A detection device

Abstract

The present application provides a detection device, in the field of detection technology. The detection device comprises: a transmitting module, the transmitting module is used to transmit a detection light source to a target object; a receiving module, the receiving module is used to receive a reflected light signal reflected by the target object; the receiving module comprises a pixel array, wherein a part of the pixels of the pixel array are used to detect a first reflected light signal reflected by the target object, and another part of the pixels are marked as invalid pixels; a control and processing module, the control and processing module is respectively connected to the transmitting module and the receiving module, and obtains the distance of the target object according to the first reflected light signal. The detection device of the present application can have a longer ranging distance under the same photoelectric power; it can save power and light under the same ranging distance, and reduce the interference caused by multipath problems.

Description

Technical Field

[0001] This application relates to the field of detection technologies, and particularly to a detection device. Background Art

[0002] As a method for measuring the distance to an object in a scene, Time-of-Flight (TOF) technology has been developed. This TOF technology can be applied to various fields such as the automotive industry, human-machine interfaces and gaming, robotics, etc. Generally, the working principle of TOF technology is to irradiate a scene with modulated light emitted by a light source and observe the reflected light reflected by an object in the scene. By measuring the phase difference between the emitted light and the reflected light, the distance to the object is calculated.

[0003] In a distance measurement device using this traditional TOF technology, multipath interference may affect the accuracy of the measured distance. Multipath interference occurs when the emitted light propagates along multiple paths with different path lengths and is then sensed as integrated light by a single light receiver. Although the phases of the light along different path lengths are different, the traditional distance measurement device calculates the distance based on the mixed phase of the integrated light. Therefore, the calculated distance may include an error value caused by multipath interference.

[0004] The prior art has proposed a technique for detecting multipath errors based on the exposure amount of a light receiver. In the prior art, a light emitter emits light to illuminate a given area. The area is divided into multiple sub-areas, and a controller is configured to control the light emitter to change the amount of emitted light in each sub-area, so as to emit different light emission modes at different times. The controller calculates the exposure amount received at the light receiver in each sub-area and detects multipath errors based on the calculated exposure amount. Specifically, the controller calculates the exposure amount at the light receiver in the first emission mode at a first timing, and then the controller calculates the exposure amount at the light receiver in the second emission mode at a second timing. Based on the difference between the exposure amount calculated at the first timing and the exposure amount calculated at the second timing, the controller determines whether multipath errors occur.

[0005] However, according to the prior art, in order to detect multipath errors, it is necessary to calculate the exposure amount in two different light emission modes (i.e., at the first timing and the second timing). Therefore, according to the method of the prior art, a time delay is inevitably generated due to the sequential calculation of the exposure amount. Due to the time delay, the detection accuracy of multipath errors may decrease. For example, in the case where multipath interference occurs during the first timing but the multipath interference has been resolved before the second timing, the controller may not be able to correctly detect the multipath errors, which may affect the accuracy of the calculated distance to the object. Summary of the Invention

[0006] The object of the present application is to provide a detection device to solve the technical problem of low measurement distance accuracy in the existing technology in view of the deficiencies in the above-mentioned existing technology.

[0007] To achieve the above object, the technical solutions adopted in the embodiments of the present application are as follows:

[0008] The embodiments of the present application provide a detection device, which is characterized by comprising:

[0009] A transmitting module, which is used to emit a detection light source to a target object;

[0010] A receiving module, which is used to receive the reflected light signal reflected back by the target object;

[0011] The receiving includes a pixel array, wherein a part of the pixels of the pixel array are used to detect the first reflected light signal reflected back by the target object, and another part of the pixels are marked as invalid

[0012] Pixels;

[0013] A control and processing module, which is respectively connected to the transmitting module and the receiving, and obtains the distance of the target object according to the first reflected light signal..

[0014] Optionally, the transmitting module includes a first transmitting mode and a second transmitting mode; the first transmitting mode is a dot matrix light source transmitting mode; the second transmitting mode is a planar array light source transmitting mode.

[0015] Optionally, the transmitting module includes a plurality of transmitting areas; the receiving module includes a plurality of receiving areas; the control and processing module is used to control the corresponding receiving areas of the transmitting areas to receive the reflected light.

