CN111896971B - TOF sensing device and distance detection method thereof - Google Patents
TOF sensing device and distance detection method thereof Download PDFInfo
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- CN111896971B CN111896971B CN202010780158.0A CN202010780158A CN111896971B CN 111896971 B CN111896971 B CN 111896971B CN 202010780158 A CN202010780158 A CN 202010780158A CN 111896971 B CN111896971 B CN 111896971B
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- 238000001514 detection method Methods 0.000 title claims abstract description 214
- 238000000034 method Methods 0.000 claims abstract description 23
- 238000009825 accumulation Methods 0.000 claims description 34
- 238000005259 measurement Methods 0.000 claims description 18
- 238000012937 correction Methods 0.000 claims description 16
- 238000004883 computer application Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 14
- 230000003287 optical effect Effects 0.000 description 6
- 238000004590 computer program Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
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Abstract
The application discloses a TOF sensing device and a distance detection method thereof, comprising the following steps: transmitting pulse detection light to irradiate a tested view field, wherein the pulse detection light at least comprises two pulses with different pulse widths; receiving the reflected pulse detection light, and obtaining initial distance information of each position in the detected field of view according to the time interval from the emission to the reception of the pulse detection light; and combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information at each position in the measured view field. The TOF sensing device and the distance measuring method thereof can reduce the influence of multipath reflected light and improve the accuracy of distance detection.
Description
Technical Field
The application relates to the technical field of sensing, in particular to a TOF sensing device and a distance detection method thereof.
Background
Time of Flight (ToF) sensors enable measurement of the distance, three-dimensional structure or three-dimensional profile of a measured object by detecting the Time interval from transmission to reception of an emitted pulse signal or the phase generated by a laser once traversing the measured object. The TOF sensor can obtain gray level images and distance images at the same time, and is widely applied to various fields such as somatosensory control, behavior analysis, monitoring, automatic driving, artificial intelligence, machine vision, automatic 3D modeling and the like.
In the actual distance detection process, due to the complex environment in the field to be detected, there are usually multiple reflecting surfaces, which causes multipath reflection problems, including: the detection light may reach the surface of the detected object after being reflected for multiple times, and the reflected light reflected by the detected object may be received by the time-of-flight sensor after being reflected for multiple times. Multipath reflection problems can result in the detection light being emitted to the reflected back where the received flight distance is greater than 2 times the actual distance of the object being measured, thereby affecting the accuracy of the distance detection.
In the prior art, aiming at the problem of multipath reflection interference (MPI, multi-path interference), the influence of multipath reflected light on a detection result is usually reduced by correcting a complex algorithm, and the requirement on the computing capability of the sensor is high, so that the cost is increased.
Disclosure of Invention
In view of the above, the present application provides a TOF sensor and a distance detection method thereof, so as to correct the influence of multipath reflected light on a detection structure and improve the accuracy of distance detection.
The application provides a distance detection method of a TOF sensing device, which comprises the following steps: transmitting pulse detection light to irradiate a tested view field, wherein the pulse detection light at least comprises two pulses with different pulse widths; receiving the reflected pulse detection light, and obtaining initial distance information of each position in the detected field of view according to the time interval from the emission to the reception of the pulse detection light; and combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information at each position in the measured view field.
Optionally, in the measuring process, each detection frame includes a plurality of detection subframes, and each detection subframe corresponds to a pulse with a pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain one frame of measurement distance information.
Optionally, the TOF sensing device generates an induced charge corresponding to reflected light energy after receiving the reflected light; the distance detection method comprises the following steps: the induced charges are accumulated by three successive charge accumulation windows, each of which has a window width consistent with the pulse width of the detection light of the current detection frame.
Optionally, the measured view field includes a plurality of measuring range ranges, according to the detection precision requirement for each measuring range, pulses with a plurality of different pulse widths corresponding to each measuring range are set, the smaller the pulse width is, the shorter the corresponding measuring range is, and the smaller the influence of multipath reflected light on the detection result is.
Optionally, the pulse width setting method of the pulse detection light includes: performing distance detection with an initial pulse detection light having a basic pulse whose pulse width corresponds to a maximum range; when a target object appears in the measured view field, the initial pulse detection light is adjusted to be modified pulse detection light, the modified pulse detection light comprises the basic pulse and the modified pulse, and the pulse width of the modified pulse is smaller than that of the basic pulse.
Optionally, before the target object appears, each detection frame adopts a basic pulse to perform distance detection; after the target object appears, each detection frame comprises at least two detection subframes, and the distance detection is carried out by adopting basic pulse and correction pulse respectively.
