Separated distance measuring device and correction method thereof

Abstract

The invention provides a separated distance measuring device and a correction method thereof, and the correction method comprises the steps: setting a calibration object and the separated distance measuring device at a preset calibration distance, the separated distance measuring device comprises a transmitter and a receiver which are packaged respectively, and the transmitter and the receiver are spaced by a preset mechanism distance; configuring a transmitter to transmit a test signal to the calibration object; configuring a receiver to receive the test signal reflected by the calibration object; the configuration processing circuit determines the calibration time corresponding to the reflection of the test signal from the calibration object to the receiver according to the test signal characteristics of the received test signal. The predetermined mechanism distance and the calibration time are used in a distance measurement program executed by the separated distance measurement device to the object to be measured, so that the separated distance measurement device calculates an object distance related to the object to be measured.

Description

Technical Field

[0001] The present invention relates to a device and a method, and particularly to a separated ranging device and a calibration method thereof. Background Art

[0002] Traditional direct time of flight (DToF) ranging methods mainly rely on accurately measuring the time it takes for a laser pulse to travel from the emitter to the target and back to the detector. The core of this method lies in calibrating the time delay in the system to ensure the accuracy of distance measurement. During the calibration process, a target with a known distance is usually used to test and adjust the system to eliminate measurement errors caused by the device itself or environmental factors (such as temperature and humidity). In addition, the accuracy of this calibration method depends on the precise alignment of the laser, the target, and the detector, as well as stable environmental conditions.

[0003] Furthermore, traditional DToF calibration methods are not applicable in separated DToF systems. In a separated DToF system, the laser emitter and the detector are placed at different positions, which increases the complexity of measurement. Since the laser pulse needs to be transmitted between different positions, the measured time delay is affected by the relative position and angle between the two devices, resulting in the reference time and the measurement time generated by the traditional calibration method being unable to accurately calibrate these variables. Therefore, separated DToF systems need to adopt more advanced calibration techniques to ensure the accuracy and reliability of measurement. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a separated ranging device and a calibration method thereof in view of the deficiencies of the prior art, which can ensure that the separated ranging device accurately senses the distance of the object to be measured only by performing calibration in advance.

[0005] To solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a calibration method for a separable ranging device. The calibration method for the separable ranging device includes: setting a calibration object and a separable ranging device at a predetermined calibration distance in a calibration program. Wherein, the separable ranging device includes a transmitter and a receiver respectively encapsulated, and the transmitter and the receiver are separated by a predetermined mechanical distance; configuring the transmitter to emit a test signal to the calibration object; configuring the receiver to receive the test signal reflected by the calibration object; and configuring a calibration processing circuit to judge a calibration time corresponding to the test signal reflected from the calibration object to the receiver according to a test signal characteristic of the received test signal. Wherein, the predetermined mechanical distance and the calibration time are used in a ranging program executed by the separable ranging device to enable the separable ranging device to calculate an object distance between the object to be measured and the separable ranging device.

[0006] Optionally, the calibration method for the separable ranging device further includes calculating a calibration measurement distance between the calibration object and the separable ranging device according to the predetermined mechanical distance and the predetermined calibration distance in the calibration program or in the ranging program. Wherein, the predetermined mechanical distance, the calibration time and the calibration measurement distance are used in the ranging program to enable the separable ranging device to calculate the object distance.

[0007] Optionally, the ranging program includes: configuring the transmitter to emit a ranging signal to the object to be measured; configuring the receiver to receive the ranging signal reflected by the object to be measured, and judging a reception time corresponding to the ranging signal reflected from the object to be measured to the receiver according to a ranging signal characteristic of the received ranging signal; configuring a ranging processing circuit to calculate a time difference between the calibration time and the reception time, and obtaining the object distance according to the time difference, the calibration measurement distance and the predetermined mechanical distance.

[0008] Optionally, the step of calculating the object distance of the object to be measured according to the time difference, the calibration measurement distance and the predetermined mechanical distance includes: calculating a measurement distance between the object to be measured and the receiver according to the time difference and the calibration measurement distance; and calculating the object distance according to the measurement distance and the predetermined mechanical distance.

[0009] Optionally, the predetermined calibration distance is a calibration vertical distance between the calibration object and a virtual connection line passing through the receiver and the transmitter, the calibration measurement distance is a transmission distance of the test signal from the calibration object reflected to the receiver, and the object distance is an actual vertical distance between the object to be measured and the virtual connection line.