[0016] Optionally, the control and processing module provides a trigger signal to the first transmitting mode and the second transmitting mode to turn on or off the first transmitting mode or the second transmitting mode.

[0017] Optionally, in the first transmitting mode, the control and processing module controls one or more of the transmitting areas to emit a dot matrix light source to the specified area.

[0018] Optionally, in the first transmitting mode, the control and processing module controls the receiving areas corresponding to the one or more transmitting areas that emit light sources to the specified area to receive the reflected light.

[0019] Optionally, there is a conjugate relationship between the transmitting area and the corresponding receiving area.

[0020] Optionally, the receiving area includes an area for receiving the light reflected by the target object and / or an area for receiving multi-path reflected light.

[0021] Optionally, in the first emission mode, the control and processing module controls the receiving area that has no corresponding relationship with the emission area to receive multi-path light.

[0022] Optionally, in the first emission mode, the control and processing module controls the receiving area that has no corresponding relationship with the emission area not to receive reflected light.

[0023] The beneficial effects of this application are as follows:

[0024] A detection device provided by an embodiment of this application includes: a transmitting module for transmitting a detection light source to a target object;

[0025] a receiving module for receiving a reflected light signal reflected back by the target object; the receiving includes a pixel array, wherein a part of the pixels of the pixel array are used to detect the first reflected light signal reflected back by the target object, and another part of the pixels are marked as invalid pixels; a control and processing module, the control and processing module is respectively connected to the transmitting module and the receiving module, and obtains the distance of the target object according to the first reflected light signal. The detection device of this application can have a longer ranging distance under the same optoelectronic power; it saves power and light under the same ranging distance; and it reduces the interference caused by the multi-path problem. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 A schematic diagram of the functional modules of an existing ITOF ranging provided by the prior art;

[0028] Figure 2 A scene diagram including multi-path for distance measurement provided by the prior art;

[0029] Figure 3 A schematic diagram of the influence of multi-path of the prior art on the measurement accuracy provided by the embodiment of this application;

[0030] Figure 4 A schematic diagram of the conjugate relationship between the focal plane and the imaging plane of the prior art provided by the embodiment of this application;

[0031] Figure 5 Schematic diagram of a dot matrix light source emission provided for the embodiments of the present application;

[0032] Figure 6 Schematic diagram of dot matrix light sources with ordered and disordered arrangements provided for this embodiment;

[0033] Figure 7 Schematic diagram of a multi - path problem under a planar array light source provided for this embodiment;

[0034] Figure 8 Schematic diagram of a multi - path problem under a dot matrix light source provided for this embodiment;

[0035] Figure 9 Schematic diagram of dot matrix light source zoning provided for the embodiments of the present application;

[0036] Figure 10 Schematic diagram of a division into 4 regions provided for the embodiments of the present application;

[0037] Figure 11a - Figure 11b Schematic diagram of dot matrix light source arranged emission provided by the present application;

[0038] Figure 12 Schematic diagram of eliminating multi - path by using dot matrix zoning emission provided for the embodiments of the present application;

[0039] Figure 13 Schematic diagrams of two sets of emission light sources provided for the embodiments of the present application. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application.

[0042] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0043] Figure 1 Schematic diagram of a functional module for existing ITOF ranging provided by an embodiment of the present application.

[0044] As Figure 1 shown, the detection device includes: a light source 110, a controller 120, a receiving unit 130, and an information acquisition unit 140. The light source 110 can be configured as a unit or an array-type light source system that emits continuous light. It can be a semiconductor laser, an LED, or other light sources that can be pulse-modulated. When a semiconductor laser is used as the light source, a vertical-cavity surface-emitting laser (VCSEL) or an edge-emitting laser (EEL) can be used. This is only an exemplary illustration and is not specifically limited. The waveform of the light output by the light source 110 is also not limited and can be a square wave, a triangular wave, a sine wave, etc. The receiving unit 130 includes a photoelectric conversion module, which has a photoelectric conversion function and can be implemented by a photodiode (PD). It can specifically be a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The type is not specifically limited here either.

