Calibration methods, calibration systems, and distance measurement devices for distance sensors

Abstract

An exemplary embodiment of the present invention provides a calibration method for a distance sensor, comprising: obtaining a first series of consecutive distance measurement results of the distance sensor; obtaining a first measurement index of the distance sensor based on the first series of consecutive measurement results, wherein the first measurement index reflects measurement accuracy; determining whether parameter calibration of the distance sensor is required based on the first measurement index of the distance sensor; if parameter calibration of the distance sensor is required, obtaining matching calibration information from a calibration information set; and controlling the distance sensor to perform parameter calibration based on the matching calibration information.

Description

Technical Field

[0001] Exemplary embodiments of the present invention generally relate to distance sensor-related technologies, and more specifically, to a distance sensor calibration method, a distance sensor calibration system, and a distance measuring device including the distance sensor. Background Technology

[0002] With the continuous development of technology, there is an increasing need to acquire or use distance data of objects in more and more scenarios. For this purpose, distance sensors are usually used to measure the distance of objects.

[0003] Figure 1 An example of the working principle of a distance sensor according to an exemplary embodiment of the present invention is shown. As an example, the distance sensor here can measure the distance to an object based on time-of-flight (ToF) technology.

[0004] like Figure 1 As shown, in order to measure the distance to an object, the distance sensor can emit light from a corresponding light source, such as modulated near-infrared light. After the emitted light encounters the object, it will be reflected back to the distance sensor. For example, a built-in timer can record the round-trip time between the emission and reflection of the light, and then the distance sensor can calculate the distance to the object based on this round-trip time.

[0005] Such distance sensors are typically calibrated once upon power-on, which often leads to inaccurate measurement results during use. Even when dynamic physical calibration of the distance sensor is performed (i.e., controlling the distance sensor to perform physical calibration according to its inherent factory settings by sending a calibration command to the distance sensor), this method is often unsatisfactory due to its lack of specificity. Summary of the Invention

[0006] An exemplary embodiment of the present invention provides a calibration method, calibration system and distance measuring device for a distance sensor, which obtains an index reflecting the measurement accuracy based on the measurement results, and calibrates the distance sensor using matching calibration information according to the index, thereby enabling the calibration process of the distance sensor to be completed in a targeted, fast and effective manner.

[0007] According to one aspect of an exemplary embodiment of the present invention, a method for calibrating a distance sensor is provided, comprising: obtaining a first series of consecutive distance measurement results of the distance sensor; obtaining a first measurement index of the distance sensor based on the first series of consecutive measurement results, wherein the first measurement index reflects measurement accuracy; determining whether parameter calibration of the distance sensor is required based on the first measurement index of the distance sensor; if parameter calibration of the distance sensor is required, obtaining matching calibration information from a calibration information set; and controlling the distance sensor to perform parameter calibration based on the matching calibration information.

[0008] Optionally, the method further includes updating the calibration information set based on the current operating state of the distance sensor if it is determined that parameter calibration of the distance sensor is not required.

[0009] Optionally, in the method, the calibration information set includes at least one pre-stored calibration information, and each calibration information includes the corresponding environmental factors, a first measurement index, and calibration parameters.

[0010] Optionally, in the method, determining whether parameter calibration of the distance sensor is required based on the first measurement index of the distance sensor includes: acquiring the environmental factors currently present to the distance sensor; selecting a subset of calibration information from the calibration information set, consisting of calibration information whose environmental factors are consistent with the environmental factors currently present to the distance sensor; determining that parameter calibration of the distance sensor is not required if the first measurement index of the distance sensor is better than or equal to the first measurement index of all calibration information in the calibration information subset; and determining that parameter calibration of the distance sensor is required if the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the calibration information subset.

[0011] Optionally, in the method, obtaining matching calibration information from the calibration information set when it is determined that parameter calibration of the distance sensor is required includes: obtaining matching calibration information based on a first measurement index from a selected subset of calibration information.

[0012] Optionally, in the method, obtaining matching calibration information based on the first measurement index in the selected subset of calibration information includes: obtaining calibration information in the selected subset of calibration information where the first measurement index is better than and closest to the first measurement index of the distance sensor, and using it as the matching calibration information.

[0013] Optionally, in the method, updating the calibration information set based on the current operating state of the distance sensor includes: constructing corresponding calibration information based on the current operating state of the distance sensor, and replacing the replaced calibration information in the calibration information set with the constructed calibration information; or constructing corresponding calibration information based on the current operating state of the distance sensor, and adding the constructed calibration information as new calibration information to the calibration information set; or constructing corresponding calibration information based on the current operating state of the distance sensor, and selectively replacing the replaced calibration information in the calibration information set with the constructed calibration information or adding the constructed calibration information as new calibration information to the calibration information set.

[0014] Optionally, in the method, the calibration information set further includes a predetermined number of reserved blank calibration information; wherein, the step of selectively replacing the replaced calibration information in the calibration information set with the constructed calibration information or adding the constructed calibration information as new calibration information to the calibration information set based on the approximation of the first measurement index includes: in the selected subset of calibration information, selecting the second-best first measurement index that is closest to the first measurement index of the distance sensor, and calculating the index difference between the two; if the index difference is less than a difference threshold, replacing the calibration information containing the second-best first measurement index with the constructed calibration information; if the index difference is greater than a difference threshold, adding the constructed calibration information as new calibration information to the blank calibration information in the calibration information set.

[0015] Optionally, the method further includes, before obtaining the first series of distance measurement results from the distance sensor, performing a physical calibration of the distance sensor.

[0016] Optionally, in the method, the physical calibration of the distance sensor includes: obtaining a second series of distance measurement results of the distance sensor; obtaining a second measurement index of the distance sensor based on the second series of measurement results, wherein the second measurement index reflects the measurement accuracy; and performing physical calibration of the distance sensor if it is determined based on the second measurement index of the distance sensor that physical calibration of the distance sensor is required.

[0017] Optionally, in the method, environmental factors include one or more combinations of temperature, light, humidity, and electromagnetic radiation.

[0018] Optionally, in the method, at least one pre-stored calibration information includes a better test result obtained from multiple calibration tests under different environments defined by light and temperature, wherein the environmental factors correspond to multiple light ranges, and each light range corresponds to multiple temperature ranges.

