Signal reading method and device of pixel unit and electronic equipment

Abstract

The embodiment of the invention discloses a signal reading method and device of a pixel unit and electronic equipment, and the method comprises the steps: controlling the pixel unit to execute a reset operation through a reset signal at the initial moment of a first exposure period, converting an optical signal into a photoelectric charge after the reset operation of the pixel unit, and transmitting the photoelectric charge to the first exposure period; the photoelectric charge is accumulated before the reading signal is received; at least one moment in the first exposure period, reading out an intermediate signal determined based on the accumulated photoelectric charge in the pixel unit at least once through control of a read-out signal to obtain at least one intermediate signal; reading out an output signal determined based on all photoelectric charges accumulated in the first exposure period by the pixel unit through control of a read-out signal at the end moment of the first exposure period; and based on the at least one intermediate signal and the output signal, determining an image signal corresponding to the pixel unit in the first exposure period.

Description

Technical Field

[0001] The present disclosure relates to the technical field of image sensors, and in particular to a signal reading method, device and electronic device for a pixel unit. Background Art

[0002] Image sensors have been widely used in digital cameras, mobile phones, medical treatment, automobiles, drones, machine recognition and other fields. In particular, the rapid development of complementary metal oxide semiconductor (CMOS) image sensor technology has led to higher requirements for the output image quality of image sensors.

[0003] The pixel units in the image sensors in the prior art mostly adopt four-transistor structure pixel units or four-transistor structure pixel units shared by multiple pixels. The four-transistor structure is used to collect photoelectric signals, and since its exposure time is a fixed value, the image resolution or sensitivity is lost. Summary of the invention

[0004] Embodiments of the present disclosure provide a method, device and electronic device for reading a signal from a pixel unit.

[0005] One aspect of an embodiment of the present disclosure provides a signal reading method for a pixel unit, comprising:

[0006] At the initial moment of the first exposure period, the pixel unit is controlled to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge and accumulates the photoelectric charge before receiving a readout signal; the first exposure period is a time period determined based on the initial moment and the end moment;

[0007] At least one time in the first exposure period, by controlling the readout signal, an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit is read out at least once to obtain at least one intermediate signal;

[0008] At the end of the first exposure period, reading out an output signal determined based on all photoelectric charges accumulated by the pixel unit during the first exposure period by controlling a readout signal;

[0009] An image signal corresponding to the pixel unit in the first exposure period is determined based on the at least one intermediate signal and the output signal.

[0010] Optionally, determining the image signal corresponding to the pixel unit based on the at least one intermediate signal and the output signal includes:

[0011] A weighted addition is performed on the at least one intermediate signal and the output signal, and a sum value obtained by the weighted addition is used as an image signal corresponding to the pixel unit.

[0012] Optionally, the at least one moment includes: a first moment and a second moment; the at least one intermediate signal includes a first intermediate signal and a second intermediate signal;

[0013] The method of reading out an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit at least once at least once during at least one moment in the first exposure period to obtain at least one intermediate signal comprises:

[0014] At the first moment, a first intermediate signal determined by the photoelectric charge accumulated by the pixel unit from the initial moment to the first moment is controlled by a readout signal;

[0015] At the second moment, a second intermediate signal determined by the photoelectric charge accumulated by the pixel unit from the initial moment to the first moment is controlled by a readout signal.

[0016] Optionally, the pixel unit includes a photodiode and a reset transistor, the drain terminal of the reset transistor is connected to the photodiode, the source terminal of the reset transistor is connected to a power supply signal, and the gate terminal of the reset transistor receives the reset signal;

[0017] At the initial moment of the first exposure period, the pixel unit is controlled to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge and accumulates the photoelectric charge before receiving a readout signal, including:

[0018] At the initial moment of the first exposure period, the reset signal is input into the gate terminal of the reset transistor to control the reset transistor to be turned on, and the photodiode is reset to a high level;

[0019] After the reset operation, the reset transistor is turned off by controlling the reset signal, the optical signal is converted into photoelectric charge by the photodiode, and the photoelectric charge is accumulated before receiving the readout signal.

