is the distance corresponding to the need to load the optical attenuation sheet to the receiving end of the standard module; Taking the reference distance as a reference, gradually reducing the actual distance between the standard module and the central area based on a preset step size; At a position corresponding to any actual distance, controlling a standard module loaded with a current optical attenuation sheet to emit a light pulse to the plane to be measured, obtaining a measured distance and an actual distance between the standard module and the central area; and determining a first distance error based on the measured distance and the actual distance; If the first distance error is greater than a preset error threshold, the current optical attenuation sheet is replaced with a next optical attenuation sheet, and the actual distance between the standard module and the central area is gradually shortened with the preset step length until a preset test condition is met; the transmittance of the next optical attenuation sheet is less than the transmittance of the current optical attenuation sheet; The distance corresponding to the test condition is determined as the target calibration distance, and the optical attenuation sheet corresponding to the test condition is determined as the target optical attenuation sheet.

8. The system according to claim 7, characterized in that The system further comprises: a module to be tested; When the target calibration distance and the target optical attenuation sheet are determined by using the standard module, the standard module is removed; the distance between the module to be measured and the plane to be measured is the target calibration distance, and the receiving end of the module to be measured is installed with the target optical attenuation sheet.

9. The system according to claim 7, characterized in that The central area of ​​the plane to be measured is the area that can be covered by the field of view angle of the standard module.

Images