[0019] Optionally, in the method, the calibration parameters include at least one of the following: the Sigma limit value and the Si gna l limit value as calculation factors, the sampling time period, the VCSEL pulse period, and the VCSEL pulse period range.

[0020] Optionally, in the method, the first measurement index indicates the variance of the results of a first series of distance measurements.

[0021] Optionally, in the method, the second measurement index indicates the variance of the results of a second series of distance measurements.

[0022] According to another aspect of an exemplary embodiment of the present invention, a calibration system for a distance sensor is provided, comprising: a ranging result acquisition unit configured to acquire a first series of consecutive distance measurement results of the distance sensor; an index calculation unit configured to acquire a first measurement index of the distance sensor based on the first series of consecutive measurement results, wherein the first measurement index reflects measurement accuracy; a determination unit configured to determine whether parameter calibration of the distance sensor is required based on the first measurement index of the distance sensor; a calibration information acquisition unit configured to acquire matching calibration information from a calibration information set when parameter calibration of the distance sensor is required; and a calibration control unit configured to control the distance sensor to perform parameter calibration based on the matching calibration information.

[0023] Optionally, the calibration system further includes an update unit configured to update the calibration information set based on the current operating state of the distance sensor when the determining unit determines that parameter calibration of the distance sensor is not required.

[0024] Optionally, in the calibration system, the calibration information set includes at least one pre-stored calibration information, each calibration information including corresponding environmental factors, a first measurement index, and calibration parameters.

[0025] Optionally, in the calibration system, the determining unit acquires the environmental factors currently present to the distance sensor; selects a subset of calibration information from the calibration information set, consisting of calibration information whose environmental factors are consistent with the environmental factors currently present to the distance sensor; if the first measurement index of the distance sensor is better than or equal to the first measurement index of all calibration information in the calibration information subset, it determines that parameter calibration of the distance sensor is not required; if the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the calibration information subset, it determines that parameter calibration of the distance sensor is required.

[0026] Optionally, in the calibration system, the updating unit constructs corresponding calibration information based on the current operating state of the distance sensor and replaces the replaced calibration information in the calibration information set with the constructed calibration information; or it constructs corresponding calibration information based on the current operating state of the distance sensor and adds the constructed calibration information as new calibration information to the calibration information set; or it constructs corresponding calibration information based on the current operating state of the distance sensor and, according to the approximation of the first measurement index, selectively replaces the replaced calibration information in the calibration information set with the constructed calibration information or adds the constructed calibration information as new calibration information to the calibration information set.

[0027] Optionally, in the calibration system, the calibration information set also includes a predetermined number of reserved blank calibration information; wherein, the updating unit selectively replaces the replaced calibration information in the calibration information set with the constructed calibration information or adds the constructed calibration information as new calibration information to the calibration information set through the following process: in the selected subset of calibration information, select the second-best first measurement index that is closest to the first measurement index of the distance sensor, and calculate the index difference between the two; if the index difference is less than the difference threshold, replace the calibration information containing the second-best first measurement index with the constructed calibration information; if the index difference is less than the difference threshold, add the constructed calibration information as new calibration information to the blank calibration information in the calibration information set.

[0028] According to another exemplary embodiment of the present invention, a distance measuring device is provided, comprising: a distance sensor for measuring distance; a memory for storing a set of calibration information; and a processor configured to perform the above-described method.

[0029] According to another exemplary embodiment of the present invention, a terminal device for applying distance measurement is provided, including the distance measuring device as described above, wherein the terminal device is an access control system, a cleaning robot, a smart building terminal, a smart agriculture terminal, or a wearable device.

[0030] According to an exemplary embodiment of the present invention, calibration can be performed directly using matching calibration information for the actual scenario of distance measurement. Compared with the traditional method of physical calibration, it can better cope with many uncontrollable factors affecting distance measurement, which not only improves the effectiveness of calibration but also reduces the time required for calibration. Attached Figure Description

[0031] Other features, objects, and advantages of exemplary embodiments of the present invention will become more apparent from the following detailed description of non-limiting embodiments, with reference to the accompanying drawings, in which like reference numerals denote like components:

[0032] Figure 1An example illustrating the working principle of a distance sensor according to an exemplary embodiment of the present invention is shown;

[0033] Figure 2 A distance measuring device according to an exemplary embodiment of the present invention is shown;

[0034] Figure 3 A flowchart illustrating a calibration method for a distance sensor according to an exemplary embodiment of the present invention is provided.

[0035] Figure 4 A flowchart illustrating the process of determining whether parameter calibration is required according to an exemplary embodiment of the present invention is shown;

[0036] Figure 5 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention;

[0037] Figure 6 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention;

[0038] Figure 7 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention;

[0039] Figure 8 A flowchart illustrating an example of a calibration process for a distance sensor according to an exemplary embodiment of the present invention; and

[0040] Figure 9 A block diagram of a distance sensor calibration system according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0041] The exemplary embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0042] The market share of distance sensors in specific segments is currently dominated by consumer electronics and automobiles. For example, as ToF sensors gradually become standard equipment in smartphones, multiple cameras can be used for recognition applications in more scenarios. For example, front and rear cameras can be used for gesture recognition or facial 3D recognition for secure payments. In addition, AR / VR is also an application direction of ToF in 3D perception.

[0043] However, with the development of technology, distance sensors such as ToF image sensors, in addition to their widespread use in consumer electronics and automotive fields, also have unlimited application prospects in fields such as the Internet of Things and smart manufacturing. For example, in fields such as smart homes, smart security, smart retail, and people monitoring, distance sensors can function independently or in combination with other devices to achieve various functions such as distance measurement, proximity detection, presence detection, ambient light detection, reflectivity detection, multi-area detection, and 3D detection. This allows them to be applied in various scenarios including access control, augmented reality / virtual reality, ATMs, barcode readers, smart trash cans, smart buildings, cleaning robots, conveyor belts, smart agriculture, home robots (e.g., indoor) drones, smart lights, smart locks, smart vanity mirrors, public parking lots, pet fitness robots, smart shelves, vending machines, smart warehousing, wearable devices, IoT devices, and smart homes. Applications include ceiling detection, content analysis, fall detection, gesture control, hands-free operation, lighting control, load management, object detection, obstacle avoidance, occupant detection, parking space detection, people counting, power saving, SLAM detection, contactless operation, user detection, and volume control.