[0020] Optionally, the pixel unit further includes a source follower transistor and a pixel selection transistor; the source follower transistor is used to follow the voltage change of the photodiode to generate a corresponding voltage signal;

[0021] The method of reading out an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit at least once at least once during at least one moment in the first exposure period to obtain at least one intermediate signal comprises:

[0022] At at least one moment in the first exposure period, the pixel selection transistor is controlled to be turned on by the readout signal, and the voltage signal generated in the source follower transistor is output as the intermediate signal to obtain the at least one intermediate signal.

[0023] Another aspect of the disclosed embodiments provides a signal reading device of a pixel unit, comprising: a pixel unit and a signal processing module;

[0024] The photoelectric conversion module in the pixel unit is used to perform a reset operation according to the control of the reset signal at the initial moment of the first exposure period, convert the light signal into a photoelectric charge after the reset operation, and accumulate the photoelectric charge before receiving the readout signal; the first exposure period is a time period determined based on the initial moment and the end moment;

[0025] The signal readout module in the pixel unit is used to read out an intermediate signal determined based on the photoelectric charge accumulated in the photoelectric conversion module at least once at least at a time point in the first exposure period, according to the control of the readout signal, to obtain at least one intermediate signal; and to read out an output signal determined based on all the photoelectric charges accumulated by the photoelectric conversion module in the first exposure period at the end time point of the first exposure period, according to the control of the readout signal;

[0026] The signal processing module is used to receive the at least one intermediate signal and the output signal output by the signal readout module, and determine the image signal corresponding to the pixel unit in the first exposure period based on the at least one intermediate signal and the output signal.

[0027] Optionally, the signal processing module is specifically configured to perform weighted addition on the at least one intermediate signal and the output signal, and use a sum value obtained by the weighted addition as an image signal corresponding to the pixel unit.

[0028] Optionally, the photoelectric conversion module includes a photodiode and a reset transistor, the drain terminal of the reset transistor is connected to the photodiode, the source terminal of the reset transistor is connected to a power supply signal, and the gate terminal of the reset transistor receives the reset signal;

[0029] At the initial moment of the first exposure period, the reset transistor receives the reset signal through the gate terminal, and the reset transistor is turned on according to the control of the reset signal; after the reset operation, the reset transistor is turned off according to the control of the reset signal;

[0030] The photodiode is reset to a high level when the reset transistor is turned on; when the reset transistor is turned off, the photodiode converts the optical signal into photoelectric charge and accumulates the photoelectric charge before receiving a readout signal.

[0031] Optionally, the signal readout module includes: a source follower transistor and a pixel selection transistor;

[0032] The gate terminal of the source follower transistor is connected to the photodiode, the source terminal of the source follower transistor is connected to a power supply signal, the drain terminal of the source follower transistor is connected to the drain terminal of the pixel selection transistor, and the source follower transistor is used to generate a corresponding voltage signal according to a voltage change in the photodiode;

[0033] The drain terminal of the pixel selection transistor is connected to the drain terminal of the source follower transistor, the source terminal of the pixel selection transistor is connected to the signal processing module as the output terminal of the pixel unit, the gate terminal of the pixel selection transistor receives the readout signal, and the voltage signal generated in the source follower transistor is read out as the intermediate signal or the output signal according to the control of the readout signal.

[0034] Another aspect of the embodiments of the present disclosure provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor, and further comprising the signal reading device of the pixel unit described in any one of the above embodiments;

[0035] The memory stores computer-executable instructions;

[0036] The processor executes the computer-executable instructions stored in the memory to control the timing signal processing device to implement the signal reading method of the pixel unit described in any one of the above embodiments.

[0037] Optionally, the electronic device is included in any one of the following: image data acquisition equipment, audio / video player, navigation equipment, entertainment equipment, communication equipment, roadside traffic facilities, equipment in motor vehicles, industrial inspection equipment, flight equipment, medical equipment, security equipment.