[0045] The controller 120 controls the light source to emit light for different times. The receiving unit 130 obtains the light reflected by the object to be detected 150 corresponding to different phase delays when the phase differences between the controller 120 and the emitted light at the moments when the light source 110 emits light are 0°, 180°, 90° and 270° respectively. The reflected light forms incident light in the receiving unit 130, and then different information is generated through photoelectric conversion in the receiving unit. In some cases, the information of the object to be detected is also obtained by using the two-phase scheme of 0° and 180°. Some documents have also disclosed the three-phase scheme of 0°, 120° and 240° to obtain target information. Even some documents have disclosed the five-phase difference delay scheme. The present invention does not specifically limit this. The obtained target information can be the image information of the target, or the distance information, contour information, etc. of the target. The present invention does not specifically limit this either. In the following, in order to illustrate specific technical problems, the problems and solutions are specifically elaborated by taking the four-phase time-of-flight distance acquisition scheme as an example. The multi-tap structure can have an independent tap for each phase. The four-phase taps are connected to a pixel unit (which can be directly connected or connected through an intermediate medium). It can also be that two phases share a tap. For example, 0° and 90° share a tap, and 180° and 270° share a tap. Such a design can not only achieve the purpose of reliable information transmission, but also further ensure the optimization of the pixel size design and layout structure. The multi-tap connection on one pixel achieves the effect of efficiently obtaining target information (such as distance, depth, contour or image, etc.).

[0046] On the basis described above, the light source 110 emits transmitted light. The receiving unit 130 is controlled by the controller 120 to obtain the light reflected by the detected object 150 at a predetermined delay phase with respect to the transmitted light, for example, four different delay phases. The returned reflected light forms incident light in the receiving unit 130. There are no special requirements for the light source in this solution. The light emitted by the light source each time is the same light without phase difference, avoiding errors caused by the need to adjust the light-emitting state parameters of the light source device during use. Moreover, the implementation of the device is very simple, ensuring the reliability of the entire detection device system. In this solution, the implementation of phase delay is achieved within the receiving unit and the controller. The controller can be integrated into the receiving unit, ensuring the simplicity and efficiency of the system structure. Additionally, the use of a multi-phase delay receiving scheme in the receiving unit also avoids the need to emit transmitted light for each phase at the transmitting end. For example, in a four-phase scheme, we can obtain the information of the target object with two phase delays of 0° and 180° in one emission, enabling the entire ranging system to achieve the goal of efficient ranging. The light emitted by the light source 110 and reflected by the detected object 150 is converted into photo-generated electrons (or photo-generated charges) in the photoelectric conversion module of the receiving unit. The photo-generated electrons are modulated by the taps and transfer charges in part according to the first circuit or the second circuit inside the device (the first circuit or the second circuit mentioned here includes the charge or electron transfer channels inside the pixel). They are respectively transmitted to different external physical circuit parts (the first circuit or the second circuit also includes the first physical circuit part and the second physical circuit part outside the pixel) through the first electron transfer channel or the second electron transfer channel inside the pixel. Then, physical operations (such as using charge storage units: capacitors, etc.) or digital operations (such as integrating the sensor and the arithmetic unit into a single-chip structure) are performed inside the pixel, or physical or digital operations are performed in the subsequent ADC or other circuit parts. The present invention does not limit the specific implementation scheme.