[0044] For example, combining traditional facial recognition patterns with depth information such as distance can significantly improve recognition accuracy. This makes distance sensors crucial components in fields like autonomous driving and in-vehicle perception, such as automotive LiDAR, in-vehicle human recognition, and in-vehicle gesture recognition. Furthermore, many current solutions integrate distance sensors into AGVs and robotic arms for precise navigation and real-time obstacle avoidance.

[0045] Figure 2 A distance measuring device according to an exemplary embodiment of the present invention is shown. This is by way of example and not limitation. Figure 2 The distance measuring device shown can be applied to various fields and scenarios as described above. Figure 2 The distance measuring device shown includes a processor 100, a distance sensor 200, and a memory 300. The processor 100 is configured to perform calibration on the distance sensor 200 according to an exemplary embodiment of the present invention. The distance sensor 200 is used to measure distances, for example, it can measure the distance to an object based on Time-of-Flight (ToF) technology under the control of the processor 100 or other controller. The memory 300 is used to store a calibration information set, which is used by the processor 100 to perform distance measurement calibration. Optionally, the distance measuring device may also include a light source for emitting light for distance measurement, such as an infrared light source, which can be a separate light source device or integrated with the distance sensor 200. Alternatively, the light source can also be used as an external device of the distance measuring device.

[0046] Specifically, according to an exemplary embodiment of the present invention, the measurement accuracy of the distance sensor can be evaluated by combining multiple consecutive measurement results of the distance sensor. If the measurement accuracy is unsatisfactory, it will be determined that the distance sensor needs to be calibrated. Accordingly, matching calibration information can be selected in a targeted manner to control the distance sensor to perform parameter calibration.

[0047] Alternatively, an exemplary embodiment of the present invention may effectively correlate calibration parameters with environmental factors of the distance sensor in the calibration information, so that the calibration process fully considers external factors of the distance sensor (such as some uncontrollable factors such as temperature, light, humidity, electromagnetic radiation, etc.).

[0048] As an alternative, exemplary embodiments of the present invention can further utilize specific pre-storage and / or update mechanisms for calibration information to ensure that the actual execution of the calibration process covers a sufficient calibration range while saving calibration time. This is particularly effective in extreme cases such as persistent failures in physical calibration, where even these failures can achieve a reasonably satisfactory measurement result.

[0049] It should be noted that Figure 2 Although the processor 100, distance sensor 200, and memory 300 are depicted as separate components, those skilled in the art will understand that this division is merely for descriptive convenience. They can be physically independent components or combined with each other, either wholly or partially, to logically perform corresponding operations or processes. For example, memory 300 can communicate with processor 100 as an external device or be a storage area internally configured therein.

[0050] Furthermore, as mentioned above, Figure 2 The distance measurement terminal shown can be applied to various fields such as consumer electronics, smart cars, smart manufacturing, and the Internet of Things. For example, by including the distance measurement terminal to measure distance, it can realize the application of distance measurement in mid-to-high-end devices, such as access control, cleaning robots, smart building terminals, smart agricultural terminals, or wearable devices.

[0051] The following will refer to Figures 3 to 9 The following describes exemplary embodiments according to the present invention. It should be understood that these exemplary embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0052] Figure 3 A flowchart illustrating a calibration method for a distance sensor according to an exemplary embodiment of the present invention is shown. Figure 3The method shown mainly involves the parameter calibration part of the distance sensor. According to an exemplary embodiment of the present invention, calibration information that can be used to calibrate the distance sensor can be preset. This information can be selectively selected when necessary to control the distance sensor to perform corresponding calibration.

[0053] Specifically, in step S100, multiple consecutive distance measurement results from the distance sensor are obtained. Here, as an example, each time the distance sensor performs a distance measurement on the target object, the measurement result can be transmitted to the corresponding processor for storage by the processor or corresponding memory. Alternatively, the distance sensor can independently perform continuous measurements and storage, sending the stored multiple consecutive measurement results to the processor all at once. The interval and specific number of consecutive measurements can be preset, dynamically adjusted, or obtained through learning or continuous updating.

[0054] After obtaining multiple consecutive distance measurement results, in step S200, a measurement index of the distance sensor is obtained based on these results. This measurement index reflects the measurement accuracy. The measurement index can be calculated using any applicable calculation method based on the multiple consecutive measurement results. For example, a measurement index reflecting the fluctuations in the multiple consecutive measurement results can be calculated to examine the effectiveness and stability of the distance sensor. For instance, the measurement index can indicate the variance of multiple consecutive (e.g., three) distance measurement results.

[0055] In step S300, it is determined whether the distance sensor needs to be calibrated based on the measurement indicators of the distance sensor.

[0056] In existing technologies, distance sensors can be physically calibrated. That is, when the distance sensor is powered on or the test results are poor, a preset calibration command is sent to the distance sensor to make it calibrate according to its built-in inherent method. This method has drawbacks in terms of time consumption and effectiveness.

[0057] Here, the parameter calibration according to an exemplary embodiment of the present invention differs from the physical calibration in the prior art. It refers to the method of directly controlling the operation of the distance sensor using calibration information containing calibration parameters. These calibration parameters can directly or indirectly indicate the operating parameters of the distance sensor. As an example and not a limitation, the operating parameters can be one or more of the following: Si gma limit value, Si gnal limit value, sampling time period, VCSEL pulse period, VCSEL pulse period range, etc. Specific combinations of these operating parameters can effectively define the operating state of the distance sensor. In particular, considering the influence of temperature and illumination, several differentiated operating states can be more specifically formed, thereby facilitating rapid and effective calibration of the distance sensor.

[0058] When determining whether parameter calibration is necessary, the current state of the distance sensor as reflected by the measured parameters can be considered. For example, the measured parameters can be compared with a specific threshold, and the comparison result can be used to determine whether parameter calibration is required.