[0038] The signal reading method, device and electronic device of the pixel unit provided based on the above-mentioned embodiments of the present disclosure include: at the initial moment of the first exposure cycle, controlling the pixel unit to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge, and accumulates the photoelectric charge before receiving a readout signal; the first exposure cycle is a time period determined based on the initial moment and the end moment; at least one moment in the first exposure cycle, through the control of the readout signal, an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit is read out at least once to obtain at least one intermediate signal; at the end moment of the first exposure cycle, through the control of the readout signal, an output signal determined based on all the photoelectric charges accumulated by the pixel unit in the first exposure cycle is read out; based on the at least one intermediate signal and the output signal, an image signal corresponding to the pixel unit in the first exposure cycle is determined. The disclosed embodiment performs multiple signal readouts on a pixel unit within one exposure cycle to obtain at least one intermediate signal and one output signal, and fuses the at least one intermediate signal and one output signal, thereby improving the dynamic range of the image signal obtained by the pixel unit without loss of resolution; and, the pixel unit is reset only at the end of the exposure cycle, that is, the photoelectric charge accumulated in the pixel unit is not cleared after each intermediate signal is read out, so that the utilization efficiency of the photoelectric charge in the pixel unit is high. At the same time, since the exposure cycle of the pixel unit is not increased, the frame rate of the image sensor using the pixel unit is indirectly improved.

[0039] The technical solution of the present disclosure is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 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.

[0041] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0042] Figure 1 is a flowchart of a signal reading method for a pixel unit provided by an exemplary embodiment of the present disclosure;

[0043] Figure 2 is a signal timing diagram in a signal reading method for a pixel unit provided by another exemplary embodiment of the present disclosure;

[0044] Figure 3 A schematic diagram of the relationship between the exposure light intensity and the time t for the pixel unit to collect signals in a signal reading method of the pixel unit is provided for an embodiment of the present disclosure;

[0045] Figure 4is a schematic structural diagram of a signal reading device for a pixel unit provided by an exemplary embodiment of the present disclosure;

[0046] Figure 5 is a schematic structural diagram of a pixel unit in a signal reading device for a pixel unit provided by an exemplary embodiment of the present disclosure;

[0047] Figure 6 The figure is a schematic diagram of the structure of an application embodiment of the electronic device disclosed in the present invention. DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] In the process of realizing the present disclosure, the inventors found that one scheme for obtaining high dynamic range image information of the image sensor of the prior art is to combine the signals output by multiple pixel units with different exposure times, for example, to fuse the pixel signal output by the long exposure pixel unit and the pixel signal output by the short exposure pixel unit to generate a high dynamic range image signal, which has the disadvantage that the image resolution is lost or the sensitivity is lost. Another scheme for obtaining high dynamic range image information is to expose the same pixel multiple times, for example, short exposure, medium exposure, and long exposure, and the pixel signal will be read after each exposure, and merged and fused into a high dynamic range image signal in the later circuit; in this scheme for obtaining high dynamic range image information, the three exposures of short exposure, medium exposure, and long exposure will reset the photodiode in the pixel unit each time, that is, clear the photoelectric charge collected in the photodiode, so this scheme is not fully beneficial to the photoelectric charge, because the pixel unit needs to be exposed three times, the cycle of obtaining the image signal is increased, the efficiency is low, and it is not conducive to the image acquisition of the image sensor with a high frame rate.

[0061] Figure 1 FIG. 1 is a flow chart of a signal reading method for a pixel unit provided by an exemplary embodiment of the present disclosure. Figure 1 As shown, the method of this embodiment includes:

[0062] Step 102, at the initial moment of the first exposure cycle, the pixel unit is controlled to perform a reset operation through a reset signal. After the reset operation, the pixel unit converts the optical signal into photoelectric charge and accumulates the photoelectric charge before receiving the readout signal.