Further comprises: and adjusting the range starting point corresponding to the correction pulse by controlling the light-emitting time sequence of the correction pulse, so that the range of the detection subframe corresponding to the correction pulse covers the distance range of the target object.
Optionally, the target object is selected according to a detection result of the initial pulse detection light.
Alternatively, an object that appears within a preset distance range is automatically set as the target object.
The technical scheme of the application also provides a TOF sensing device, which comprises: a light source module for emitting pulse detection light; the sensing module is used for receiving the reflected light of the pulse detection light reflected by the object to be detected; the processor is connected with the light source module and the sensing module and used for controlling the light source module and the sensing module; a memory storing a computer application capable of running on the processor; wherein the computer program, when executed by the processor, implements the distance detection method of any one of the above.
According to the distance measuring method of the TOF sensing device, the distance detection is carried out through the pulse detection light with different pulse widths, a larger detection range is obtained through the wide pulse, meanwhile, the influence of multipath reflected light can be reduced through the narrow pulse, the measuring accuracy in a certain range is improved, a complex algorithm is not needed, the implementation mode is simple, and the cost is low.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a ranging method of a TOF sensing device according to an embodiment of the application;
FIG. 2a is a schematic diagram of a pulse detection light according to an embodiment of the present application;
FIG. 2b is a schematic diagram of a pulse detection light according to an embodiment of the present application;
FIG. 3a is a timing diagram of a charge accumulation window and pulse detection light and reflected light according to an embodiment of the present application;
FIG. 3b is a timing diagram of a charge accumulation window and pulse detection light and reflected light according to an embodiment of the present application;
FIG. 3c is a timing diagram of a charge accumulation window and pulse detection light and reflected light according to an embodiment of the present application;
FIG. 3d is a timing diagram of a charge accumulation window and pulse detection light and reflected light according to an embodiment of the present application;
FIG. 4 is a timing diagram of a pulse detection light employed in an embodiment of the present application;
FIG. 5 is a flow chart illustrating a method for setting pulse width of pulse detection light according to an embodiment of the application;
FIG. 6 is a schematic diagram of a pulse detection light employed in an embodiment of the present application;
fig. 7 is a schematic structural diagram of a TOF sensor according to an embodiment of the application.
Detailed Description
The following description of the embodiments of the present application will be made in detail and with reference to the accompanying drawings, wherein it is apparent that the embodiments described are only some, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application. The various embodiments described below and their technical features can be combined with each other without conflict.
Fig. 1 is a flow chart of a ranging method of a TOF sensor according to an embodiment of the application.
The ranging method comprises the following steps:
step S101: the method comprises the steps of emitting pulse detection light to irradiate a tested view field, wherein the pulse detection light at least comprises two pulses with different pulse widths.
The TOF sensing device comprises a light source module for emitting detection light into a field of view to be measured. The pulse detection light is modulated pulse light, and the pulse light can be light which is easy to modulate, such as LED light or laser light, and irradiates all objects in the range of the detected view field through the pulse detection light. The pulse detection light reaches the surface of the detected object and is reflected on the surface of the detected object to form reflected light; and meanwhile, the environment where the object to be measured is located also has the environment light. In an actual use scenario, the optical signal received by the time-of-flight sensing device through the sensing module includes both pulsed reflected light and ambient light. In the following description of the embodiments, the reflected light received by the sensor array includes both pulsed reflected light and ambient light.
The TOF sensing device further comprises a sensing module, wherein the sensing array comprises a plurality of pixel units, namely optical sensing units, and can convert optical signals into electric signals, so that received reflected light can be converted into a certain amount of induced charges corresponding to the energy of the reflected light through the sensing module, and detection values corresponding to the energy of the reflected light are accumulated and output through a charge accumulation window.
In this embodiment, the pulse detection light includes pulses of at least two different pulse widths. Different pulse widths correspond to different measuring ranges, and the larger the pulse width is, the larger the measuring range is. In the case of a pulse width T, the range is 0 to cT/2. The starting point of the measuring range can be adjusted by adjusting the time sequence of the pulse relative to the charge accumulation window, for example, the pulse with the same pulse width of T, the corresponding measuring range can be d-cT/2+d, and d is determined by the time of pulse width translation, and the analysis in the following embodiment is specific.
Fig. 2a is a schematic diagram of pulse detection light according to an embodiment of the application.