[0010] Optionally, the step of calculating the object distance of the object to be measured according to the time difference, the calibration measurement distance, and the predetermined mechanism distance further includes: calculating a distance difference according to the time difference, and adding the distance difference to the calibration measurement distance to obtain the measurement distance.

[0011] Optionally, the transmitter is a vertical cavity surface emitting laser.

[0012] Optionally, the test signal characteristics include one or more of a signal intensity or a signal quantity of the test signal, and the ranging signal characteristics include one or more of a signal intensity or a signal quantity of the ranging signal.

[0013] Optionally, at least one of the predetermined calibration distance and the calibration measurement distance, the predetermined mechanism distance, and the calibration time are stored in a ranging memory circuit, and the ranging processing circuit is configured to access the ranging memory circuit to execute the ranging program.

[0014] To solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a separate ranging device, the separate ranging device includes: a transmitter configured to transmit a ranging signal to an object to be measured in a ranging program; a receiver spaced apart from the transmitter by a predetermined mechanism distance and configured to receive the ranging signal reflected by the object to be measured and determine a reception time required for the ranging signal to be reflected from the object to be measured to the receiver according to a ranging signal characteristic of the received ranging signal; and a ranging processing circuit electrically connected to the transmitter and the receiver and configured to calculate a time difference between a calibration time and the reception time, and calculate an object distance of the object to be measured according to the time difference, a calibration measurement distance, and the predetermined mechanism distance, wherein the calibration time is obtained by the transmitter and the receiver executing a calibration program, and the calibration measurement distance is obtained by the transmitter and the receiver executing the calibration program or the ranging program.

[0015] Optionally, in the split ranging device, the calibration procedure includes: setting a calibration object at a predetermined calibration distance from the split ranging device; configuring the transmitter to transmit a test signal to the calibration object; configuring the receiver to receive the test signal reflected by the calibration object; and configuring a calibration processing circuit to determine a calibration time corresponding to the receiver based on a test signal feature of the received test signal, where the test signal is reflected from the calibration object.

[0016] Optionally, in the split ranging device, the calibration measurement distance between the calibration object and the split ranging device is obtained by configuring the ranging processing circuit or the calibration processing circuit to calculate based on the predetermined mechanism distance and the predetermined calibration distance.

[0017] Optionally, in the split ranging device, the step of calculating the object distance of the object to be measured based on the time difference, the calibration measurement distance, and the predetermined mechanism distance includes: calculating a measurement distance between the object to be measured and the receiver based on the time difference and the calibration measurement distance; and calculating the object distance based on the measurement distance and the predetermined mechanism distance.

[0018] Optionally, in the split ranging device, the predetermined calibration distance is a calibration vertical distance between the calibration object and a virtual connection line passing through the receiver and the transmitter, the calibration measurement distance is the transmission distance of the test signal from the calibration object to the receiver, and the object distance is an actual vertical distance between the object to be measured and the virtual connection line.

[0019] Optionally, in the split ranging device, the step of calculating the object distance of the object to be measured based on the time difference, the calibration measurement distance, and the predetermined mechanism distance further includes calculating a distance difference based on the time difference and adding the distance difference to the calibration measurement distance to obtain the measurement distance.

[0020] Optionally, in the split ranging device, the transmitter is a vertical cavity surface emitting laser.

[0021] Optionally, in the split ranging device, the test signal feature includes one or more of a signal intensity or a signal quantity of the test signal, and the ranging signal feature includes one or more of a signal intensity or a signal quantity of the ranging signal.

[0022] Optionally, the separate ranging device further includes a ranging memory circuit electrically connected to the ranging processing circuit, and at least one of the predetermined calibration distance and the calibrated measurement distance, and the predetermined mechanism distance and the calibration time are stored in the ranging memory circuit.

[0023] To enable a further understanding of the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the provided drawings are only for reference and illustration, and are not intended to limit the present invention. Description of the Drawings

[0024] Figure 1 It is a functional block diagram of a separate ranging device according to an embodiment of the present invention.

[0025] Figure 2 It is a calibration program flowchart of a calibration method for a separate ranging device according to an embodiment of the present invention.

[0026] Figure 3 It is a schematic diagram of the calibration configuration of a calibration object and a separate ranging device according to an embodiment of the present invention.