[0047] Taking the four-phase two-tap structure as an example for illustration, where 0° and 90° share one tap, and 180° and 270° share one tap (however, in the specific operation, sharing one tap does not mean sharing a fixed tap, and the taps shared by the two phase delays can be interchanged). The controller 120 controls the light source 110 to emit light. After the light is reflected by the object 150 to be detected, the controller 120 controls the receiving unit 130 to receive with two phase delays. For example, it receives with the two phase delays of 0° and 180° in the above four-phase. The photoelectric conversion module in the receiving unit 130 converts the delayed-phase optical signal into photo-generated electrons in the pixel. The tap of the first circuit receives the first modulation signal, transfers the photo-generated electrons converted from the 0° phase in the pixel by the photoelectric conversion module, and forms an electrical signal. This electrical signal is output by the first circuit. The tap of the second circuit receives the second modulation signal, transfers the photo-generated electrons converted from the 180° phase in the pixel by the photoelectric conversion module, and forms an electrical signal. This electrical signal is output by the second circuit. It is also possible that each phase delay corresponds to one tap. In the first circuit, 0° and 90° share one floating diffusion node (FD), and 180° and 270° share one floating diffusion node (FD). However, in the specific operation, sharing one floating diffusion node does not mean sharing a fixed floating diffusion node, and the floating diffusion nodes shared by the two phase delays can be interchanged. In this embodiment, the electrical signals corresponding to the 0° and 180° phase delays can be obtained in one light source emission. In the next control of the controller, it receives with the two phase delays of 90° and 270° in the four-phase. The photoelectric conversion module in the receiving unit 130 converts the delayed-phase optical signal into photo-generated electrons in the pixel. The tap of the first circuit receives the first modulation signal, transfers the photo-generated electrons converted from the 90° phase in the pixel by the photoelectric conversion module, and forms an electrical signal. This electrical signal is output by the first circuit. The tap of the second circuit receives the second modulation signal, transfers the photo-generated electrons converted from the 270° phase in the pixel by the photoelectric conversion module, and forms an electrical signal. This electrical signal is output by the second circuit. In this mode, the information corresponding to 90° and 270° is obtained at one time.The final controller 120 can also control the light source 110 to output transmitted light, and at least control the two-phase delays of 0° and 180° in the four phases for reception. The photoelectric conversion module in the receiving unit 130 converts the delayed-phase optical signal into photo-generated electrons in the pixel. The tap of the first circuit receives the first modulation signal, transfers the photo-generated electrons converted by the 180° phase in the pixel, and forms an electrical signal, which is output by the first circuit. The tap of the second circuit receives the second modulation signal, transfers the photo-generated electrons converted by the 0° delayed phase in the pixel, and forms an electrical signal, which is output by the second circuit. Thus, the effect that two circuits respectively obtain electrical signals corresponding to at least one same-phase reception control signal is achieved. During the final target information calculation process, the at least two electrical signals obtained by the two circuits can be calculated to obtain the target information. For example, for image or distance information, the signals obtained by the two circuits can be used for the following calculations:

[0048] f(0°) = mf(0°_1) + nf(0°_2);

[0049] f(180°) = lf(180°_1) + hf(180°_2); (1)

[0050] The 90° and 270° delay-phase results are obtained through a similar scheme, and can be corrected by performing an operation similar to that in Equation (1), and the corrected result can be used in the final target information acquisition. The corrected result can be the process result in the detection by the detection device, or can be directly used in the specific expression of the final image or distance calculation. The present invention does not limit the specific implementation manner. In the formula, f(0°) refers to the final information result corresponding to the 0° phase to be corrected, f(0°_1) refers to the information result corresponding to the 0° phase obtained by the first circuit, f(0°_2) refers to the information result corresponding to the 0° phase obtained by the second circuit, where m, n, l, and h can be correction coefficients taking values in the range of [-1, 1].

[0051] In the above embodiments, the received phases with phase delays of 0° and 180° have a phase difference of 180°; the modulation signals corresponding to the two delayed received phases in the first circuit and the second circuit are inverse signals. That is, when the 0° phase delay receives and outputs an electrical signal through the first circuit or the second circuit during the first time period, the corresponding 180° delayed reception on the pixel does not output an electrical signal through any of the above two circuits, and the opposite operation is exactly performed during another time period. The same operation is also performed on the received phases with phase delays of 90° and 270° having a phase difference of 180°. In this way, a scheme is obtained in which the circuit modulation signals corresponding to the received phases with a phase difference of 180° are inverse signals, achieving the effects of obtaining signal reliability and efficient system operation when multiple phases share taps or floating diffusions (FD) or other circuit elements. When obtaining the phase information with a phase difference of 90°, there is a first time interval, which is the autonomous adjustment time interval within the system and can be designed in cooperation with the reset timing to ensure the reliability of the output of different phase signal results.

[0052] When charges are allocated to the first tap and the second tap according to the distance to the object, by using all eight detections (for each phase signal, electrical signals corresponding to the phase delay are obtained through two circuits), the signal performs an operation of calculating the depth representing the distance to the object. Different-phase electrical information, such as the accumulated charge quantity signal, can be output through two different circuits. During the distance acquisition process, taking the case where the phase difference φ of the light signal traveling back and forth between the lidar and the target can be calculated based on the 4 groups of integrated charges for sinusoidally modulated light as an example, the phase difference φ between the echo signal corresponding to the modulated light and the transmitted signal is:

[0053] φ = arctan[(Q90° - Q270°) / (Q0° - Q180°)] (2)

