Depth data measurement head, measurement device, control system and corresponding methods

Abstract

A depth data measurement head, a measurement device, a control system and corresponding methods are disclosed. The measurement head comprises: a light source module configured to project laser pulses to a measured space in a region-by-region manner; a time-of-flight (ToF) sensor configured to receive return light of the measured space in a region-by-region manner and generate a sensing signal, the sensing signal representing a time of flight of the light to calculate a distance of a photographed object in the measured space; and a controller configured to control the light source module and the ToF sensor to work in a corresponding region-by-region manner respectively. The depth data measurement scheme of the present application utilizes a ToF sensor, especially a rolling shutter Geiger mode sensor, to realize high-precision depth data measurement based on direct time of flight. The scheme further combines a region-by-region working light emitting module to reduce power consumption while ensuring normal exposure of the corresponding sensing region.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to depth imaging, and in particular to a depth data measurement head, a measurement device, a control system and corresponding methods. BACKGROUND

[0002] In recent years, three-dimensional imaging technology has been developing rapidly. This is inseparable from the rapid progress of depth data measurement technology in addition to conventional two-dimensional image acquisition.

[0003] Currently, a depth measurement scheme based on structured light can perform real-time three-dimensional measurement on the surface of an object. Simply put, the scheme first projects a two-dimensional laser texture pattern with coded information, such as a discretized speckle pattern, onto the surface of a natural object. Subsequently, monocular or binocular image acquisition is implemented to calculate depth information based on comparison with a reference image or parallax between binocular images.

[0004] The above-mentioned active projection of structured light scheme has been widely used in fields where the shooting device is relatively fixed, such as security, intelligent device face recognition, factory quality inspection, etc. However, in the application scenario where the shooting device is located in a moving mechanism (e.g., driving or other motion scenarios), the existing structured light scheme has problems such as limited ranging range and unsuitability for high-speed movement.

[0005] Therefore, there is a need for a depth data measurement scheme suitable for motion scenarios. SUMMARY

[0006] One technical problem to be solved by the present disclosure is to provide a depth data measurement scheme, especially suitable for application scenarios where the measurement device itself is in a motion state. Specifically, a depth data measurement head of the present disclosure includes a light source module that emits laser pulses in partitions, and a ToF sensor, especially a dToF (direct time of flight) sensor, that receives return light in corresponding partitions, for acquiring sensing information in partitions, especially columns, to match existing computing power limitations and reduce power consumption.

[0007] According to a first aspect of the present disclosure, a depth data measurement head is provided, comprising: a light source module configured to project laser pulses to a measured space in partitions; a time-of-flight (ToF) sensor configured to receive return light of the measured space in the partitions and generate a sensing signal, the sensing signal representing a time of flight of the light to calculate a distance of a photographed object in the measured space; and a controller configured to control the light source module and the ToF sensor to work using corresponding partitions, respectively.

[0008] Optionally, the light source module and the ToF sensor each use corresponding partitions to work includes: the light source module corresponding partition projected laser pulse irradiated by the measured space region covers the ToF sensor corresponding partition for receiving the measured space region of the return light.

[0009] Optionally, the light source module includes a plurality of light emitting regions, and the ToF sensor includes a sensor array based on the Geiger mode, and the light source module and the ToF sensor each use corresponding partitions to work includes: the sensor controls the plurality of light emitting regions to take turns to light, and controls the sensor array corresponding to one or more columns illuminated by the measured space region to receive the return light.

[0010] Optionally, the plurality of light emitting regions includes N light emitting regions, each light emitting region corresponds to M columns in the sensor array, wherein MxN is equal to the total number of columns of the sensor array, the sensor controls the plurality of light emitting regions to take turns to light, and controls the sensor array corresponding to one or more columns illuminated by the measured space region to receive the return light includes: the sensor controls each light emitting region to emit M times of light pulse, for M columns in the sensor array corresponding to the light emitting region to receive the return light one by one.

[0011] Optionally, each of the plurality of light emitting regions includes a plurality of VCSEL monomers. Optionally, a VCSEL chip composed of a plurality of groups of VCSEL monomers capable of being partitioned to light.