[0059] As an example, the measured parameters can be compared with those in the calibration information to determine whether parameter calibration is required. That is, if there are calibration parameters in the calibration information that provide better performance, then such calibration parameters can be used to calibrate the distance sensor.

[0060] For example, according to an exemplary embodiment of the present invention, a calibration information set can be set. This calibration information set may include at least one pre-stored calibration information entry, each entry including corresponding environmental factors, measurement indicators, and calibration parameters. As an example, correspondence here means that each calibration information entry as a whole corresponds to a relatively ideal measurement state, including the environmental conditions of the distance sensor at that time, the calibration parameters used, and the achieved measurement indicators. The environmental conditions here can be represented by corresponding environmental factors. These environmental factors may include one or more factors affecting the measurement performance of the distance sensor. These factors can be a single factor or a combination of two or more factors. For example, environmental factors may include one or more combinations of temperature, light intensity, humidity, and electromagnetic radiation.

[0061] It can be seen that environmental factors, based on the range of their components, can divide the working environment of the distance sensor into several countable cases. By conducting multiple different calibration tests under each case, multiple corresponding test results can be obtained. For one or more relatively ideal test results under different cases, the corresponding environmental factors, measurement indicators, and calibration parameters can be packaged into calibration information. Here, as an optional approach, the multiple calibration tests under each case can only involve the selection of different calibration parameters. That is, the multiple calibration tests are simply used to compare the differences in effects brought about by different calibration parameters under the same conditions. In addition, the multiple calibration tests under each case can also involve other factors besides calibration parameters, such as relevant factors that define the environment, which are the same as or different from the environmental factors. In this way, the multiple calibration tests will correspond to different calibration parameters under different sub-case intervals. When selecting which test results to use to construct the final calibration information, it is necessary to consider screening the test results with relatively ideal measurement indicators under each sub-case interval.

[0062] According to an exemplary embodiment of the present invention, calibration information can correspond to a more ideal test state in various ways. In particular, by effectively configuring the calibration information set, on the one hand, calibration parameters that achieve better measurement accuracy can be selected for distance sensor calibration in a matching scenario; on the other hand, the time to search for matching calibration parameters can be reduced, and space for storing the calibration parameter set can be saved.

[0063] As an example, the pre-stored calibration information described above may include better test results obtained from multiple calibration tests under different environments defined by light and temperature, wherein the environmental factors correspond to multiple light ranges, and each light range corresponds to multiple temperature ranges.

[0064] Table 1 shows an example of a calibration information set according to an exemplary embodiment of the present invention.

[0065]

[0066]

[0067] In the calibration information set shown in Table 1, the temperature range in the rightmost column is not part of the calibration information itself, but rather indicates the temperature range corresponding to each calibration message. This temperature range information can be stored separately for technical personnel to refer to when needed, or it can be recorded in technical documents such as technical manuals without any electronic storage. As shown in Table 1, calibration parameters include, for example, the Si gma limit value and Si gna l limit value as calculation factors, the sampling time period, the VCSEL pulse period, and the VCSEL pulse period range. Specific combinations of these operating parameters can effectively define the operating state of the distance sensor, especially considering the effects of temperature and illumination, allowing for several differentiated operating states, thus facilitating rapid and effective calibration of the distance sensor.

[0068] To obtain the calibration information set in Table 1, multiple calibration tests can be pre-designed to cover common operating environments of distance sensors. For example, considering the influence of temperature and light on distance sensors, both of which can be detected by the corresponding sensors, an exemplary embodiment of the present invention designs a calibration test using the light range as an environmental factor. It should be understood that, as described above, the light range as an environmental factor is merely an example. Exemplary embodiments of the present invention can employ appropriate environmental factors; for example, the temperature range collected during use by a temperature sensor can be used as an environmental factor to construct the calibration information.

[0069] Specifically, considering that distance sensors mostly require calibration when the ambient temperature changes by 8-10 degrees Celsius, the exemplary embodiment of the present invention limits the operating temperature of the distance sensor to -40°C to 85°C, setting 16 temperature ranges. Each temperature range corresponds to 3 light levels according to the light changes over 24 hours a day (each light level corresponds to a corresponding light interval), thus generating 48 different operating environments. For each of these 48 operating environments, multiple actual calibration tests can be performed, and the corresponding environmental factors, measurement indicators, and calibration parameters are recorded for calibration tests with better measurement indicators. Based on the above information, 48 sets of calibration information are pre-stored before the actual operation of the distance sensor.

[0070] Furthermore, according to an exemplary embodiment of the present invention, in addition to the pre-stored calibration information, the calibration information set may also include a predetermined number of reserved blank calibration information. This blank calibration information can be used after the distance sensor is actually put into use to record better measurement indicators generated by the distance sensor during actual use, along with their corresponding environmental factors and calibration parameters. In this way, self-learning regarding calibration parameters can be achieved, solidifying effective calibration scenarios generated during actual use. This not only effectively supplements the pre-stored calibration information but also allows for the retrieval of applicable calibration parameters even in extreme cases where physical calibration repeatedly fails, by searching the entire calibration information set or a portion thereof.

[0071] As an example, in conjunction with the pre-stored calibration information in Table 1, an exemplary embodiment of the present invention can also reserve 16 sets of blank calibration information at a ratio of 1:3, so that a total of 64 sets of calibration information space needs to be set in a memory such as flash memory.

[0072] The following, combined with Figure 4 This describes the process of determining whether parameter calibration is required according to an exemplary embodiment of the present invention. Figure 4 In the example shown, however, it should be understood that exemplary embodiments of the present invention are not limited to this in determining whether parameter calibration is required; for example, the determination can be made without comparison with calibration information.

[0073] Reference Figure 4 In step S310, the environmental factors currently present to the distance sensor are acquired. This can be achieved by setting the sensor to detect these environmental factors, or by acquiring relevant data from external sources using other methods. For example, based on the calibration information shown in Table 1, the light intensity can be obtained from the light sensor as the current environmental factor for the distance sensor.