[0054] In Equation (2) above, Q0°, Q90°, Q180°, and Q270° are the electrical signals converted by the receiving circuit corresponding to different phase delays respectively. Combining the relationship between the distance and the phase difference, the final distance result can be obtained:

[0055]

[0056] In Equation (3) above, c is the speed of light and f is the laser frequency emitted by the light source 110. For the case where the light emitted by the light source 110 is a square wave, it can be divided into different situations, and the final distance information can be obtained according to the following calculation method:

[0057] When Q0° > Q180° and Q90° > Q270°,

[0058]

[0059] When Q0° < Q180° and Q90° > Q270°,

[0060]

[0061] When Q0° < Q180° and Q90° < Q270°,

[0062]

[0063] When Q0° > Q180° and Q90° < Q270°,

[0064]

[0065] Figure 2 A scene graph including multipath for distance measurement provided for the prior art. Figure 2 To illustrate the so-called multipath phenomenon. Figure 2 A standard TOF detection system 9 is shown, which includes an illumination unit 8 for illuminating the scene 24 in multiple directions, a TOF sensor 6 for detecting the reflection of the emitted light, and a processing device 7 for processing the data obtained by the TOF sensor 6.

[0066] Pixels (not shown) of the TOF sensor 6 measure the direct path 25 from the illumination unit 8 to the scene 24 and back from the scene 24 to the pixels. However, secondary reflections 26 or higher-order reflections can also be captured on the same pixels and disrupt the delay perceived by the first direct reflection 25. The light captured by the sensor 6 can originate from both the direct path 25 and the secondary reflection 26, and the measured depth map 27 (representing the depth associated with each point of the scene) is thus incorrect.

[0067] Figure 3 A schematic diagram showing the influence of multipath in the prior art on measurement accuracy provided for the embodiments of the present application. As Figure 3 shown, where waveform (1) is the light source waveform emitted by the transmitting end (A). The transmitting end (A) emits the light source waveform (1) to the object B to be measured, and the object B to be measured reflects the received light to the receiving end (C). As Figure 2 shown, according to the principle, the distance of the object B to be measured can be obtained based on the waveform reflected by the object B to be measured. The principle is the same as that Figure 2 shown and will not be elaborated here. However, in a multipath scenario, the light source waveform (1) emitted by the transmitting end (A) will be received by an object D near the object B to be measured and then reflected to the object B to be measured. After being reflected twice by the object to be measured, it reaches the receiving end C. The secondary reflected light in the multipath is as Figure 3 shown by waveform (3). Finally, the echo signal received by the receiving end (C) is the combined effect of waveform (2) and waveform (3).

[0068] At this time, due to an additional reflection in the movement path of the multipath light (3) and an increase in the optical path by a certain distance compared to before, a weak echo signal with a relatively later timing is generated at the received signal end. When testing by the integration method, it will cause certain interference to the electric charges obtained by different integration channels, thereby interfering with the actual ranging result and affecting the accuracy of distance measurement.

[0069] Figure 4 Schematic diagram of the conjugate relationship between the focal plane and the imaging plane of a prior art provided by an embodiment of the present application. As Figure 4 shown, the light source 401 is divided into four sub-regions A, B, C, and D for emission. The light emitted from each sub-region is projected onto the detection surface 402. The light projected onto the detection surface 402 undergoes diffuse reflection, and the receiving lens 403 receives the light entering the field of view of the lens 403, thereby forming an image on the receiving end 404. Among them, the imaging ranges of each sub-region A, B, C, and D on the receiving end 404 respectively correspond to the target ranges of sub-regions A, B, C, and D on the detection surface 402. For example, all target points on the detector sub-region A will enter the field of view of the receiving lens and be imaged on the receiving end. Each target point corresponds to an imaging point on the receiving end sub-region A, and only the light within the solid angle Ω as Figure 4 shown can enter the receiving lens.

[0070] Figure 5 Schematic diagram of the emission of a dot matrix light source provided by an embodiment of the present application; when the power of the emitted light is fixed, the energy received at the receiving end is inversely proportional to the square of the distance. When the ranging range L is increased, the power increase multiple at the transmitting end is L 2 , which limits the feasibility of further expanding the ranging distance. Moreover, the ranging accuracy is proportional to the square root of the number of generated photo-electrons, that is to say, the ranging accuracy has a great relationship with the emission energy. In the actual detection process, it is impossible to infinitely increase the emission energy for the sake of measuring distance and measurement accuracy. The emission of the dot matrix can solve this problem.

