CN112946678A

CN112946678A - Detection device

Info

Publication number: CN112946678A
Application number: CN202110140487.3A
Authority: CN
Inventors: 雷述宇
Original assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Current assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2021-06-11

Abstract

The application provides a detection device, and belongs to the technical field of detection. The detection device comprises: the transmitting module is used for transmitting a detection light source to a target object; the receiving module is used for receiving a reflected light signal reflected by a target object; the receiving comprises a pixel array, wherein one part of pixels of the pixel array are used for detecting a first reflected light signal reflected by the target object, and the other part of pixels are marked as invalid pixels; and the control and processing module is respectively connected with 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 can have a longer distance measurement distance under the same photoelectric power; the power and light are saved under the same distance measurement, and the interference generated by the multipath problem is reduced.

Description

Detection device

Technical Field

The application relates to the technical field of detection, in particular to a detection device.

Background

As a method of measuring a distance from an object in a scene, a time of flight (TOF) technique is developed. Such TOF technology can be applied in various fields, such as the automotive industry, human-machine interfaces and games, robotics, etc. In general, TOF technology operates on the principle of illuminating a scene with modulated light from a light source and observing the reflected light reflected from objects in the scene. By measuring the phase difference between the emitted light and the reflected light, the distance to the object is calculated.

In a distance measuring apparatus using such a conventional TOF technique, multipath interference may affect the accuracy of the measured distance. When the emitted light travels along multiple paths having different path lengths, multi-path interference occurs and is then sensed as integrated light by a single optical receiver. Although the phases of the lights along different path lengths are different from each other, the conventional distance measuring apparatus calculates the distance based on the mixed phase of the integrated lights. Thus, the calculated distance may include an error value caused by multipath interference.

The prior art proposes a technique for detecting a multipath error based on the exposure amount of an optical receiver. In the prior art, a light emitter emits light that illuminates a given area. The area is divided into a plurality of sub-areas, and the controller is configured to control the light emitters to vary the amount of emitted light for each sub-area to emit different light emission patterns at different times. The controller calculates an exposure amount received at the light receiver of each sub-area, and detects a multipath error 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. The controller determines whether a multipath error occurs based on a difference between the exposure amount calculated at the first timing and the exposure amount calculated at the second timing.

However, in order to detect a multipath error according to the related art, it is necessary to calculate the exposure amount at two different light emission modes (i.e., at the first timing and the second timing). Therefore, according to the method of the related 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 the multipath error may be degraded. For example, in the case where a multipath interference occurs during the first timing but is resolved before the second timing, the controller may not be able to correctly detect the multipath error, which may affect the accuracy of the calculated distance to the object.

Disclosure of Invention

An object of the present application is to provide a detection device for solving the technical problem of low accuracy of the existing measuring distance, which is not enough in the prior art.

In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present application are as follows:

the embodiment of the application provides a detection device, which is characterized by comprising:

the transmitting module is used for transmitting a detection light source to a target object;

the receiving module is used for receiving a reflected light signal reflected by a target object;

the receiving comprises a pixel array, wherein one part of pixels of the pixel array are used for detecting a first reflected light signal reflected by the target object, and the other part of pixels are marked as invalid

A pixel;

and the control and processing module is respectively connected with the transmitting module and the receiving module and obtains the distance of the target object according to the first reflected light signal. .

Optionally, the transmission module comprises a first transmission mode and a second transmission mode; the first emission mode is a dot matrix light source emission mode; the second emission mode is an area array light source emission mode.

Optionally, the transmitting module comprises a plurality of transmitting areas; the receiving module comprises a plurality of receiving areas; the control and processing module is used for controlling the receiving area corresponding to the transmitting area to receive the reflected light.

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

Optionally, in the first emission mode, the control and processing module controls one or more of the emission areas to emit a dot matrix light source to the designated area.