[0027] Figure 4 It is a calibration program flowchart of a calibration method for a separate ranging device according to another embodiment of the present invention.

[0028] Figure 5 It is a flowchart of a ranging program of a calibration method for a separate ranging device according to an embodiment of the present invention.

[0029] Figure 6 It is a schematic diagram of the ranging configuration of a test object and a separate ranging device according to an embodiment of the present invention. Detailed Embodiments

[0030] The following are specific examples to illustrate the embodiments of the present invention regarding "a separate ranging device and its calibration method". Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Additionally, the drawings of the present invention are only for simple schematic illustration and are not drawn according to actual dimensions, which is stated in advance. The following embodiments will further detail the related technical content of the present invention, but the disclosed content is not intended to limit the protection scope of the present invention. In addition, the term "or" used herein should, depending on the actual situation, possibly include any one or a combination of more of the associated listed items.

[0031] Figure 1 It is a functional block diagram of a separate ranging device according to an embodiment of the present invention. Refer toFigure 1 As shown in Figure 1 , the first embodiment of the present invention provides a separated ranging device 1, which includes a transmitter 10, a receiver 12, and a ranging processing circuit 14. The separated ranging device 1 can be, for example, a separated direct time of flight (DToF) device. The transmitter 10 and the receiver 12 can be separately packaged. The transmitter 10 can be, for example, a laser diode (LD) or a vertical-external-cavity surface-emitting-laser (VECSEL), and is responsible for generating and emitting short pulse lasers. During the ranging process, these laser pulses are emitted to the target object and reflected after encountering the target object.

[0032] The receiver 12 can, for example, include a high-sensitivity photoelectric sensor, usually an avalanche photodiode (APD), a single-photon avalanche diode (SPAD), or an array thereof, but the present invention is not limited thereto. The receiver 12 can be used to capture the laser pulses reflected after the laser encounters the target object and convert the optical signal into an electrical signal.

[0033] The number of ranging processing circuits 14 can be one or more, and can, for example, include a microprocessing unit (MCU), a digital signal processor (DSP), or an application-specific integrated circuit (ASIC), and is used for data processing and calculation. As a core component in the separated ranging device 1, the main function of the ranging processing circuit 14 is to process the received electrical signals and calculate the distance. For example, the ranging processing circuit 14 can measure the time difference between the emission and reflection of the laser pulse, and combine it with the speed of light to calculate the distance data. In some embodiments, when the receiver 12 and the transmitter 10 are disposed in an electronic device, such as a mobile phone or a tablet computer, the ranging processing circuit 14 can be the central processing unit (CPU) of the electronic device.

[0034] On the other hand, the separated ranging device 1 further includes a ranging memory 16, electrically connected to the ranging processing circuit 14. The ranging memory 16 can store a plurality of executable instructions for the ranging processing circuit 14 to access and execute. In addition, in this embodiment, the ranging memory 16 stores a ranging program for the ranging processing circuit 14 to access and execute.

[0035] However, in the process of the above distance measurement processing circuit 14 calculating the distance data, it is impossible to simply obtain the accurate distance based on the time difference. It is also necessary to consider the mechanical distance between the transmitter 10 and the receiver 12 and the performance conditions of the transmitter 10 and the receiver 12. Since the transmitter 10 and the receiver 12 are placed at different positions respectively, and the laser pulse needs to be transmitted between different positions, the measurement will be more complex, and the time delay will be affected by the relative position and angle between the two devices, resulting in the reference time and the measurement time generated by the traditional calibration method being unable to accurately correct the time delay caused by the above factors.

[0036] On the other hand, in the separate type distance measurement device 1, compared with the traditional DToF distance measurement device, since the transmitter 10 and the receiver 12 are farther apart, the farther the distance, the greater the difference in the optical path. And the closer the distance of the object to be measured, the greater the distance measurement error value. To solve the above problems, generally speaking, the calibration method of the present invention needs to use the absolute mechanical distance between the transmitter 10 and the receiver 12 and the initial distance obtained by the distance measurement to calculate the differences in angle and optical path, and then obtain the actual distance for correcting the optical path.

