Image sensor and signal processing method, device, program and medium

Abstract

The present disclosure provides an image sensor and a signal processing method, device, program and medium, by comparing whether the first electrical signal output by the pixel unit is greater than a reference electrical signal of a maximum value within a preset threshold range; wherein the first electrical signal is obtained by the photogenerated charge generated by the pixel unit based on the light signal received within a preset exposure time; in response to the first electrical signal being greater than the reference electrical signal of the maximum value, the pixel unit is controlled to start exposure after being reset and continuously output a second electrical signal during the exposure process, wherein the second electrical signal is obtained by generating photogenerated charge based on the light signal received by the pixel unit during the exposure process; the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal of the minimum value within the threshold range is obtained as the first time and the first time is output. The present disclosure increases the dynamic range of the image sensor without increasing the hardware cost.

Description

Technical Field

[0001] The present disclosure relates to image sensing technology and signal processing technology, and in particular to an image sensor and a signal processing method, device, program and medium. Background Art

[0002] Photoelectric image sensor is a new type of neuromorphic vision sensor. It imitates the imaging method of the retina in primates and records the continuous light intensity information in the scene by emitting high-density single-bit pulse sequences. It can achieve high-precision capture and recording of high-speed light processes and reconstruct the texture details in the scene. Therefore, it has great application value in machine vision and dynamic scene capture.

[0003] The dynamic range of an image sensor refers to the range of light intensities between the maximum and minimum light intensities that the image sensor can distinguish. Dynamic range is an important evaluation indicator of photoelectric image sensors. Summary of the invention

[0004] Embodiments of the present disclosure provide an image sensor and a signal processing method, device, program, and medium to improve the dynamic range of a photoelectric image sensor.

[0005] In one aspect of an embodiment of the present disclosure, a signal processing method is provided, which is applied to an image sensor, wherein the image sensor includes a pixel unit, and the method includes:

[0006] Comparing whether a first electrical signal output by the pixel unit is greater than a reference electrical signal with a maximum value within a preset threshold range; wherein the first electrical signal is obtained by photogenerated charges generated by the pixel unit based on a light signal received within a preset exposure time;

[0007] In response to the reference electrical signal that the first electrical signal is greater than the maximum value, controlling the pixel unit to start exposure after being reset and continuously output a second electrical signal during the exposure process, wherein the second electrical signal is obtained by generating photogenerated charges based on the light signal received by the pixel unit during the exposure process;

[0008] Acquire the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range as the first time;

[0009] The first time is output.

[0010] Optionally, in any method embodiment of the present disclosure, the method further includes:

[0011] In response to the first electrical signal being no greater than the maximum value of the reference electrical signal, sequentially outputting a reference electrical signal in a reference signal sequence as a current reference signal, the reference signal sequence comprising a plurality of reference electrical signals whose signal values ​​gradually increase within the threshold range;

[0012] Acquire the time required for the current reference signal to reach the first electrical signal as the second time;

[0013] The second time is output.

[0014] Optionally, in any method embodiment of the present disclosure, the minimum value in the reference signal sequence is the minimum value within the threshold range;

[0015] In the reference signal sequence, the difference between any two adjacent reference electrical signals is a preset interval value, or the ratio between any two adjacent reference electrical signals is a preset ratio.

[0016] Optionally, in any method embodiment of the present disclosure, the method further includes:

[0017] When outputting the first time, first exposure mode identification information for identifying a quantitative exposure mode is also output;

[0018] When the second time is output, second exposure mode identification information for identifying the timed exposure mode is also output.

[0019] Optionally, in any method embodiment of the present disclosure, the image sensor includes a pixel array formed by arranging the pixel units in m rows and n columns, m signal readout circuits, and m processing circuits, each of the signal readout circuits and each of the processing circuits corresponds to a row of pixel units in the pixel array, and the values ​​of m and n are respectively integers greater than 1;

[0020] Each column of pixel units in each row of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the corresponding row processing circuit;

[0021] The signal readout circuit corresponding to each row of pixel units, according to the control of the corresponding row processing circuit, sequentially polls the pixel units of each column connected to the corresponding row of pixel units, performs the operation of comparing whether the first electrical signal output by the pixel unit is greater than the reference electrical signal with the maximum value within the preset threshold range and outputs the comparison result signal; and performs the operation of obtaining the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range, and the operation of outputting the first time, or performs the operation of sequentially outputting a reference electrical signal in the reference signal sequence as the current reference signal, the operation of obtaining the time required for the current reference signal to reach the first electrical signal, and the operation of outputting the second time;

[0022] The processing circuit of the row corresponding to the signal readout circuit executes the operation of controlling the pixel unit to start exposure after resetting and continuously outputting the second electrical signal during the exposure process in response to the reference electrical signal that the first electrical signal is greater than the maximum value, based on the comparison result signal.

[0023] Optionally, in any method embodiment of the present disclosure, the image sensor includes a pixel array formed by arranging m rows and n columns of pixel units, n signal readout circuits, and n processing circuits, each of the signal readout circuits and each of the processing circuits corresponds to a column of pixel units in the pixel array, and the values ​​of m and n are respectively integers greater than 1;

[0024] Each column of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the processing circuit;

[0025] The signal readout circuit corresponding to each column of pixel units, according to the control of the corresponding row processing circuit, sequentially polls the pixel units of each row connected to the corresponding column of pixel units, performs the operation of comparing whether the first electrical signal output by the pixel unit is greater than the reference electrical signal with the maximum value within the preset threshold range and outputs the comparison result signal; and performs the operation of obtaining the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range, and the operation of outputting the first time, or performs the operation of sequentially outputting a reference electrical signal in the reference signal sequence as the current reference signal, the operation of obtaining the time required for the current reference signal to reach the first electrical signal, and the operation of outputting the second time;

[0026] The processing circuit of the column corresponding to the signal readout circuit executes the operation of controlling the pixel unit to start exposure after resetting and continuously outputting the second electrical signal during the exposure process in response to the reference electrical signal that the first electrical signal is greater than the maximum value, based on the comparison result signal.

[0027] Optionally, any method embodiment of the present disclosure may be applied to, and implemented by, the image sensor provided by any embodiment of the present disclosure.

[0028] Another aspect of the embodiments of the present disclosure provides an image sensor, including a pixel unit and a signal readout circuit;

[0029] The pixel unit is used to receive a light signal within a preset exposure time to generate photogenerated charges, and output a first electrical signal based on the photogenerated charges; and start exposure after being reset according to the control of the processing circuit, receive a light signal during the exposure process to generate photogenerated charges, and obtain and continuously output a second electrical signal based on the photogenerated charges;

[0030] The signal readout circuit is used to compare whether the first electrical signal is greater than a reference electrical signal with a maximum value within a preset threshold range; in response to the first electrical signal being greater than the reference electrical signal with the maximum value, obtain the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with a minimum value within the threshold range as the first time, and output the first time.

[0031] Optionally, in any of the image sensor embodiments disclosed herein, the signal readout circuit is further configured to:

[0032] In response to a reference electrical signal in which the first electrical signal is not greater than the maximum value, one reference electrical signal in a reference signal sequence is output in sequence as a current reference signal, the reference signal sequence includes a plurality of reference electrical signals whose signal values ​​gradually increase within the threshold range and are arranged in sequence, and the time required for the current reference signal to reach the first electrical signal is obtained as a second time, and the second time is output.

[0033] Optionally, in any image sensor embodiment of the present disclosure, the minimum value in the reference signal sequence is the minimum value within the threshold range;

[0034] In the reference signal sequence, the difference between any two adjacent reference electrical signals is a preset interval value, or the ratio between any two adjacent reference electrical signals is a preset ratio.

[0035] Optionally, in any image sensor embodiment disclosed herein, the signal readout circuit is further used to: output first exposure mode identification information for identifying a quantitative exposure mode when outputting the first time; and output second exposure mode identification information for identifying a timed exposure mode when outputting the second time.

[0036] Optionally, in any image sensor embodiment of the present disclosure, the signal readout circuit includes: a comparator, a threshold signal output circuit and a timer;

[0037] The positive input terminal of the comparator is connected to the output terminal of the pixel unit, and is used to receive the electrical signal output by the pixel unit; the negative input terminal of the comparator is connected to the first output terminal of the threshold signal output circuit, and is used to receive the reference electrical signal output by the threshold signal output circuit; the output terminal of the comparator is respectively connected to the first input terminal of the threshold signal output circuit and the first input terminal of the timer, and is used to output a comparison result signal to the threshold signal output circuit and the timer;

[0038] The first input terminal of the threshold signal output circuit is connected to the output terminal of the comparator, and is used to receive the comparison result signal; the second input terminal of the threshold signal output circuit is used to receive a first external control signal, and the first external control signal is used to control the threshold signal output circuit to output a reference electrical signal within the preset threshold range; the first output terminal of the threshold signal output circuit is connected to the negative input terminal of the comparator, and is used to output the reference electrical signal within the preset threshold range; the second output terminal of the threshold signal output circuit is used to output exposure mode identification information according to the comparison result signal;

[0039] The first input end of the timer is connected to the output end of the comparator for receiving the comparison result signal; the output end of the timer is used to output the timing result when the comparison result signal changes.

[0040] Optionally, in any image sensor embodiment of the present disclosure, the second input terminal of the timer is used to receive a clock signal of a preset frequency for timing.

[0041] Optionally, in any image sensor embodiment of the present disclosure, the threshold signal output circuit includes: an operational amplifier, a constant current power supply, a capacitor, a trigger, a first switch, a second switch, a third switch and a fourth switch;

[0042] The positive input terminal of the operational amplifier is connected to the reference electrical signal source of the minimum value through the third switch, and is connected to the reference electrical signal source of the maximum value through the fourth switch; the negative input terminal of the operational amplifier is connected to the constant current power supply through the second switch, and is connected to the output terminal of the operational amplifier through the first switch, and is connected to the positive electrode of the capacitor; the output terminal of the operational amplifier is respectively connected to the negative input terminal of the comparator and the negative electrode of the capacitor;

[0043] The first input terminal of the trigger is connected to a power supply signal; the second input terminal of the trigger is connected to the output terminal of the comparator for receiving the comparison result signal; the output terminal of the trigger is used to output a data flag bit for indicating the exposure mode identification information.

