Detection Unit, Detection Device and Method

Abstract

The present application provides a detection pixel unit, a detection device and a detection method using the detection device. The detection device includes a photosensitive module capable of obtaining N different exposure information. The first exposure time and the second exposure time with different exposure durations are included in the N groups of different exposure information. The processing module receives different signals and performs different processing on the information obtained with different exposure durations. The information generation module outputs the final target information according to the different information processing results of the processing unit. Through the setting of this detection device, different working modes are prefabricated inside the system, which can realize the accurate tracking of multiple objects at different distances in the field of view by the detection system. At the same time, the result output is rapid and reliable, enhancing the user experience.

Description

Technical Field

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

[0002] In the field of detection technologies, more and more technologies are being continuously introduced. To ensure the target information for efficient and fast detection in application fields such as imaging or ranging, the acquisition efficiency of detection information has also received increasing attention. When acquiring images, whether the detection system can efficiently and quickly process high-quality pictures will directly affect the user experience, especially in the field of ranging. For example, when the detection device has a certain relative speed with the detected object, it becomes very important to quickly and accurately acquire and process distance data. Especially when the detection device is a vehicle-mounted device, fast and accurate distance information will be very helpful for users to achieve fully automated driving during fast driving and can also ensure the safety of autonomous driving.

[0003] In relatively early disclosed technologies, when acquiring images, multiple images with different exposure parameters are taken for the same scene, and the images are segmented. The information entropy of each image block of a single-frame image in the image sequence is calculated, and the image block with the largest amount of information is saved and merged into a new scene image. In this design, a solution for obtaining an image with a larger dynamic range is proposed. Briefly speaking, in image acquisition, high dynamic range means that the image can obtain a more hierarchical effect of light and dark, and the picture is not easily formed into pure black or pure white (that is, bright spots and dark spots). In the field of ranging, more and more attention is also paid to the accuracy of ranging. Especially with the current development of laser sources becoming more and more arrayed, emission and reception can detect multiple targets in the field of view. In the detection field of view, the far and near distance states of the target objects may be different or there may be large differences. For objects at a relatively far distance, the returned information of the detection light may be very weak, while for objects very close, the returned information of the detection light may be very strong. Thus, if the same exposure is used, it will cause defects such as missing information acquisition in the field of view. Using the method of obtaining the field of view information with different exposure times multiple times to synthesize the final distance information of the field of view target objects can solve this problem. However, the images obtained with information multiple times will require particularly complex storage and operations, which will reduce the acquisition speed of the distance information of multiple objects in the field of view during ranging. This may pose potential risks to vehicle-mounted and other devices and affect the user experience of image acquisition devices.

[0004] For example, in the current process of detecting distance or depth information, the commonly used method is the Time of Flight (TOF) ranging method. Its principle is to continuously send optical pulses to the target object, and then use a sensor to receive the light returned from the object. By detecting the flight (round-trip) time of the optical pulse, the distance to the target object can be obtained. In TOF technology, the technique of directly measuring the flight time of light is called DTOF (direct-TOF); the transmitted optical signal is modulated periodically, and by measuring the phase delay of the reflected optical signal relative to the transmitted optical signal, and then calculating the flight time from the phase delay, the measurement technique is called ITOF (Indirect-TOF) technology. According to the different types of modulation and demodulation methods, it can be divided into Continuous Wave (CW) modulation and demodulation method and Pulse Modulated (PM) modulation and demodulation method. Furthermore, adopting the ITOF scheme can also obtain a distance detection scheme with high precision and high sensitivity. Therefore, the application of the ITOF scheme has also been more widely used.

[0005] In order to obtain efficient measurement results and higher chip integration, the ranging is often achieved by using two or more taps. The distance information of the target object can be obtained according to the phase ranging algorithm. For example, the simplest two-phase method can be used, or the three-phase, four-phase method or even the 5-phase scheme can be used to obtain the distance information. Here, taking a four-phase algorithm as an example, at least two exposures (usually four exposures are required to ensure the measurement accuracy) are required to complete the acquisition of four-phase data and output a frame of depth image. At the same time, different exposure times of different phases need to be arranged based on the four-phase ranging. Therefore, it is more difficult to obtain a high frame rate. Therefore, there is an urgent need for a solution that can solve the detection information, especially to ensure that the detection device has a very high dynamic range characteristic during the ranging process and can also ensure the efficient and rapid output of the entire ranging device. Summary of the Invention

[0006] The purpose of this application is to provide a detection unit to solve the technical problem that the existing detection unit cannot cope with multi-target high-precision and fast detection in view of the above-mentioned deficiencies in the prior art.

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

[0008] In a first aspect, the embodiments of this application provide a detection pixel unit, including: a photosensitive module that performs exposure processing on the pixel at N different exposure times, and the photosensitive module receives N groups of exposures, where N is an integer greater than or equal to 2;

[0009] A processing module that can process the N groups of exposures respectively to obtain N groups of exposure signals; at least two groups of exposures with different exposure times are included in the N groups of exposures, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time;

[0010] The processing module can receive a first signal, establish a corresponding relationship with the photosensitive module, and output a first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset;

[0011] An information generation module that receives the first exposure time signal output by the processing module and generates final target information.