Optionally, in the first transmission mode, the control and processing module controls the receiving area corresponding to the one or more transmitting areas for transmitting the light source to the designated area to receive the reflected light.

Optionally, the transmitting region and the corresponding receiving region have a conjugate relationship.

Optionally, the receiving area includes an area that receives light reflected by the target object and/or an area that receives multipath reflected light.

Optionally, in the first transmission mode, the control and processing module controls the receiving area, which does not have a corresponding relationship with the transmission area, to receive the multi-path light.

Optionally, in the first transmission mode, the control and processing module controls the receiving area, which does not have a corresponding relationship with the transmission area, not to receive the reflected light.

The beneficial effect of this application is:

the embodiment of the application provides a detection device, this detection device includes: the transmitting module is used for transmitting a detection light source to a target object;

the receiving module is used for receiving a reflected light signal reflected by a target object; the receiving comprises a pixel array, wherein one part of pixels of the pixel array are used for detecting a first reflected light signal reflected by the target object, and the other part of pixels are marked as invalid pixels; and the control and processing module is respectively connected with 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 can have a longer distance measurement distance under the same photoelectric power; the electricity and light are saved under the same distance measurement; reducing interference due to multipath problems.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic diagram of functional modules of a conventional ITOF ranging method provided in the prior art;

FIG. 2 is a diagram of a prior art distance measurement scenario involving multiple paths;

FIG. 3 is a diagram illustrating the effect of multipath on measurement accuracy in the prior art provided by an embodiment of the present application;

FIG. 4 is a schematic diagram illustrating a conjugate relationship between a focal plane and an imaging plane according to the prior art provided by an embodiment of the present application;

FIG. 5 is a schematic view of an emission from a lattice light source according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of the dot matrix light source with ordered arrangement and disordered arrangement provided in this embodiment;

fig. 7 is a schematic diagram illustrating a multipath problem under an area array light source according to this embodiment;

fig. 8 is a schematic diagram illustrating a multipath problem under a lattice light source according to this embodiment;

FIG. 9 is a schematic view of a partition of a lattice light source according to an embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a 4-zone partition provided in the examples of the present application;

FIGS. 11 a-11 b are schematic diagrams of the emission of a lattice light source arrangement provided herein;

fig. 12 is a schematic diagram of multipath cancellation using lattice sectorized transmission according to an embodiment of the present application;

fig. 13 is a schematic diagram of two sets of emission light sources provided in the present embodiment.

Detailed Description

In order to make the objects, 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 drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

Fig. 1 is a schematic diagram of functional modules of a conventional ITOF ranging method according to an embodiment of the present disclosure.

As shown in fig. 1, the detecting device includes: the light source 110, the controller 120, the receiving unit 130, and the information acquiring unit 140, wherein the light source 110 may be configured as a unit or an array light source system that emits continuous light, and may be a semiconductor laser, an LED, or another light source 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 semiconductor laser (EEL) may be used, which is only exemplary and not particularly limited herein, and a waveform of light output by the light source 110 is also not limited, and may be a square wave, a triangular wave, or a sine wave. The receiving unit 130 includes a photoelectric conversion module, which has a photoelectric conversion function and can be implemented by a Photodiode (PD), and can be specifically a Charge-coupled Device (CCD), a Complementary Metal Oxide Semiconductor (CMOS), and the type of the photoelectric conversion module is not specifically limited herein.