[0074] In step S320, a subset of calibration information is selected from the calibration information set, consisting of calibration information whose environmental factors are consistent with the environmental factors currently present in the distance sensor. Here, as an example, the environmental factors of the distance sensor's current location can be compared with those of all calibration information in the calibration information set, or it can be compared with a subset of calibration information (e.g., pre-stored calibration information or subsequently added calibration information). As an example, using the calibration information shown in Table 1, the light intensity obtained from the light sensor can be converted into the corresponding light range (e.g., represented as light levels 300, 800, or 1500 in the calibration information of Table 1). Assuming the light intensity obtained from the light sensor is 1400, it will be converted to the closest light intensity of 1500, and accordingly, a subset of calibration information in the calibration information set with a light intensity of 1500 is selected.

[0075] After selecting a subset of calibration information, in step S330, it is determined whether there is a measurement index in the subset of calibration information that is better than the current measurement index of the distance sensor. If the measurement index of the distance sensor is better than or equal to the measurement index of all calibration information in the subset of calibration information, for example, if the variance of the detection distance of the distance sensor is equal to or less than the variance of the detection distance of all calibration information in the calibration information, in step S350, it is determined that parameter calibration of the distance sensor is not required; conversely, if the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the subset of calibration information, for example, if there is a detection distance variance in the calibration information that is smaller than the variance of the detection distance of the distance sensor, in step S340, it is determined that parameter calibration of the distance sensor is required.

[0076] Refer to the return Figure 3 In step S400, if parameter calibration of the distance sensor is required, matching calibration information is obtained from the calibration information set. Here, when parameter calibration of the distance sensor is required, calibration information that can improve the performance of the distance sensor can be obtained from the calibration information set. This calibration information matches the current condition of the distance sensor and is expected to achieve satisfactory measurement results when applied to the distance sensor.

[0077] Here, as an example, in the example described above where a subset of calibration information is used to determine whether parameter calibration is needed, matching calibration information can be obtained based on measurement metrics within the selected subset of calibration information. Specifically, each calibration information in the subset of calibration information is consistent with the current environment of the distance sensor, and at least one calibration information has a measurement metric superior to that of the distance sensor. Accordingly, calibration information for performing parameter calibration can be selected from these, for example, the calibration information with the optimal measurement metric can be selected for calibration. Alternatively, considering that the environmental factors affecting the distance sensor may be very complex, in order to improve the reliability of parameter calibration and avoid overly drastic changes in operating state, calibration information whose measurement metric is superior to and closest to that of the distance sensor can be obtained from the selected subset of calibration information as the matching calibration information.

[0078] In step S500, the distance sensor is controlled to perform parameter calibration based on the matched calibration information. Here, as an example, the corresponding calibration parameters can be obtained from the matched calibration information, and instructions for calibrating the distance sensor can be generated according to the calibration parameters to control the distance sensor to perform the corresponding parameter calibration, that is, to operate according to the configuration of the calibration parameters.

[0079] As can be seen, the exemplary embodiments of the present invention enable effective parameter calibration of the distance sensor during use, thus improving upon the physical calibration process in the prior art. In particular, it further fully considers the usage environment of the distance sensor, covering sufficient usage scenarios while allowing for targeted calibration for the current environment.

[0080] Figure 5 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention is shown. Figure 5 In the example method shown, steps S100-S500 are the same as the reference. Figures 3 to 4 The descriptions are the same, so I will not repeat them here.

[0081] The difference is that the method further includes: in step S300, if it is determined that no parameter calibration of the distance sensor is required, updating the calibration information set based on the current operating state of the distance sensor.

[0082] Specifically, determining that no parameter calibration of the distance sensor is needed can indicate that the sensor's current operating state is relatively good, for example, better than a preset threshold level, better than the comparison results with relevant calibration information, or other metrics. Accordingly, new calibration information can be constructed using the current operating state of the distance sensor, and the current calibration information set can be updated using this new information, thus enabling the calibration parameters to continuously learn in real-world use.

[0083] For example, calibration information can be constructed based on the current operating state of the distance sensor, and the constructed calibration information can replace the replaced calibration information in the calibration information set. Specifically, the calibration parameters corresponding to the current distance sensor can be obtained. Based on this, other relevant information, such as environmental factors and / or measurement indicators, can be further packaged according to the elements of the calibration information to obtain the corresponding calibration information. The replaced calibration information in the calibration information set can be replaced with the newly constructed calibration information. Here, the replaced calibration information can be selected according to certain rules. It can be calibration information selected from the entire calibration information set, or it can be calibration information selected from a part of the calibration information set (e.g., pre-stored calibration information, subsequently added calibration information, and / or related subsets of calibration information). The selected calibration information can be information that should be replaced relatively, such as the worst-performing calibration information or the closest but worse-performing calibration information.

[0084] Alternatively, calibration information can be constructed based on the current operating state of the distance sensor, and this constructed calibration information can be added to the calibration information set as new calibration information. Specifically, the corresponding calibration information can be constructed in a similar manner to the above, and the constructed calibration information can be added to the calibration information set. Here, the calibration information set can reserve limited or sufficient blank space to accommodate subsequent additions of calibration information.

[0085] Alternatively, the two methods described above can be combined. For example, based on the current operating state of the distance sensor, corresponding calibration information can be constructed, and the constructed calibration information can be selectively used to replace the replaced calibration information in the calibration information set or added as new calibration information to the calibration information set. For example, after constructing the corresponding calibration information, the degree of difference between the distance sensor's measurement index and the calibration index in the existing calibration information can be measured, and replacement or supplementation can be selectively performed. For example, when the calibration information includes at least environmental factors, measurement indexes, and calibration parameters, in the subset of calibration information selected above where the environmental factors are consistent with those of the distance sensor, the second-best measurement index that is closest to the distance sensor's measurement index is selected, and the index difference between the two is calculated. If the index difference is less than the difference threshold, the constructed calibration information replaces the calibration information containing the second-best measurement index; if the index difference is greater than the difference threshold, the constructed calibration information is added as new calibration information to the blank calibration information in the calibration information set. In this way, calibration information can be supplemented only when the distance sensor performs exceptionally well, and calibration parameters can be replaced when the performance is not significantly better. This effectively executes the self-learning process of calibration information, ensuring that the calibration information set as a whole always maintains relatively effective calibration parameters, and also reserving sufficient space for better scenarios.