[0012] Optionally, the processing module can also receive a second signal, establish a corresponding relationship with the photosensitive module, and output a second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset;

[0013] The information generation module receives the second exposure time signal output by the processing module and generates final target information.

[0014] Optionally, a judgment module is further included. The judgment module generates a third signal, and the processing module can also receive the third signal. The processing module performs an operation based on the results of the first exposure time signal and the second exposure time signal;

[0015] The information generation module receives the operation result of the first exposure time signal and the second exposure time signal output by the processing module and generates final target information.

[0016] Optionally, the pixel unit is a distance acquisition pixel unit, and the target information is distance information.

[0017] Optionally, the first signal and the second signal are related to the distance of the object to be measured.

[0018] Optionally, the judgment module outputs the third signal based on the charge storage threshold of the pixel and the current charge storage value of the pixel under the first or second exposure.

[0019] On the other hand, the present invention also provides a detection device, including a light source, and the light source can be operated to emit light to illuminate the object to be detected;

[0020] The pixel array is exposed and processed at N different exposure times. The pixel array receives N groups of exposures, where N is an integer greater than or equal to 2;

[0021] A processing module that can process the N groups of exposures respectively to obtain N groups of exposure signals; at least two groups of exposures with different exposure times are included in the N groups of exposures, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time;

[0022] The processing module can receive a first signal, establish a corresponding relationship with the pixel array, and output a first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset;

[0023] An information generation module that receives the first exposure time signal output by the processing module and generates final target information.

[0024] Optionally, the processing module can also receive a second signal, establish a corresponding relationship with the pixel array, and output a second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset;

[0025] The information generation module receives the second exposure time signal output by the processing module and generates final target information.

[0026] Optionally, a judgment module is further included. The judgment module generates a third signal, and the processing module can also receive the third signal. The processing module performs an operation based on the results of the first exposure time signal and the second exposure time signal, and the signals of some pixel units of the pixel array use the result signal output by the processing module as the output signal of the some pixel units;

[0027] The information generation module receives the output signals of all pixel units of the pixel array output by the processing module and generates final target information.

[0028] Optionally, the output information corresponding to the reception control signals including four different phase information in the N groups of exposures includes 0°, 90°, 180°, and 270°.

[0029] Optionally, the first exposure time and / or the first exposure time in the N groups of exposures include the output information corresponding to the reception control signals including four different phase information.

[0030] Optionally, each pixel output information in the pixel array includes two sub-frames, and the same number of times of the first exposure time is included in the two sub-frames, and the first exposure time includes the output information corresponding to the reception control signals including four different phase information.

[0031] Optionally, the same number of second exposure times are included in the two sub-frames. The first sub-frame includes at least one second exposure time, and the output information corresponding to the reception control signals of two phase information with a phase difference of 180° is included in the second exposure time. The second sub-frame includes at least one second exposure time, and the output information corresponding to the reception control signals of two phase information with a phase difference of 180° is included in the second exposure time. Moreover, the reception control signals with a phase difference of 180° within the second exposure time included in the two sub-frames can form the output signals of the four reception control signals with different phases.

[0032] Optionally, the output information of each pixel in the pixel array includes multiple sub-frames. In the multiple sub-frames, the output information corresponding to the reception control signals of two phase information with a phase difference of 180° is included in at least one of the adjacent two sub-frames. Moreover, the reception control signals with a phase difference of 180° within the second exposure time included in the adjacent two sub-frames can form the output signals of the four reception control signals with different phases. The processing module can also receive a fourth control signal and output the first exposure time and second exposure time signals of the adjacent two sub-frames. The information generation module receives the different exposure time signals output by the processing module and generates the final target information.

[0033] In a third aspect, an embodiment of the present application provides a detection method, which is applied to the detection device described in the second aspect above. The detection method includes:

[0034] The light source is operable to emit light to illuminate the object to be detected;

[0035] The photosensitive module exposes the pixels at N different exposure times respectively. The photosensitive module receives N groups of exposures, where N is an integer greater than or equal to 2;

[0036] The processing module can process the N groups of exposures respectively to obtain N groups of exposure signals. At least two groups of exposures with different exposure times are included in the N groups of exposures, namely a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time;

[0037] The processing module can receive a first signal control and output the first exposure time signal corresponding to the first exposure time processed by the processing module, and the second exposure time signal is reset;

[0038] The information generation module receives the first exposure time signal output by the processing module and generates the final target information.

[0039] Optionally, the processing module may further receive a second signal control, output a second exposure time signal processed by the processing module corresponding to the second exposure time, and reset the first exposure time signal; the information generation module receives the second exposure time signal output by the processing module and generates final target information.

[0040] Optionally, it further includes a judgment module, the judgment module generates a third signal, and the processing module receives the third signal control and performs an operation based on the results of the first exposure time signal and the second exposure time signal. The signal of some pixel units of the pixel array uses the result signal output by the processing module as the output signal of the partial pixel units;

[0041] The information generation module receives the output signals of all pixel units of the pixel array output by the processing module and generates final target information.

[0042] Optionally, the output information corresponding to the reception control signals of four different phase information in the N groups of exposures includes 0°, 90°, 180°, and 270°.