The controller 120 controls the light source to emit the emitting light for different times, the receiving part 130 obtains the light reflected back by the detected object 150 corresponding to different phase delays when the controller 120 respectively obtains four values of 0 °, 180 °, 90 ° and 270 ° from the phase delay of the emitting light at the moment when the light source 110 emits the emitting light, the reflected light forms incident light at the receiving portion 130, and is further photoelectrically converted by the receiving portion to generate different information, in some cases, a two-phase scheme of 0 ° and 180 ° is also used to achieve information acquisition of the detected object, and documents also disclose three-phase schemes of 0 °, 120 ° and 240 ° to obtain target information, and even documents also disclose a five-phase-difference delay scheme. In the following, to illustrate the specific technical problem, a solution of obtaining the distance by using time-of-flight of four phases is taken as an example to specifically illustrate the existing problems and solutions, and a multi-tap structure may have a separate tap for each phase, and four phase taps are connected to a pixel unit (either directly or through an intermediate medium), or two phases share a tap, for example, 0 ° and 90 ° share a tap, and 180 ° and 270 ° share a tap, so that not only can the purpose of reliably transmitting information be achieved, but also optimization of pixel size design and layout structure can be further ensured, and multi-tap connection on a pixel achieves the effect of efficiently obtaining target information (such as distance, depth, contour or image).

On the basis of the above, the light source 110 emits the emitting light, the receiving part 130 is controlled by the controller 120, the light reflected by the detected object 150 is obtained under the delay phase with the predetermined delay phase, for example, four different delay phases, the returned reflected light forms the incident light at the receiving part 130, the scheme does not make special requirements for the light source, the light emitted by the light source is the same light each time, there is no phase difference, the error caused by the light source device needing to be adjusted in the using process due to the light emitting state parameter is avoided, the device is very simple to realize, the reliability of the whole detecting device system is ensured, the realization of the phase delay in the scheme is realized in the receiving part and the controller, the controller can be integrated in the receiving part to ensure the simplicity and high efficiency of the system structure, and the adoption of the multi-phase delay receiving scheme in the receiving part also avoids the need of emitting light at each phase at the emitting end, for example, in the four-phase scheme, two phase delays of 0 ° and 180 ° can be obtained in one transmission, which enables the whole 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 a photoelectric conversion module of the receiving part, the photo-generated electrons are modulated by a tap, charges are transferred according to a part of a first circuit or a second circuit in the device (the first circuit or the second circuit mentioned here contains charges or electron transfer channels inside the pixel), the charges are respectively transmitted to different external entity circuit parts through the first electron transfer channel or the second electron transfer channel inside the pixel (the first circuit or the second circuit also contains a first entity circuit part and a second entity circuit part outside the pixel), and then physical scheme operation (for example, a charge storage unit: a capacitor and the like) or digital operation (for example, a structure that a sensor and an operation unit are integrated into a whole chip) is carried out on the pixel, or may perform physical or digital operations in subsequent ADCs or other circuit units, and the present invention is not limited to a specific implementation.