[0086] Figure 6 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention is shown. Figure 6 In the example method shown, steps S100-S500 are the same as the reference. Figures 3 to 4 The descriptions are the same, so I will not repeat them here.

[0087] The difference lies in the fact that, before performing parameter calibration, Figure 6 The exemplary embodiment shown also includes additional physical calibration. It should be understood that the parameter calibration process described above with reference to the accompanying drawings can be performed at any suitable time, such as upon power-on or at the start of measurement, while... Figure 6In the exemplary embodiment shown, parameter calibration is performed after physical calibration. That is, step S50 is executed first to physically calibrate the distance sensor. Here, a specific calibration command can be sent to the distance sensor to instruct it to perform physical calibration. However, since physical calibration is often based on calibration parameters built into the distance sensor by the manufacturer, and the parameter content is not exposed to the outside world during the process, only related calling interfaces are provided, it has problems such as ambiguity. In addition, the distance sensor is affected by the usage environment, and it is difficult to achieve satisfactory results through physical calibration in environments with drastic changes or extreme conditions. In this regard, as an example, the parameter calibration of the exemplary embodiment of the present invention can effectively supplement traditional physical calibration, not only improving the accuracy of calibration, but also saving a lot of time consumed by physical calibration.

[0088] In step S50, physical calibration can be performed based on the measurement results of the distance calibrator. Specifically, multiple consecutive distance measurement results from the distance sensor can be obtained. Based on these multiple measurement results, the measurement index of the distance sensor is obtained, where the measurement index reflects the measurement accuracy. For example, this measurement index can be the variance of the multiple consecutive distance measurement results. If the measurement index of the distance sensor determines that physical calibration of the distance sensor is necessary, then physical calibration of the distance sensor is performed. It should be noted that the specific number of consecutive measurements, the specific calculation method of the measurement index, and / or the specific rules for determining whether to perform parameter calibration can be the same as or different from those used when determining whether to perform parameter calibration.

[0089] Figure 7 A flowchart illustrating another calibration method for a distance sensor according to an exemplary embodiment of the present invention is shown. Figure 7 In the exemplary embodiment shown, how the distance sensor is calibrated during the detection process from initialization is described.

[0090] Reference Figure 7 First, the distance sensor is initialized. For example, initialization can be performed when the distance sensor is initially powered on or reset.

[0091] After initialization, in step S1000, a calibration process according to an exemplary embodiment of the present invention can be executed. Here, when the calibration process is executed for the first time after initialization, only physical calibration itself can be performed, or a complete process combining physical calibration and parameter calibration can be performed. In subsequent use, when it is determined that physical calibration is required, additional parameter calibration can be performed after the physical calibration. An example process combining physical calibration and parameter calibration will be referred to... Figure 8 A detailed description will not be provided here.

[0092] In step S2000, the measurement results from the distance sensor are read, for example, the distance measurement results for the target object. As an example, this step can continue while the distance sensor is in operation, unless it is determined that the measurement results are so poor that calibration is required, at which point the calibration process is interrupted.

[0093] In step S3000, it is determined whether the measurement results have been read a preset number of times (e.g., 3 times). If it is determined that the number of reads is less than three, in step S4000, the read measurement results are stored, and then the determination continues. When the number of reads reaches three, in step S5000, the variance between the third measurement result read this time and the previously stored first two measurement results is calculated.

[0094] Next, in step S6000, it is determined whether the calculated variance is less than a preset calibration threshold. If the comparison result indicates that the calculated variance is less than the calibration threshold, it means that the current operating state of the distance sensor is satisfactory, and no related physical calibration or parameter calibration is required. On the other hand, if the comparison result indicates that the calculated variance is greater than the calibration threshold, then the calibration process according to an exemplary embodiment of the present invention needs to be performed.

[0095] The following will combine Figure 8 Here is an example of a calibration process for a distance sensor according to an exemplary embodiment of the present invention.

[0096] Reference Figure 8 In step S1010, the current illumination value of the distance sensor can be obtained. It should be noted that any method or procedure described herein does not restrict the execution order of specific operations to strictly conform to the order shown in the accompanying drawings. For example, step S1010 does not necessarily have to be executed at the very beginning, but can be performed at any appropriate location, or even concurrently with other steps. Those skilled in the art can make corresponding adjustments based on the substantial disclosure of the technology.

[0097] In step S1020, a calibration command is sent to the distance sensor to perform a physical calibration process.

[0098] After physical calibration, in step S1030, the measurement results from the distance sensor are read. As an example, this step can continue while the distance sensor is in operation until a preset number of times (e.g., 3 times) is reached, at which point it is interrupted to proceed with the subsequent parameter calibration process.

[0099] In step S1040, it is determined whether the number of reads has reached the preset 3 times. If it has not been reached, in step S1041, the measurement result of the reads is stored and the determination continues.

[0100] If three measurement results have been read consecutively, then in step S1042, the variance of the three reading results is calculated.

[0101] In step S1053, a subset of calibration information corresponding to the current illumination value of the distance sensor can be selected from the calibration information set based on the consistency of environmental factors (i.e., light intensity).

[0102] In step S1044, it is determined whether the variance calculated in step S1042 is the optimal result in the calibration information subset, that is, whether there is calibration information in the calibration information subset whose variance measurement index is smaller than the calculated variance.

[0103] If better calibration information exists, i.e., the calculated variance is not the minimum, then matching calibration information needs to be found for parameter calibration. To this end, in step S1051, among at least one calibration information with a variance index smaller than the calculated variance, the one whose variance is closest to the calculated variance is selected as the closest calibration information. Next, in step S1052, the corresponding calibration parameters are read from the calibration information selected in step S1051 to control the distance sensor to perform parameter calibration.

[0104] If, in step S1044, it is determined that no better calibration information exists in the subset of calibration information, then updating the calibration parameter set using the current state of the distance sensor can be further considered. Figure 9 In the example shown, the newly constructed calibration information can be used to selectively replace the original calibration information, or it can be added as new calibration information to the calibration information set.

[0105] Specifically, in step S1050, the variance value closest to the calculated variance can be selected from the variance measurement index of each calibration information in the calibration information subset, that is, the second smallest variance value, and then the difference between the calculated variance and the selected second smallest variance value can be obtained.