[0043] Optionally, the output information of each pixel in the pixel array includes two sub-frames. The two sub-frames include the first exposure time of the same number of times, and the first exposure time includes the output information corresponding to the reception control signals of four different phase information.

[0044] Optionally, the output information of each pixel in the pixel array includes multiple sub-frames. In the multiple sub-frames, the output information corresponding to the reception control signals of two phase information with a phase difference of 180° is included in at least one of the adjacent two sub-frames, and the reception control signals with a phase difference of 180° within the second exposure time included in the adjacent two sub-frames can form the output signals of the four phase-different reception control signals; the processing module may further receive a fourth control signal, output the first exposure time and the second exposure time signals of the adjacent two sub-frames, and the information generation module receives the different exposure time signals output by the processing module and generates final target information.

[0045] The beneficial effects of this application are:

[0046] A detection unit, a detection device and a method provided by an embodiment of the present application. The detection device includes: a light source operable to emit light to illuminate an object to be detected; the pixel array is exposed at N different exposure times respectively, and the pixel array receives N groups of exposures, where N is an integer greater than or equal to 2; a processing module that can process the N groups of exposures respectively to obtain N groups of exposure signals; at least two groups of exposures with different exposure times are included in the N groups of exposures, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time; the processing module can receive a first signal, the processing module establishes a corresponding relationship with the pixel array, and outputs a first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset; thus, the detection device has an intelligent selection function. In the first mode, for example, when the distance between the detection device and a certain object to be detected in the field of view is very small, at this time, it is necessary to quickly obtain the distance, and within this distance range, the first exposure time, that is, the short exposure information, can fully meet the distance calculation. Therefore, the device can quickly output distance information and achieve efficient and intelligent operation of the device; furthermore, the device can also receive a second signal, the processing module establishes a corresponding relationship with the pixel array, and outputs a second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset; the information generation module receives the second exposure time signal output by the processing module and generates the final target information. In this mode, the device can detect a farther distance and only use the signal with a long exposure time to obtain the distance of the final target object, thus achieving a high dynamic effect; finally, the detection device further includes a judgment module, the judgment module generates a third signal, the processing module can also receive the third signal, the processing module performs an operation based on the results of the first exposure time signal and the second exposure time signal, and the signals of some pixel units of the pixel array use the result signal output by the processing module as the output signals of the some pixel units. In this mode, when the state of the target object in the field of view is relatively complex, the information of the first exposure time and the second exposure time can be used for correction to obtain the final and most reliable target information. When obtaining multiple times, complementary information acquisition between the previous sub-frame and the subsequent sub-frame is achieved through the arrangement of multiple sub-frames, thereby forming an arrangement in which the information of the previous and subsequent sub-frames can be reused, so that the effect of quickly obtaining target information without reducing the frame rate is achieved during the image or distance acquisition process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0048] Figure 1 Schematic diagram of the functional modules of a detection device provided by an embodiment of the present application;

[0049] Figure 2 Schematic diagram of the functional modules of another detection device provided by an embodiment of the present application;

[0050] Figure 3 Schematic diagram of the working principle of a detection system provided by an embodiment of the present application;

[0051] Figure 4 Schematic diagram of a long and short exposure arrangement scheme provided by an embodiment of the present application;

[0052] Figure 5 Schematic diagram of another long and short exposure arrangement scheme provided by an embodiment of the present application;

[0053] Figure 6 Schematic diagram of a long and short exposure arrangement scheme in multiple sub - frames provided by an embodiment of the present application;

[0054] Figure 7 Schematic diagram of a detection timing provided by an embodiment of the present application;

[0055] Figure 8 Schematic diagram of another detection timing provided by an embodiment of the present application;

[0056] Figure 9 Schematic diagram of yet another detection timing provided by an embodiment of the present application;

[0057] Figure 10 Schematic diagram of a detection timing in multiple sub - frames provided by an embodiment of the present application;

[0058] Figure 11 Schematic diagram of the flowchart of a detection method provided by an embodiment of the present application;

[0059] Figure 12 Schematic diagram of the flowchart of another detection method provided by an embodiment of the present application;

[0060] Figure 13 Schematic diagram of the flowchart of yet another detection method provided by an embodiment of the present application. Detailed implementation manners

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Apparently, the described embodiments are some but not all of the embodiments of this application. The components of the embodiments of this application usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0062] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application.

[0063] 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.

[0064] Figure 1 It is a schematic diagram of the functional modules of a detection device provided for the embodiments of this application. As Figure 1 shown, the detection device includes: a light source 110, a processing module 120, a photosensitive module 130, and an information generation module 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 photosensitive module 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.

[0065] The processing module 120 may include a control module, which can control the light source to emit light a different number of times. The processing module 120 can cause the photosensitive module 130 to obtain the light reflected back by the detected object 150 corresponding to different phase delays respectively when the phase difference delays between the emission time of the light source 110 and the emitted light are 0°, 180°, 90°, and 270°. The reflected light forms incident light at the photosensitive module 130, and then different information is generated through photoelectric conversion by the photosensitive module. In some cases, the information of the detected object is also obtained 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 the 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 the specific technical problem, the problems and solutions are specifically elaborated by taking the four-phase time-of-flight distance acquisition scheme as an example.