[0044] Optionally, in any of the image sensor embodiments disclosed herein, the threshold signal output circuit further comprises: a first inverter, a second inverter group, or a logic circuit, a third inverter, and a fifth switch; wherein the second inverter group comprises 2k+1 second inverters connected in sequence, and the value of k is an integer not less than 0;

[0045] The input end of the first inverter is used as the second input end of the threshold signal output circuit to receive a first external control signal, and the first external control signal is used to control the fourth switch and the fifth switch to be turned on or off; the output end of the first inverter is connected to the input end of the first second inverter in the second inverter group, and is used to output a third control signal, and the third control signal is used to control the third switch to be turned on or off;

[0046] The output end of any second inverter in the second inverter group is connected to the input end of the next adjacent second inverter, and the output end of the last second inverter in the second inverter group is connected to the first input end of the OR logic circuit;

[0047] The second input end of the OR logic circuit is connected to the ground end of the fifth switch, and the output end of the OR logic circuit is connected to the input end of the third inverter for outputting a first control signal, wherein the first control signal is used to control the third switch to be turned on or off;

[0048] The output end of the third inverter is connected to the second switch and is used to output a second control signal, where the second control signal is used to control the second switch to be turned on or off.

[0049] Optionally, in any of the image sensor embodiments disclosed herein, a processing circuit is further included, which is connected to the input end of the first inverter and is used to output the first external control signal to the input end of the first inverter.

[0050] Optionally, in any of the image sensor embodiments disclosed herein, the image sensor specifically comprises a pixel array formed by arranging m rows and n columns of pixel units, m signal readout circuits, and m processing circuits, each of the signal readout circuits and each of the processing circuits is connected to a row of pixel units in the pixel array, and each of the processing circuits controls the connection with the signal readout circuit of the corresponding row;

[0051] or,

[0052] The image sensor specifically comprises a pixel array formed by arranging m rows and n columns of pixel units, n signal readout circuits, and n processing circuits, each of the signal readout circuits and each of the processing circuits is connected to a column of pixel units in the pixel array, and each of the processing circuits controls the connection of the signal readout circuit of the corresponding column;

[0053] Wherein, the values ​​of m and n are integers greater than 1 respectively.

[0054] Optionally, in any image sensor embodiment of the present disclosure, the pixel unit includes: a photodiode, a transfer transistor, a floating diffusion region, a reset transistor, a source follower transistor and a selection transistor;

[0055] One end of the photodiode is grounded; the other end of the photodiode is connected to one end of the floating diffusion region and the gate end of the source follower transistor respectively through the transfer transistor;

[0056] The source terminal of the transfer transistor is connected to the other end of the photodiode; the drain terminal of the transfer transistor is respectively connected to one end of the floating diffusion region and the gate terminal of the source follower transistor; the gate terminal of the transfer transistor is used to receive a second external control signal to control the transfer transistor to be turned on or off;

[0057] One end of the floating diffusion region is respectively connected to the source end of the reset transistor and the gate end of the source follower transistor, and is connected to the other end of the photodiode through the transfer transistor; the other end of the floating diffusion region is grounded;

[0058] The source terminal of the reset transistor is connected to one end of the floating diffusion area; the drain terminal of the reset transistor is connected to a power signal; the gate terminal of the reset transistor is used to receive a third external control signal to control the reset transistor to be turned on or off;

[0059] The source terminal of the source follower transistor is connected to the drain terminal of the selection transistor; the drain terminal of the source follower transistor is connected to a power signal; the gate terminal of the source follower transistor is respectively connected to one end of the floating diffusion region and the drain terminal of the transfer transistor;

[0060] The source terminal of the selection transistor is connected to the input terminal of the signal readout circuit as the output terminal of the pixel unit; the drain terminal of the selection transistor is connected to the source terminal of the source follower transistor; the gate terminal of the selection transistor is used to receive a fourth external control signal to control the selection transistor to be turned on or off.

[0061] Optionally, in any image sensor embodiment of the present disclosure, the processing circuit is also respectively connected to the gate terminal of the transfer transistor, the gate terminal of the reset transistor and the gate terminal of the selection transistor in the pixel unit of the corresponding row or column, and is used to output the second external control signal, the third external control signal and the fourth external control signal to the gate terminal of the transfer transistor, the gate terminal of the reset transistor and the gate terminal of the selection transistor in the pixel unit of the corresponding row or column.

[0062] Another aspect of the embodiments of the present disclosure provides an electronic device, comprising: a processor, a memory communicatively connected to the processor, and the image sensor according to any one of the embodiments of the present disclosure;

[0063] The memory is used to store computer-executable instructions;

[0064] The processor is used to execute the computer instructions stored in the memory to control the image sensor to implement the signal processing method described in any embodiment of the present disclosure.

[0065] Optionally, in any device embodiment of the present disclosure, the electronic device includes any one of the following: a pulse camera, a high-speed camera, a visual camera, an audio player, a video player, a navigation device, a fixed-position terminal, an entertainment unit, a smart phone, a communication device, a mobile device, a device in a motor vehicle, a vehicle-mounted camera, a mobile phone camera, a sports or wearable camera, a traffic camera, an industrial inspection camera, a camera mounted on a flying object, a medical camera, a security camera, or a household appliance camera.

[0066] Another aspect of the embodiments of the present disclosure provides a computer program product, including computer instructions, which are executed by a processor to perform the signal processing method described in any embodiment of the present disclosure.

[0067] According to another aspect of the embodiments of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed, the computer executes the signal processing method described in any embodiment of the present disclosure.

[0068] Based on the embodiments of the present disclosure, the pixel unit in the image sensor can adopt a timed exposure mode, that is, a first electrical signal is obtained based on the accumulation of photoelectric signals within a fixed exposure time (that is, a preset exposure time), and by comparing whether the first electrical signal output by the pixel unit under the timed exposure is greater than a reference electrical signal with a maximum value within a preset threshold range, it is determined whether the light intensity received by the pixel unit during this timed exposure process exceeds its photosensitivity upper limit. If the first electrical signal is greater than the reference electrical signal with the maximum value, it means that the photosensitivity of the pixel unit has been saturated during this timed exposure process, and the pixel unit is controlled to reset and re-expose, and the obtained second electrical signal is continuously output during the exposure process, and the time required for the second electrical signal to reach the reference electrical signal with a minimum value within the threshold range is obtained as the first time output. The first time can accurately reflect the exposure intensity of the pixel unit, thereby achieving accurate recording of strong light signals. On the basis of being able to perform photosensitivity imaging for weak light signals through the timed exposure mode, the maximum detection light intensity is improved, thereby increasing the dynamic range of the image sensor without increasing the hardware cost, and effectively avoiding limiting the dynamic range of the image sensor due to hardware limitations such as hardware area.

[0069] The technical solution of the present disclosure is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0071] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0072] Figure 1 The present invention is a flowchart of an embodiment of a signal processing method.

[0073] Figure 2 The present invention is a flowchart of another embodiment of the signal processing method.

[0074] Figure 3 The figure is a schematic diagram of the structure of an image sensor according to an embodiment of the present invention.

[0075] Figure 4 It is a structural schematic diagram of an embodiment of a signal readout circuit in the embodiment of the present disclosure.

[0076] Figure 5 It is a structural schematic diagram of an embodiment of a threshold signal output circuit in the embodiment of the present disclosure.

[0077] Figure 6 It is a structural schematic diagram of another embodiment of the threshold signal output circuit in the embodiment of the present disclosure.

[0078] Figure 7 FIG. 4 is a schematic diagram of the structure of another embodiment of the image sensor disclosed in the present invention.

[0079] Figure 8 FIG. 4 is a schematic structural diagram of another embodiment of the image sensor disclosed in the present invention.

[0080] Fig. 9 Schematic diagram of the structure of a pixel unit in an embodiment of the present disclosure.

[0081] Fig.10 The figure is a schematic diagram of the structure of an embodiment of the electronic device disclosed in the present invention.

[0082] Fig.11 The figure is a schematic diagram of the structure of an application embodiment of the electronic device disclosed in the present invention. DETAILED DESCRIPTION

[0083] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0084] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0085] It should also be understood that in the embodiments of the present disclosure, “plurality” may refer to two or more than two, and “at least one” may refer to one, two, or more than two.

[0086] It should also be understood that any component, data or structure mentioned in the embodiments of the present disclosure can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0087] In addition, the term "and / or" in the present disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are in an "or" relationship.

[0088] It should also be understood that the description of the various embodiments in the present disclosure focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0089] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0090] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0091] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0092] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0093] The embodiments of the present disclosure can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0094] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0095] In the process of realizing the present disclosure, the inventors have found through research that in the related art, photoelectric image sensors reflect light intensity by recording the cumulative value of photoelectric signals at a fixed time. There are two main ways to broaden the dynamic range of photoelectric image sensors: one is to increase the number of photodiodes in the photoelectric image sensor to achieve separate photosensitivity to strong and weak light; the other is to increase multiple signal conversion readout channels to achieve different gains for strong and weak light signals, etc. These methods require increasing the hardware area and the complexity of process preparation, increasing the hardware cost, and the dynamic range improvement effect is directly related to the hardware cost. In addition, the dynamic range of photoelectric image sensors is limited by hardware limitations such as the inability to increase the hardware area indefinitely.

[0096] Figure 1 1 is a flow chart of an embodiment of the signal processing method of the present disclosure. The signal processing method of the embodiment of the present disclosure is applied to an image sensor, and the image sensor includes a pixel unit. Figure 1 As shown, the signal processing method of this embodiment includes:

[0097] 102 , comparing whether the first electrical signal output by the pixel unit is greater than a reference electrical signal having a maximum value within a preset threshold range.

[0098] The first electrical signal is an electrical signal obtained by the pixel unit based on the photogenerated charge generated by the light signal received within the preset exposure time, and the electrical signal may be a voltage signal or a current signal, which is not limited in the embodiments of the present disclosure. The embodiments of the present disclosure are described by taking the electrical signal as a voltage signal as an example, and the same is true for the case where the electrical signal is a current signal.

[0099] In the disclosed embodiment, before the pixel unit is exposed, the pixel unit can be reset to clear the charge in the pixel unit, and then the pixel unit can be controlled to be exposed. The exposure of the pixel unit refers to the photogenerated charge generated by the light signal received by the pixel unit, and the electrical signal that can reflect the intensity of the collected light signal (also called exposure intensity) is obtained based on the photogenerated charge.