Taking a four-phase two-tap structure as an example, wherein 0 ° and 90 ° share one tap, and 180 ° and 270 ° share one tap (although the specific operation of sharing one tap does not mean that a fixed tap is shared, and taps shared by two phase delays can be interchanged), the controller 120 controls the light source 110 to emit emission light, and after the emission light is reflected by the detected object 150, the controller 120 controls the receiving part 130 to receive the emission light with two phase delays, for example, two phase delays of 0 ° and 180 ° in the four phases, the photoelectric conversion module in the receiving part 130 converts the delayed phase light signal into photo-generated electrons in the pixel, the tap of the first circuit receives the first modulation signal, and converts the photo-generated electrons converted by the photoelectric conversion module in the 0 ° phase in the pixel into an electric signal, and the electric signal 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 photoelectric conversion module in 180-degree phase in the pixel to form an electric signal, and the electric signal is output by the second circuit. It is also possible to have one tap per phase delay, with 0 ° and 90 ° sharing one floating diffusion node (FD) and 180 ° and 270 ° sharing one floating diffusion node (FD) in the first circuit, but the sharing of one floating diffusion node in a particular operation does not mean sharing one fixed floating diffusion node, and the two phase delays sharing one floating diffusion node may be interchanged. In this embodiment, the electrical signals corresponding to the 0 ° and 180 ° phase delays can be obtained in one light source emission, and in the next controller control, two of the four phases, 90 ° and 270 °, are received, the photo-conversion module in the receiving portion 130 converts the delayed phase light signal into photo-generated electrons in the pixel, the tap of the first circuit receives the first modulation signal, the photo-generated electrons converted by the photo-conversion module in the 90 ° phase in the pixel are converted to form an electrical signal, which is output by the first circuit, the tap of the second circuit receives the second modulation signal, the photo-generated electrons converted by the photo-conversion module in the 270 ° phase in the pixel are converted to form an electrical signal, which is output by the second circuit, and in this mode, the information corresponding to the 90 ° and 270 ° is obtained at one time. Finally, the controller 120 can also control the light source 110 to output the emitted light, and at least control two phases of 0 ° and 180 ° in the four phases to be delayed and received, the photoelectric conversion module in the receiving portion 130 converts the delayed phase light signal into photo-generated electrons in the pixel, the tap of the first circuit receives the first modulation signal, and transfers the 180 ° phase light-generated electrons converted by the photoelectric conversion module in the pixel to form an electrical signal, the electrical signal is output by the first circuit, the tap of the second circuit receives the second modulation signal, and transfers the 0 ° delayed phase light-generated electrons converted by the photoelectric conversion module in the pixel to form an electrical signal, the electrical signal is output by the second circuit, so that the effect that the two circuits respectively obtain the electrical signals corresponding to at least one same phase receiving control signal is achieved, and at least two electrical signals obtained by the two circuits can be operated to obtain the target information in the final target information operation process, for example, the following operations can be performed on the signals obtained by the two circuits for image or distance information:

f(0°)＝mf(0°_1)+nf(0°_2)；

f(180°)＝lf(180°_1)+hf(180°_2)； (1)

the 90 ° and 270 ° delayed phase results are obtained by a similar scheme, and may be corrected by performing an operation similar to equation 1, and the corrected result is used for obtaining the final target information, where the corrected result may be a process result in detection by a detection device, or may be directly used in a specific expression of a final image or distance operation, and the present invention is not limited to a specific implementation manner, where f (0 °) refers to a final information result corresponding to a phase of 0 ° that needs to be corrected, f (0 ° _1) refers to an information result corresponding to a phase of 0 ° obtained by a first circuit, and f (0 ° _2) refers to an information result corresponding to a phase of 0 ° obtained by a second circuit, where m, n, l, and h may be correction coefficients taken within an interval of [ -1, 1 ].

In the above embodiments, the phase delay is the reception phase of 0 ° and 180 °, and the phase difference is 180 °; when the modulation signals corresponding to the first circuit and the second circuit of the two delayed receiving phases are reciprocal signals, namely when the modulation signals corresponding to the first circuit and the second circuit are received in a 0-degree phase delayed manner in a first time period, the 180-degree delayed receiving on the pixel does not output the electric signals through any circuit of the two circuits, but just performs opposite operation in another time period, and the same operation is performed on the receiving phases with the phase delay of 180 degrees and the phase delay of 90 degrees and 270 degrees, so that the scheme that the modulation signals of the circuit corresponding to the 180-degree received phase are reciprocal signals is obtained, the effects of signal reliability acquisition and system high-efficiency work when a multi-phase common tap or Floating Diffusion (FD) or other circuit elements are realized, the phase information acquisition with the phase difference of 90 degrees has a first time interval, and the time interval is an autonomous adjustment time interval inside the system, the design can be matched according to the reset time sequence, and the reliability of the output of different phase signal results is ensured.