[0066] On the basis described above, the light source 110 emits emitted light. The photosensitive module 130 is controlled by the processing module 120 to obtain the light reflected by the object to be detected 150 at a predetermined delay phase with respect to the emitted light, for example, four different delay phases. The returned reflected light forms incident light in the photosensitive module 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 during the use of the light source device. Moreover, the implementation of the device is very simple, ensuring the reliability of the entire detection device system. In this solution, the implementation of the phase delay is achieved in the receiving part and the controller. The processing module and / or the information generation module 140 can be integrated in the photosensitive module 130, ensuring the simplicity and efficiency of the system structure. In addition, the multi-phase delay receiving scheme adopted in the receiving part also avoids the need to emit emitted light for each phase at the transmitting end. For example, in the four-phase scheme, we can obtain the object information with two phase delays of 0° and 180° in one emission, which enables the entire ranging system to achieve the goal of efficient ranging. The light emitted by the light source 110 and reflected by the object to be detected 150 is converted into photo-generated electrons (or photo-generated charges) in the photoelectric conversion module of the photosensitive module 130. The N-group exposure includes a first exposure with a first exposure duration and a second exposure with a second exposure duration. The first exposure is an exposure with a short exposure time. The two exposures are implemented on the same pixel or pixel array, which can ensure the adaptability of the entire receiving array to the field of view, and will not produce blind spots due to different units of the receiving array receiving different exposures. Moreover, it is easier to implement in terms of control. The long and short exposures are implemented on the same pixel using different time sequences, and a reset control time sequence can be set between the time sequences, thereby ensuring that there is no interference effect between different exposure information, and there is no need to design complex isolation techniques at the pixel level. The photo-generated electrons are modulated and output through taps (here, the results of different phase information can be output by the same circuit or multiple different circuits, which is not limited here). Then, physical operations (such as using charge storage units: capacitors, etc.) or digital operations (such as integrating the sensor and the operation unit into an integrated chip structure) are performed inside the pixel, or physical operations or digital operations are performed in the subsequent ADC or other circuit parts. The present invention does not limit the specific implementation scheme.

[0067] When the photosensitive module 130 receives the emitted light reflected by the object 150 according to different delay phases and different exposure times, it generates different information. The information generation module 140 can receive different control signals, and then perform different operation processes on the different information obtained by the photosensitive module to complete the final information acquisition. The different control signals can include signals of the object distance. For example, the detection system can obtain the approximate distance information of the target object in a preset manner, and select the final information acquisition scheme based on this. When the distance of the detected object in the field of view is very close, the detection device only uses the short-exposure result for distance calculation. When there is no detected object at a short distance in the field of view, the detection system only uses the long-exposure result for calculation. When there are detected objects at both relatively long distances and relatively short distances in the field of view, the information obtained by both the long and short exposure modes is used. The results obtained by using two different exposure times are used to correct the results obtained by some units in the array photosensitive module, ensuring the high dynamic range characteristics of the detection device. The correction of the pixel information of the photosensitive module part in the detection device can be performed using the expression shown in Equation 1.

[0068] f(x) = mf s (x) + nf l (x); (1)

[0069] In Equation 1, f(x) refers to the corrected information, and f s (x) refers to the result information obtained by short exposure, and f l(x) refers to the result information obtained by long exposure. m and n are correction coefficients, which can be fixed values or empirical coefficients obtained based on experiments, etc. When implementing the utilization of both long and short exposure information in the third mode, the system can include a judgment module. On the one hand, this judgment module can be a mode for users to select. In this selected mode, the detection system can perform comprehensive operations on the long and short exposure information to obtain the final information. It can also be an adaptive judgment in an automatic state. For example, it can be a module similar to a comparator that compares the information values obtained by pixel units with thresholds (including at least two thresholds, such as the maximum threshold and the minimum threshold). When the short exposure information values of some units are less than the minimum threshold (indicating that there are distant objects in the field of view and there are dark spots in the obtained information), or when the long exposure information values of some units are greater than the maximum threshold (indicating that there are close objects in the field of view and there are white spots in the obtained information), under this condition, the judgment module autonomously generates a control signal. At this time, the detection system can use the information of two different exposure times to obtain the final information. In this way, on the one hand, the detection system can meet the user's needs to obtain a high dynamic range and, on the other hand, can also autonomously obtain a high dynamic range effect, and can autonomously select the way to obtain the final information according to different scenarios, greatly improving the user experience and ensuring the accuracy of detection on the basis of high efficiency. In addition, through the timing control of the system, different information is interspersed in multiple frames of information, so that the information of adjacent two sub-frames can be mutually corrected, and the frame rate during the entire detection process will not decrease, nor will it affect the ranging efficiency. In the implementation of the control signal, the first control signal and the second control signal can be signals related to the distance of the object to be detected, and obtain the pre-distance according to historical data or a preset mode, and then generate the first and second control signals.