[0106] In step S1060, the difference between the difference and a preset update threshold is determined. If the difference is less than the update threshold, in step S1062, new calibration information is constructed based on the current light intensity (as an environmental factor), variance (as a measurement indicator), and calibration parameters of the distance sensor. In step S1064, the newly constructed calibration information replaces the calibration information corresponding to the second smallest variance value. Alternatively, if the difference is greater than the update threshold, new calibration information is constructed in step S1061, and in step S1063, the newly constructed calibration information is added to the reserved blank calibration information. Here, as an option, if the reserved blank area is full, existing calibration information can be replaced or discarded directly.

[0107] Figure 8The parameter calibration and related calibration information update methods can comprehensively consider the influence of external conditions such as environmental factors, balance comprehensiveness and effectiveness, and save operation time and parameter reserve space.

[0108] Reference above Figures 3 to 8 A calibration process according to an exemplary embodiment of the present invention is described. As an example, the process can be performed by... Figure 1 The calibration can be performed by the processor 100, or by a dedicated calibration system, which can consist of software modules that perform the corresponding operations, hardware modules, or a combination of software and hardware.

[0109] Figure 9 A block diagram of a distance sensor calibration system according to an exemplary embodiment of the present invention is shown. Figure 9 The calibration system shown includes: a ranging result acquisition unit 10, configured to acquire a first series of distance measurement results from a distance sensor; an index calculation unit 20, configured to acquire a first measurement index of the distance sensor based on the first series of measurement results, wherein the first measurement index reflects the measurement accuracy; a determination unit 30, configured to determine whether parameter calibration of the distance sensor is required based on the first measurement index of the distance sensor; a calibration information acquisition unit 40, configured to acquire matching calibration information from a calibration information set when parameter calibration of the distance sensor is required; and a calibration control unit 50, configured to control the distance sensor to perform parameter calibration based on the matching calibration information.

[0110] Furthermore, as an example, Figure 9 The calibration system shown may also include an update unit (not shown) configured to update the calibration information set based on the current operating state of the distance sensor when the determining unit determines that parameter calibration of the distance sensor is not required.

[0111] As an example, the determining unit 30 can acquire the environmental factors currently present to the distance sensor; select a subset of calibration information from the calibration information set, consisting of calibration information whose environmental factors are consistent with the environmental factors currently present to the distance sensor; if the first measurement index of the distance sensor is better than or equal to the first measurement index of all calibration information in the calibration information subset, determine that parameter calibration of the distance sensor is not required; if the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the calibration information subset, determine that parameter calibration of the distance sensor is required. Specifically, the determining unit 30 can...

[0112] Furthermore, as an example, when the determining unit 30 determines that parameter calibration of the distance sensor is required, the calibration information acquisition unit 40 can acquire matching calibration information based on the first measurement index from a selected subset of calibration information. Specifically, the calibration information acquisition unit 40 can acquire calibration information from the selected subset of calibration information where the first measurement index is better than and closest to the first measurement index of the distance sensor, and use this as the matching calibration information.

[0113] Furthermore, as an example, the update unit may construct corresponding calibration information based on the current operating state of the distance sensor and replace the replaced calibration information in the calibration information set with the constructed calibration information; or it may construct corresponding calibration information based on the current operating state of the distance sensor and add the constructed calibration information as new calibration information to the calibration information set; or it may construct corresponding calibration information based on the current operating state of the distance sensor and, depending on the approximation of the first measurement index, selectively replace the replaced calibration information in the calibration information set with the constructed calibration information or add the constructed calibration information as new calibration information to the calibration information set. For example, in the selected subset of calibration information, the update unit selects the second-best first measurement index that is closest to the first measurement index of the distance sensor and calculates the index difference between the two; if the index difference is less than the difference threshold, it replaces the calibration information containing the second-best first measurement index with the constructed calibration information; if the index difference is greater than the difference threshold, it adds the constructed calibration information as new calibration information to the blank calibration information in the calibration information set.

[0114] also, Figure 9 The calibration system shown may also include a physical calibration unit (not shown) for physically calibrating the distance sensor. Specifically, the physical calibration unit can obtain multiple consecutive distance measurements from the distance sensor; acquire measurement parameters of the distance sensor based on the multiple consecutive measurements, wherein the measurement parameters reflect the measurement accuracy; and perform physical calibration on the distance sensor if the measurement parameters of the distance sensor determine that physical calibration is required.

[0115] The above description is merely an exemplary embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A calibration method for a distance sensor, comprising: Obtain the first series of distance measurement results from the distance sensor; A first measurement index of the distance sensor is obtained based on the first series of measurement results, wherein the first measurement index reflects the measurement accuracy; The first measurement metric of the distance sensor determines whether parameter calibration of the distance sensor is required; When parameter calibration of the distance sensor is required, matching calibration information is obtained from a calibration information set. This calibration information set includes at least one pre-stored calibration information entry. Each calibration information entry includes corresponding environmental factors, a first measurement index, and calibration parameters, where the calibration parameters indicate the operating parameters of the distance sensor. The distance sensor is controlled to perform parameter calibration based on the matched calibration information, so that the distance sensor operates according to the configured calibration parameters.

2. The method of claim 1 further includes updating the calibration information set based on the current operating state of the distance sensor when it is determined that parameter calibration of the distance sensor is not required.

3. The method as described in claim 1 or 2, wherein, The determination of whether the distance sensor needs parameter calibration based on the first measurement index of the distance sensor includes: Obtain the current environmental factors of the distance sensor; Select a subset of calibration information from the calibration information set that contains calibration information whose environmental factors are consistent with the environmental factors currently present to the distance sensor; If the first measurement index of the distance sensor is better than or equal to the first measurement index of all calibration information in the subset of calibration information, it is determined that no parameter calibration of the distance sensor is required. If the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the subset of calibration information, it is determined that the distance sensor needs to be parameter calibrated.

4. The method of claim 3, wherein, When it is determined that parameter calibration of the distance sensor is required, the matching calibration information obtained from the calibration information set includes: Within the selected subset of calibration information, matching calibration information is obtained based on the first measurement index.