[0063] Among them, the first exposure cycle is a time period determined based on the initial moment and the end moment; optionally, the first exposure cycle can be any exposure cycle (frame cycle) corresponding to the pixel unit. In this embodiment, the pixel unit can be an existing three-transistor pixel unit. Since the three-transistor pixel unit performs signal output according to a fixed exposure cycle, the first exposure cycle provided by this embodiment can be a fixed exposure cycle corresponding to the pixel unit. This embodiment does not change the circuit structure and exposure duration of the pixel unit, and still only performs a reset operation on the pixel unit at the initial moment of the exposure cycle, which fully benefits the accumulated photoelectric charge in the pixel unit.

[0064] Step 104 , at least once during at least one moment in the first exposure period, an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit is read out by controlling the readout signal to obtain at least one intermediate signal.

[0065] In this embodiment, at least one moment may be any moment within the first exposure cycle. For example, a high-level readout signal is respectively given at the moments corresponding to the short-duration exposure and the medium-duration exposure in the prior art, so that the pixel unit reads out an intermediate signal determined by the accumulated photoelectric charge at the corresponding moment. Optionally, the intermediate signal may be a voltage signal, a pulse signal, or a converted digital signal. The number of outputs of the intermediate signal may be one or more, and the number of outputs depends on the timing of the readout signal. The more the number of intermediate signal outputs, the higher the dynamic range of the obtained image signal. However, too many intermediate signal outputs will increase the amount of data processed by the signal processing circuit and slow down the signal processing speed. Therefore, the number of intermediate signals may be determined by the actual application scenario, for example, two intermediate signals are obtained.

[0066] Step 106 , at the end of the first exposure period, by controlling the readout signal, read out an output signal determined based on all photoelectric charges accumulated by the pixel unit during the first exposure period.

[0067] Optionally, the output signal can be a voltage signal, a pulse signal or a converted digital signal. Optionally, at the end of the first exposure period corresponding to the pixel unit, according to the normal pixel signal reading process, according to the control of the readout signal, the output signal determined by all the photoelectric charges accumulated by the pixel unit during the exposure period is read out; usually the output signal is a normal output signal output by the pixel unit at the end of the exposure period by the existing technology; for example, the output signal corresponds to the pixel signal obtained by long-term exposure in the existing technology. In this embodiment, since the pixel unit is not reset before outputting the output signal, the photoelectric charge collected in the photoelectric conversion module is not cleared, which fully benefits the photoelectric charge, and does not change the duration of the exposure period of the pixel unit, thereby improving the efficiency of image signal acquisition.

[0068] Step 108 , determining an image signal of the pixel unit in the first exposure period based on the at least one intermediate signal and the output signal.

[0069] This embodiment is based on fusing at least one intermediate signal and an output signal into an image signal with a high dynamic range. Optionally, the fusing method may be to add at least one intermediate signal and the output signal, or to accumulate and average, or to perform weighted summing, etc.

[0070] The signal reading method of the pixel unit provided based on the above-mentioned embodiment of the present disclosure includes: at the initial moment of the first exposure cycle, controlling the pixel unit to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge, and accumulates the photoelectric charge before receiving a readout signal; the first exposure cycle is a time period determined based on the initial moment and the end moment; at least one moment in the first exposure cycle, through the control of the readout signal, reading out an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit at least once to obtain at least one intermediate signal; at the end moment of the first exposure cycle, through the control of the readout signal, reading out an output signal determined based on all the photoelectric charges accumulated by the pixel unit in the first exposure cycle; based on the at least one intermediate signal and the output signal, determining the image signal corresponding to the pixel unit in the first exposure cycle. The disclosed embodiment performs multiple signal readouts on a pixel unit within one exposure cycle to obtain at least one intermediate signal and one output signal, and fuses the at least one intermediate signal and one output signal, thereby improving the dynamic range of the image signal obtained by the pixel unit without loss of resolution; and, the pixel unit is reset only at the end of the exposure cycle, that is, the photoelectric charge accumulated in the pixel unit is not cleared after each intermediate signal is read out, so that the utilization efficiency of the photoelectric charge in the pixel unit is high. At the same time, since the exposure cycle of the pixel unit is not increased, the frame rate of the image sensor using the pixel unit is indirectly improved.