[0100] Since the preset exposure duration is a fixed duration, the exposure mode in which the pixel unit obtains an electrical signal based on the photogenerated charge generated by the light signal received within the preset exposure duration can be called a timed exposure mode.

[0101] The pixel unit in the embodiment of the present disclosure may be any pixel unit in an image sensor, that is, the operation of the embodiment of the present disclosure may be performed on any pixel unit in an image sensor.

[0102] In response to the first electrical signal being greater than the reference electrical signal having a maximum value, operation 104 is performed.

[0103] 104 , controlling the pixel unit to start exposure after being reset and to continuously output a second electrical signal during the exposure process.

[0104] The second electrical signal is obtained based on photogenerated charges generated by the light signal received by the pixel unit during the exposure process.

[0105] In operation 104, the pixel unit no longer outputs an electrical signal based on the photogenerated charge generated by the light signal received within the preset exposure time, but obtains a second electrical signal during the exposure process and continuously outputs it. This exposure mode can be called a quantitative exposure mode.

[0106] 106 , obtaining the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range as the first time.

[0107] 108, output the first time.

[0108] Based on this embodiment, the pixel unit in the image sensor can be exposed in a timed exposure mode and output a first electrical signal. By comparing whether the first electrical signal output by the pixel unit under the timed exposure is greater than a reference electrical signal with a maximum value within a preset threshold range, it is determined whether the light intensity received by the pixel unit during this timed exposure process exceeds its photosensitivity upper limit. If the first electrical signal is greater than the reference electrical signal with the maximum value, it means that the photosensitivity of the pixel unit has been saturated during this timed exposure process. The pixel unit is controlled to reset and re-expose, and the obtained second electrical signal is continuously output during the exposure process, and the time required for the second electrical signal to reach the reference electrical signal with the minimum value within the threshold range is obtained. The first time is output, and the first time can accurately reflect the exposure intensity of the pixel unit, thereby realizing accurate recording of the strong light signal. The disclosed embodiment can realize two exposure modes, namely, timed exposure and quantitative exposure. The timed exposure mode can be used to perform photosensitivity imaging for weak light signals, and the quantitative exposure mode can be used to perform photosensitivity imaging for strong light signals, thereby improving the maximum detection light intensity. It can give play to the advantages of low noise and high sensitivity of the timed exposure mode and the advantages of high-speed recording of the quantitative exposure mode, thereby increasing the dynamic range of the image sensor without increasing the hardware cost, and effectively avoiding the limitation of the dynamic range of the image sensor due to hardware limitations such as hardware area.

[0109] In the embodiment of the present disclosure, the reference electrical signal of the threshold range is determined based on the light intensity detection range of the image sensor, and may correspond to the entire light intensity detection range of the image sensor, or may correspond to a section of the light intensity detection range of the image sensor, and the embodiment of the present disclosure does not impose any restrictions on this. In the timed exposure mode, the reference electrical signal with the maximum value within the preset threshold range is used as a comparison standard to compare whether the first electrical signal output by the pixel unit is greater than the reference electrical signal with the maximum value within the preset threshold range, so as to determine whether the first electrical signal exceeds the photosensitivity upper limit. When the first electrical signal exceeds the photosensitivity upper limit, the pixel unit is controlled to perform quantitative exposure. In the quantitative exposure mode, the reference electrical signal with the minimum value within the preset threshold range is used as a comparison standard, which is more sensitive to the detected light intensity of the pixel unit, and helps to achieve a larger dynamic range, and makes the detectable light intensity of the timed exposure mode and the quantitative exposure mode effectively correspond to the entire range corresponding to the preset threshold range, and effectively connects the light intensity detection ranges of the two exposure modes.

[0110] Figure 2 FIG. 1 is a flow chart of another embodiment of the signal processing method disclosed in the present invention. Figure 2 As shown, in Figure 1 On the basis of the illustrated embodiment, the signal processing method of this embodiment further includes:

[0111] According to the comparison result of operation 102 , operation 202 is performed in response to the first electrical signal being not greater than the reference electrical signal of the maximum value.

[0112] 202 , output one reference electrical signal in a reference signal sequence in sequence as a current reference signal.

[0113] The reference signal sequence includes a plurality of reference electrical signals arranged in a sequence with gradually increasing signal values ​​within a threshold range.

[0114] Optionally, in some of the implementations, the above-mentioned threshold range can be expressed as [Vmin, Vmax], and can be pre-set, and the minimum value in the reference signal sequence can be the minimum value Vmin within the threshold range [Vmin, Vmax]; or, the minimum value in the reference signal sequence can also be an intermediate value or a nearby value within [Vmin, Vmax], or, it can also be any value between Vmin and the intermediate value, and the embodiments of the present disclosure are not limited to this.

[0115] In the reference signal sequence, the difference between any two adjacent reference electrical signals may be a preset interval value, that is, the multiple reference electrical signals in the reference signal sequence increase in sequence according to the preset interval value ΔV.

[0116] Alternatively, in the reference signal sequence, the ratio between any two adjacent reference electrical signals is a preset ratio c, that is, the multiple reference electrical signals in the reference signal sequence are linearly increased in sequence according to the preset ratio c.

[0117] 204 , obtaining the time required for the current reference signal to reach the first electrical signal as the second time.

[0118] 206, output the second time.

[0119] Based on this embodiment, the first electrical signal is not greater than the reference electrical signal of the maximum value, which indicates that the first electrical signal is not saturated during this timed exposure process and can accurately reflect the exposure intensity of the pixel unit. The reference electrical signals starting from the minimum value within the threshold range and gradually increasing to the maximum value according to the preset interval value are output in sequence, and the time required for the current reference signal to reach the first electrical signal is obtained. The size of the first electrical signal can be represented by the time, and the exposure intensity of the pixel unit can be reflected by the time, thereby realizing the analog-to-digital conversion of the first electrical signal.

[0120] Optionally, see Figure 2 In some implementations, in operation 108, specifically, a first time and first exposure mode identification (ID) information for identifying a quantitative exposure mode may be output; in operation 206, specifically, a second time and second exposure mode identification information for identifying a timed exposure mode may be output.

[0121] The exposure mode identification information is outputted simultaneously with the output time, so as to determine the meaning of the output time based on the exposure mode identification information, thereby determining the exposure intensity of the pixel unit.

[0122] Optionally, in some of the implementations, the image sensor of the embodiment of the present disclosure specifically includes a pixel array formed by m rows and n columns of pixel units, m signal readout circuits and m processing circuits, wherein each signal readout circuit and each processing circuit corresponds to a row of pixel units in the pixel array, and the values ​​of m and n are respectively integers greater than 1.

[0123] In this implementation, each column of pixel units in each row of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the corresponding row processing circuit. Depending on the exposure mode, the electrical signal may be a first electrical signal or a second electrical signal. The signal readout circuit corresponding to each row of pixel units sequentially polls each column of pixel units in the corresponding row of pixel units in turn according to the control of the corresponding row processing circuit, and performs operations 102, 106-108 in the above embodiment, or performs operations 202-206 in the above embodiment. The processing circuit of the row corresponding to the signal readout circuit performs the above operation 104 in response to the reference electrical signal that the first electrical signal is greater than the maximum value according to the comparison result signal output by the signal readout circuit.

[0124] Optionally, in some other implementations, the image sensor of the embodiment of the present disclosure specifically includes a pixel array formed by m rows and n columns of pixel units, n signal readout circuits and n processing circuits, each signal readout circuit corresponds to a column of pixel units in the pixel array, and the values ​​of m and n are respectively integers greater than 1.

[0125] In this implementation, each column of pixel units in each column of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the processing circuit. Depending on the exposure mode, the electrical signal may be a first electrical signal or a second electrical signal. The signal readout circuit corresponding to each column of pixel units, in turn, polls and connects to each row of pixel units in the corresponding column of pixel units according to the control of the corresponding row processing circuit, and performs operations 102, 106-108 in the above embodiment, or performs operations 202-206 in the above embodiment. The processing circuit of the column corresponding to the signal readout circuit performs the above operation 104 in response to the reference electrical signal that the first electrical signal is greater than the maximum value according to the comparison result signal output by the signal readout circuit.

[0126] The following is an example of an application embodiment of processing an electrical signal output by a pixel unit to illustrate the signal processing method of the embodiment of the present disclosure:

[0127] In the initial reset stage, the pixel unit is controlled to reset and the charge in the pixel unit is cleared;

[0128] In the timed exposure stage, the pixel unit is controlled to perform timed exposure, the pixel unit is exposed for a fixed time (i.e., a preset exposure time), the pixel unit receives the light signal to generate photogenerated charge, and generates a first electrical signal representing the intensity of this exposure;

[0129] In the signal reading stage, the pixel unit is controlled to output a first electrical signal to the outside, and at the same time output a reference electrical signal of the maximum value within a preset threshold range, and compare whether the first electrical signal is greater than the reference electrical signal of the maximum value, to determine whether the first electrical signal exceeds the upper limit of photosensitivity. If the first electrical signal is greater than the reference electrical signal of the maximum value, it means that the first electrical signal exceeds the upper limit of photosensitivity, and the pixel unit has generated saturated first electrical signals during this timed exposure. Otherwise, it means that the first electrical signal is not saturated during this timed exposure. Only when the first electrical signal is not saturated can its exposure intensity be accurately reflected. Therefore, if the first electrical signal is saturated, the first electrical signal at this time cannot correctly reflect the exposure intensity this time, and another quantitative exposure is required. Before the quantitative exposure, the pixel unit is first controlled to reset, and the charge in the pixel unit is cleared and then the pixel unit is controlled to start exposure. At the same time, a reference electrical signal with a minimum value within the threshold range is output, and the timer starts timing. The pixel unit continuously outputs an electrical signal (i.e., the second electrical signal) during the exposure process until the second electrical signal reaches the reference electrical signal with the minimum value, stops timing, and outputs the timing result (i.e., the first time) and the first exposure mode identification information. The first exposure mode identification information is used to indicate that the timing result at this time is a data result under the quantitative exposure mode. The exposure intensity can be reflected according to the first time when the second electrical signal reaches the reference electrical signal with the minimum value, and the light intensity of the pixel unit detection space can be known. Among them, the shorter the first time, the greater the light intensity of the pixel unit detection space in the first time, and the accurate recording of the strong light signal is achieved. If the first electrical signal is not saturated, a reference electrical signal is output in sequence, starting from the minimum value within the threshold range and gradually increasing to the maximum value according to the preset interval value. At the same time, the timer starts timing until the reference electrical signal reaches the first electrical signal, and the timing is stopped. The timing result at this time can represent the size of the first electrical signal, thereby realizing the analog-to-digital conversion of the first electrical signal, and outputting the timing result (i.e., the second time) and the second exposure mode identification information. The second exposure mode identification information is used to indicate that the timing result at this time is the data result under the timed exposure mode, wherein the longer the second time is, the greater the light intensity of the pixel unit detection space within the second time is.