[0037] It should be noted that when the distance measurement processing circuit 14 controls the transmitter 10 to generate and transmit the test signal TS, only the starting time point can be known. Considering the control and driving delay times, it is actually impossible to know whether the test signal TS starts to fly from the starting time point. On the other hand, when the test signal TS flies and contacts the object to be measured and is reflected and then received by the receiver 12, although the arrival time point can be known, it is impossible to accurately confirm that the actual flight time of the test signal TS is exactly the time difference between the arrival time point and the starting time point. Considering the control, driving, receiving and other delay errors, the actual flight time of the test signal TS may be less than this time difference. Therefore, on the premise that it is not calibrated and the test signal TS travels at the speed of light, if the time difference between the arrival time point and the starting time point is directly used to calculate the distance of the object to be measured, a huge error will be generated.

[0038] The present invention provides a calibration method for a separate type distance measurement device, which can be executed, for example, by a processor of an external electronic device (such as an external computer, a machine tool). For example, refer to Figure 1, the separate ranging device 1 can be connected to an external computer, and the calibration program can be executed by the calibration processing circuit 20 of the external computer. The calibration program can be stored in the calibration memory 22 electrically connected to the calibration processing circuit 20. In other embodiments, an electronic device (such as a mobile phone or a tablet computer) provided with the separate ranging device 1 can be connected to an external electronic device, and the calibration program can be executed by the external electronic device. In another embodiment, the CPU of the electronic device (such as a mobile phone or a tablet computer) assembled with the separate ranging device 1 can also be used as the calibration processing circuit 20 to execute the calibration program. In another embodiment, the calibration processing circuit 20 and the aforementioned ranging processing circuit 14 can be integrated into the same circuit, that is, the calibration program is executed by the processing circuit of the separate ranging device 1 itself.

[0039] Figure 2 is a flowchart of the calibration program of the calibration method of the separate ranging device according to an embodiment of the present invention. The calibration program described in this embodiment can be calibrated before the electronic device equipped with the separate ranging device 1 leaves the factory, or can be executed when the electronic device needs to be recalibrated after maintenance, or can also be used to calibrate the separate ranging device 1 itself that has not been installed on the electronic device. Please refer to Figure 2 , the calibration method can, for example, after accessing the calibration program in the calibration memory 22 through the calibration processing circuit 20 shown in Figure 1 , control the transmitter 10 and the receiver 12 to execute the following steps:

[0040] Step S10: Set the calibration object and the separate ranging device at a predetermined calibration distance.

[0041] Please refer to Figure 3 together with Figure 3 is a schematic diagram of the calibration configuration of the calibration object and the separate ranging device according to an embodiment of the present invention. As shown in Figure 3As shown, the separated ranging device 1 includes a separately encapsulated transmitter 10 and a receiver 12. The transmitter 10 and the receiver 12 are separated by a predetermined mechanism distance L1, and the calibration object 2 is disposed at a predetermined calibration distance L2 above the separated ranging device 1. In this embodiment, ideally, the predetermined calibration distance L2 can be, for example, the vertical distance between the calibration object 2 and a virtual connection line IL passing through the receiver 12 and the transmitter 10 (referred to as the calibration vertical distance L3 herein). The virtual connection line IL refers to the virtual horizontal connection line at the top of the receiver 12 and the transmitter 10, the virtual horizontal connection line at the bottom of the receiver 12 and the transmitter 10, or the virtual horizontal connection line on the surface of the signal sensing area of the receiver 12 and the signal emitting area surface of the transmitter 10. In some embodiments, when the receiver 12 and the transmitter 10 are disposed in an electronic device, such as a mobile phone or a tablet computer, the predetermined calibration distance L2 is the vertical distance between the calibration object 2 and the device plane. The values of the predetermined mechanism distance L1 and the predetermined calibration distance L2 can be pre-stored in the calibration memory 22 for reading.

[0042] Step S11: Configure the transmitter 10 to transmit a test signal TS to the calibration object 2, and configure the receiver 12 to receive the test signal TS reflected by the calibration object 2.

[0043] Step S12: Configure the calibration processing circuit 20 to determine the calibration time t1 corresponding to the test signal TS reflected from the calibration object 2 to the receiver 12 according to the test signal characteristics of the received test signal TS.

[0044] In the above steps, the test signal characteristics can include the signal strength or the signal quantity of the test signal TS. Specifically, the receiver 12 can include, for example, a photodiode and an integrating circuit. When the test signal TS is reflected by the calibration object 2 and received, the photodiode converts the light energy into an electrical signal. This electrical signal will pass through the integrating circuit, and the integrating circuit will integrate the signal, which means that the cumulative effect of the signal changing with time is calculated. By the change of the output voltage of the integrating circuit, the intensity of the input signal can be obtained. The peak value or the average value of the output voltage can reflect the intensity of the test signal.