[0070] Figure 2 This is another embodiment of the present invention. The functions corresponding to each module are the same as Figure 1 which will not be elaborated here. Compared with Figure 1 it shows the judgment module 260. In practice, the judgment module can be made into one module with the processing module, or can be made into one module with the information generation module, etc. It can be set within the pixel array or arranged physically at intervals. This is not limited here. The third control signal of the judgment module 260 can be a control signal given for the user's selection signal judgment, or can be a control signal obtained by the adaptive judgment of the detection device. This is not limited here. During the multi-sub-frame detection process, the fourth signal of the system control signal can be generated in the same way as the third signal, that is, it can be a user's selection signal or an adaptive control signal. Even the fourth signal and the said electrical signal are substantially the same signal, which will not be elaborated here either.

[0071] Figure 3 This is the principle block diagram of the implementation of the present invention. Compared with the previous one inFigure 1 The systems described work in the same way. It should be noted that this detection system has achieved higher automation and intelligence due to its different working modes, ensuring high efficiency during system operation and very high ranging accuracy, thus guaranteeing the reliability of the entire system. The working principle will not be elaborated here.

[0072] Figure 4 Taking the four-phase method as an example, the processing module 120 controls the light source 110 to emit light. After being reflected by the object to be detected 150, the processing module 120 controls the photosensitive module 130 to receive it with four-phase delays. All four phases use short exposure for reception, and Figure 4 in this sub-frame, multiple sets of four-phase short exposures and two-phase long exposures with a phase difference of 180° are set. It is also possible to set four-phase long exposures and at least one set of four-phase short exposure data. This is not limited here. The length of the frame is related to the frame rate of the detection system. For example, the currently widely used 15 FPS, 30 FPS, or 60 FPS in the detection system. Through reasonable arrangement, the present invention includes at least one set of four-phase short exposure and one set of two-phase long exposure in one sub-frame. The exposure time of the long exposure can be four times or more that of the short exposure. Through the above settings, information values with different phases and different exposure times are included in the detection system, and it can adapt to multi-target detection and precise detection of different distances of multiple targets in the detection system.

[0073] Figure 5 And Figure 4 Similar to the setting, in order to compensate for the ranging accuracy problem of the long exposure information included in the detection system at high frame rates, in another sub-frame, four-phase is set to form four complementary sub-frames with the Figure 4 long exposure sub-frame. Of course, Figure 4 and Figure 5 can also set four-phase long exposure information in one sub-frame. The detection system can autonomously control according to different frame rates and different short and long exposure delays, and the delays of short exposure and long exposure can also be adjusted autonomously. This is not specifically limited here.

[0074] Figure 6 Schematically shows the setting diagrams of different phase delays and different exposure durations in multiple sub-frames. For example, when the frame rates are 15 FPS, 30 FPS, or 60 FPS respectively, that is, 15, 30, or 60 sub-frames can be included per second. In the Nth frame and the N + 1th frame, according to the above Figure 4 and Figure 5Four-phase information of long and short exposures can be obtained in the following way. Complementary sub-frames can be formed using the previous sub-frame and the subsequent sub-frame. In this way, in the detection of multiple sub-frames, the information of two adjacent sub-frames can achieve different detection distances for a multi-target scene. And through this setting, the distance information of the detected object can be obtained in the same way, such as the four-phase algorithm. The information of every two adjacent sub-frames can form complementary information. Therefore, in the result output, the frame rate of the result output will not be reduced due to the large amount of information required to obtain the result.

[0075] 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 reciprocal signals. That is to say, 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° delay reception on the pixel does not output an electrical signal through any of the above two circuits. And in another time period, the opposite operation is exactly performed. The same operation is also carried out for the received phases with phase delays of 90° and 270° whose phase difference is 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 reciprocal 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.

[0076] During the distance acquisition process, the phase difference of the round-trip of the optical signal between the lidar and the target can be calculated according to the 4 groups of integrated charges. Taking the sinusoidal modulated light as an example, the phase difference between the echo signal corresponding to the modulated light and the transmitted signal is:

[0077]

[0078] In Equation 2 above, Q 0° , Q 90° , Q 180° , Q 270° are the electrical signals converted by the receiving part circuits corresponding to different phase delays respectively. Combining the relationship between the distance and the phase difference, the final distance result can be obtained:

[0079]

[0080] 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:

[0081] When Q 0° > Q 180° and Q 90° > Q 270° at that time,

[0082]

[0083] When Q 0° < Q 180° and Q 90° > Q 270° at that time

[0084]

[0085] When Q 0° < Q 180° and Q 90° < Q 270° at that time

[0086]

[0087] When Q 0° > Q 180° and Q 90° < Q 270° at that time

[0088]

[0089] In Equation 4 - 7 for calculating the distance of the above - mentioned square wave, Q 0° 、Q 90° 、Q 180° 、Q 270° are respectively the electrical signals converted by the receiving - part circuit corresponding to different phase delays. c is the speed of light, and f is the laser frequency. Of course, in some special cases, some companies directly use the sine - wave method to approximately calculate the distance of the square wave.

[0090] Figure 7 Schematically shows a timing diagram for setting different phase and different exposure - time information. When there is only one output circuit or a floating - diffusion node, etc. in the pixel unit, multiple different receptions are set in the Nth sub - frame, including at least one complete four - phase information, ensuring that the distance information of the detected object within the field of view can be obtained from the information of one sub - frame. It can also be adaptively adjusted to include the long - exposure information of two phases, so that the target information of the detected object at a long distance can be obtained by the two - phase method.