[0130] For example, if the maximum value of the reference electrical signal within the preset threshold range is 1V, the minimum value of the reference electrical signal is 1mV, the preset exposure time of the timed exposure is 10ms, and the period of the timer input clock signal is 10ns. If the exposure intensity can make the first electrical signal reach 1V within the exposure time of 10ms, it is equivalent to making the electrical signal reach 1mV within the exposure time of 10μs. Therefore, the maximum exposure time of the quantitative exposure mode can be set to 10us, and the minimum time resolution of the quantitative exposure is the period of the clock signal of 10ns. The maximum light intensity that can be detected can make the electrical signal reach 1mV within the exposure time of 10ns, which is equivalent to 1000 times the maximum detection light intensity of the timed exposure. Therefore, the maximum detection light intensity is increased relative to the timed exposure mode, and the dynamic range of the image sensor is increased without increasing the hardware cost.

[0131] In the embodiment of the present disclosure, for the same pixel unit, after the timing result T and the exposure mode ID are output based on the embodiment of the present disclosure, it can be determined based on the exposure mode ID whether the exposure mode adopted is a timed exposure mode or a quantitative exposure mode. Since in the quantitative exposure mode, the shorter the timing result T (as the first time), the greater the light intensity of the pixel unit detection space in the corresponding time, the light intensity value in the corresponding time can be estimated based on the timing result T in a preset manner. For example, the light intensity value i in the time can be obtained in the following manner: i=a*1 / T. Wherein, a is a constant greater than zero, and the specific value of a can be set according to actual needs. Since in the timed exposure mode, the longer the timing result T (as the second time), the greater the light intensity of the pixel unit detection space in the corresponding time, the light intensity value in the corresponding time can be estimated based on the timing result T in a preset manner. For example, the light intensity value i in the time can be obtained in the following manner: i=b*T. Wherein, b is a constant greater than zero, and the specific value of b can be set according to actual needs. Based on the timing result T and exposure mode ID output by the pixel unit each time, the light intensity value of the detection space within the corresponding time can be determined. Based on the timing result T and exposure mode ID output by the pixel unit multiple times and arranged based on the time sequence relationship, the light intensity value and its change in the detection space in time sequence can be determined accordingly.

[0132] For an image sensor including a pixel array formed by m rows and n columns of pixel units, each pixel unit in the pixel array works independently of each other, and respectively realizes the time domain acquisition timing result and exposure mode ID output of the light signal in a space in the observation scene. The spaces corresponding to different pixel units do not overlap, and the pixel units in the pixel array cooperate with each other to cover the entire observation scene, thereby realizing the time domain acquisition, timing result and exposure mode ID output, and light intensity value acquisition of the light signal in the entire observation scene. Therefore, the light intensity value and its change of the light signal corresponding to the entire observation scene can be obtained.

[0133] The embodiments of the present disclosure do not limit the specific method of determining the light intensity based on the time result output by each pixel unit and the exposure mode identification information, nor the application based on the light intensity.

[0134] Optionally, in an application of an embodiment of the present disclosure, after obtaining the light intensity value and its change of the light signal corresponding to the entire observation scene, target detection can also be performed based on the light intensity value of one or more spaces in the observation scene at each moment. Since the visual information of a specific target is basically unchanged in a specific observation scene, target tracking can be achieved based on the light intensity value of one or more spatial regions in the observation scene in the time domain.

[0135] Optionally, in another application of the embodiments of the present disclosure, after obtaining the light intensity value of the corresponding space at each corresponding time, a preset pulse reconstruction algorithm can be used to generate a reconstructed image of the observation scene at each sampling moment based on the light intensity value of all spaces in the observation scene at each moment; wherein the grayscale value of each pixel point in the reconstructed image represents the light intensity value of the spatial area corresponding to the corresponding pixel unit, that is, in the reconstructed image at each moment, the pixel value of each pixel point (i, j) is the light intensity value of the spatial area corresponding to the pixel unit corresponding to the pixel point.

[0136] The above-mentioned preset pulse reconstruction algorithm can be, for example, a pulse reconstruction algorithm (TFI) based on inter-peak potential interval (ISI), a pulse reconstruction algorithm (TFP) based on fixed window sliding, a pulse reconstruction algorithm based on convolutional neural network (CNN), etc. The embodiments of the present disclosure do not limit the specific pulse reconstruction algorithm used.

[0137] Figure 3 The structure diagram of an embodiment of the image sensor of the present disclosure is shown in FIG. The image sensor of the embodiment of the present disclosure can be used to implement the signal processing method of any embodiment of the present disclosure, that is, the signal processing method of any embodiment of the present disclosure can be implemented based on the image sensor provided by any embodiment of the present disclosure, and the two can refer to and quote each other. The signal processing method of the embodiment of the present disclosure is further described below in conjunction with the image sensor of the embodiment of the present disclosure.

[0138] like Figure 3 As shown, the image sensor according to the embodiment of the present disclosure includes a pixel unit 302 and a signal readout circuit 304 .

[0139] The pixel unit 302 is used to receive a light signal within a preset exposure time to generate photogenerated charges, and output a first electrical signal based on the photogenerated charges generated within the preset exposure time; and start exposure after resetting according to the control of the processing circuit, receive a light signal during the exposure process to generate photogenerated charges, obtain a second electrical signal based on the photogenerated charges and continuously output the second electrical signal.

[0140] The signal readout circuit 304 is used to compare whether the first electrical signal output by the pixel unit 302 is greater than a reference electrical signal of a maximum value within a preset threshold range; in response to the first electrical signal being greater than the reference electrical signal of a maximum value, obtain the time required for the second electrical signal output by the pixel unit 302 to reach the reference electrical signal of a minimum value within the threshold range as the first time, and output the first time, so as to obtain, based on the first exposure mode identification information, that the first time is the time information in the quantitative exposure mode, that is, the first time is the time required for the electrical signal to reach the reference electrical signal of a minimum value within the threshold range, thereby determining the exposure intensity.

[0141] In some optional embodiments, when the signal readout circuit 304 outputs the first time, it may also output first exposure mode identification information for identifying the quantitative exposure mode.

[0142] Based on this embodiment, a hardware implementation scheme of an image sensor is provided, in which a pixel unit in the image sensor can be exposed in a timed exposure mode and output a first electrical signal, and by comparing whether the first electrical signal output by the pixel unit under the timed exposure is greater than a reference electrical signal with a maximum value within a preset threshold range, it is determined whether the light intensity received by the pixel unit during this timed exposure process exceeds its photosensitivity upper limit, if the first electrical signal is greater than the reference electrical signal with the maximum value, it means that the photosensitivity of the pixel unit during this timed exposure process has been saturated, the pixel unit is controlled to reset and re-expose, and the obtained second electrical signal is continuously output during the exposure process, and the reference electrical signal with the second electrical signal reaching the minimum value within the threshold range is obtained. The time required for the signal is output as the first time, and the first time can accurately reflect the exposure intensity of the pixel unit, thereby realizing accurate recording of the strong light signal. The embodiment of the present disclosure can realize two exposure modes: timed exposure and quantitative exposure. The timed exposure mode can be used to perform photosensitivity imaging for weak light signals, and the quantitative exposure mode can be used to perform photosensitivity imaging for strong light signals, thereby improving the maximum detected light intensity, and can give play to the advantages of low noise and high sensitivity of the timed exposure mode and the high-speed recording advantage of the quantitative exposure mode, thereby increasing the dynamic range of the image sensor without increasing the hardware cost, and effectively avoiding the limitation of the dynamic range of the image sensor due to hardware limitations such as hardware area.

[0143] Optionally, in some other embodiments, the signal readout circuit 304 may also be used to: in response to a reference electrical signal in which the first electrical signal is not greater than a maximum value, sequentially output a reference electrical signal in a reference signal sequence as a current reference signal, the reference signal sequence including a plurality of reference electrical signals whose signal values ​​gradually increase within a threshold range, and obtain the time required for the current reference signal to reach the first electrical signal as a second time, and output the second time.

[0144] In some optional embodiments, the signal readout circuit 304 may also output second exposure mode identification information for identifying the timed exposure mode when outputting the second time, so as to determine the exposure intensity based on the second exposure mode identification information, that the second time is the time information in the timed exposure mode, and that the second time is the time required for the current reference signal to reach the first electrical signal.

[0145] Optionally, in some of the implementations, the minimum value in the reference signal sequence may be the minimum value Vmin within the threshold range [Vmin, Vmax]; or, it may be an intermediate value or a value nearby within the threshold range [Vmin, Vmax]; or, it may be any value between Vmin and the intermediate value, which is not limited in this regard in the embodiments of the present disclosure.

[0146] In the reference signal sequence, the difference between any two adjacent reference electrical signals may be a preset interval value, that is, the multiple reference electrical signals in the reference signal sequence increase in sequence according to the preset interval value △V. Alternatively, in the reference signal sequence, the ratio between any two adjacent reference electrical signals is a preset ratio c, that is, the multiple reference electrical signals in the reference signal sequence increase linearly in sequence according to the preset ratio c. The embodiments of the present disclosure are not limited to this.