[0071] Optionally, in some possible implementations of the present disclosure, step 108 may include:

[0072] A weighted addition is performed on at least one intermediate signal and an output signal, and a sum value obtained by the weighted addition is used as an image signal corresponding to the pixel unit.

[0073] In this embodiment, the weight value corresponding to each intermediate signal and the output signal may be a weight coefficient, and the weight coefficient corresponding to each signal (each intermediate signal and the output signal) may be set according to a specific application scenario, for example, the weight coefficient corresponding to each signal may be determined by an empirical value. In some optional examples, when two intermediate signals are output, the image signal may be determined based on the following formula (1):

[0074] Sig=k1* Sig1+k2* Sig2+k3* Sig3 formula (1)

[0075] Among them, Sig is the image signal; Sig1 and Sig2 are two intermediate signals respectively; Sig3 is the output signal; k1 and k2 are two weight coefficients corresponding to the two intermediate signals; k3 is the weight coefficient corresponding to the output signal. The image signal determined by this formula contains three types of signals: weak light, medium intensity light, and strong light. Therefore, the dynamic range of the image is expanded, more image details can be distinguished, and it has the advantage of a high image dynamic range.

[0076] In some optional embodiments, in order to achieve a balance between the image dynamic range and the amount of data calculation, two intermediate signals can be collected. In this case, at least one moment includes: a first moment and a second moment; at least one intermediate signal includes a first intermediate signal and a second intermediate signal.

[0077] Correspondingly, step 104 may include:

[0078] At a first moment, a first intermediate signal determined by photoelectric charges accumulated by the pixel unit from an initial moment to the first moment is controlled by a readout signal.

[0079] At the second moment, the second intermediate signal determined by the photoelectric charge accumulated by the pixel unit from the initial moment to the first moment is controlled by the readout signal.

[0080] In this embodiment, the first moment and the second moment may be any moment in the first exposure period, and the control is implemented specifically according to the timing of the readout signal, for example, Figure 2 As shown, in this embodiment, the frame period (i.e., the exposure period of the pixel unit) is T. At the beginning of the frame period, the pixel unit is reset by providing a high level through the reset signal RST. After the reset, the pixel unit is first selected at the first moment t1 through the control of the readout signal Selest (high level), and the first intermediate signal is output. The pixel unit is secondly selected at the second moment t2, and the second intermediate signal is output. At the end of the frame period t3, the readout signal Select (high level) is controlled to output the readout signal (which can be understood as the third selection). Figure 2 It can be seen from the embodiment that the readout of the intermediate signal is controlled according to the timing of the readout signal, and the timing of the readout signal can be set according to the specific application scenario and written into the control circuit in advance. In addition, at the first moment t1, the second moment t2 and the end moment t3, the subsequent processing circuit that processes the output first intermediate signal, the second intermediate signal and the output signal will provide a corresponding high level to realize signal acquisition (the first intermediate signal Sig1, the second intermediate signal Sig2 and the output signal Sig3 are collected by high level at the first moment t1, the second moment t2 and the end moment t3, respectively), and the image signal is determined based on the first intermediate signal, the second intermediate signal and the output signal.

[0081] Figure 3 The present disclosure provides a schematic diagram of the relationship between the exposure light intensity and the time t for the pixel unit to collect the signal in the signal reading method of the pixel unit. Figure 3 As shown, the horizontal axis represents light intensity (P3>P2>P1), and the vertical axis represents time t (t3>t2>t1).