[0071] Next, let's analyze the detection distance and detection accuracy under the dot matrix light source. The following table (1) is the initial condition for the analysis:

[0072] Table (1)

[0073]

[0074]

[0075] The echo efficiency beyond 5m is:

[0076]

[0077] When using area array emission, without considering the target reflectivity and the optical loss of the system, the electrons integrated by each pixel within 1 ms are as follows:

[0078]

[0079] Then the ranging error of the original data is:

[0080]

[0081] When using dot array emission, if 1152 points are used and each point covers 4 pixels, the number of electrons integrated by each effective pixel within 1 ms under the same conditions can be obtained as follows:

[0082]

[0083] The error is:

[0084]

[0085] It can be obtained that at the same distance, through dot array emission, the energy is concentrated, the ranging error is effectively reduced, and the emission power can also be reduced.

[0086] Such as Figure 5 The emission module shown emits dot array light sources instead of area array light sources. The dot array light source is a light spot composed of several points, and its light coverage area is less than or equal to the total coverage area of the field of view. The number of dot array lights generated by the dot array light source can be more or less than the number of pixels. The dot array light source can be arranged orderly or disorderly.

[0087] Figure 6 This is a schematic diagram of the orderly and disorderly arranged dot array light sources provided by this embodiment. Such as Figure 6 shown, the dot array light source can be regularly arranged or irregularly arranged. Preferably, regular arrangement will make the depth value distribution more regular.

[0088] Figure 7 This is a schematic diagram of the multi-path problem under an area array light source provided by this embodiment; when detecting a continuous curved surface or a plane with a corner, using the area array mode will generate continuous multi-path interference, thus deforming the generated echo. Since the entire reflection surface is a continuous surface, it can be approximated as the superposition of an infinite number of distances, making it more difficult to eliminate multi-path. Such as Figure 7As shown in the figure, the target object to be measured is point B. The transmitting end emits a surface array light source to the object B to be measured. The object to be measured returns the main path echo to the receiving end. At the same time, a part of the light source at the transmitting end will be emitted to a continuous reflecting surface. The continuous reflecting surface emits the received light to the object point B to be measured, and then is emitted by point B to the receiving end. This part is the multipath echo, which will reach the receiving end together with the main path echo directly from point B. The receiving end cannot effectively distinguish the multipath echo and the main path echo; ideally, the receiving end only hopes to receive the echo signal of the main path, but because a lot of multipath echo signals are superimposed, the ranging accuracy will be reduced.

[0089] Figure 8 This is a schematic diagram of the multipath problem under a dot matrix light source provided by this embodiment; when dot matrix emission is adopted, the number of paths that can be reflected to the detection surface at the same time is significantly reduced and is discrete points. These discrete points can be solved by the multipath algorithm, so that more accurate results can be obtained. As Figure 8 shown, the transmitting end uses a dot matrix light source. It can be seen that the transmitting end emits a dot matrix light source to the object B to be measured. The object to be measured returns the main path echo to the receiving end. At the same time, a part of the light source at the transmitting end will be emitted to a continuous reflecting surface. The continuous reflecting surface emits the received light to the object point B to be measured, and then is emitted by point B to the receiving end. This part is the multipath echo, which will reach the receiving end together with the main path echo directly from point B. From Figure 8 it can be seen that compared with Figure 7 , Figure 8 because the dot matrix light source is used in , the number of multipaths can be significantly reduced, and the ranging accuracy can be improved.

[0090] In order to further eliminate the influence of multipaths and improve the ranging accuracy, a dot matrix light source can be used for zonal emission, so that the number of interfering paths generated at the same time is less, the required frequency number can be reduced, and finally more accurate results can be obtained.