[0147] Figure 4 FIG. 1 is a schematic diagram of a structure of a signal readout circuit according to an embodiment of the present disclosure. Figure 4 As shown, in Figure 3 Based on the embodiment shown, the signal readout circuit 304 may include: a comparator 3042, a threshold signal output circuit 3044 and a timer 3046. Wherein:

[0148] The positive input terminal of the comparator 3042 is connected to the output terminal of the pixel unit 302, and is used to receive the electrical signal Vpixel output by the pixel unit 302, including the first electrical signal or the second electrical signal; the negative input terminal of the comparator 3042 is connected to the first output terminal of the threshold signal output circuit 3044, and is used to receive the reference electrical signal output by the threshold signal output circuit 3044; the output terminal of the comparator 3042 is respectively connected to the first input terminal of the threshold signal output circuit 3044 and the first input terminal of the timer 3046, and is used to output a comparison result signal to the threshold signal output circuit 3044 and the timer 3046. The comparator 3042 can output a high level (1) as a comparison result signal when its positive input signal is greater than its negative input signal, that is, when the electrical signal output by the pixel unit 302 is greater than the reference electrical signal output by the threshold signal output circuit 3044, and output a low level (0) as a comparison result signal otherwise. Thus, based on the comparison result signal output by the comparator, it can be determined whether the electrical signal output by the pixel unit 302 is greater than the reference electrical signal output by the threshold signal output circuit 3044.

[0149] The first input terminal of the threshold signal output circuit 3044 is connected to the output terminal of the comparator 3042, and is used to receive the comparison result signal; the second input terminal of the threshold signal output circuit 3044 is used to receive the first external control signal, and the first external control signal is used to control the threshold signal output circuit 3044 to output a reference electrical signal within a preset threshold range; the first output terminal of the threshold signal output circuit 3044 is connected to the negative input terminal of the comparator 3042, and is used to output a reference electrical signal within a preset threshold range; the second output terminal of the threshold signal output circuit 3044 is used to output exposure mode identification information according to the comparison result signal.

[0150] The first input terminal of the timer 3046 is connected to the output terminal of the comparator 3042 for receiving the comparison result signal; the output terminal of the timer 3046 is used to output the timing result when the comparison result signal changes.

[0151] Based on this embodiment, a hardware circuit structure implementation scheme of a signal readout circuit is provided. Based on this hardware circuit structure implementation scheme, it is possible to realize exposure of the pixel unit using a timing exposure mode and a quantitative exposure mode, as well as reading and encoding of the exposure signal.

[0152] In a specific application, the reference electric signal Vth output by the threshold signal output circuit 3044 by default is a reference electric signal of the maximum value within the preset threshold range, and the output exposure mode identifier is 0. Corresponding to the above-mentioned timed exposure mode and quantitative exposure mode, the threshold signal output circuit 3044 also has a corresponding working mode, a timed exposure mode consistent with the timed exposure mode of the pixel unit, and according to the comparison result signal output by the comparator, when the electric signal output by the pixel unit 302 is greater than the reference electric signal output by the threshold signal output circuit 3044, it enters the quantitative exposure mode consistent with the quantitative exposure mode of the pixel unit; when the electric signal output by the pixel unit 302 is not greater than the reference electric signal output by the threshold signal output circuit 3044, it enters the scanning mode to output a reference signal sequence with gradually increasing signal values ​​within the threshold range.

[0153] Optionally, in some of the implementations, the timer may start timing when receiving a comparison result signal output by the comparator 3042, and stop timing and output the timing result when the comparison result signal changes (i.e., flips), for example, when the comparison result signal changes from 1 to 0, and from 0 to 1.

[0154] The timer 3046 may also be provided with a second input terminal for receiving a clock signal of a preset frequency for timing. That is, the timer 3046 may be timed by a clock signal (1, 0) of a preset frequency set internally, or by a clock signal of a preset frequency inputted from an external second input terminal, and the disclosed embodiment does not limit this. The timing result of the timer 3046 may be specifically represented by a counting result. After the timing starts, the timer 3046 may add 1 to the counting result every time the clock signal flips twice (i.e., the clock signal flips from 1 to 0, and then from 0 to 1, or vice versa). The timing function may be realized by a clock signal of a preset frequency, and the counting result may be outputted as the timing result. Since the clock signal changes at a fixed frequency (i.e., a fixed period), the counting result multiplied by the clock period may represent the time.

[0155] Figure 5 FIG. 1 is a schematic diagram of a structure of a threshold signal output circuit according to an embodiment of the present disclosure. Figure 5 As shown, in Figure 4 Based on the embodiment shown, the threshold signal output circuit 3044 includes: an operational amplifier 402, a constant current power supply 404, a capacitor 406, a trigger 408, a first switch (S1) 410, a second switch (S2) 412, a third switch (S3) 414 and a fourth switch (S4) 416. Wherein:

[0156] The positive input terminal of the operational amplifier 402 is connected to a reference electrical signal source of a minimum value through a third switch 414, and the reference electrical signal source of the minimum value can provide a reference electrical signal Vmin of a minimum value within a threshold range, and is connected to a reference electrical signal source of a maximum value through a fourth switch 416, and the reference electrical signal source of the maximum value can provide a reference electrical signal Vmax of a maximum value within the threshold range; the negative input terminal of the operational amplifier 402 is connected to a constant current power supply 404 through a second switch 412, and is connected to the output terminal of the operational amplifier 402 through a first switch 410, and is connected to the positive electrode of the capacitor 406; the output terminal of the operational amplifier 402 is respectively connected to the negative input terminal of the comparator 3042 and the negative electrode of the capacitor 402.

[0157] The first input terminal of the trigger 408 is connected to the power signal VDD; the second input terminal of the trigger 408 is connected to the output terminal of the comparator 3042 for receiving the comparison result signal; the output terminal of the trigger 408 is used to output a data flag for indicating the exposure mode identification information.

[0158] Based on this embodiment, a specific implementation circuit structure of a threshold signal output circuit is provided. When it is necessary to output a reference electrical signal Vmin of the minimum value within a preset threshold range, S1 and S3 are closed, S2 and S4 are disconnected, the positive terminal of the operational amplifier is connected to Vmin, the negative terminal and the output terminal are short-circuited, and the operational amplifier can output Vmin. When it is necessary to output a reference electrical signal Vmax of the maximum value within the preset threshold range, S1 and S4 are closed, S2 and S3 are disconnected, the positive terminal of the operational amplifier is connected to Vmax, the negative terminal and the output terminal are short-circuited, and the operational amplifier can output Vmax. When it is necessary to output a reference signal sequence with a gradually increasing signal value within the threshold range, S1 and S3 are first closed, S2 and S4 are disconnected, the reference electrical signal is reset to Vmin, and then S2 and S3 are closed, S1 and S4 are disconnected, the constant current power supply charges the capacitor with a fixed current, and the voltage across the capacitor gradually increases, so that the reference signal sequence (multiple voltage signals) output by the operational amplifier increases at a fixed ratio. Thus, it is realized that the threshold signal output circuit can output a reference electrical signal of any value within the threshold range.

[0159] Figure 6 FIG. 2 is a schematic diagram of the structure of another embodiment of the threshold signal output circuit in the disclosed embodiment. Figure 6 As shown, in Figure 5 On the basis of the embodiment shown, the threshold signal output circuit 3044 of this embodiment may further include: a first inverter 502, a second inverter group 504, or a logic circuit 506, a third inverter 508 and a fifth switch 510. The second inverter group 504 includes 2k+1 second inverters connected in sequence, k is an integer not less than 0, and the specific value of k can be set according to actual needs, which is not limited in the embodiment of the present disclosure.

[0160] The input end of the first inverter 502 serves as the second input end of the threshold signal output circuit 3044, and is used to receive the first external control signal Vs4. The first external control signal Vs4 can be input to the processing circuit, and is used to control the fourth switch 416 and the fifth switch (S5) 510 to be turned on or off; the output end of the first inverter 502 is connected to the input end of the first second inverter in the second inverter group 504, and is used to output the third control signal Vs3, and the third control signal Vs3 is used to control the third switch 414 to be turned on or off.

[0161] The output terminal of any second inverter in the second inverter group 504 is connected to the input terminal of the next adjacent second inverter, and the output terminal of the last second inverter in the second inverter group 504 is connected to the first input terminal of the OR logic circuit 506 .

[0162] The second input of the OR logic circuit 506 is connected to the ground terminal VSS through the fifth switch 510 , and the output of the OR logic circuit 506 is connected to the input of the third inverter 508 for outputting a first control signal Vs1 for controlling the third switch 414 to be turned on or off.

[0163] The output end of the third inverter 508 is connected to the second switch 412 for outputting a second control signal Vs2 . The second control signal Vs2 is used to control the second switch 412 to be turned on or off.

[0164] In this embodiment, when the comparison result signal flips from a low level to a high level (i.e., 1), the trigger will output a high level (i.e., 1), that is, the data flag is a high level (i.e., 1), until S5 is turned on, the data flag will be reset to a low level (i.e., 0).

[0165] Based on the threshold signal output circuit of this embodiment, during the timed exposure of the pixel unit, the processing circuit continuously inputs a high-level first external control signal Vs4 (i.e., 1) to the first inverter 502. At this time, the high-level Vs4 controls S4 and S5 to close and turn on the circuit in which they are located; Vs4 passes through an inverter to obtain a low-level third control signal Vs3 (i.e., 0), thereby controlling S3 to be disconnected and the circuit in which it is located to be disconnected; the low-level Vs3 passes through 2n+1 inverters for a certain period of time and is inverted to a high level before being input to one input terminal of the OR logic circuit, or the other input terminal of the logic circuit is input The low-level signal VSS (i.e. 0) outputs the high-level first control signal Vs1 (i.e. 1), thereby controlling S1 to close and turn on the circuit it is in; the high-level Vs1 then passes through an inverter to obtain the low-level second control signal Vs2 (i.e. 0), thereby controlling S2 to open and turn off the circuit it is in. Therefore, during the timed exposure process, s1, s4, and s5 are closed to turn on the circuit they are in, and s2 and s3 are opened to turn off the circuit they are in, and the data flag bit output by the trigger is reset to a low level (i.e. 0), so that the threshold signal output circuit outputs a reference electrical signal Vmax with the maximum value within the preset threshold range.