[0012] Optionally, the light source module further includes: a diffusion sheet in the outgoing direction of the VCSEL chip; and / or a power detection element for detecting whether the VCSEL chip is working normally.

[0013] Optionally, each group of VCSEL monomers includes: at least two VCSEL monomer subgroups, and the controller can control any group of VCSEL monomer subgroups in the group of VCSEL monomers to emit light pulses at the same time.

[0014] Optionally, the ToF sensor includes: a silicon photomultiplier (SiPM) that receives return light column by column.

[0015] According to a second aspect of the present disclosure, a depth data measurement device is provided, comprising: a depth data measurement head as described in the first aspect; a processor for: performing distance calculation based on the sensor signals generated by the ToF sensor sub-regions; and integrating the sensor signal calculation results for a plurality of ToF sensor partitions into the depth data output of the measured space.

[0016] Optionally, the processor integrates the functions of the controller.

[0017] According to a third aspect of the present disclosure, there is provided a motion device control system, comprising: a depth data measurement device as described in the second aspect, configured to collect return light of a measured space during a motion of a motion device and generate a depth data output; a control unit configured to generate a control signal based on the depth data output; and an action unit configured to change or maintain the motion of the motion device based on the control signal.

[0018] According to a fourth aspect of the present disclosure, there is provided a depth data measurement method, comprising:

[0019] controlling a light source module to project laser pulses to a measured space in a region-by-region manner; and controlling a time-of-flight (ToF) sensor to receive return light of the measured space in a region-by-region manner and generate a sensing signal, wherein the light source module and the ToF sensor are each controlled to work using a corresponding subregion, and the sensing signal characterizes a flight time of the light to calculate a distance of a photographed object in the measured space.

[0020] Optionally, the ToF sensor is a Geiger-mode based sensing array with MxN columns, and the light source module is configured as N light emitting regions, wherein the controlling the light source module to project laser pulses to the measured space in a region-by-region manner comprises: controlling each of the N light emitting regions to emit M pulses one by one, and the controlling the ToF sensor to receive return light of the measured space in a region-by-region manner and generate a sensing signal comprises: controlling the ToF sensor to receive the MxN pulses column by column and generate a sensing signal column by column.

[0021] Optionally, the method further comprises: performing distance calculation based on the sensing signal generated by the ToF sensor in a region-by-region manner; and synthesizing sensing signal calculation results for a plurality of ToF sensor subregions into a depth data output of the measured space.

[0022] The ToF sensor and the light source module can be a depth data measurement device installed on a motion device. To this end, the method can further comprise: generating a control signal based on the depth data output; and changing or maintaining an action of the motion device based on the control signal.

[0023] Thus, the depth data measurement scheme of the present disclosure utilizes a ToF sensor, especially a SiPM working in a rolling shutter mode, to achieve high-precision depth data measurement based on direct flight time. The scheme further combines a light emitting module working in a subregion-by-subregion manner, to reduce power consumption while ensuring normal exposure of a corresponding sensing region. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, and in which:

[0025] Figure 1 A schematic diagram of a depth data measurement head is shown.

[0026] Figure 2 A schematic diagram of a light source module working partition covering a ToF sensor working partition is shown.

[0027] Figure 3 An example of a VCSEL chip including multiple light emitting areas is shown.

[0028] Figure 4 An example of a VCSEL chip including subgroups within a partition is shown.

[0029] Figure 5 A composition example of a light source module is shown.

[0030] Figure 6 An example flow chart of a depth data measurement method according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0031] Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0032] In order to obtain depth data of the third dimension in three-dimensional data, it is necessary to obtain it with the help of a depth sensor. A depth sensor refers to an optical sensor that uses a pixel array to obtain a high-resolution depth distribution of the entire scene. The mechanisms commonly used to measure depth include structured light, binocular, and ToF (Time of Flight). Among them, structured light and binocular technology (including their combination) are both based on geometric principles to make indirect depth estimation, while ToF measures the flight time between emitted light and reflected light and directly estimates the depth according to the speed of light.

[0033] Further, although both are directly estimating the distance of the target according to the flight time between the emitted light and the reflected light, unlike the line scanning type conventional radar which can only obtain a low-density point cloud, the ToF sensor used in the present disclosure can obtain a high-resolution distance / depth distribution of the measurement scene through a high-density ToF sensor pixel array.