In this embodiment, the pulse detection light has two pulses with different pulse widths, namely a first pulse P1 and a second pulse P2, and the pulse width of the second pulse P2 is smaller than that of the first pulse P1. The detection frame intervals corresponding to the first pulse P1 and the second pulse P2 are set, for example, in which the detection subframe 1 and the detection subframe 2 each correspond to a plurality of pulses of the same pulse width.
Fig. 2b is a schematic diagram of a pulse detection light according to another embodiment of the application.
In this embodiment, the pulse detection light employs the first pulse P1 and the second pulse P2 in stages, and after transmitting a plurality of first pulses P1 and completing a plurality of detection frames corresponding to the first pulses P1, a plurality of second pulses P2 are transmitted to perform detection of a plurality of detection frames corresponding to the second pulses P2.
In other embodiments, the pulse detection light may further include three or more pulses with different pulse widths, and pulse timings with different pulse widths are set reasonably according to actual requirements.
Step S102: and receiving the reflected detection light, and obtaining initial distance information at each position in the detected field of view according to the time interval from the emission to the reception of the pulse detection light.
The pulse detection light is received by the sensing module after being reflected. The time when the reflected light is received is different according to the distance between the measured object and the object, and the initial distance information at each position can be calculated according to the time interval from the sending of the pulse detection light to the receiving after the pulse detection light is reflected.
Specifically, after receiving the reflected light, the sensing module of the TOF sensing device generates an induced charge corresponding to the energy of the reflected light; in this embodiment, the induced charges are accumulated using three consecutive charge accumulation windows, each of which has a window width consistent with the detected light pulse width of the current detected frame.
Referring to fig. 3a, a timing diagram of a charge accumulation window and pulse detection light and reflected light within a detection frame is shown.
The detection frame shown in fig. 3a corresponds to a first pulse P1 of the pulse detection light LO1, the first pulse P1 having a pulse width T 1 。
The first charge accumulation window G11, the second charge accumulation window G12, and the third charge accumulation window G13 correspond to a capacitive shutter structure, respectively, induce charges through capacitance accumulation, and control signals having a certain timing,the opening and closing of the respective charge accumulation windows are controlled. The window widths of the first charge accumulation window G11, the second charge accumulation window G12 and the third charge accumulation window G13 are consistent with the pulse width of the first pulse width P1 and are T 1 。
Wherein, G11, G12 and G13 are turned on in sequence, and since the ambient light is always present during the distance detection process, the first charge accumulation window G1 is used for accumulating the induced charges generated by the ambient light. In this embodiment, the opening edge of the second charge accumulating window G12 is aligned with the generating edge of the first pulse P1, and the second charge accumulating window G12 and the third charge accumulating window G13 are used to accumulate induced charges generated by the ambient light and the reflected light of the pulse detection light.
The amounts of induced charges accumulated by G11, G12, and G13 are Q11, Q12, and Q13, respectively. The initial detection distance can be calculated according to the quantity of the induced chargesThe range of the first pulse P1 which can be detected is 0 to cT 1 /2。
In the detection process, the second charge accumulation window G12 and the third charge accumulation window G13 can accumulate the induced charges generated by the multipath reflected light MPI at the same time, and the multipath reflected light MPI is received after the effective reflected light LB1 due to multiple reflections, which is larger in optical path length, and accumulated by the second charge accumulation window G12 and the third charge accumulation window G13, so that the detection result is larger. In the process of charge accumulation, the second charge accumulation window G12 and the third charge accumulation window G13 cannot distinguish the induced charges generated by the normal reflected light and the multipath reflected light, and therefore, cannot eliminate the influence of the multipath reflected light on the detection result.
Referring to fig. 3b, a timing chart of the charge accumulation window corresponding to the second pulse P2 of the pulse detection light, the pulse detection light and the reflected light is shown.
The second pulse P2 has a pulse width T 2 In the detection frame, the first, second and third charge accumulation windows G21, G22 and G23 have a width corresponding to the pulse width P2 of the second pulse widthThe widths are consistent and are all T 2 。
Under this detection frame, there is also interference of the multipath reflected light MPI. In the case where the detection scene is the same, the intensity and energy of the multipath reflected light MPI within the detection frame shown in fig. 3a and 3b remain substantially identical. However, since the pulse width T of the second pulse P2 is adopted in the detection frame of FIG. 3b 2 Pulse width T smaller than first pulse P1 1 T, i.e 2 <T 1 The method comprises the steps of carrying out a first treatment on the surface of the The window width of the corresponding charge accumulation windows G22 and G23 is also smaller than that of the windows G12 and G13, so that the charge accumulation time is shortened, and therefore, the charges generated by part of the multipath reflected light MPI cannot be accumulated, thereby reducing the influence of the multipath reflected light on the detection result, compared with the pulse width T with a larger pulse width 1 The accuracy of distance detection can be improved by using the second pulse P2 for the first pulse P1.