[0082] like Figure 3 As shown, the time sequence of t1, t2, and t3 is t1 first, then t2, and finally t3. The first intermediate signal Sig1 collected at time t1 is an image signal for strong light, and the time from the reset operation of the photoelectric photodiode to the time t1 is short (for example, 10ns, 20ns, etc.); therefore, the image dynamic range in the direction of strong light is expanded, and the highest light intensity that can be distinguished is marked as P3. The second intermediate signal Sig2 collected at time t2 is an image signal for medium-strong light, and the time from the reset operation of the photoelectric photodiode to the time t2 is moderate (for example, 1ms, 2ms, etc.); the details of conventional image information can be distinguished, and the highest light intensity that can be distinguished is marked as P2. The output signal Sig3 collected at time t3 is an image signal for weak light, and the time from the reset operation of the photoelectric photodiode to the time t3 is long (for example, 50ms, 60ms, etc.); therefore, the image dynamic range in the direction of weak light is expanded, and the highest light intensity that can be distinguished is marked as P1. In the present embodiment, the relationship among the first intermediate signal Sig1, the second intermediate signal Sig2 and the output signal Sig3 is that the photoelectric charge in the second intermediate signal Sig2 contains the photoelectric charge of the first intermediate signal Sig1, and the photoelectric charge in the output signal Sig3 contains the photoelectric charge of the second intermediate signal Sig2. Therefore, it can be seen that the pixel unit reads out the signal three times, and the signal obtained by each signal readout is determined by the photoelectric charge accumulated by the pixel unit from reset, thereby making full use of the photoelectric charge and causing no signal loss.

[0083] In some optional embodiments, the pixel unit includes a photodiode and a reset transistor, the drain terminal of the reset transistor is connected to the photodiode, the source terminal of the reset transistor is connected to the power signal, and the gate terminal of the reset transistor receives the reset signal.

[0084] Step 102 may include:

[0085] At the initial moment of the first exposure period, a reset signal is input to the gate terminal of the reset transistor to control the reset transistor to be turned on and reset the photodiode to a high level.

[0086] After the reset operation, the reset transistor is turned off by the reset signal, and the optical signal is converted into photoelectric charge by the photodiode, and the photoelectric charge is accumulated before receiving the readout signal.

[0087] In the present embodiment, the circuit structure in the pixel unit mainly includes a photodiode for realizing photoelectric conversion and a reset transistor for realizing resetting the photodiode. The reset signal is received through the gate terminal of the reset transistor. In some optional embodiments, the reset transistor is an N-type transistor, and the external circuit provides a high-level reset signal according to a preset period. The reset transistor is turned on by sending a high-level reset signal to the gate terminal of the reset transistor, thereby controlling the reset of the photodiode; in other optional embodiments, the reset transistor is a P-type transistor, and the external circuit provides a low-level reset signal according to a preset period. The reset transistor is turned on by sending a low-level reset signal to the gate terminal of the reset transistor, thereby controlling the reset of the photodiode.

[0088] Optionally, the pixel unit further includes a source follower transistor and a pixel selection transistor; the source follower transistor is used to follow the voltage change of the photodiode to generate a corresponding voltage signal.

[0089] Step 104 may include:

[0090] At at least one moment in the first exposure period, the pixel selection transistor is controlled to be turned on by the readout signal, and the voltage signal generated in the source follower transistor is output as an intermediate signal to obtain at least one intermediate signal.

[0091] The pixel unit structure in this embodiment is a universal three-transistor pixel unit structure, in which the pixel selection transistor acts as a switch, and the signal generated in the source follower transistor is output by receiving the readout signal through the gate terminal of the pixel selection transistor. Therefore, the output of the intermediate signal in this embodiment is realized by inputting the readout signal into the pixel selection transistor according to the timing control.

[0092] Any pixel unit signal reading 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 pixel unit signal reading method provided in the embodiments of the present disclosure may be executed by a processor, such as the processor executing any pixel unit signal reading method mentioned in the embodiments of the present disclosure by calling corresponding instructions stored in a memory. This will not be described in detail below.

[0093] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0094] Figure 4FIG. 1 is a schematic diagram of a signal reading device for a pixel unit provided by an exemplary embodiment of the present disclosure. Figure 4 As shown, the device provided in this embodiment includes: a pixel unit 41 and a signal processing module 42;

[0095] The photoelectric conversion module 411 in the pixel unit 41 is used to perform a reset operation at the initial moment of the first exposure cycle according to the control of the reset signal, convert the light signal into photoelectric charge after the reset operation, and accumulate the photoelectric charge before receiving the readout signal; the first exposure cycle is a time period determined based on the initial moment and the end moment.