[0045] When the receiver 12 includes an avalanche photodiode (APD) or a single-photon avalanche diode (SPAD), photons enter and are absorbed by the semiconductor material, generating electron-hole pairs. The number of these electrons and holes is proportional to the number of incident photons. In an avalanche photodiode, a high voltage is applied to create a strong electric field. These generated electrons and holes are accelerated under the strong electric field and generate more electron-hole pairs during the collision process, which is the "avalanche effect" to amplify the input signal. The majority carriers (electrons and holes) generated by the avalanche effect are collected on the electrodes to form a current. This current is proportional to the number of incident photons, representing the intensity of the optical signal. The high gain characteristic of the APD enables it to detect extremely weak optical signals and provide accurate measurement of signal intensity.

[0046] Therefore, in step S12, the time point when the detected test signal TS has the maximum signal intensity or the largest number of photons can be used as the arrival time point, and a time difference is obtained by subtracting the start time point when the configured transmitter 10 emits the test signal TS to the calibration object 2. This time difference can be used to calculate the calibration time t1 corresponding to the reflection of the test signal TS from the calibration object 2 to the receiver 12 (for example, dividing the aforementioned time difference by two).

[0047] Step S13: Store the calculated calibration time t1, the known predetermined mechanism distance L1, and the predetermined calibration distance L2 into the ranging memory 16 of the separated ranging device 1.

[0048] Please refer to Figure 4 , Figure 4 which is the calibration program flowchart of the calibration method of the separated ranging device according to another embodiment of the present invention. Please refer to it in conjunction with Figure 3 for reference. Figure 4 The steps S20, S21, and S22 are the same as the steps S10, S11, and S12 shown in Figure 2 and will not be elaborated here. Different from the embodiment shown in Figure 2 , the calibration method of this embodiment may further include:

[0049] Step S23: Configure the calibration processing circuit 20 to calculate the calibration measurement distance L4 between the calibration object 2 and the separated ranging device 1 according to the predetermined mechanism distance L1 and the predetermined calibration distance L2. As shown in Figure 3As shown, the calibration measurement distance L4 in this example can be defined as the transmission distance of the test signal TS reflected from the calibration object 2 to the receiver 12. It should be noted that after the transmitter 10 emits the test signal TS, the test signal TS arrives at the calibration object 2 at an incident angle and is reflected from the calibration object 2 to the receiver 12 at the same angle of reflection. The calibration measurement distance L4 is the distance between the calibration object 2 and the receiver 12 determined by the reflection angle. In step S23, since the predetermined mechanism distance L1 and the predetermined calibration distance L2 are known (in this configuration, that is, the lengths of the adjacent side and the opposite side of a right triangle are known), the calibration measurement distance L4 (the length of the hypotenuse) between the calibration object 2 and the receiver 12 can be further calculated by, for example, trigonometric functions or the Pythagorean theorem. Thus, the calculated calibration time t1 corresponds to the calculated calibration measurement distance L4.

[0050] Step S24: Store the calculated calibration time t1, the calibration measurement distance L4, and the known predetermined mechanism distance L1 into the ranging memory 16 of the separate ranging device 1. Among them, the predetermined calibration distance L2 can also be stored into the ranging memory 16, but the present invention is not limited thereto.

[0051] As mentioned above, due to the distance between the transmitter 10 and the receiver 12 and the delay that may be caused by the characteristics of the laser used by the transmitter 10 itself, both may affect the detection of time. Therefore, the calibration time t1 calculated in step S12 or S22 is not necessarily the accurate flight time of the test signal TS. However, since the predetermined mechanism distance L1 and the predetermined calibration distance L2 are known in the calibration procedure, the corresponding relationship between the predetermined calibration distance L2 and / or the calibration measurement distance L4 and the calibration time t1 can be used as the basis for subsequent calculation of the ranging result. Therefore, the above-mentioned values stored in the ranging memory 16, such as at least one of the predetermined calibration distance L2 and the calibration measurement distance L4, the predetermined mechanism distance L1, and the calibration time t1, can be used in the ranging procedure performed by the separate ranging device 1 on the object to be measured. For example, when the user operates an electronic device equipped with the separate ranging device 1 and an object to be measured appears within the sensing range, the separate ranging device 1 can calculate the object distance between itself and the object to be measured. The detailed description will be described later.