[0034] ToF can be divided into iToF (indirect flight time) and dToF (direct flight time). The principle of dToF is to directly emit a light pulse, and then measure the time interval between the reflected light pulse and the emitted light pulse to obtain the flight time of the light. The principle of iToF is relatively complex. In iToF, not a light pulse is emitted, but modulated light. There is a phase difference between the received reflected modulated light and the emitted modulated light, and the flight time can be measured by detecting the phase difference, so as to estimate the distance.

[0035] iToF has a contradiction between the maximum ranging distance and the ranging accuracy in principle. For example, if the current target distance is 0.15m, the total flight time of the emitted and reflected light is 1ns. When the modulation frequency of the modulated light is 100MHz (the period is 10ns), the flight time difference of 1ns is converted into a phase difference of 36 degrees, and if the modulation frequency of the modulated light is 10MHz (the period is 100ns), the flight time difference of 1ns is converted into a phase difference of 3.6 degrees. The phase difference of 36 degrees is easier to detect than the phase difference of 3.6 degrees, so the higher the modulation frequency of the modulated light of iToF, the better the ranging accuracy. But the higher the modulation frequency also limits the maximum ranging distance. For example, when the modulation frequency is 100MHz, the modulation period is 10ns, and the maximum ranging distance is limited by the modulation period. For example, the maximum ranging distance is the distance corresponding to the flight time equal to the modulation period (1.5m). Therefore, the main application scenario of iToF at present is the application of ranging distance in the range of several meters (such as mobile phones, etc.). In contrast, dToF does not have this contradiction between ranging distance and ranging accuracy.

[0036] In specific implementation, dToF is much more difficult than iToF. The difficulty of dToF lies in that the light signal to be detected is a pulse signal, so the sensitivity of the detector to light needs to be very high. The implementation of the ToF sensor can use SPAD (single-photon avalanche diode). The working area of SPAD is near the breakdown region of the diode. When a single photon enters the SPAD, a large number of electron-hole pairs will be generated, so SPAD can detect very weak light pulses. However, the integration of existing SPAD is low, resulting in poor 2D resolution of dToF sensor. In addition, dToF needs to distinguish very fine time differences, so extremely accurate readout circuit is required.

[0037] Existing structured light and binocular solutions suffer from limitations in ranging range and suitability for high-speed movement when the imaging device is positioned within a moving mechanism (e.g., driving or other motion scenarios). Therefore, this invention utilizes Time-of-Flight (ToF), particularly dToF arrays, for time-of-flight-based depth distance measurement. This measurement can be combined with a partitioned, illuminated light source module to reduce power consumption while acquiring high-precision images.

[0038] Figure 1 A schematic diagram illustrating the composition of a depth data measurement head according to an embodiment of the present disclosure is shown. Figure 1 As shown, the depth data measurement head 100 may include a light source module 110 and a ToF sensor 120. The light source module 110 and the ToF sensor 120 may be fixed to a base for subsequent installation within a housing. Although not shown in the figure, the depth data measurement 100 also needs to include a controller for controlling the operation of the light source module 110 and the ToF sensor 120 (e.g., it may be located on the back of the base).

[0039] In this invention, the light source module 110 can project laser pulses into the measured space in sections. The ToF sensor 120 can receive the reflected light from the measured space in sections and generate sensing signals. Here, "sectioned" can refer to the components operating in sections. For example, the light source module 110 can illuminate only one section at a time for pulse emission; while the ToF sensor 120 can activate only one section at a time for reflected light sensing. The "sensing signal" can characterize the time of flight of light to calculate the distance to the object being photographed within the measured space. Preferably, the ToF sensor 120 can be a sensor that uses the dToF (direct time of flight) principle for distance calculation. The controller is used to control the light source module 110 and the ToF sensor 120 to operate in their respective sections.

[0040] Here, the regional operation of the light source module 110 can be such that the light source module 110 is fixedly or variably divided into N regions. At each working moment, only the light source module of a certain region is lit, that is, only the light-emitting unit in that region emits light pulses. Correspondingly, the regional operation of the ToF sensor 120 can be such that the ToF sensor 120 is fixedly or variably divided into P regions. At each working moment, only one region of the sensor is activated, that is, only the sensing unit in that region receives the returned light.