[0096] The signal readout module 412 in the pixel unit 41 is used to read out an intermediate signal determined based on the photoelectric charge accumulated in the photoelectric conversion module at least once at least at a moment in the first exposure cycle, according to the control of the readout signal, to obtain at least one intermediate signal; and at the end moment of the first exposure cycle, read out an output signal determined based on all photoelectric charges accumulated by the photoelectric conversion module 411 during the exposure cycle, according to the control of the readout signal.

[0097] The signal processing module 42 is used to receive at least one intermediate signal and the output signal output by the signal readout module 412, and determine the image signal corresponding to the pixel unit in the first exposure period based on the at least one intermediate signal and the output signal.

[0098] A signal reading device for a pixel unit provided based on the above-mentioned embodiment of the present disclosure includes: at the initial moment of a first exposure cycle, controlling the pixel unit to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge, and accumulates the photoelectric charge before receiving a readout signal; the first exposure cycle is a time period determined based on an initial moment and an end moment; at least one moment in the first exposure cycle, through the control of a readout signal, an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit is read out at least once to obtain at least one intermediate signal; at the end moment of the first exposure cycle, through the control of a readout signal, an output signal determined based on all the photoelectric charges accumulated by the pixel unit in the first exposure cycle is read out; based on the at least one intermediate signal and the output signal, an image signal corresponding to the pixel unit in the first exposure cycle is determined. The disclosed embodiment performs multiple signal readouts on a pixel unit within one exposure cycle to obtain at least one intermediate signal and one output signal, and fuses the at least one intermediate signal and one output signal, thereby improving the dynamic range of the image signal obtained by the pixel unit without loss of resolution; and, the pixel unit is reset only at the end of the exposure cycle, that is, the photoelectric charge accumulated in the pixel unit is not cleared after each intermediate signal is read out, so that the utilization efficiency of the photoelectric charge in the pixel unit is high. At the same time, since the exposure cycle of the pixel unit is not increased, the frame rate of the image sensor using the pixel unit is indirectly improved.

[0099] In some optional embodiments, the signal processing module 42 is specifically configured to perform weighted addition on at least one intermediate signal and the output signal, and use the sum value obtained by the weighted addition as the image signal corresponding to the pixel unit 41 .

[0100] In this embodiment, the weight value corresponding to each intermediate signal and output signal can be a weight coefficient. The weight coefficient corresponding to each signal (each intermediate signal and output signal) can be set according to the specific application scenario. For example, the weight coefficient corresponding to each signal is determined by empirical values.

[0101] Figure 5 FIG. 1 is a schematic diagram of the structure of a pixel unit in a signal reading device for a pixel unit provided by an exemplary embodiment of the present disclosure. Figure 5 As shown, in the pixel unit 41 provided in this embodiment, the photoelectric conversion module 411 includes a photodiode 413 and a reset transistor 414, the drain end of the reset transistor 414 is connected to the photodiode 413, the source end of the reset transistor 414 is connected to the power signal Vdd, and the gate end of the reset transistor 414 receives the reset signal RST.

[0102] At the initial moment of the first exposure period, the reset transistor 414 receives the reset signal RST through the gate terminal, and is turned on according to the control of the reset signal RST (high level); after the reset operation, the reset transistor 414 is turned off according to the control of the reset signal RST (low level).

[0103] In this embodiment, the reset transistor is an N-type transistor, which is turned on when the reset signal RST is at a high level and turned off when the reset signal RST is at a low level. The timing of the reset signal RST in this embodiment can refer to Figure 2 In the illustrated embodiment, a high level is provided at the beginning of a frame period to turn on the reset transistor, and the reset signal RST is at a low level at other times.

[0104] The photodiode 413 is reset to a high level when the reset transistor 414 is turned on; when the reset transistor 414 is turned off, the photodiode 413 converts the optical signal into photoelectric charge and accumulates the photoelectric charge before receiving the readout signal.