[0091] Figure 8 Schematically shows a timing - control diagram capable of outputting different phase - delay information through two different circuits. The pixel unit can output information through two circuits, which can ensure the efficiency of information. Figure 8The timing can include multiple short-exposure information with four-phase delays, which can ensure the credibility of short-exposure detection results. It can also include long-exposure information with two delayed phases having a phase difference of 180°. On the one hand, distance acquisition in a two-phase scheme can be based on the long-exposure information with two delayed phases having a phase difference of 180°. On the other hand, multiple sub-frames can be arranged in a complementary manner, and then the same four-phase delay is used to obtain the target distance, ultimately achieving the effect of not reducing the result output frame rate.

[0092] During the four-phase ranging process, the results of different phase delay signals output by different circuits (including the internal charge transfer channels of pixels and the external physical circuit parts of pixels) will be involved. However, in actual use, due to the influence of the delay and offset of column lines and comparators, etc., there are also differences in the results obtained by the two circuits for the same-phase received signals. For example, these influences are classified as Q 0° , Q 180° If the inherent deviation electron numbers of Q are △Q1 and △Q2, then in reality, for Q 0° , Q 180° There are certain deviations in the obtained electron numbers. For example, the electrical signals corresponding to the four-phase delays obtained by the first circuit and the second circuit respectively are:

[0093] Q 0°，r1 = Q 0° + △Q1; Q 180°，r2 = Q 180° + △Q2; (8)

[0094] In formula (8), Q 0°，r1 refers to the electrical signal value converted by the first circuit for the 0° delay phase actually substituted into the distance calculation formula. Q 0° refers to the ideal calculation true value obtained without considering the differences between the first circuit and the second circuit in the ideal situation. △Q1 refers to the deviation electrical signal value generated when the first circuit converts the 0° delay phase signal. The meanings of the symbols in the electrical signal calculation formula corresponding to the 180° delay phase in formula (8) are similar to those in the 0° delay phase calculation formula, and will not be elaborated here. The value of △Q1 can be a linear function relationship or a polynomial function relationship, and this value can be simulated according to the actual situation. This deviation electrical signal is very difficult to obtain in actual use. Therefore, substituting the actual values of the electrical signals converted by different delays for different phases into the distance solution formula will cause certain deviations, resulting in inaccurate final distance calculation. In the solution of the present invention, to solve this technical problem, two electrical signal values can be obtained for each of the four delay phases by the first circuit and the second circuit respectively, and then the arithmetic mean scheme (or a similar algorithm) is used to obtain the electrical signal value finally substituted into the expression, which can be expressed by the following formula:

[0095] Q 0°，r1 = Q 0° + △Q1; Q 0°，r2 = Q 0° + △Q2; Q 0°，r = (Q 0°，r1 + Q 0°，r2 ) / 2

[0096] Q 180°，r1 = Q 180° + △Q1; Q 180°，r2 = Q 180° + △Q2; Q 180°，r = (Q 180°，r1 + Q 180°，r2 ) / 2

[0097] Q 90°，r1 = Q 90° + △Q1; Q 90°，r2 = Q 90° + △Q2; Q 90°，r = (Q 90°，r1 + Q 90°，r2 ) / 2 (9)

[0098] Q 270°，r1 = Q 270° + △Q1; Q 270°，r2 = Q 270° + △Q2; Q 270°，r = (Q 270°，r1 + Q 270°，r2 ) / 2

[0099] That is, the signals obtained from two circuits are subjected to an addition operation. After the addition operation, the results obtained at the outputs of different circuits with the same phase are superimposed. On this basis, the influencing factors △Q1 and △Q2 are also superimposed. Therefore, the differences in the outputs of the same phase of different circuits are considered in the result, and the superimposed result can be used in the subsequent distance calculation to obtain an accurate distance result. Taking the case of square wave detection formula 4 as an example:

[0100] When Q 0° > Q 180° and Q 90° > Q 270° then,

[0101]

[0102] In the above formula (10), in the final distance acquisition, the sum result can be directly used without averaging to obtain the final accurate distance information. The implementation can be achieved through the result of physical capacitance charge accumulation or through digital operations in subsequent arithmetic circuits. In the calculation, since the subtraction operation of different phases is involved, the offset caused by column comparators, etc., can be eliminated. On the other hand, the transfer function mismatch phenomenon caused by non-ideal factors such as taps can also be removed. The deviation charge caused by the transfer function mismatch can also be classified into linear or non-linear relationships, and its fundamental principle is similar to the charge difference caused by offset. A scheme similar to using the values obtained from two channels in image sensing applications can be adopted to correct and obtain the most accurate value, such as the previous formula (1).

[0103] Figure 9 Fig. shows a timing layout schematic diagram of outputting at least one same-phase delay signal using different circuits. On the one hand, this layout can eliminate the offset and transfer function mismatch phenomena caused by various reasons. On the other hand, as described above, through the setting of complementary phases of different sub-frames, the effect of not reducing the frame rate of the result output is achieved. Of course, the long exposure in one sub-frame can contain all four delay phase information. The four delay phases of the long exposure in another sub-frame are obtained by different second circuits. In this way, in fact, adjacent two sub-frames can be complementary, improving the accuracy of long and short exposure information without reducing the frame rate of the result output. Details are not elaborated here.