[0052] Next, please refer to Figure 5 and Figure 6 , Figure 5 which is the flowchart of the ranging procedure of the calibration method of the separate ranging device according to an embodiment of the present invention, Figure 6 and Figure 5 is the schematic diagram of the ranging configuration between the object to be measured and the separate ranging device according to an embodiment of the present invention. Figure 6 The said ranging procedure can be applicable to the separate ranging device 1 such as Figure 5 shown. The process includes the following steps:

[0053] Step S30: Configure the transmitter 10 to transmit a ranging signal DS to the object under test 3.

[0054] Step S31: Configure the receiver 12 to receive the ranging signal DS reflected by the object under test 3, and determine the reception time t2 corresponding to the ranging signal DS reflected from the object under test 3 to the receiver 12 based on the ranging signal characteristics of the received ranging signal DS.

[0055] As Figure 6 shown, in steps S30 and S31, the transmitter 10 transmits a ranging signal DS to the object under test 3 with an unknown distance from the separate ranging device 1, and the ranging signal DS after being reflected by the object under test 3 is received by the receiver 12.

[0056] Step S32: Configure the ranging processing circuit 14 to calculate a calibrated measurement distance L4 based on a predetermined mechanism distance L1 and a predetermined calibration distance L2. Specifically, the ranging processing circuit 14 of the separate ranging device 1 can read the predetermined mechanism distance L1 and the predetermined calibration distance L2, and calculate the calibrated measurement distance L4 corresponding to the calibration object 3 and the separate ranging device 1 in the calibration process. The predetermined mechanism distance L1 and the predetermined calibration distance L2 can be information stored in the ranging memory 16 through a calibration process as Figure 2 shown.

[0057] Step S33: Configure the ranging processing circuit 14 to calculate the time difference between the calibration time t1 and the reception time t2, and obtain the object distance L6 between the object under test 3 and the separate ranging device 1 based on the time difference, the calibrated measurement distance L4, and the predetermined mechanism distance L1.

[0058] More specifically, in step S33, the receiver 12 takes the time point when the detected ranging signal DS has the maximum signal intensity or the largest number of photons as the arrival time point, and subtracts it from the start time point when the transmitter 10 transmits the ranging signal DS to the object under test 3 to obtain a time difference. This time difference can be used to calculate the reception time t2 corresponding to the ranging signal DS reflected from the object under test 3 to the receiver 12 (for example, dividing the aforementioned time difference by two). Then, according to the known calibration time t1 stored in the ranging memory 16, calculate the time difference Δt between the calibration time t1 and the reception time t2. Multiply the time difference Δt by the speed of light (c) to obtain the distance difference ΔL between the measured distance L5 between the object under test 3 and the receiver 12 and the calibrated measurement distance L4. Then, add the distance difference ΔL to the calibrated measurement distance L4 obtained in step S32 to obtain the measured distance L5 (the hypotenuse in this ranging configuration), that is, the transmission distance of the ranging signal DS from the object under test 3 to the receiver 12.

[0059] As previously described, the reception time t2 calculated in step S33 does not necessarily exactly correspond to the flight time of the ranging signal DS. However, for the same split ranging device 1, when the distance between the transmitter 10 and the receiver 12, the characteristics of the transmitter 10, etc. are the same, the delay effects generated in both the calibration procedure and the ranging procedure are consistent. Therefore, for the calibration method described in this embodiment, it only needs to calculate the difference between the calibration time t1 already obtained in the calibration procedure and the reception time t2, that is, the flight time difference of the ranging signal DS compared to the test signal TS, from which the transmission distance increased or decreased by the ranging signal DS compared to the test signal TS (i.e., the distance difference ΔL in this embodiment) can be calculated. When the calibration measurement distance L4 corresponding to the calibration time t1 is known, the sum of the calibration measurement distance L4 and the distance difference ΔL is the transmission distance of the ranging signal DS reflected from the object 3 to the receiver 12 (i.e., the measurement distance L5 in this embodiment).