[0166] After the comparator has finished comparing the first electrical signal output by the pixel unit with the reference electrical signal Vmax and outputs the comparison result signal, Vs4 changes from a high level to a low level, and controls S4 and S5 to be disconnected so that the circuit in which they are located is disconnected; Vs3 changes from a low level to a high level, and controls S3 to be closed so that the circuit in which it is located is turned on. If the comparison result signal is a high level, that is, the first electrical signal is greater than the reference electrical signal Vmax, the data flag will become a high level, and the quantitative exposure mode is entered at this time, and Vs1 is also a high level, thereby controlling S1 to be closed so that the circuit in which it is located is turned on; Vs2 is a low level, thereby controlling S2 to be disconnected so that the circuit in which it is located is turned off. At this time, S1 and S3 are turned on, and S2 and S4 are turned off, so that the threshold signal output circuit outputs the reference electrical signal Vmin with the minimum value within the preset threshold range. If the comparison result signal is a low level, that is, the first electrical signal is not greater than the reference electrical signal Vmax, the data flag will also be a low level, Vs4 changes from a high level to a low level, and controls S4 and S5 to be disconnected so that the circuit in which it is located is disconnected; Vs3 changes from a low level to a high level, and controls S3 to be closed so that the circuit in which it is located is turned on. Since Vs4 needs to pass through 2k+1 second inverters to be transmitted to the OR logic circuit, there is a certain transmission delay. After Vs4 changes to a low level, Vs1 is a high level and Vs2 is a low level in a short period of time corresponding to the transmission delay. Therefore, in this short period of time, S1 and S3 are closed, and S2 and S4 are disconnected, so that the threshold signal output circuit outputs a reference electrical signal Vmin with the minimum value within the preset threshold range. After this short period of time, Vs1 becomes a low level and Vs2 becomes a high level. The constant current power supply starts to charge the capacitor, so that the reference electrical signal output by the threshold signal output circuit starts to rise at a fixed ratio from the minimum reference electrical signal Vmin, thereby realizing the scanning mode.

[0167] Figure 7 FIG. 1 is a schematic diagram of the structure of another embodiment of the image sensor disclosed in the present invention. Figure 7 As shown, on the basis of any of the above embodiments, in this embodiment, the image sensor also includes a processing circuit 306, which is connected to the input end of the first inverter 502, and is used to output a first external control signal Vs4 to the input end of the first inverter 502. Specifically, during the timed exposure of the pixel unit, a high-level first external control signal Vs4 can be continuously input to the first inverter 502 to control the threshold signal output circuit 3044 to implement the corresponding functions of the above-mentioned signal reading stage.

[0168] Figure 8 FIG. 1 is a schematic diagram of the structure of another embodiment of the image sensor disclosed in the present invention. Figure 8As shown, in some implementations, the image sensor specifically includes a pixel array 60 formed by m rows and n columns of pixel units 302, m signal readout circuits 304, and m processing circuits 306, each signal readout circuit 304 and each processing circuit 306 are connected to a row of pixel units in the pixel array 60, and each processing circuit 306 is connected to the signal readout circuit 304 of the corresponding row. Among them, the values ​​of m and n are respectively integers greater than 1. Each processing circuit 306 can control each pixel unit in the corresponding row of pixel units to perform exposure after reset according to the preset logic, and output an electrical signal to the signal readout circuit 304 of the corresponding row after the exposure is completed, and control the signal readout circuit 304 of the corresponding row to process the electrical signal output by the pixel unit.

[0169] Alternatively, in some other implementations, the image sensor may also specifically include a pixel array 60 formed by arranging m rows and n columns of pixel units 302, n signal readout circuits 304, and n processing circuits 306 (not shown in the figure), each signal readout circuit 304 and each processing circuit 306 are correspondingly connected to a column of pixel units 302 in the pixel array, and each processing circuit 306 is connected to the signal readout circuit 304 of the corresponding column. Each processing circuit 306 can control each pixel unit in the corresponding column to perform exposure after reset according to a preset logic, and output an electrical signal to the signal readout circuit 304 of the corresponding column after the exposure is completed, and control the signal readout circuit 304 of the corresponding row to process the electrical signal output by the pixel unit.

[0170] Fig. 9 FIG. 1 is a schematic diagram of the structure of an embodiment of a pixel unit in the present disclosure. Fig. 9 As shown, based on any embodiment of the present disclosure, the pixel unit 302 may include: a photodiode (PD) 3022, a transfer transistor (TX) 3024, a floating diffusion region (FD) 3026, a reset transistor (RST) 3028, a source follower transistor (SF) 3030 and a selection transistor (SEL) 3032. Wherein:

[0171] One end of the photodiode 3022 is grounded; the other end of the photodiode 3022 is connected to one end of the floating diffusion region 3026 and the gate end of the source follower transistor 3030 through the transfer transistor 3024. Optionally, the photodiode can also be other photoelectric conversion components that can realize photoelectric conversion, so as to realize the conversion of light signals into photoelectric charges. Under illumination conditions, the photodiode receives light signals and generates photogenerated charges. Before the transfer transistor is closed, the photogenerated charges are confined in the depletion region of the photodiode by the energy potential well, and the photoelectric charges in the photodiode will gradually accumulate.

[0172] The source terminal of the transfer transistor 3024 is connected to the other end of the photodiode 3022; the drain terminal of the transfer transistor 3024 is respectively connected to one end of the floating diffusion area 3026 and the gate terminal of the source follower transistor 3030; the gate terminal of the transfer transistor 3024 is used to receive a second external control signal to control the transfer transistor 3024 to be turned on or off according to the second external control signal. After the transfer transistor 3024 is turned on, the photogenerated charge generated by the photodiode 3022 can be transferred from the photodiode 3022 to the floating diffusion area 3026.

[0173] One end of the floating diffusion region 3026 is respectively connected to the source end of the reset transistor 3028, the gate end of the source follower transistor 3030, and the other end of the photodiode 3022 through the transfer transistor 3024; the other end of the floating diffusion region 3026 is grounded. The floating diffusion region performs reset when the reset transistor is turned on; when the reset transistor is turned off and the transfer transistor is turned on, the floating diffusion region receives the photogenerated charge generated by the photodiode.

[0174] The source terminal of the reset transistor 3028 is connected to one end of the floating diffusion area 3026; the drain terminal of the reset transistor 3028 is connected to the power supply signal VDD; the gate terminal of the reset transistor 3028 is used to receive a third external control signal to control the reset transistor 3028 to be turned on or off according to the third external control signal. After the reset transistor 3028 is turned on, the voltage signal of the floating diffusion area 3026 can be reset to reset the floating diffusion area 3026. When the reset transistor is turned on, the floating diffusion area is turned on by the power supply signal VDD to achieve the reset of the floating diffusion area, and the voltage on the floating diffusion area is charged to a high level. Under normal circumstances, the floating diffusion area is reset before generating photoelectric charges. Under illumination conditions, photogenerated charges are generated in both the photodiode and the floating diffusion area, and the voltage on the floating diffusion area will gradually decrease under the action of the photogenerated charges.

[0175] The source terminal of the source follower transistor 3030 is connected to the drain terminal of the selection transistor 3032; the drain terminal of the source follower transistor 3030 is connected to the power supply signal VDD; the gate terminal of the source follower transistor 3030 is respectively connected to one end of the floating diffusion area 3026 and the drain terminal of the transfer transistor 3024. The gate terminal of the source follower transistor is connected to the floating diffusion area, and follows the potential change of the floating diffusion area to obtain a potential signal. This process does not affect the photoelectric conversion of the photodiode. Under the premise that the transfer transistor is disconnected, the source follower transistor reads the potential change of the floating diffusion area, and the photodiode can continue to collect light signals and generate photoelectric charges through photoelectric conversion.

[0176] The source terminal of the selection transistor 3032 is connected to the input terminal of the signal readout circuit 304 as the output terminal of the pixel unit 302; the drain terminal of the selection transistor 3032 is connected to the source terminal of the source follower transistor 3030; the gate terminal of the selection transistor 3032 is used to receive a fourth external control signal to control the selection transistor 3032 to be turned on or off according to the fourth external control signal. After the selection transistor 3032 is turned on, the input terminal of the signal readout circuit 304 (specifically, the positive input terminal of the comparator 3042) inputs the electrical signal Vpixel, including the first electrical signal or the second electrical signal.

[0177] Optionally, in some of the implementations, the processing circuit 3026 is also respectively connected to the gate terminal of the transfer transistor 3024, the gate terminal of the reset transistor 3028, and the gate terminal of the selection transistor 3032 in the pixel unit of the corresponding row or column, and is used to output a second external control signal, a third external control signal, and a fourth external control signal to the gate terminal of the transfer transistor 3024, the gate terminal of the reset transistor 3028, and the gate terminal of the selection transistor 3032 in the pixel unit of the corresponding row or column, so as to control the transfer transistor 3024, the reset transistor 3028, and the selection transistor 3032 to be turned on or off.

[0178] The following is an example of an image sensor including a pixel array formed by an arrangement of m*n pixel units, n signal readout circuits and n processing circuits 306, where each signal readout circuit and each processing circuit corresponds to a column of pixel units in the pixel array, to illustrate the working process of the image sensor of the embodiment of the present disclosure. Each processing circuit sends a second external control signal, a third external control signal and a fourth external control signal to the pixel units of the corresponding column in sequence according to a preset logic to control the corresponding pixel unit to perform timed exposure after resetting, and sends a first external control signal to the signal readout circuit of the corresponding column during the timed exposure of the corresponding pixel unit, and sends a second external control signal and a fourth external control signal to the pixel unit after the timed exposure of the corresponding pixel unit ends, so as to control the corresponding pixel unit to be turned on with the signal readout circuit of the corresponding column to output a first electrical signal to the signal readout circuit. Taking a pixel unit as an example, specifically:

[0179] In the initial reset stage, the pixel unit is reset by sending a second external control signal, a third external control signal and a fourth external control signal to the pixel unit to control the transfer transistor, the reset transistor and the selection transistor to close, thereby clearing the charge on the photodiode and the floating diffusion area of ​​the pixel unit;

[0180] Timed exposure stage: Control the pixel unit to perform timed exposure, that is, expose for a preset exposure time. By sending the second external control signal, the third external control signal and the fourth external control signal to the pixel unit, the transfer transistor, the reset transistor and the selection transistor are controlled to be disconnected, and the photodiode receives the light signal within the preset exposure time to generate photogenerated charge and store the photogenerated charge; at the same time, during the timed exposure of the pixel unit, a high-level first external control signal is sent to the corresponding signal readout circuit;