[0104] Figure 10 Fig. schematically shows the timing diagrams of different phase delays and different exposure durations in two adjacent sub-frames in multiple sub-frames. Its setting takes into account the information differences output by different circuits, can solve problems such as offset, and can also ensure that the frame rate of the result output is not reduced through the complementary design of adjacent sub-frames.

[0105] The above examples are based on the timing control between pixel units. In an actual detection system, the detection units will form a detection array. In this way, different detection units in the array may correspond to different detected objects in the field of view, and there are distance differences between different detected objects. Therefore, in actual operation, the detection system may only need to correct the information obtained by some detection units. For example, the detection system can directly receive control signals (such as button signals), or it can be an adaptive control scheme. For example, it can be judged based on the obtained information. When there are dark spots in the obtained information, the long exposure information is used to replace the information at the dark spots. When there are white spots in the obtained information, the short exposure information is used to replace the information at the white spots. Of course, under the control of button signals or adaptive signals, the information obtained for at least one delay phase can also be corrected, and the corresponding correction is made using the long and short exposure information values twice to ensure the accuracy of the detection information. Details are not elaborated here either.

[0106] Figure 11 It schematically shows the method steps for implementing the present invention. The processing module 120 in S101 controls the light source 110 to emit light, which can be a square wave, a triangular wave, a sine wave, etc., and is not specifically limited here. Under the action of the emitted light, the field of view is illuminated, and the detected object 150 reflects the emitted light, thereby forming a reflected light echo. In S102, while the processing module 120 controls the light source to emit the emitted light, it controls the photosensitive module 130 to receive the echo of the reflected light with a control signal having a different phase delay from the light source 110. In S103, the photosensitive module 130 obtains N groups of exposure signals including different exposure fields of view. The different exposure time signals of the N groups of exposure signals are utilized according to different control signals. The specific processing method has been elaborated in detail before and will not be repeated here.

[0107] Figure 12 It schematically shows another method step for implementing the present invention. Similar to the steps shown in Figure 11 In Figure 12 It further defines a scheme for obtaining target information by a four-phase delay scheme for long and short exposures in the N groups of exposure signals. The implementation method of the corresponding steps can refer to the steps described in Figure 11 and will not be repeated here.

[0108] Figure 13 It schematically shows another method step for implementing the present invention. Similar to the steps shown in Figure 7 and Figure 8 In Figure 13 It further defines a scheme for obtaining target information by a four-phase scheme, and defines that each phase of at least one of the long and short exposures of the four delay phases is obtained by two circuits to obtain the corresponding electrical signals. The implementation method of the corresponding steps can refer to the steps described in Figure 11 and will not be repeated here.

[0109] 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 elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the said element.

[0110] 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, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, 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 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. 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, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, 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 pixel unit, characterized in that Including: A photosensitive module that exposes the pixels at N different exposure times respectively. The photosensitive module receives N groups of exposures, where N is an integer greater than or equal to 2; A processing module that can process the N groups of exposures respectively to obtain N groups of exposure signals; Among the N groups of exposures, there are at least two groups of exposures with different exposure times, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time; in the previous sub-frame, a four-phase first exposure time and a two-phase second exposure time are set, and in the subsequent sub-frame, a four-phase first exposure time and a two-phase second exposure time complementary to that in the previous sub-frame are set; Wherein, at least one group of four-phase short exposure and one group of two-phase long exposure are included in one sub-frame, and the exposure time of the long exposure is four times that of the short exposure; The processing module can receive a first signal, establish a corresponding relationship with the photosensitive module, and output a first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset; An information generation module that receives the first exposure time signal output by the processing module and generates a final target information; Or the processing module receives a second signal, establishes a corresponding relationship with the photosensitive module, and outputs a second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset; The information generation module receives the second exposure time signal output by the processing module and generates a final target information; Or further includes a judgment module that generates a third signal, and the processing module can also receive the third signal, and the processing module performs an operation based on the results of the first exposure time signal and the second exposure time signal; The information generation module receives the operation result of the first exposure time signal and the second exposure time signal output by the processing module and generates a final target information.

2. The detection pixel unit according to claim 1, characterized in that, The pixel unit is a distance acquisition pixel unit, and the target information is distance information.

3. The detection pixel unit according to claim 1, characterized in that, The first signal and the second signal are related to the distance of the object to be measured.

4. The detection pixel unit according to claim 1, wherein The judgment module outputs the third signal based on the charge storage threshold of the pixel and the current charge storage value of the pixel under the first or second exposure.