[0041] Since the return light can only be received when there is light irradiation, the working partition of the ToF sensor needs to be coordinated with the working partition of the light source module. To this end, the light source module 110 and the ToF sensor 120 each using the corresponding partition to work can include: the light irradiated by the laser pulse projected by the light source module 110 corresponding partition to the measured space region covers the measured space region used by the ToF sensor 120 corresponding partition to receive the return light. In other words, the space region irradiated by the working partition of the light source module is at least not less than the sensor region receiving the return light.

[0042] Figure 2 A schematic diagram showing that the working partition of the light source module covers the working partition of the ToF sensor is shown. As shown, the overall irradiation range of the light source module can be comparable to the overall framing range of the ToF sensor, for example, the irradiation range (thick solid line) is slightly larger than the framing range (thick dashed line). Since the light source module is partitioned to work, as shown, at a certain moment, the range irradiated by the laser pulse emitted by a certain region of the light source module is as shown by the thin solid line. In order to be able to image the emitted light pulse, the framing range corresponding to the working partition of the ToF sensor should be as shown by the thin dashed line, which should not exceed the pulse projection range shown by the thin solid line. Figure 2

[0043] More specifically, the light source module 110 can include a plurality of light emitting regions, and the ToF sensor includes a sensor array. To this end, the controller controlling the light source module and the ToF sensor each using the corresponding partition to work can include: the sensor controls the plurality of light emitting regions to be lit in turn, and controls the corresponding one or more columns of the sensor array to receive the return light.

[0044] When the framing range corresponding to the working partition of the ToF sensor is less than the irradiation range corresponding to the working partition of the light source module as shown in Figure 2 In a complete sensor imaging process, each light emitting region of the light source module needs to be lit multiple times to facilitate each column of the sensor unit in the corresponding framing region to obtain the return light. For example, if the projection range of a light emitting region corresponds to the framing range of 50 columns of sensor units, and the number of sensor units that can receive the return light at a time is less than 50 (for example, 1 column at a time, or 10 columns at a time), it means that the light emitting region needs to be projected multiple times (for example, 50 times, or 5 times, respectively) so that each column of the corresponding sensor unit can obtain the return light.

[0045] ​In one embodiment, the plurality of light emitting regions comprises N light emitting regions, each corresponding to M columns in the sensing array, where MxN equals the total number of columns in the sensing array. The sensor can control the plurality of light emitting regions to be illuminated in turn, and controlling the sensing array to receive return light corresponding to one or more columns illuminated in the measured space region comprises the sensor controlling each light emitting region to emit M light pulses for the M columns in the sensing array corresponding to the light emitting region to receive return light one by one.

[0046] For example, a ToF sensor can be a 400x100 sensing array, i.e. comprising 400 columns, each column having 100 sensing units (i.e. P=400). The light source module can comprise 8 light emitting regions arranged vertically (N=8), each light emitting region can correspond to 50 columns in the sensing array (M=P / N=50). In one embodiment, the controller can first control the first light emitting region to be put into work, e.g. to emit 50 pulses at a fixed interval, so that the 1st-50th columns in the sensor are exposed one by one; then the second light emitting region can be controlled to be put into work, e.g. to emit 50 pulses at a fixed interval, so that the 51st-100th columns in the sensor are exposed one by one; and so on until the eighth region is put into work, e.g. to emit 50 pulses at a fixed interval, so that the 351st-400th columns in the sensor are exposed one by one. In this way, the light source module completes the exposure of the 400 columns of sensing units after experiencing 400 pulse emissions in total in 8 regions. In this way, compared with the scheme of full illumination each time, 7 / 8 of the light emitting efficiency is saved.