In this embodiment, the rising edge of the second pulse P2 is aligned with the opening edge of the second charge accumulation window G22, so that the second pulse P2 can be detected in a range of 0-cT 2 /2. Thus ranging from 0 to cT 2 Within the range of/2, the accuracy of the initial distance information obtained with the second pulse P2 is greater than the accuracy of the initial distance information obtained with the first pulse P1.
In another embodiment, the start point of the range corresponding to the second pulse P2 may be moved by adjusting the timing of the second pulse P2 with respect to the second charge accumulation window G22.
Referring to fig. 3c, the pulse detection light second pulse P2 is delayed by a time t with respect to the second charge accumulation window G22. At this time, the detectable range is
Referring to fig. 3d, the pulse detection light second pulse P2 is advanced by a time t with respect to the second charge accumulation window G22. At this time, the detectable range is
By controlling the timing of the second pulse P2, the range of the second pulse P2 can be adjusted to cover 0-cT 1 Any distance range within/2.
Step S103, combining the initial distance information obtained according to the pulses with different pulse widths to obtain the measured distance information at each position in the measured view field.
Specifically, the distance initial information at each position obtained according to the second pulse P2 replaces the distance initial information at the corresponding position obtained according to the first pulse P1, and actual measured distance information at each position in the whole field of view to be measured is formed.
Specifically, a plurality of detection frames are adopted for distance detection, each detection frame comprises a plurality of detection subframes, and each detection subframe corresponds to a pulse with a pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain one frame of measurement distance information.
In this embodiment, the pulse detection light includes a first pulse P1 corresponding to the detection subframe 1 and a second pulse P2 corresponding to the detection subframe 2, please refer to fig. 2a, the detection subframe 1 and the detection subframe 2 are set at intervals, the distance information obtained by the detection subframe 1 and the detection subframe 2 are combined to obtain one frame of measurement distance number information, and finally 2n frames of data are combined to obtain n frames of data.
Taking fig. 3b as an example, in the data merging process, the range can be 0-cT for each pixel unit 2 Searching initial distance information acquired by the detection subframe 2 in the range of the measuring range of/2; when searching initial distance information corresponding to the detection subframe 1 in an out-of-range, merging the searched data of the detection subframe 1 and the detection subframe 2 in the initial distance information in the detection frame of the detection subframe 1 to finally obtain measurement distance information corresponding to all pixel units, thereby obtaining 0-cT in the whole detected view field 1 A depth image in the range of/2. In the depth image, 0 to cT 2 The measurement depth information in the range of/2 has higher accuracy and is less affected by MPI.
In the above embodiment, the distance detection is performed by the pulse detection light with different pulse widths, a larger detection range is obtained by the wide pulse, meanwhile, the influence of the multipath reflected light can be reduced by the narrow pulse, the measurement accuracy in a certain range is improved, a complex algorithm is not needed, the implementation mode is simple, and the cost is lower.
In other embodiments, the pulse width of each pulse in the pulse detection light corresponding to each range may be set according to the detection precision requirements in different range ranges in the detected field of view, where the smaller the pulse width is, the smaller the corresponding range is, and the higher the detection precision is.
For example, in one embodiment, the field of view being measured may be divided into three ranges, including 0-d 1, d 1-d 2, d 2-d 3, with higher accuracy requirements for measurement of areas closer in distance.
Please refer to fig. 4, which is a timing diagram of the pulse detection light used in the embodiment. In this embodiment, according to the detection accuracy of different ranges, the pulse detection light includes three pulses with different pulse widths, which are sequentially set, and are respectively a first pulse P41, a second pulse P42, and a third pulse P43. The pulse width of the first pulse P41 is maximum, and the maximum measuring range is 0-d 3; the pulse width of the second pulse P42 is smaller than that of the first pulse P41, and corresponds to the second measuring range d 1-d 2; the pulse width of the third pulse P43 is smaller than that of the second pulse P42, corresponding to the third measuring range 0-d 1.