5. A detection device comprising an array composed of the detection pixel units described in claim 1, characterized in that Including a light source that can be operated to emit light to illuminate the object to be detected; Exposing the pixel array at N different exposure times respectively. The pixel array receives N groups of exposures, where N is an integer greater than or equal to 2; A processing module that can process the N groups of exposures respectively to obtain N groups of exposure signals; Among the N groups of exposures, there are at least two groups of exposures with different exposure times, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time; in the previous sub-frame, a four-phase first exposure time and a two-phase second exposure time are set, and in the subsequent sub-frame, a four-phase first exposure time and a two-phase second exposure time complementary to that in the previous sub-frame are set; Among them, at least one set of four-phase short exposures and one set of two-phase long exposures are included in one sub-frame, where the exposure time of the long exposure is four times that of the short exposure; The processing module can receive a first signal, establish a corresponding relationship with the pixel array, and output a first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset; The information generation module receives the first exposure time signal output by the processing module and generates the final target information; Or the processing module can also receive a second signal, establish a corresponding relationship with the pixel array, and output a second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset; The information generation module receives the second exposure time signal output by the processing module and generates the final target information; Or it further includes a judgment module, the judgment module generates a third signal, the processing module can also receive the third signal, the processing module performs an operation based on the results of the first exposure time signal and the second exposure time signal, and the signals of some pixel units of the pixel array use the result signal output by the processing module as the output signal of the some pixel units; The information generation module receives the output signals of all pixel units of the pixel array output by the processing module and generates the final target information.

6. The detection device according to claim 5, characterized in that, The output information corresponding to the reception control signals including four different phase information in the N groups of exposures includes 0°, 90°, 180°, and 270°.

7. The detection device according to claim 6, characterized in that The first exposure time and / or the first exposure time in the N groups of exposures include the output information corresponding to the reception control signals including four different phase information.

8. The detection device according to claim 6, wherein, Each pixel output information in the pixel array includes two sub-frames, the two sub-frames include the same number of first exposure times, and the first exposure time includes the output information corresponding to the reception control signals including four different phase information.

9. The detection device according to claim 8, characterized in that The two sub-frames include the same number of second exposure times, the first sub-frame includes at least one second exposure time, and the second exposure time includes the output information corresponding to the reception control signals of two phase information with a phase difference of 180°, the second sub-frame includes at least one second exposure time, and the second exposure time includes the output information corresponding to the reception control signals of two phase information with a phase difference of 180°, and the reception control signals with a phase difference of 180° within the second exposure time included in the two sub-frames can form the output signals of the four-phase different reception control signals.

10. The detection device according to claim 6, wherein The output information of each pixel in the pixel array includes multiple sub-frames. For two adjacent sub-frames among the multiple sub-frames, the output information corresponding to the reception control signals of at least one pair of phase information with a phase difference of 180° is included. Moreover, the reception control signals with a phase difference of 180° within the second exposure time included in the two adjacent sub-frames can form the output signals of the four reception control signals with different phases. The processing module can also receive a fourth control signal and output the first exposure time and the second exposure time signals of the two adjacent sub-frames. The information generation module receives the different exposure time signals output by the processing module and generates the final target information.

11. A detection method, characterized in that, Applied to the detection device according to any one of claims 5-10 above, the detection method includes: The light source is operable to emit light to illuminate the object to be detected; The photosensitive module exposes the pixels at N different exposure times respectively. The photosensitive module receives N groups of exposures, where N is an integer greater than or equal to 2; The processing module can process the N groups of exposures respectively to obtain N groups of exposure signals; Among the N groups of exposures, there are at least two groups of exposures with different exposure times, a first exposure time and a second exposure time, and the first exposure time is less than the second exposure time; Set the first exposure time with four phases and the second exposure time with two phases in the previous sub-frame, and set the first exposure time with four phases and the second exposure time with two phases complementary to those in the previous sub-frame in the subsequent sub-frame; Among them, at least one group of short exposure with four phases and one group of long exposure with two phases are included in one sub-frame, and the exposure time of the long exposure is four times that of the short exposure; The processing module can receive the first signal control and output the first exposure time signal processed by the processing module corresponding to the first exposure time, and the second exposure time signal is reset; The information generation module receives the first exposure time signal output by the processing module and generates the final target information; Or the processing module can also receive the second signal control and output the second exposure time signal processed by the processing module corresponding to the second exposure time, and the first exposure time signal is reset; the information generation module receives the second exposure time signal output by the processing module and generates the final target information; Or a judgment module is further included. The judgment module generates a third signal. The processing module receives the control of the third signal and performs an operation based on the results of the first exposure time signal and the second exposure time signal. The result signal output by the processing module is used as the output signal of some pixel units of the pixel array; The information generation module receives the output signals of all pixel units of the pixel array output by the processing module and generates the final target information.

12. The detection method according to claim 11, characterized in that, The output information corresponding to the reception control signals of four different phase information included in the N groups of exposures includes 0°, 90°, 180°, and 270°.

13. The detection method according to claim 12, characterized in that, The output information of each pixel in the pixel array includes two sub-frames. The two sub-frames include the first exposure time for the same number of times, and the first exposure time includes output information corresponding to reception control signals with four different phase information.

14. The detection method according to claim 11, characterized in that, The output information of each pixel in the pixel array includes multiple sub-frames. For two adjacent sub-frames among the multiple sub-frames, each includes output information corresponding to reception control signals with two phase information having a phase difference of 180°. Moreover, the reception control signals with a phase difference of 180° within the second exposure time included in the two adjacent sub-frames can form output signals of the four reception control signals with different phases. The processing module can also receive a fourth control signal and output the first exposure time and second exposure time signals of the two adjacent sub-frames. The information generation module receives the different exposure time signals output by the processing module and generates the final target information.

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