[0047] In certain embodiments, the plurality of light emitting regions comprised by the light emitting module can each be a single light emitting region, and in other embodiments, the plurality of light emitting regions can each comprise a plurality of VCSEL (Vertical Cavity Surface Emitting Laser) units. Preferably, the light source module can comprise one VCSEL chip composed of a plurality of groups of VCSEL units capable of being illuminated in zones. Figure 3 An example of a VCSEL chip comprising a plurality of light emitting regions is shown. As shown, the VCSEL chip comprises 5 light emitting regions (N=5), each region comprising 32 light emitting units, i.e. 160 light emitting units are divided into 5 groups, each group having 32 units. In operation, the chip is usually placed vertically, so that each independently illuminated group of units can illuminate a certain vertical length region in the measured space, for use in combination with a ToF sensor that is put into work column by column, for example, to measure the depth distance of a subject within a range of 20 meters.

[0048] In certain embodiments, each group of VCSEL units can be further grouped. Figure 4 An example of a VCSEL chip comprising subgroups within zones is shown. Compared with the example shown in FIG. 4, the VCSEL chip shown in FIG. 5 comprises 5 light emitting regions (N=5), each region comprising 32 light emitting units, i.e. 160 light emitting units are divided into 5 groups, each group having 32 units. In operation, the chip is usually placed vertically, so that each independently illuminated group of units can illuminate a certain vertical length region in the measured space, for use in combination with a ToF sensor that is put into work column by column, for example, to measure the depth distance of a subject within a range of 20 meters. Figure 3 , Figure 4VCSEL monomers on the VCSEL chip are further shown in dashed lines. As shown in the figure, the VCSEL monomers are grouped into 5 groups (N=5) on the VCSEL chip. Each group includes 32 VCSEL monomers, i.e. 160 VCSEL monomers are divided into 5 groups, each group including 32 monomers. But different from the VCSEL chip in Figure 3 Similarly, the VCSEL chip includes 5 light emitting areas (N=5), each area including 32 light emitting monomers, i.e. 160 light emitting monomers are divided into 5 groups, each group including 32 monomers. But different from the VCSEL chip in Figure 3 In the VCSEL chip in each group of light emitting monomers are simultaneously used for work, Figure 4 In the VCSEL chip in each group of 32 light emitting monomers are further divided into two subgroups (hollow circles and solid circles). The monomers belonging to the two subgroups are preferably staggered with each other, so as to uniformly illuminate the corresponding measured space when the subgroups are separately lit. The controller can control any subgroup of the VCSEL monomers in the group to emit light pulses simultaneously. For example, under the requirement of 10-meter ranging, low power and / or small external interference, only one subgroup can be used for projection each time, i.e. 16 light emitting monomers are lit each time. While under the requirement of 20-meter ranging, sufficient power and / or large external interference, all subgroups can be used for projection each time, i.e. all 32 light emitting monomers in the group are lit each time.

[0049] In addition to the VCSEL chip, the light source module can also include a diffusion sheet. Figure 5 An example of the composition of the light source module is shown. As shown in the figure, the light source module 510 can include a VCSEL chip 511, and a diffusion sheet 512 located in the emission direction of the VCSEL chip 511, for making the emitted light distribution more uniform. The light source module can also include a packaging shell for fixing the chip 511 and the diffusion sheet 512. In addition, although not shown, the light source module can also include a power detection element for detecting whether the VCSEL chip is working normally.

[0050] As mentioned before, the ToF sensor is a device that obtains a high-resolution distance / depth distribution of a measured scene based on direct time of flight through a high-density array of ToF sensor pixels. In a preferred embodiment, the ToF sensor can be a sensor array based on Geiger mode.

[0051] For the convenience of understanding the present application, the "Geiger mode" is explained here. A conventional avalanche photodiode (APD) is different from a common p-n junction photodiode in that the APD can withstand a higher bias voltage. When a photon is absorbed by the APD to generate a pair of electron-hole pairs, the pair of electron-hole pairs is referred to as a primary electron. The primary electron is accelerated by a strong electric field generated by a high bias voltage, thereby obtaining sufficient energy, and then collides with a lattice to generate another pair of electron-hole pairs, and the collision loses some kinetic energy, which is a familiar process of collision ionization. Then the electron (or hole) and the secondary electron (or hole) are accelerated by the strong electric field to generate more pairs of electron-hole pairs, i.e., the so-called "avalanche" phenomenon, and the current increases exponentially. After several transitions, the generation rate and absorption rate of the electron-hole pairs reach a balance. If the bias voltage of the APD is lower than its breakdown voltage, the absorption rate of the electron-hole pairs will be greater than the generation rate, so that the electron-hole pairs decrease, and the average photocurrent generated by the APD is proportional to the incident light, with a proportionality coefficient being a gain factor M, so this process is called linear working mode. By using the linear proportionality relationship, the intensity of the incident light signal can be measured.