[0181] Signal reading stage: After the preset exposure time, the pixel unit is controlled to output the first electrical signal. By sending the second external control signal and the fourth external control signal to the pixel unit, the transfer transistor and the selection transistor are controlled to close, and the photogenerated charge on the photodiode is transferred to the floating diffusion area. The high-level voltage on the floating diffusion area closes the source follower diode, and the source follower transistor generates a signal voltage Vpixel (as the above-mentioned first electrical signal) representing the intensity of this exposure. Since the selection transistor is turned on, the signal voltage Vpixel is transmitted to the positive input terminal of the comparator in the corresponding signal readout circuit through the selection transistor;

[0182] The reference signal Vth input to the negative input terminal of the comparator defaults to the maximum threshold voltage Vmax (as the reference electrical signal of the maximum value within the above preset threshold range). At this time, the comparator determines whether the signal voltage Vpixel is greater than the maximum threshold voltage Vmax. If the signal voltage Vpixel is greater than the maximum threshold voltage Vmax, the comparator outputs a comparison result signal 1, indicating that the signal voltage Vpixel exceeds the upper limit of the sensitivity of the pixel unit, indicating that the pixel unit has been saturated during this timed exposure. Otherwise, the comparator outputs a comparison result signal 0, indicating that the pixel unit is not saturated during this timed exposure. Only when it is not saturated can the signal voltage Vpixel accurately reflect the exposure intensity of the pixel unit. Therefore, if the pixel unit is saturated, the signal voltage Vpixel at this time cannot correctly reflect the exposure intensity, and another quantitative exposure is required.

[0183] If the pixel unit is saturated, the pixel unit is reset by the above method before quantitative exposure, and the charge in the pixel unit is cleared before controlling the pixel unit to start exposure. At the same time, the threshold signal output circuit outputs the minimum threshold voltage Vmin (as the reference electrical signal of the minimum value within the preset threshold range), and the timer starts timing. The pixel unit continuously outputs the signal voltage Vpixel (as the above second electrical signal) during the exposure process until the signal voltage Vpixel reaches the minimum threshold voltage Vmin. At this time, the comparison result signal output by the comparator is 0, and the comparison result signal is flipped (i.e., from 1 to 0). The timer stops timing and outputs the timing result (as the first time), and the threshold signal output circuit outputs the data flag 1, indicating that the timing result at this time is the data result of the quantitative exposure mode. The timing result when the signal voltage Vpixel reaches the minimum threshold voltage Vmin can reflect the exposure intensity, and can achieve accurate recording of stronger light signals.

[0184] If the pixel unit is not saturated, the threshold signal output circuit starts to scan the output reference signal Vth from the minimum value to the maximum value at a fixed slope. At the same time, the timer starts timing until the reference signal Vth reaches the signal voltage Vpixel. At this time, the comparison result signal 1 output by the comparator is flipped (i.e., from 0 to 1). The timer stops timing and outputs the timing result (as the second time). The threshold signal output circuit outputs the data flag bit 0, indicating that the timing result at this time is the data result of the timed exposure mode. The timing result at this time can represent the size of the signal voltage Vpixel, thereby completing the analog-to-digital conversion of the signal voltage Vpixel.

[0185] In addition, the pixel unit in the embodiment of the present disclosure may also be implemented using other circuit structures. As long as the pixel unit can be reset, exposed, generate an electrical signal representing the exposure intensity and output it to the outside according to the control of the processing circuit, the embodiment of the present disclosure does not limit the specific structure of the pixel unit.

[0186] The image sensor of the embodiment of the present disclosure may adopt various exposure incident modes, such as a direct incidence exposure mode or a back-illumination exposure mode; in addition, different shutter modes may also be adopted, such as a global exposure shutter and a rolling exposure shutter, which is not limited by the embodiment of the present disclosure.

[0187] The image sensor and the signal processing method of the embodiments of the present disclosure correspond to each other in terms of specific implementation and beneficial technical effects, and the relevant contents can be referenced to each other and will not be repeated here.

[0188] Fig.10 FIG. 1 is a schematic diagram of the structure of an embodiment of the electronic device disclosed in the present invention. Fig.10As shown, the electronic device includes: a processor 70, a memory 80 connected to the processor 70 for communication, and an image sensor 90 provided by any embodiment of the present disclosure.

[0189] The memory 80 is used to store computer executable instructions.

[0190] The processor 70 is used to execute the computer-executable instructions stored in the memory 70 to control the image sensor 90 to implement the signal processing method of any embodiment of the present disclosure.

[0191] Optionally, in some of the implementations, the electronic device of the embodiments of the present disclosure may include, but is not limited to, any one of the following: a pulse camera, a high-speed camera, a visual camera, an audio player, a video player, a navigation device, a fixed-position terminal, an entertainment unit, a smart phone, a communication device, a mobile device, a device in a motor vehicle, a vehicle-mounted camera, a mobile phone camera, a sports or wearable camera, a traffic camera, an industrial inspection camera, a camera mounted on a flying object, a medical camera, a security camera, or a household appliance camera, etc., that is, the image sensor 90 of the embodiments of the present disclosure may be applied to any of the above-mentioned electronic devices.

[0192] Fig.11 This is a schematic diagram of the structure of an application embodiment of the electronic device disclosed in the present invention. Fig.11 The electronic device according to the embodiment of the present disclosure is described. The electronic device may be any one or both of the first device and the second device, or a stand-alone device independent of them, and the stand-alone device may communicate with the first device and the second device to receive the collected input signals from them.

[0193] like Fig.11 As shown, the electronic device includes one or more processors, a memory and an image sensor. The processor may be a central processing unit (CPU) or other forms of processing units with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device, such as an image sensor, to perform desired functions.

[0194] The memory may store one or more computer program products, and the memory may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include, for example, a read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program products may be stored on the computer-readable storage medium, and the processor may execute the computer instructions to implement the signal processing methods of the various embodiments of the present disclosure described above and / or other desired functions.

[0195] In one example, the electronic device may further include: an input device and an output device, and these components are interconnected through a bus system and / or other forms of connection mechanisms (not shown). In addition, the input device may also include, for example, a keyboard, a mouse, etc. The output device may output various information to the outside, including determined distance information, direction information, etc. The output device may include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, etc.

[0196] Of course, to simplify, Fig.11 Only some of the components related to the present disclosure in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, according to specific application situations, the electronic device may further include any other appropriate components.

[0197] In addition to the above-mentioned methods and devices, an embodiment of the present disclosure may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the signal processing method according to various embodiments of the present disclosure described in the above part of this specification.

[0198] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the disclosed embodiments, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0199] In addition, an embodiment of the present disclosure may also be a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the signal processing method according to various embodiments of the present disclosure described in the above part of this specification.

[0200] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0201] Any signal processing method provided in the embodiments of the present disclosure may be executed by any appropriate device with data processing capabilities, including but not limited to: a terminal device and a server, etc. Alternatively, any signal processing method provided in the embodiments of the present disclosure may be executed by a processor, such as the processor executing any signal processing method mentioned in the embodiments of the present disclosure by calling corresponding instructions stored in a memory.

[0202] The basic principles of the present disclosure are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, and are not limitations. The above details do not limit the present disclosure to the necessity of adopting the above specific details to be implemented.

[0203] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0204] The block diagrams of the devices, apparatuses, equipment, and systems involved in this disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including," "comprising," "having," and the like are open words, referring to "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or," and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0205] The method and apparatus of the present disclosure may be implemented in many ways. For example, the method and apparatus of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above order of steps for the method is for illustration only, and the steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Therefore, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0206] It should also be noted that in the apparatus, device and method of the present disclosure, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present disclosure.

[0207] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0208] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A signal processing method, applied to an image sensor, wherein the image sensor comprises a pixel unit, the method comprising: Comparing whether a first electrical signal output by the pixel unit is greater than a reference electrical signal with a maximum value within a preset threshold range; wherein the first electrical signal is obtained by photogenerated charges generated by the pixel unit based on a light signal received within a preset exposure time; In response to the reference electrical signal that the first electrical signal is greater than the maximum value, controlling the pixel unit to start exposure after being reset and continuously output a second electrical signal during the exposure process, wherein the second electrical signal is obtained by generating photogenerated charges based on the light signal received by the pixel unit during the exposure process; Acquire the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range as the first time; The first time is output.

2. The method according to claim 1, characterized in that Also includes: In response to the first electrical signal being no greater than the maximum value of the reference electrical signal, sequentially outputting a reference electrical signal in a reference signal sequence as a current reference signal, the reference signal sequence comprising a plurality of reference electrical signals whose signal values ​​gradually increase within the threshold range; Acquire the time required for the current reference signal to reach the first electrical signal as the second time; The second time is output.

3. The method according to claim 2, characterized in that The minimum value in the reference signal sequence is the minimum value within the threshold range; In the reference signal sequence, the difference between any two adjacent reference electrical signals is a preset interval value, or the ratio between any two adjacent reference electrical signals is a preset ratio.

4. The method according to any one of claims 2-3, characterized in that: Also includes: When outputting the first time, first exposure mode identification information for identifying a quantitative exposure mode is also output; When the second time is output, second exposure mode identification information for identifying the timed exposure mode is also output.

5. The method according to any one of claims 2-3, characterized in that: The image sensor comprises a pixel array formed by arranging the pixel units in m rows and n columns, m signal readout circuits and m processing circuits, each of the signal readout circuits and each of the processing circuits corresponds to a row of pixel units in the pixel array, and the values ​​of m and n are respectively integers greater than 1; Each column of pixel units in each row of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the corresponding row processing circuit; The signal readout circuit corresponding to each row of pixel units, according to the control of the corresponding row processing circuit, sequentially polls the pixel units of each column connected to the corresponding row of pixel units, performs the operation of comparing whether the first electrical signal output by the pixel unit is greater than the reference electrical signal with the maximum value within the preset threshold range, and outputs a comparison result signal; and performing the operation of obtaining the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range and the operation of outputting the first time, or performing the operation of sequentially outputting a reference electrical signal in a reference signal sequence as the current reference signal, the operation of obtaining the time required for the current reference signal to reach the first electrical signal and the operation of outputting the second time; The processing circuit of the row corresponding to the signal readout circuit executes the operation of controlling the pixel unit to start exposure after resetting and continuously outputting the second electrical signal during the exposure process in response to the reference electrical signal that the first electrical signal is greater than the maximum value, based on the comparison result signal.