When distributing electric charges to the first tap and the second tap according to the distance to the object, by using all eight detections (for each phase signal, an electric signal corresponding to a phase delay is obtained by two circuits), the signal performs an operation of calculating a depth indicating the distance to the object, electric information of different phases, such as an accumulated electric charge amount signal, can be output by two different circuits, a phase difference Φ that can calculate a round trip of an optical signal between the laser imaging radar and the target from 4 sets of integrated electric charges in the distance acquisition process can be used as an example of a sinusoidal modulated light, and a phase difference Φ between an echo signal corresponding to the modulated light and a transmission signal is:

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

in the above formula 2, Q0 °, Q90 °, Q180 °, and Q270 ° are the electrical signals converted by the receiving circuit corresponding to different phase delays, respectively, and the final distance result can be obtained by combining the relationship between the distance and the phase difference:

in the above equation 3, c is the speed of light, f is the frequency of the laser emitted by the light source 110, and the case that the emitted light of the light source 110 is a square wave can be divided into different cases, and the final distance information is obtained according to the following calculation method:

when Q0 ° > Q180 ° and Q90 ° > Q270 °,

when Q0 ° < Q180 ° and Q90 ° > Q270 °,

when Q0 ° < Q180 ° and Q90 ° < Q270 °,

when Q0 ° > Q180 ° and Q90 ° < Q270 °,

fig. 2 is a diagram of a distance measurement scene including multiple paths according to the prior art. Fig. 2 illustrates a so-called multipath phenomenon. Fig. 2 shows a standard TOF detection system 9 comprising an illumination unit 8 for illuminating a scene 24 in a plurality of directions, a TOF sensor 6 for detecting reflections of the emitted light, and processing means 7 for processing data obtained by the TOF sensor 6.

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

Fig. 3 is a schematic diagram illustrating an influence of multipath on measurement accuracy in the prior art according to an embodiment of the present application. As shown in fig. 3, the waveform (1) is a light source waveform emitted by the emitting end (a), the emitting 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) according to the principle shown in fig. 2, and the distance between the object B to be measured and the receiving end can be obtained according to the waveform reflected by the object B to be measured, and the principle is the same as the principle shown in fig. 2, and is not repeated. However, in a multipath scene, the light source waveform (1) emitted by the emitting end (A) is received by an object D near the object B to be detected, then reflected to the object B to be detected, and reaches the receiving end C after being reflected by the object to be detected for the second time. The secondary reflected light of the multipath is shown as a waveform (3) in fig. 3. Finally, the echo signal received by the receiving end (C) is the common effect of the waveform (2) and the waveform (3).

At the moment, because the multi-path light (3) has more reflections in the moving path and the optical path is increased by a distance, an echo signal with weak strength and relatively later time sequence is generated at the received signal end. When the test is carried out by the integration method, certain interference is generated on the charge quantity obtained by integrating different integrals, so that the interference is generated on the actual ranging result, and the accuracy of distance measurement is influenced.

Fig. 4 is a schematic diagram of a conjugate relationship between a focal plane and an imaging plane according to the prior art provided by an embodiment of the present application. As shown in fig. 4, the light source 401 is divided into four sub-regions A, B, C, D for emission, each of which projects light onto the detection surface 402. The light projected onto the detection surface 402 is diffusely reflected, and the light entering the field of view of the lens 403 is received by the receiving lens 403, thereby being imaged on the receiving end 404. The imaging range of each sub-area A, B, C, D on the receiving end 404 corresponds to the target range of A, B, C, D on the sub-area of the detection plane 402. For example, all target points on the detector sub-area a enter the field of view of the receiving lens and are imaged on the receiving end, each target point corresponds to one imaging point on the receiving sub-area a, and only light scattered by each target point within the solid angle range of Ω shown in fig. 4 can enter the receiving lens.

FIG. 5 is a schematic view of an emission from a lattice light source according to an embodiment of the present disclosure; when the power of the emitted light is fixed, the energy received by the receiving end is inversely proportional to the square of the distance, and when the ranging range L is increased, the power of the emitting end is increased by a factor L²And the feasibility of further expanding the distance measurement distance is limited. And the accuracy of the distance measurement is proportional to the square root of the number of generated photogenerated electrons, namely the relation between the distance measurement precision and the emission energy is large. In the actual detection process, it is impossible to increase the generated energy infinitely for measuring the distance and measuring the precision. The emission of the lattice can solve this problem.