[0091] Figure 9 This is a schematic diagram of the zonal division of a dot matrix light source provided by an embodiment of this application. In the actual detection process, the influence of multipaths should be eliminated. As Figure 9 shown, the transmitting end 901 and the receiving end 903 are modulated for zonal emission and reception. As Figure 9 shown, the transmitting end is divided into N regions, which are respectively marked as region 1, 2, 3... N. At the same time, the receiving end is also divided into N regions, which are respectively marked as region 1, 2, 3... N. According to as Figure 4The principle of focal plane imaging is shown in the figure. The N areas of the transmitter and the N areas of the receiver are in an optical conjugate relationship, that is, one-to-one correspondence. When area 1 of the transmitter 901 emits light, without considering the influence of multipath, after being reflected by the object to be tested 902, the reflected light of the object to be tested will be received in the receiving area 1 corresponding to the receiving area 903. The reflected light received in other non-corresponding areas is considered to be the influence of multipath. In this way, multipath light can be identified in the reflected light received by the receiving end 903, and then the multipath light can be eliminated. Then according to Figure 1 The distance measurement principle shown in the figure can be used to obtain the distance of the object to be measured. Of course, in the actual distance measurement process, the receiving area that does not correspond to the transmitting area can also be turned off and does not receive multipath reflected light, which will not be described here.

[0092] Furthermore, in the actual distance measurement process, only M areas will simultaneously transmit the modulated waveform, and try to make these M areas not adjacent to each other. When these M areas start to transmit the modulated optical signal, only the area corresponding to these M areas on the receiving end will be turned on to receive the reflected light generated by the target. The reflected light received by these M areas is obtained, and then according to Figure 1 The distance measurement principle shown in the figure can get the distance of the object to be measured. The influence of multipath can be eliminated. The multipath effect generated in the ITOF ranging process can be significantly reduced, and the ranging accuracy can be improved.

[0093] Figure 10 This is a schematic diagram of a four-region system provided in the embodiment of this application. Figure 10 As shown in , the transmitting end 1001 and the receiving end 1003 are divided into four parts, and the transmission and reception are divided into four parts, and only one area is opened at a time. Figure 10 As shown, the transmitting end opens area A, and the light source of area A reaches the corresponding area A of the receiving end 1003 after being reflected by the object to be tested 1002. In this embodiment, only the receiving area A is opened. Of course, the receiving areas B, C, and D can also be opened, but the reflected light received by the receiving areas B, C, and D is considered to be multi-path light. It should be noted that the areas divided by the object to be tested 1002 are only for illustrative purposes, and there is no one-to-one correspondence between the transmitting area and the receiving area. This embodiment is not limited here.

[0094] Figure 11a - Figure 11b ​​This is a schematic diagram of the emission of a dot matrix light source provided by the present application, where the numbers on the diagram represent the emission order. For example, when the dot matrix light source labeled 1 in the figure emits light, the dot matrix light sources with other numbers do not emit. Then, the pixels in the receiving area corresponding to 1 at the receiving end receive the echo signal. The pixels in the receiving areas corresponding to the dot matrix light sources with other numbers do not receive the echo signal, and these pixels are temporarily marked as invalid pixels. When the dot matrix light source corresponding to them emits light, these pixels will be marked as valid pixels to receive the echo signal. The principles of the other numbers are the same as those of the dot matrix light source labeled 1 and will not be elaborated here. Figure 11a and Figure 11b Only two schematic diagrams of zonal emission are given as examples, and the present invention is not limited thereto.

[0095] Figure 12 This is a schematic diagram for eliminating multipath by using zonal emission of a dot matrix provided by an embodiment of the present application; as Figure 12 shown, the transmitting end uses zonal emission of dot matrix light sources. It can be seen that the transmitting end emits dot matrix light sources to the object to be measured B. The object to be measured returns the main path echo to the receiving end. At the same time, a part of the light sources at the transmitting end will emit to a continuous reflecting surface. The continuous reflecting surface emits the received light to the object point B to be measured, and then it is emitted by point B to the receiving end. This part is the multipath echo, which will reach the receiving end together with the main path echo directly from point B. From Figure 12 it can be seen that in contrast to Figure 7 and Figure 8 , Figure 12 in [reference], because zonal emission of dot matrix light sources is used, the number of multipaths can be further reduced and the ranging accuracy can be further improved.