6. The method according to any one of claims 2-3, characterized in that: The image sensor comprises a pixel array formed by arranging the pixel units in m rows and n columns, n signal readout circuits and n processing circuits, each of the signal readout circuits and each of the processing circuits corresponds to a column of pixel units in the pixel array, and the values ​​of m and n are integers greater than 1 respectively; Each column of pixel units is exposed and generates an electrical signal after being reset in turn according to the control of the processing circuit; The signal readout circuit corresponding to each column of pixel units, according to the control of the corresponding row processing circuit, sequentially polls the pixel units of each row connected to the corresponding column of pixel units, performs the operation of comparing whether the first electrical signal output by the pixel unit is greater than the reference electrical signal with the maximum value within the preset threshold range, and outputs a comparison result signal; and performing the operation of obtaining the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with the minimum value within the threshold range and the operation of outputting the first time, or performing the operation of sequentially outputting a reference electrical signal in a reference signal sequence as the current reference signal, the operation of obtaining the time required for the current reference signal to reach the first electrical signal and the operation of outputting the second time; The processing circuit of the column corresponding to the signal readout circuit executes the operation of controlling the pixel unit to start exposure after resetting and continuously outputting the second electrical signal during the exposure process in response to the reference electrical signal that the first electrical signal is greater than the maximum value, based on the comparison result signal.

7. An image sensor comprising a pixel unit and a signal readout circuit; The pixel unit is used to receive a light signal within a preset exposure time to generate photogenerated charges, and output a first electrical signal based on the photogenerated charges; and starting exposure after resetting according to the control of the processing circuit, receiving a light signal to generate photogenerated charges during the exposure process, and obtaining and continuously outputting a second electrical signal based on the photogenerated charges; The signal readout circuit is used to compare whether the first electrical signal is greater than a reference electrical signal with a maximum value within a preset threshold range; in response to the first electrical signal being greater than the reference electrical signal with the maximum value, obtain the time required for the second electrical signal output by the pixel unit to reach the reference electrical signal with a minimum value within the threshold range as the first time, and output the first time.

8. The image sensor according to claim 7, characterized in that: The signal readout circuit is further used for: In response to a reference electrical signal in which the first electrical signal is not greater than the maximum value, one reference electrical signal in a reference signal sequence is output in sequence as a current reference signal, the reference signal sequence includes a plurality of reference electrical signals whose signal values ​​gradually increase within the threshold range and are arranged in sequence, and the time required for the current reference signal to reach the first electrical signal is obtained as a second time, and the second time is output.

9. The image sensor according to claim 8, characterized in that: The minimum value in the reference signal sequence is the minimum value within the threshold range; In the reference signal sequence, the difference between any two adjacent reference electrical signals is a preset interval value, or the ratio between any two adjacent reference electrical signals is a preset ratio.

10. The image sensor according to any one of claims 8 to 9, characterized in that: The signal readout circuit is further configured to: output first exposure mode identification information for identifying a quantitative exposure mode when outputting the first time; and output second exposure mode identification information for identifying a timing exposure mode when outputting the second time.

11. The image sensor according to claim 10, characterized in that: The signal readout circuit includes: a comparator, a threshold signal output circuit and a timer; The positive input terminal of the comparator is connected to the output terminal of the pixel unit, and is used to receive the electrical signal output by the pixel unit; the negative input terminal of the comparator is connected to the first output terminal of the threshold signal output circuit, and is used to receive the reference electrical signal output by the threshold signal output circuit; the output terminal of the comparator is respectively connected to the first input terminal of the threshold signal output circuit and the first input terminal of the timer, and is used to output a comparison result signal to the threshold signal output circuit and the timer; The first input terminal of the threshold signal output circuit is connected to the output terminal of the comparator, and is used to receive the comparison result signal; the second input terminal of the threshold signal output circuit is used to receive a first external control signal, and the first external control signal is used to control the threshold signal output circuit to output a reference electrical signal within the preset threshold range; the first output terminal of the threshold signal output circuit is connected to the negative input terminal of the comparator, and is used to output the reference electrical signal within the preset threshold range; the second output terminal of the threshold signal output circuit is used to output exposure mode identification information according to the comparison result signal; The first input end of the timer is connected to the output end of the comparator for receiving the comparison result signal; the output end of the timer is used to output the timing result when the comparison result signal changes.

12. The image sensor according to claim 11, characterized in that The second input terminal of the timer is used to receive a clock signal of a preset frequency for timing.

13. The image sensor according to any one of claims 11 to 12, characterized in that: The threshold signal output circuit comprises: an operational amplifier, a constant current power supply, a capacitor, a trigger, a first switch, a second switch, a third switch and a fourth switch; The positive input terminal of the operational amplifier is connected to the reference electrical signal source of the minimum value through the third switch, and is connected to the reference electrical signal source of the maximum value through the fourth switch; the negative input terminal of the operational amplifier is connected to the constant current power supply through the second switch, and is connected to the output terminal of the operational amplifier through the first switch, and is connected to the positive electrode of the capacitor; the output terminal of the operational amplifier is respectively connected to the negative input terminal of the comparator and the negative electrode of the capacitor; The first input terminal of the trigger is connected to a power supply signal; the second input terminal of the trigger is connected to the output terminal of the comparator for receiving the comparison result signal; the output terminal of the trigger is used to output a data flag bit for indicating the exposure mode identification information.

14. The image sensor according to claim 13, characterized in that: The threshold signal output circuit further includes: a first inverter, a second inverter group, an OR logic circuit, a third inverter and a fifth switch; wherein the second inverter group includes 2k+1 second inverters connected in sequence, and the value of k is an integer not less than 0; The input end of the first inverter is used as the second input end of the threshold signal output circuit to receive a first external control signal, and the first external control signal is used to control the fourth switch and the fifth switch to be turned on or off; the output end of the first inverter is connected to the input end of the first second inverter in the second inverter group, and is used to output a third control signal, and the third control signal is used to control the third switch to be turned on or off; The output end of any second inverter in the second inverter group is connected to the input end of the next adjacent second inverter, and the output end of the last second inverter in the second inverter group is connected to the first input end of the OR logic circuit; The second input end of the OR logic circuit is connected to the ground end of the fifth switch, and the output end of the OR logic circuit is connected to the input end of the third inverter for outputting a first control signal, wherein the first control signal is used to control the third switch to be turned on or off; The output end of the third inverter is connected to the second switch and is used to output a second control signal, where the second control signal is used to control the second switch to be turned on or off.

15. The image sensor according to claim 14, characterized in that: It also includes a processing circuit connected to the input end of the first inverter and configured to output the first external control signal to the input end of the first inverter.

16. The image sensor according to claim 15, characterized in that The image sensor specifically comprises a pixel array formed by arranging m rows and n columns of pixel units, m signal readout circuits, and m processing circuits, each of the signal readout circuits and each of the processing circuits is connected to a row of pixel units in the pixel array, and each of the processing circuits controls the connection with the signal readout circuit of the corresponding row; or, The image sensor specifically comprises a pixel array formed by arranging m rows and n columns of pixel units, n signal readout circuits, and n processing circuits, each of the signal readout circuits and each of the processing circuits is connected to a column of pixel units in the pixel array, and each of the processing circuits controls the connection of the signal readout circuit of the corresponding column; Wherein, the values ​​of m and n are integers greater than 1 respectively.

17. The image sensor according to claim 16, characterized in that: The pixel unit includes: a photodiode, a transfer transistor, a floating diffusion region, a reset transistor, a source follower transistor and a selection transistor; One end of the photodiode is grounded; the other end of the photodiode is connected to one end of the floating diffusion region and the gate end of the source follower transistor respectively through the transfer transistor; The source terminal of the transfer transistor is connected to the other end of the photodiode; the drain terminal of the transfer transistor is respectively connected to one end of the floating diffusion region and the gate terminal of the source follower transistor; the gate terminal of the transfer transistor is used to receive a second external control signal to control the transfer transistor to be turned on or off; One end of the floating diffusion region is respectively connected to the source end of the reset transistor and the gate end of the source follower transistor, and is connected to the other end of the photodiode through the transfer transistor; the other end of the floating diffusion region is grounded; The source terminal of the reset transistor is connected to one end of the floating diffusion area; the drain terminal of the reset transistor is connected to a power signal; the gate terminal of the reset transistor is used to receive a third external control signal to control the reset transistor to be turned on or off; The source terminal of the source follower transistor is connected to the drain terminal of the selection transistor; the drain terminal of the source follower transistor is connected to a power signal; the gate terminal of the source follower transistor is respectively connected to one end of the floating diffusion region and the drain terminal of the transfer transistor; The source terminal of the selection transistor is connected to the input terminal of the signal readout circuit as the output terminal of the pixel unit; the drain terminal of the selection transistor is connected to the source terminal of the source follower transistor; the gate terminal of the selection transistor is used to receive a fourth external control signal to control the selection transistor to be turned on or off.

18. The image sensor according to claim 17, characterized in that: The processing circuit is also respectively connected to the gate end of the transfer transistor, the gate end of the reset transistor and the gate end of the selection transistor in the pixel unit of the corresponding row or column, and is used to output the second external control signal, the third external control signal and the fourth external control signal to the gate end of the transfer transistor, the gate end of the reset transistor and the gate end of the selection transistor in the pixel unit of the corresponding row or column.

19. An electronic device comprising: A processor, a memory communicatively connected to the processor, and an image sensor according to any one of claims 7 to 18; The memory is used to store computer instructions; The processor is used to execute the computer instructions stored in the memory to control the image sensor to implement the signal processing method according to any one of claims 1 to 6.

20. The device according to claim 19, characterized in that The electronic device includes any one of the following: a pulse camera, a high-speed camera, a visual camera, an audio player, a video player, a navigation device, a communication device vehicle camera, a mobile phone camera, a traffic camera, or a household appliance camera.

21. A computer program product, comprising computer instructions, which, when executed by a processor, implement the signal processing method according to any one of claims 1 to 6.

22. A computer-readable storage medium, wherein computer instructions are stored in the computer-readable storage medium, and when the instructions are executed, the computer executes the signal processing method according to any one of claims 1 to 6.

Images