[0060] Next, since the predetermined mechanism distance L1 and the measurement distance L5 are known (in this configuration, that is, the lengths of the adjacent side and the hypotenuse of a right triangle are known), the object distance L6 (the length of the opposite side) between the object 3 and the split ranging device 1 can be further calculated by, for example, trigonometric functions or the Pythagorean theorem, that is, the actual vertical distance between the object 3 and the virtual connection line IL of the receiver 12 and the transmitter 10 (see Figure 3 ). That is, it is the distance between the general ranging device or the electronic device equipped with the ranging device and the object to be sensed. Thus, even when the split ranging device 1 is separated between the transmitter 10 and the receiver 12 and cannot accurately estimate the flight time completely, it can still obtain the correct object distance L6 between the object 3 and the split ranging device 1.

[0061] It should be noted that Figure 5 in the shown process, the order of step S32 is not limited to after step S31, as long as the calibration measurement distance L4 can be obtained before calculating the object distance L6. Therefore, the order of step S32 can also be before step S30 or S31. In addition, if the split ranging device 1 has stored the calibration measurement distance L4 in the ranging memory 16 through the Figure 4 shown calibration procedure before performing the ranging procedure, then in the Figure 5 shown ranging procedure of the calibration method, step S32 can also be omitted.

[0062] Beneficial effects of the embodiment

[0063] One of the beneficial effects of the present invention is that for the provided separated ranging device and its calibration method, by pre-calibrating the separated ranging device, when performing time-of-flight ranging, it is not necessary to obtain a reference signal representing the starting time of flight, and the actual distance between the object to be measured and the separated ranging device can be accurately sensed without being affected by the physical distance between the transmitting component and the receiving component to cause misjudgment. For example, only by executing a calibration program once before the product leaves the factory or before it is restarted after maintenance, it can be ensured that the separated ranging device can continue to operate correctly after leaving the factory, improving the user experience of the device.

[0064] In addition, compared with traditional DToF modules, the provided separated ranging device and its calibration method of the present invention do not require the setting of a reference sensing component, nor do they require additional setting of a retaining wall and a light-shielding layer above for the transmitter, the reference sensing component, and the receiver. Only the receiver and the transmitter need to be retained, so that the module structure can be simplified and the size can be reduced.

[0065] The content disclosed above is only the preferred feasible embodiment of the present invention, and does not limit the protection scope of the claims of the present invention. Therefore, all equivalent technical changes made by using the content of the specification and drawings of the present invention are included in the protection scope of the claims of the present invention.

Claims

1. A calibration method for a separable ranging device, characterized in that The calibration method of the split-type ranging device includes: In a calibration program, a calibration object and the split-type ranging device are set at a predetermined calibration distance. The split-type ranging device includes a separately encapsulated transmitter and a receiver, and the transmitter and the receiver are separated by a predetermined mechanism distance. Configure the transmitter to emit a test signal to the calibration object. Configure the receiver to receive the test signal reflected by the calibration object. Configure the calibration processing circuit to judge the calibration time corresponding to the test signal reflected from the calibration object to the receiver according to the test signal characteristics of the received test signal. Among them, the predetermined mechanism distance and the calibration time are used in the ranging program executed by the split-type ranging device to enable the split-type ranging device to calculate the object distance between the object to be measured and the split-type ranging device.

2. The calibration method of the separable ranging device according to claim 1, characterized in that, The calibration method of the split-type ranging device further includes calculating the calibration measurement distance between the calibration object and the split-type ranging device according to the predetermined mechanism distance and the predetermined calibration distance in the calibration program or in the ranging program. Among them, the predetermined mechanism distance, the calibration time, and the calibration measurement distance are used in the ranging program to enable the split-type ranging device to calculate the object distance.

3. The calibration method of the separable ranging device according to claim 2, wherein, The ranging program includes: Configure the transmitter to emit a ranging signal to the object to be measured. Configure the receiver to receive the ranging signal reflected by the object to be measured, and judge the reception time corresponding to the ranging signal reflected from the object to be measured to the receiver according to the ranging signal characteristics of the received ranging signal. Configure the ranging processing circuit to calculate the time difference between the calibration time and the reception time, and obtain the object distance according to the time difference, the calibration measurement distance, and the predetermined mechanism distance.

4. The calibration method of the separable ranging device according to claim 3, characterized in that, The step of obtaining the object distance of the object to be measured according to the time difference, the calibration measurement distance, and the predetermined mechanism distance includes: Calculating the measurement distance between the object to be measured and the receiver according to the time difference and the calibration measurement distance; and Calculating the object distance according to the measurement distance and the predetermined mechanism distance.