After the initial distance information data of three subframes are obtained through the first pulse P41, the second pulse P42 and the third pulse P43 respectively, the three subframe data are combined to obtain one frame of measurement distance information. Specifically, in the range of 0-d 1, the initial distance information of the detection subframe corresponding to the third pulse P43 is adopted; in the range of the measuring range d 1-d 2, adopting initial distance information in a detection frame corresponding to the second pulse P42; in the range of d 2-d 3, adopting the initial distance information of the detection frame corresponding to the first pulse P41; finally, measuring distance information of each position in a distance range of 0 to d3 in a measured view field is obtained, and the measuring distance information in three measuring ranges of 0 to d1, d1 to d2 and d2 to d3 respectively correspond to different detection accuracies.
By adopting the distance measuring method, higher detection precision can be obtained in a short-distance range, and the method is more beneficial to ground navigation equipment, such as equipment with higher requirements on short-distance detection precision, such as a sweeping robot, a navigation robot and the like.
In another embodiment, the pulse width of the pulse detection light can be dynamically adjusted.
Fig. 5 is a flowchart illustrating a method for setting pulse width of pulse detection light according to an embodiment of the application.
In this embodiment, the pulse width setting method of the pulse detection light includes the steps of:
step S501, performing distance detection with an initial pulse detection light having a basic pulse whose pulse width corresponds to the maximum range.
In the initial stage of detection, the initial pulse detection light LO1 (refer to fig. 6) has only a basic pulse P61 with a single pulse width, which corresponds to the maximum range within the field of view. Distance information at each position within the range of the whole measured view field can be obtained through the basic pulse P61.
And step S502, when a target object appears in the tested view field, the initial pulse detection light is adjusted to be modified pulse detection light, the modified pulse detection light comprises the basic pulse and the modified pulse, and the pulse width of the modified pulse is smaller than that of the basic pulse.
The target object may be selected by the user according to the depth image obtained by the initial detection light LO1, for example, the depth image is presented to the user through a display screen, when the user finds that an object of interest appears in the selected field of view, for example, a portrait appears, the person is selected as the target object, and the selection of the target object may be achieved by touching or other manipulation manners.
In other embodiments, it is also possible to automatically set an object that appears within a preset distance range as the target object. For example, when the TOF sensor apparatus is used for real-time monitoring, a sensitive area may be set, and when any object appears in the sensitive area, the object is taken as a target object.
After the target object appears, the initial detection light LO1 is adjusted according to the distance range of the target object to form the corrected detection light LO2 so as to improve the detection precision of the target object. Specifically, after the distance range of the target object is obtained through the initial detection light LO1, a correction pulse P62 is formed, and the pulse width of the correction pulse P62 and the range corresponding to the time sequence cover the distance range of the target object. For example, the distance range at each position of the target object is a 1-a 2, the pulse width and the timing of the correction pulse P62 correspond to the ranges a1 'to a2', a2 'are equal to or slightly greater than a2, and a1' is equal to or slightly less than a1.
Before the appearance of the target object, each detection frame adopts a basic pulse P61 to carry out distance detection; after the target object appears, each detection frame includes at least two detection subframes, and the basic pulse P61 and the correction pulse P62 are used for distance detection respectively.
And the correction pulse P62 and the detection subframe corresponding to the basic pulse P61 are arranged at intervals, each detection frame respectively comprises a subframe corresponding to the correction pulse P62 and a subframe corresponding to the basic pulse P61, and the initial distance information of the two subframes is combined to obtain one frame of measurement distance information. Referring to fig. 6, initial distance information of the detection subframe 11 and the detection subframe 12 are combined to form measurement distance information of the detection frame 1; the initial distance information of the detection sub-frame 21 and the detection sub-frame 22 are combined to form the measurement distance information of the detection frame 2. In the finally obtained measurement distance information, the detection precision of the area where the target object is located is higher. In fig. 6, each detection subframe is only indicated by one pulse, and in the actual measurement process, a plurality of repeated light pulses of the same type correspond to one detection subframe, and the repeated light pulses are repeated hundreds, thousands or even tens of thousands of times, so that enough charge is accumulated to improve the detection accuracy.
In the case where the distance range of the target object is relatively large, the measurement range of the sub-detection corresponding to the correction pulse P62 may also be made to cover the distance range to the target object by shifting the partial sub-detection frame correction pulse P62 forward or backward.
In an embodiment of the application, a TOF sensing device is also provided.
Please refer to fig. 7, which is a schematic diagram of the structure of the TOF sensor.
The TOF sensing device includes: a light source module 701, a sensing module 702, a processor 703 and a memory 704.