[0096] Figure 13 These are two schematic diagrams of emission light sources provided by an embodiment of the present application. As Figure 13 shown, 1301 is a dot matrix emission light source, 1303 is a planar array emission light source, and 1302 is a receiving end. The dot matrix light source 1301 can be in the form of VCSEL + collimating mirror + DOE, or can be realized by using other lasers + prisms and other optical systems. The planar array light source 1303 can be realized by using VCSEL plus a light homogenizing sheet. The two usage modes of the dot matrix light source and the planar array light source are used in the following situations. In this embodiment, the dot matrix light source is called the first emission mode, and the planar array light source is called the second emission mode. When the target is far away, the dot matrix light source is used. When the target is close or high resolution is required, the planar array light source is adopted. Further, the dot matrix light and the planar array light can assist each other for distance correction.

[0097] The process of distance correction is as follows:

[0098] (1) Use the planar array light to obtain the preliminary distance information L1 of the target.

[0099] (2) Emit a set of dot matrix light in N partition emission regions to obtain the distance information L2 of several points.

[0100] (3) According to the scatter point data L2 measured in the second step, perform fitting, smoothing, and transformation on L1 to obtain the preliminary ranging result L3.

[0101] (4) Another region in the dot matrix region emits light to obtain the distance information L4 of the corresponding several scatter points.

[0102] (5) Compare the preliminary correction result L3 with the second scatter point test result L4 and correct to obtain L5.

[0103] (6) If the average value of the deviation between L3 and L5 is greater than the threshold (such as 1%), then enter the next correction. If it is less than this threshold, output the test result L5.

[0104] (7) When entering the next correction, activate a partition different from that in step 4 to obtain L6, compare the result of L5 with L6, and perform correction to obtain L7.

[0105] (8) Continue to compare L7 with L5, make a judgment according to the method in step 6, and then repeat step 7 until the error is less than the threshold or the number of correction times reaches the upper limit, and output the final correction result.

[0106] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such process, method, article or device. Without further limitation, an element defined by the statement "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0107] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A detection device, characterized in that: Include: A transmitting module, wherein the transmitting module is used to transmit a detection light source to a target object; A receiving module, the receiving module is used to receive a reflected light signal reflected by the target object; the receiving module includes a pixel array, wherein a part of the pixels of the pixel array are used to detect the first reflected light signal reflected by the target object, and another part of the pixels are marked as invalid pixels; A control and processing module, wherein the control and processing module is connected to the transmitting module and the receiving module respectively, and obtains the distance of the target object according to the first reflected light signal; the transmitting module includes a first transmitting mode and a second transmitting mode; the first transmitting mode is a dot matrix light source transmitting mode; the second transmitting mode is a planar array light source transmitting mode; The second transmission mode is used to obtain preliminary distance information L1 of the target; Using the first transmission mode, distance information L2 of a plurality of points is obtained; Process L1 according to L2 to obtain the preliminary ranging result L3; Another area in the dot matrix area emits light, and the first emission mode is used to obtain distance information L4 of the corresponding plurality of scattered points; L5 is obtained by modifying L3 and L4; If the average value of the deviation between L3 and L5 is greater than the threshold, the next correction is entered; if it is less than the threshold, the test result L5 is output.

2. The detection device according to claim 1, characterized in that: The transmitting module includes a plurality of transmitting areas; the receiving module includes a plurality of receiving areas; and the control and processing module is used for controlling the receiving areas corresponding to the transmitting areas to receive reflected light.

3. The detection device according to claim 1, characterized in that: The control and processing module provides a trigger signal to the first emission mode and the second emission mode to turn on or off the first emission mode or the second emission mode.

4. The detection device according to claim 2, characterized in that: In the first emission mode, the control and processing module controls one or more of the emission areas to emit point matrix light sources to a designated area.

5. The detection device according to claim 2, characterized in that: In the first emission mode, the control and processing module controls the receiving areas in the receiving area corresponding to one or more emission areas that emit light sources to a designated area to receive reflected light.

6. The detection device according to claim 2, characterized in that: The transmitting area and the corresponding receiving area are in a conjugate relationship.

7. The detection device according to claim 2, characterized in that: The receiving area includes an area for receiving reflected light from a target object and / or an area for receiving multipath reflected light.

8. The detection device according to claim 2, characterized in that: In the first emission mode, the control and processing module controls the receiving area that has no corresponding relationship with the emission area to receive the multi-path light.

9. The detection device according to claim 2, characterized in that: In the first emission mode, the control and processing module controls the receiving area that has no corresponding relationship with the emission area to not receive the reflected light.

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