5. The calibration method of the separable ranging device according to claim 4, characterized in that The predetermined calibration distance is the calibration vertical distance between the calibration object and the virtual connection line passing through the receiver and the transmitter, the calibration measurement distance is the transmission distance of the test signal from the calibration object to the receiver, and the object distance is the actual vertical distance between the object to be measured and the virtual connection line.

6. The calibration method of the separable ranging device according to claim 5, characterized in that, The step of obtaining the object distance of the object to be measured according to the time difference, the calibration measurement distance, and the predetermined mechanism distance further includes: calculating the distance difference according to the time difference, and adding the distance difference to the calibration measurement distance to obtain the measurement distance.

7. The calibration method of the separable ranging device according to any one of claims 1 to 6, characterized in that, The transmitter is a vertical cavity surface emitting laser.

8. The calibration method of the separable ranging device according to any one of claims 3 to 6, characterized in that The test signal characteristics include one or more of the signal intensity or signal quantity of the test signal, and the ranging signal characteristics include one or more of the signal intensity or signal quantity of the ranging signal.

9. The calibration method of the separable ranging device according to any one of claims 2 to 6, characterized in that, At least one of the predetermined calibration distance and the calibration measurement distance, the predetermined mechanism distance, and the calibration time are stored in a ranging memory circuit, and the ranging processing circuit is configured to access the ranging memory circuit to execute the ranging program.

10. A separable ranging device, characterized in that, The separate ranging device includes: A transmitter configured to transmit a ranging signal to a target object in a ranging program; A receiver spaced apart from the transmitter by a predetermined mechanism distance and configured to receive the ranging signal reflected by the target object and determine a reception time required for the ranging signal to be reflected from the target object to the receiver based on a ranging signal characteristic of the received ranging signal; and A ranging processing circuit electrically connected to the transmitter and the receiver, configured to calculate a time difference between a calibration time and the reception time, and calculate an object distance of the target object based on the time difference, a calibration measurement distance, and the predetermined mechanism distance, wherein the calibration time is obtained by the transmitter and the receiver executing a calibration program, and the calibration measurement distance is obtained by the transmitter and the receiver executing the calibration program or the ranging program.

11. The separable ranging device according to claim 10, wherein, The calibration program includes: Setting a calibration object spaced apart from the separate ranging device by a predetermined calibration distance; Configuring the transmitter to transmit a test signal to the calibration object; Configuring the receiver to receive the test signal reflected by the calibration object; and Configuring a calibration processing circuit to determine the calibration time corresponding to the test signal being reflected from the calibration object to the receiver based on a test signal characteristic of the received test signal.

12. The separable ranging device according to claim 11, characterized in that, The calibration measurement distance between the calibration object and the separate ranging device is obtained by configuring the ranging processing circuit or the calibration processing circuit to calculate based on the predetermined mechanism distance and the predetermined calibration distance.

13. The separable ranging device according to claim 12, wherein The step of calculating the object distance of the target object based on the time difference, the calibration measurement distance, and the predetermined mechanism distance includes: Calculating a measurement distance between the target object and the receiver based on the time difference and the calibration measurement distance; and Calculating the object distance based on the measurement distance and the predetermined mechanism distance.

14. The separable ranging device according to claim 11, wherein, The predetermined calibration distance is a calibration vertical distance between the calibration object and a virtual connection line passing through the receiver and the transmitter, the calibration measurement distance is a transmission distance of the test signal from the calibration object to the receiver, and the object distance is an actual vertical distance between the target object and the virtual connection line.

15. The separable ranging device according to claim 14, characterized in that, The step of calculating the object distance of the target object based on the time difference, the calibration measurement distance, and the predetermined mechanism distance further includes calculating a distance difference based on the time difference and adding the distance difference to the calibration measurement distance to obtain the measurement distance.

16. The separable ranging device according to any one of claims 10 to 15, characterized in that, The transmitter is a vertical cavity surface emitting laser.

17. The separable ranging device according to any one of claims 11 to 15, characterized in that, The test signal characteristic includes one or more of a signal intensity or a signal quantity of the test signal, and the ranging signal characteristic includes one or more of a signal intensity or a signal quantity of the ranging signal.

18. The separable ranging device according to any one of claims 11 to 15, characterized in that, The described separable ranging device further includes a ranging memory circuit electrically connected to the ranging processing circuit, and at least one of the predetermined calibration distance and the calibrated measurement distance, and the predetermined mechanism distance and the calibration time are stored in the ranging memory circuit.

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