The following is an analysis of the detection distance and detection accuracy under the lattice light source, and the following table (1) is the initial conditions of the analysis:

watch (1)

The echo efficiency outside 5m is:

when area array emission is adopted, the electrons obtained by integrating each pixel within 1ms do not consider the target reflectivity and the optical loss of the system:

then the range error from the raw data is:

when dot matrix emission is adopted, if 1152 points are adopted and each point covers 4 pixels, the number of electrons obtained by integrating each effective pixel within 1ms under the same condition can be obtained as follows:

the error is:

the method can obtain that under the same distance, energy is concentrated through lattice emission, the distance measurement error is effectively reduced, and the emission power can also be reduced.

The emitting module shown in fig. 5 emits a dot matrix light source instead of an area matrix light source. The lattice light source is a light spot formed by a plurality of points, and the light coverage area of the lattice light source is smaller than or equal to the total coverage area of the field of view. The amount of dot matrix light generated by the dot matrix light source may be more or less than the number of pixels. The lattice light sources can be arranged orderly or in disorder.

Fig. 6 is a schematic diagram of the dot matrix light source with ordered arrangement and disordered arrangement provided in this embodiment. As shown in fig. 6, the lattice light sources may be arranged regularly or irregularly, and preferably, the regular arrangement is adopted, so that the depth value distribution is more regular.

Fig. 7 is a schematic diagram illustrating a multipath problem under an area array light source according to this embodiment; when a continuous curved surface or a plane with a corner is detected, a planar array mode is adopted, continuous multipath interference can be generated, and therefore generated echoes are deformed. Since the entire reflecting surface is a continuous surface, it can be approximated to superposition of an infinite number of distances, thereby making it difficult to eliminate multipath. As shown in fig. 7, the target object to be measured is point B, the transmitting end transmits the area array light source to the object to be measured B, the object to be measured returns the main path echo to the receiving end, meanwhile, a part of the light source of the transmitting end can transmit to the continuous reflecting surface, the continuous reflecting surface transmits the received light to the object point B to be measured, and then the light is transmitted to the receiving end by point B, this part is the multi-path echo, and the multi-path echo and the main path echo can reach the receiving end together with the main path echo directly from point B, and the receiving end cannot effectively distinguish the multi-path echo from the; the receiving end ideally only expects to receive the echo signal of the main path, but the ranging accuracy is reduced because of the superposition of many multipath echo signals.

Fig. 8 is a schematic diagram illustrating a multipath problem under a lattice light source according to this embodiment; when the lattice is adopted for transmission, the number of paths capable of being reflected to the detection surface is obviously reduced and the paths are discrete points, and the discrete points can be solved through a multipath algorithm, so that a more accurate result can be obtained. As shown in fig. 8, the transmitting end uses a dot matrix light source, and it can be seen that the transmitting end transmits the dot matrix light source to the object B to be detected, the object to be detected returns a main path echo to the receiving end, and at the same time, a part of the light source of the transmitting end can transmit to the continuous reflecting surface, and the continuous reflecting surface transmits the received light to the object point B to be detected, and then the light is transmitted to the receiving end by the point B, and this part is a multi-path echo, and the light can reach the receiving end together with the main path echo directly from the point B. As can be seen from fig. 8, compared with fig. 7, the number of multipaths can be significantly reduced by using the lattice light source in fig. 8, and the ranging accuracy can be improved.

In order to further eliminate the influence of multipath, the dot matrix light source can be used for emitting in a subarea mode to improve the ranging accuracy, the number of paths which generate interference simultaneously is less, the required frequency number can be reduced, and finally a more accurate result can be obtained.