5. The method of claim 4, wherein, The step of obtaining matching calibration information based on the first measurement index from the selected subset of calibration information includes: Within the selected subset of calibration information, calibration information that is superior to and closest to the first measurement index of the distance sensor is obtained as the matching calibration information.

6. The method of claim 2, wherein, The current operating state update calibration information set based on the distance sensor includes: Based on the current operating state of the distance sensor, corresponding calibration information is constructed, and the constructed calibration information replaces the replaced calibration information in the calibration information set; or Based on the current operating state of the distance sensor, corresponding calibration information is constructed, and the constructed calibration information is added to the calibration information set as new calibration information; or Based on the current operating state of the distance sensor, corresponding calibration information is constructed. The constructed calibration information is selectively used to replace the replaced calibration information in the calibration information set or to add the constructed calibration information as new calibration information to the calibration information set.

7. The method of claim 6, wherein, The calibration information set also includes a predetermined number of blank calibration information entries; Among these, selectively replacing the replaced calibration information in the calibration information set with the constructed calibration information or adding the constructed calibration information as new calibration information to the calibration information set, based on the approximation of the first measurement index, includes: In the selected subset of calibration information, the second-best first measurement index that is closest to the first measurement index of the distance sensor is selected, and the difference between the two indices is calculated. If the difference between the indicators is less than the difference threshold, the calibration information of the second-best first measurement indicator is replaced with the constructed calibration information. If the difference in indicators exceeds the difference threshold, the constructed calibration information will be added as new calibration information to the blank calibration information in the calibration information set.

8. The method of claim 1, further comprising, before obtaining the first series of distance measurement results from the distance sensor: Perform physical calibration on the distance sensor.

9. The method of claim 8, wherein, The physical calibration of the distance sensor includes: obtaining a second series of consecutive distance measurement results from the distance sensor; A second measurement index of the distance sensor is obtained based on the results of multiple consecutive measurements, wherein the second measurement index reflects the measurement accuracy. If a second measurement metric based on the distance sensor determines that physical calibration of the distance sensor is required, then physical calibration of the distance sensor is performed.

10. The method as claimed in claim 1 or 2, wherein, Environmental factors include one or more of the following: temperature, light, humidity, and electromagnetic radiation.

11. The method as claimed in claim 1 or 2, wherein, The pre-stored calibration information includes at least one good test result corresponding to multiple calibration tests in different environments defined by light and temperature, wherein the environmental factors correspond to multiple light ranges, and each light range corresponds to multiple temperature ranges.

12. The method of claim 11, wherein, The calibration parameters include at least one of the following: Si gma limit value and Si gna l limit value as calculation factors, sampling time period, VCSEL pulse period, and VCSEL pulse period range.

13. The method of claim 1, wherein, The first measurement index indicates the variance of the first series of distance measurements.

14. The method of claim 9, wherein, The second measurement index indicates the variance of the results of a second series of distance measurements.

15. A calibration system for a distance sensor, comprising: The ranging result acquisition unit is configured to acquire the first consecutive multiple distance measurement results from the distance sensor; The index calculation unit is configured to obtain a first measurement index of the distance sensor based on the first series of measurement results, wherein the first measurement index reflects the measurement accuracy; The determining unit is configured to determine whether parameter calibration of the distance sensor is required based on a first measurement index of the distance sensor; The calibration information acquisition unit is configured to acquire matching calibration information from a calibration information set when parameter calibration of the distance sensor is required. The calibration information set includes at least one pre-stored calibration information entry, each entry including corresponding environmental factors, a first measurement index, and calibration parameters, wherein the calibration parameters indicate the operating parameters of the distance sensor. The calibration control unit is configured to control the distance sensor to perform parameter calibration based on matched calibration information, so that the distance sensor operates according to the configured calibration parameters.

16. The calibration system of claim 15, further comprising: The update unit is configured to update the calibration information set based on the current operating state of the distance sensor when the determination unit determines that parameter calibration of the distance sensor is not required.

17. The calibration system as described in claim 15 or 16, wherein, The determining unit acquires the environmental factors currently present to the distance sensor; selects a subset of calibration information from the calibration information set, which consists of calibration information whose environmental factors are consistent with the environmental factors currently present to the distance sensor; and determines that parameter calibration of the distance sensor is not required if the first measurement index of the distance sensor is better than or equal to the first measurement index of all calibration information in the calibration information subset. If the first measurement index of the distance sensor is not better than or equal to the first measurement index of all calibration information in the subset of calibration information, it is determined that the distance sensor needs to be parameter calibrated.

18. The calibration system as described in claim 15 or 16, wherein, The updating unit constructs corresponding calibration information based on the current operating state of the distance sensor and replaces the replaced calibration information in the calibration information set with the constructed calibration information; or it constructs corresponding calibration information based on the current operating state of the distance sensor and adds the constructed calibration information as new calibration information to the calibration information set; or it constructs corresponding calibration information based on the current operating state of the distance sensor and, according to the approximation of the first measurement index, selectively replaces the replaced calibration information in the calibration information set with the constructed calibration information or adds the constructed calibration information as new calibration information to the calibration information set.

19. The calibration system of claim 18, wherein, The calibration information set also includes a predetermined number of blank calibration information entries; The updating unit selectively replaces the replaced calibration information in the calibration information set with the constructed calibration information or adds the constructed calibration information as new calibration information to the calibration information set through the following processes: In the selected subset of calibration information, the second-best first measurement index that is closest to the first measurement index of the distance sensor is selected, and the difference between the two indices is calculated. If the difference between the indicators is less than the difference threshold, the calibration information of the second-best first measurement indicator is replaced with the constructed calibration information. If the difference in indicators is less than the difference threshold, the constructed calibration information will be added as new calibration information to the blank calibration information in the calibration information set.

20. A distance measuring device, comprising: Distance sensor, used to measure distance; Memory, used to store calibration information sets; The processor is configured to perform the method described in any one of claims 1 to 14.

21. A terminal device for applying distance measurement, comprising the distance measuring device as described in claim 20, wherein, The terminal equipment can be an access control system, a cleaning robot, a smart building terminal, a smart agriculture terminal, or a wearable device.

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