[0052] However, if the bias voltage of the APD is higher than its breakdown voltage, the rate of generating electron-hole pairs by collision ionization of the APD will be greatly accelerated, and the absorption rate of the electron-hole pairs will be faster, which will make the current increase exponentially with time, thereby causing an avalanche, generating a current pulse. The increase in photocurrent will weaken the strong electric field formed by the high bias voltage of the APD, which will slow down the rate of the avalanche, so that the photocurrent decreases, and eventually reaches a balance, after which the photocurrent will no longer change. The formation of the balance process is mainly due to the fact that the equivalent resistance on the APD will provide a negative feedback, and the rise of the photocurrent will cause the voltage drop on the equivalent resistance to rise, thereby offsetting part of the bias voltage, so that the bias voltage on the APD decreases, which leads to a decrease in the rate of the avalanche, thereby reducing the photocurrent, which in turn causes the voltage drop on the equivalent resistance to decrease, and the reverse process occurs, so that the photocurrent rises. After a period of time, a balance state is formed. If the photocurrent is stable and greater than several hundred microamperes, the photocurrent will remain unchanged, i.e., it will remain in this balanced state, and at this time it will no longer respond to incident photons. This is the Geiger mode, and the most notable feature of this mode is that it can respond to single-photon events. The biggest difference between this mode and the linear mode is that it only responds to the presence or absence of photons, but cannot distinguish the number of photons, which is also the biggest feature of the GAPD (Geiger-mode avalanche photodiode). In order to be able to respond to the next photon event, the APD must be connected to a quenching circuit for quenching, and then recharged, so that the APD can work normally. In an ideal state, the APD does not respond to any photons during the quenching process until the charging is completed, and this period of time is referred to as "blind time".

[0053] SPAD is a photodiode working in Geiger mode, like a photon triggered switch, in the "on" or "off" state. The ToF sensor preferred to be used in the present application is a silicon photomultiplier (SiPM) composed of multiple independent SPAD sensors. SiPM is composed of multiple independent SPAD sensors, each sensor has its own quenching resistor, so as to overcome the deficiency of single SPAD that cannot measure multiple photons at the same time. Since the present application uses SiPM that receives return light column by column, it can achieve efficient and fast calculation of depth data under the limitation of computing power and blind time.

[0054] In addition, it should be understood that the laser pulse emitted by the light source module of the present application is a pulse outside the visible light band, such as a near-infrared pulse, which can filter out the interference of irrelevant ambient light in combination with a band-pass filter.

[0055] The present application can also be implemented as a depth data measurement device, comprising a depth data measurement head as described above and a processor. The processor is configured to: perform distance calculation based on the sensing signals generated by the ToF sensors in different regions; and combine the calculation results of the sensing signals for the ToF sensors in different regions into a depth data output of the measured space.

[0056] In some embodiments, the measurement device can have a separate controller and processor, and in other embodiments, the processor can integrate all or part of the functions of the controller.

[0057] The depth data measurement device of the present application is particularly suitable for depth data measurement on a moving device. For this purpose, the present application can also be implemented as a motion device control system, comprising: a depth data measurement device as described above, configured to collect return light of a measured space and generate a depth data output during the movement of a motion device; a control unit configured to generate a control signal based on the depth data output; and an action unit configured to change or maintain the movement of the motion device based on the control signal.

[0058] In one embodiment, the motion device can be an automatic or unmanned device, such as an unmanned vehicle, and the depth data measurement device of the present application can be implemented as a vehicle-mounted radar to collect and calculate the distance status of each object in the environment in real time, so as to facilitate the vehicle to take corresponding actions (e.g., evasion, deceleration, etc.). In another embodiment, the motion device can also be a handling device, such as a handling robot in a logistics warehouse, or an automatic delivery device moving in a wider space, etc. The installation of the depth measurement device of the present application helps it to complete the loading and unloading of goods and daily operation.