Fig. 9 is a schematic view of a partition of a dot matrix light source according to an embodiment of the present disclosure. The multipath effect is eliminated in the actual detection process. The transmission end 901 and the reception end 903 are modulated by divisional transmission and reception as shown in fig. 9. The transmitting end is divided into N regions, labeled as

regions

1, 2, 3 … N, as shown in fig. 9. Meanwhile, the receiving end is also divided into N regions, which are respectively labeled as

regions

1, 2, and 3 … N. According to the principle of focal plane imaging as shown in fig. 4, the N regions of the transmitting end and the N regions of the receiving end are in an optical conjugate relationship, i.e., in a one-to-one correspondence. When the 1 region of the transmitting end 901 emits light, under the influence of multipath, the reflected light of the object to be measured is received in the receiving region 1 corresponding to the receiving region 903 after being reflected by the object to be measured 902, and the reflected light received in other regions not corresponding to the receiving region is considered as the influence of multipath. Thus, multipath light can be identified from the reflected light received by the receiving end 903, and then the multipath light is eliminated, and then the distance of the object to be measured is obtained according to the distance measuring principle shown in fig. 1. Certainly, in the actual ranging process, the receiving area not corresponding to the transmitting area may not be opened, and the multipath reflected light is not received, which is not described herein again.

Furthermore, only M regions emit the modulated waveform simultaneously each time during the actual distance measurement, and the M regions are not adjacent to each other as much as possible. When the M areas start to emit modulated optical signals, only the areas corresponding to the M areas on the receiving end are started, and reflected light generated by a target is received. The reflected light received by the M regions is obtained, and then the distance of the object to be measured is obtained according to the distance measuring principle shown in fig. 1. The effects of multipath can be eliminated. The multi-path effect generated in the ITOF ranging process can be obviously reduced, and the ranging precision is improved.

Fig. 10 is a schematic diagram of a partition into 4 regions according to an embodiment of the present disclosure. As shown in fig. 10, the transmitting terminal 1001 and the receiving terminal 1003 are divided into four parts, and transmission and reception are divided into partitions, and only one area is opened at a time. As shown in fig. 10, the emitting end opens the area a, and the light source in the area a reaches the corresponding area a of the receiving end 1003 after being reflected by the object 1002. In the present embodiment, only the reception area a is opened, but of course, the reception areas B, C, and D may be opened, but the reflected light received by the reception areas B, C, and D is considered as multipath light. It should be noted that the regions divided by the object to be measured 1002 are only for schematic illustration, and there is no one-to-one correspondence relationship between the regions and the transmitting regions and the receiving regions. The present embodiment is not limited thereto.

Fig. 11 a-11 b are schematic diagrams of emission of a dot matrix light source arrangement provided in the present application, wherein the numbers on the diagrams represent the emission sequence. For example, when the dot matrix light source denoted by 1 in the figure emits light, the dot matrix light sources of other numbers do not emit light, and then the receiving end and the pixels of the receiving area corresponding to 1 receive the echo signal. The pixels of the receiving area corresponding to the other digital dot matrix light sources do not receive the echo signals, and are temporarily identified as invalid pixels, and the pixels are identified as valid pixels to receive the echo signals when the corresponding transmitting dot matrix light source transmits. The principle of other numbers is the same as the principle of the operation of the dot matrix light source marked with 1, and is not repeated here. Fig. 11a and 11b are schematic diagrams showing two types of partitioned transmission for only the column rows, and the present invention is not limited thereto.

Fig. 12 is a schematic diagram of multipath cancellation using lattice sectorized transmission according to an embodiment of the present application; as shown in fig. 12, the transmitting end uses the partition transmission of the dot matrix light source, and it can be seen that the transmitting end transmits the dot matrix light source to the object B to be detected, the object to be detected returns the main path echo to the receiving end, and at the same time, a part of the light source of the transmitting end can transmit to the continuous reflecting surface, and the continuous reflecting surface transmits the received light to the object point B to be detected, and then is transmitted to the receiving end by the point B, and this part is the multi-path echo, and reaches the receiving end together with the main path echo directly from the point B. It can be seen from fig. 12 that comparing fig. 7 and 8, the number of multipath can be further reduced and the ranging accuracy can be further improved in fig. 12 because of the use of the partitioned emission of the lattice light source.