The light source module 701 is configured to emit pulse detection light. The light source module 701 may be an infrared light source, and the processor 703 may send a control signal to the light source module 701 to adjust parameters such as light emitting intensity, pulse width, and period of the light source module 701.
The sensing module 702 is configured to receive reflected light of the pulse detection light reflected by the object to be detected. The sensing module 702 includes an array of pixel cells capable of receiving an optical signal and converting the optical signal into an electrical signal, producing an induced charge corresponding to the received light. The processor 703 is connected to the sensing module 702, and is configured to obtain an induction signal of the sensing module 702.
The memory 704 may be a non-volatile memory, storing a computer application program capable of running on the processor 703, wherein the computer program when executed by the processor 703 implements the distance detection method described in any of the embodiments above.
In some embodiments, during distance detection, the processor 703 can control the light source module 701 to emit pulsed detection light to illuminate the field of view under test, the pulsed detection light comprising pulses of at least two different pulse widths; the sensor module 702 receives the reflected pulse detection light, the processor 703 may invoke a computer application program in the memory 704, obtain initial distance information at each position in the field of view to be measured according to a time interval from transmitting to receiving the pulse of the pulse detection light, and combine the initial distance information obtained according to the pulses with different pulse widths to obtain measured distance information at each position in the field of view to be measured.
That is, the foregoing embodiments of the present application are merely examples, and are not intended to limit the scope of the present application, and all equivalent structures or equivalent processes using the descriptions of the present application and the accompanying drawings, such as the combination of technical features of the embodiments, or direct or indirect application in other related technical fields, are included in the scope of the present application.
Claims (6)
1. A distance detection method of a TOF sensor apparatus, comprising:
transmitting pulse detection light to irradiate a tested view field, wherein the pulse detection light at least comprises two pulses with different pulse widths; the pulse width setting method of the pulse detection light comprises the following steps: performing distance detection with an initial pulse detection light having a basic pulse whose pulse width corresponds to a maximum range; when a target object appears in the measured view field, the initial pulse detection light is adjusted to be modified pulse detection light, the modified pulse detection light comprises the basic pulse and the modified pulse, and the pulse width of the modified pulse is smaller than that of the basic pulse; before the appearance of the target object, each detection frame adopts basic pulse to carry out distance detection; after the target object appears, each detection frame comprises at least two detection subframes, and the distance detection is carried out by adopting basic pulse and correction pulse respectively; adjusting a range starting point corresponding to the correction pulse by controlling the light-emitting time sequence of the correction pulse, so that the range of the detection subframe corresponding to the correction pulse covers the distance range of the target object;
receiving the reflected pulse detection light, and obtaining initial distance information of each position in the detected field of view according to the time interval from the emission to the reception of the pulse detection light;
combining initial distance information obtained according to pulses with different pulse widths to obtain measurement distance information at each position in a measured view field, wherein each detection frame adopted in the measurement process comprises a plurality of detection subframes, and each detection subframe corresponds to a pulse with one pulse width; and combining the initial distance information obtained by detecting each detection subframe to obtain one frame of measurement distance information.
2. The distance detection method according to claim 1, wherein the TOF sensing device generates an induced charge corresponding to reflected light energy upon receiving reflected light; the distance detection method comprises the following steps: the induced charges are accumulated using three successive charge accumulation windows, each of which has a window width consistent with the current pulse width of the detected light.
3. The distance detection method according to claim 1, wherein the field of view to be detected includes a plurality of measuring ranges, pulses of a plurality of different pulse widths corresponding to the respective measuring ranges are set according to the detection accuracy requirements for the respective measuring ranges, the smaller the pulse width is, the shorter the corresponding measuring range is, and the less the detection result is affected by multipath reflected light.
4. The distance detection method according to claim 1, wherein the target object is selected based on a detection result of the initial pulse detection light.
5. The distance detection method according to claim 1, wherein objects that appear within a preset distance range are automatically set as target objects.
6. A TOF sensing device, comprising:
a light source module for emitting pulse detection light;
the sensing module is used for receiving the reflected light of the pulse detection light reflected by the object to be detected;
the processor is connected with the light source module and the sensing module and used for controlling the light source module and the sensing module;
a memory storing a computer application capable of running on the processor;
wherein the computer application, when executed by the processor, implements the distance detection method of any of claims 1 to 5.
Priority Applications (1)
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| CN113093213B (en) * | 2021-04-08 | 2023-05-09 | 上海炬佑智能科技有限公司 | ToF sensing device and distance detection method thereof |
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