[0059] The present application can also be implemented as a depth data measurement method. The method can be implemented by the depth measurement head or the controller and / or processor of the measurement device as disclosed above.Figure 6 An exemplary flowchart of a depth data measurement method according to an embodiment of the present invention is shown.

[0060] In step S610, the light source module is controlled to project laser pulses into the measured space in sections. In step S620, the time-of-flight (ToF) sensor is controlled to receive the reflected light from the measured space in sections and generate sensing signals. The light source module and the ToF sensor are each controlled to operate using their respective sections, and the sensing signals characterize the time of flight of the light to calculate the distance to the object being photographed within the measured space.

[0061] The depth data measurement method of the present invention can perform the respective operations described above in conjunction with the measuring head and measuring device. In a preferred embodiment, the ToF sensor is a Geiger-pattern-based sensing array with MxN columns, and the light source module is configured with N emitting regions. To this end, controlling the light source module to project laser pulses into the measured space in a regional manner can include controlling each of the N emitting regions to emit M pulses sequentially. Controlling the ToF sensor to receive the reflected light from the measured space in a regional manner and generate sensing signals includes controlling the ToF sensor to receive the MxN pulses column by column and generate sensing signals column by column.

[0062] It should be understood that, although for the sake of design and control simplicity, it is possible to address issues such as... Figure 3 The illustrated light-emitting partitions are activated sequentially from left to right or right to left (i.e., partitions 1, 2, 3, 4, and 5 emit M pulses each in sequence), and the ToF sensor performs rolling-screen imaging column by column from left to right or right to left (i.e., sequentially connecting with the sensing unit columns 1-400). However, the invention is not limited to this order. In other embodiments, it is not necessary to activate partitions 1, 2, 3, 4, 5 or 5, 4, 3, 2, 1 in that order; any order such as 1, 3, 5, 2, 4 or 4, 3, 5, 1, 2 is acceptable. Furthermore, the sensor that operates column by column does not need to activate the next adjacent column each time; it is not even necessary to expose all sensing columns corresponding to a given light-emitting partition before projecting and exposing the next light-emitting partition. It is sufficient that each column of the ToF sensor is exposed during the acquisition of a single sensing image. For example, as described above in conjunction with vertical light-emitting partitions and sensor columns, in other embodiments, it can also be implemented as horizontal light-emitting partitions and row-by-row exposure, and the present invention does not limit this.

[0063] Further, the depth data measurement method further comprises: performing distance calculation based on the sensing signals generated by the ToF sensors in the sub-regions; and synthesizing the calculation results of the sensing signals of the ToF sensors in the sub-regions into the depth data output of the measured space.

[0064] Preferably, the ToF sensors and the light source module can be a depth data measurement device installed on a motion device. To this end, the measurement method can further comprise: generating a control signal based on the depth data output; and changing or maintaining the action of the motion device based on the control signal.

[0065] The depth data measurement scheme according to the present application has been described in detail above with reference to the accompanying drawings. The scheme utilizes ToF sensors, especially SiPMs working in rolling shutter mode, to realize high-precision depth data measurement based on direct time of flight. The scheme further combines the light-emitting module working in sub-regions, to reduce power consumption while ensuring normal exposure of the corresponding sensing regions.

[0066] The flow diagrams and block diagrams in the drawings show the architectural, functional and operational views of possible implementations of systems and methods according to various embodiments of the present application. In this regard, each block in the flow diagrams and block diagrams can represent a module, a segment, or a portion of code that comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may

[0067] The embodiments of the present application have been described above, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A depth data measurement head for collecting return light of a measured space during movement of a moving device, comprising: a light source module for projecting laser pulses to the measured space in sub-regions, the light source module comprising a plurality of light emitting regions; a time-of-flight (ToF) sensor for receiving return light of the measured space in sub-regions and generating sensing signals representing direct time-of-flight of the light for calculating distances of objects in the measured space; a controller for controlling the light source module and the ToF sensor to work in respective sub-regions, wherein the light source module projects laser pulses to the measured space in corresponding sub-regions covering the ToF sensor receiving return light in corresponding sub-regions, each of the plurality of light emitting regions is controlled to be lit in turn, and the light source module projects pulses from one region at a time, and the ToF sensor senses return light from one region at a time, wherein the plurality of light emitting regions comprises N light emitting regions, the ToF sensor is a sensing array having MxN columns, each light emitting region corresponds to M columns of the sensing array, and controlling the light source module and the ToF sensor to work in respective sub-regions comprises: controlling M columns of the sensing array corresponding to the lit region of the measured space to receive return light.