Fig. 13 is a schematic view of two sets of emission light sources provided in the embodiment of the present application, and as shown in fig. 13, 1301 is a dot matrix emission light source, 1303 is an area matrix emission light source, and 1302 is a receiving end. The lattice light source 1301 can be implemented by using a VCSEL + collimating mirror + DOE, or other optical systems such as other lasers + prisms, and the area-array light source 1303 can be implemented by using a VCSEL and a dodging sheet. Two usage modes of the lattice light source and the area array light source are used in a case where the lattice light source is referred to as a first emission mode and the area array light source is referred to as a second emission mode in this embodiment. A dot matrix light source is used when the target is far away. And an area array light source is used when the target is close or high resolution is required. Further, the lattice light and the area array light can assist each other to correct the distance.

The distance correction process is as follows:

(1) the area array light is used to obtain the distance preliminary information L1 of the target.

(2) A group of dot matrixes in the N subarea emitting areas emit light, and distance information L2 of a plurality of dots is obtained.

(3) And fitting, smoothing and transforming the L1 according to the scatter data L2 measured in the second step to obtain a preliminary ranging result L3.

(4) And the other area in the dot matrix area emits light to obtain distance information L4 of a plurality of corresponding scattered dots.

(5) The result of the preliminary correction L3 is compared with the result of the second scatter test L4, and corrected to L5.

(6) If the average value of the deviation of the L3 and the L5 is larger than a threshold value (such as 1 percent), the next correction is carried out, and if the average value is smaller than the threshold value, a test result L5 is output.

(7) When entering the next correction, a different partition from that in step 4 is started to obtain L6, and the result of L5 is compared with L6 and corrected to obtain L7.

(8) And continuing to compare the L7 with the L5, judging according to the method of the step 6, then repeating the step 7 until the error is smaller than the threshold value or the correction times reach the upper limit, and outputting the final correction result.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A probe apparatus, comprising:

the receiving module is used for receiving a reflected light signal reflected by a target object; the receiving comprises a pixel array, wherein one part of pixels of the pixel array are used for detecting a first reflected light signal reflected by the target object, and the other part of pixels are marked as invalid pixels;

and the control and processing module is respectively connected with the transmitting module and the receiving module and obtains the distance of the target object according to the first reflected light signal.

2. The apparatus of claim 1, wherein the transmission module comprises a first transmission mode and a second transmission mode; the first emission mode is a dot matrix light source emission mode; the second emission mode is an area array light source emission mode.

3. The apparatus of claim 2, wherein the transmission module comprises a plurality of transmission areas; the receiving module comprises a plurality of receiving areas; the control and processing module is used for controlling the receiving area corresponding to the transmitting area to receive the reflected light.

4. The apparatus of claim 2, wherein the control and processing module provides a trigger signal to the first transmission mode and the second transmission mode to turn on or off the first transmission mode or the second transmission mode.

5. The detection apparatus according to claim 3, wherein the control and processing module controls one or more of the emission areas to emit a dot matrix light source to the designated area in the first emission mode.

6. The detection apparatus according to claim 3, wherein the control and processing module controls a receiving area corresponding to the one or more light sources emitting to the designated area among the receiving areas to receive the reflected light in the first emission mode.

7. The apparatus of claim 3, wherein the transmitting region is in conjugate relationship with the corresponding receiving region.

8. A detection apparatus according to claim 3, wherein the receiving area comprises an area for receiving light reflected from the target object and/or an area for receiving multipath reflected light.

9. The apparatus of claim 3, wherein in the first transmission mode, the control and processing module controls the receiving area not corresponding to the transmission area to receive multi-path light.

10. The apparatus according to claim 3, wherein in the first transmission mode, the control and processing module controls the receiving area not corresponding to the transmission area not to receive the reflected light.