2. The depth data measurement head of claim 1, wherein, The sensing array is a Geiger-mode based sensing array.

3. The depth data measurement head of claim 2, wherein, The controller controls M columns of the sensing array corresponding to the lit region of the measured space to receive return light comprises: controlling each light emitting region to emit M light pulses for M columns of the sensing array corresponding to the light emitting region to receive return light one by one.

4. The depth data measurement head of claim 2, wherein, Each of the plurality of light emitting regions comprises a plurality of VCSEL units.

5. The depth data measurement head of claim 4, wherein, The light source module comprises: one VCSEL chip composed of a plurality of groups of VCSEL units capable of being lit in sub-regions.

6. The depth data measurement head of claim 5, wherein, The light source module further comprises: a diffusion sheet in an exit direction of the VCSEL chip; and / or a power detection element for detecting whether the VCSEL chip is working properly.

7. The depth data measurement head of claim 5, wherein, Each group of VCSEL units comprises: at least two sub-groups of VCSEL units, the controller is capable of controlling any of the sub-groups of VCSEL units in the group of VCSEL units to emit light pulses at the same time.

8. The depth data measurement head of claim 2, wherein, The ToF sensor comprises: a silicon photomultiplier (SiPM) for receiving return light column by column.

9. A depth data measurement device, comprising: the depth data measurement head according to any one of claims 1-8; a processor for: performing distance calculation based on the sensing signals generated by the ToF sensor in sub-regions; and integrating results of the sensing signal calculation for a plurality of the ToF sensor sub-regions into a depth data output of the measured space. The processor integrates the functions of the controller.

10. The depth data measurement device of claim 9, wherein, 11. A moving device control system, comprising: the depth data measurement device according to claim 9 or 10 for collecting return light of a measured space during movement of a moving device and generating a depth data output; a control unit for generating a control signal based on the depth data output; and ​ ​ An action unit is configured to change or maintain the motion of the motion device based on the control signal.

12. A method for measuring depth data, configured to collect return light of a measured space during motion of a motion device, and the method comprising: controlling a light source module to project laser pulses to the measured space in a region-by-region manner; controlling a time-of-flight (ToF) sensor to receive return light of the measured space in a region-by-region manner and generate a sensing signal, wherein the light source module comprises a plurality of light emitting regions, the light source module and the ToF sensor are each controlled to be put into operation using a corresponding partition, a region of the measured space irradiated by the laser pulses projected by the light source module in the corresponding partition covers a region of the measured space used by the ToF sensor in the corresponding partition to receive return light, and the sensing signal represents a direct time of flight of the light to calculate a distance of a photographed object in the measured space, each of the plurality of light emitting regions is controlled to be lit in turn, wherein the plurality of light emitting regions comprises N light emitting regions, the ToF sensor is a sensing array having MxN columns, each light emitting region corresponds to M columns in the sensing array, and controlling the light source module to project laser pulses to the measured space in a region-by-region manner comprises: controlling each of the N light emitting regions to emit M pulses one by one, 13. The method of claim 12, wherein, controlling the ToF sensor to receive return light of the measured space in a region-by-region manner and generate a sensing signal comprises: controlling the ToF sensor to receive the MxN pulses column by column and generate a sensing signal column by column.

14. The method of claim 12, further comprising: performing distance calculation based on the sensing signal generated by the ToF sensor in a region-by-region manner; and integrating the calculation results of the sensing signal for a plurality of the ToF sensor partitions into a depth data output of the measured space. the ToF sensor and the light source module are a depth data measuring device installed on the motion device, the method further comprises: generating a control signal based on the depth data output; and 15. The method of claim 14, wherein, changing or maintaining the action of the motion device based on the control signal. ​ ​ ​

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