[0105] A photodiode is a light detector that can convert light into a current or voltage signal depending on how it is used. In this embodiment, it is converted into a voltage signal. The die often uses a PN junction with a photosensitive characteristic, which is very sensitive to changes in light and has unidirectional conductivity. Moreover, the electrical characteristics will change when the light intensity is different. Therefore, the light intensity can be used to change the voltage or current in the circuit.

[0106] like Figure 5 As shown, the photodiode 413 in this embodiment can be arranged in a semiconductor substrate, and the structure of the photodiode 413 can include: P-epi is a P-type epitaxial layer, the N region is a photoelectric charge collection region, the P region is a P-type well region, and the P+ region is a protective layer. The photodiode in this embodiment has a through hole in the middle of the P+ region, so that the N region is directly connected to the reset transistor 414 and the source follower transistor 415.

[0107] like Figure 5 As shown, the signal readout module 412 includes: a source follower transistor 415 and a pixel selection transistor 416;

[0108] The gate terminal of the source follower transistor 415 is connected to the photodiode 413, the source terminal of the source follower transistor 415 is connected to the power supply signal Vdd, the drain terminal of the source follower transistor 415 is connected to the drain terminal of the pixel selection transistor 416, and the source follower transistor 415 is used to generate a corresponding voltage signal according to the voltage change in the photodiode 413.

[0109] In this embodiment, the gate terminal of the source follower transistor 415 is connected to the N region of the photodiode 413, and is configured to detect and follow the voltage change of the photodiode 413 and output a corresponding voltage signal.

[0110] The drain terminal of the pixel selection transistor 416 is connected to the drain terminal of the source follower transistor 415, and the source terminal of the pixel selection transistor 416 is connected to the signal processing module 42 as the output terminal of the pixel unit. The gate terminal of the pixel selection transistor 416 receives the readout signal Select, and the voltage signal generated in the source follower transistor 415 is read out as an intermediate signal or an output signal according to the control of the readout signal Select.

[0111] Optionally, the timing of the pixel selection transistor output signal can refer to Figure 2 The embodiment shown is understood in that a high level pulse indicates that the transistor is turned on; and a low level pulse indicates that the transistor is turned off.

[0112] like Figure 2 As shown, at the beginning of the exposure period T (frame period), the reset transistor 414 is given a conduction pulse operation to perform a reset operation on the photodiode 413 to clear the photoelectric charge in the N region of the photodiode 413, and then the pixel unit 41 starts to be exposed, and the N region of the photodiode 413 starts to collect the light-sensitive photoelectric charge;

[0113] Next, at the first moment t1, the pixel selection transistor 416 is turned on, the pixel unit is selected for the first time, and the subsequent signal acquisition circuit acquires the signal of the pixel unit, which is recorded as the first intermediate signal Sig1, and then the pixel selection transistor 416 is turned off;

[0114] Next, at the second time t2, the pixel selection transistor 416 is turned on, the pixel unit is selected for the second time, and the subsequent signal acquisition circuit collects signals from the pixel unit, which is recorded as the second intermediate signal Sig2, and then the pixel selection transistor 416 is turned off;

[0115] Next, at the end time t3, the pixel selection transistor 416 is turned on, and the pixel unit is selected for the third time. The subsequent signal acquisition circuit collects signals from the pixel unit, which is recorded as the output signal Sig3, and then the pixel selection transistor 416 is turned off; after the exposure cycle T of the pixel unit is completed, it enters the next exposure cycle and repeats the above steps.

[0116] In addition, an embodiment of the present disclosure further provides an electronic device, including:

[0117] A processor, and a memory connected to the processor in communication, further comprising the signal reading device of the pixel unit described in any one of the above embodiments;

[0118] The memory stores computer-executable instructions;

[0119] The processor executes the computer-executable instructions stored in the memory to control the timing signal processing device to implement the signal reading method of the pixel unit described in any one of the above embodiments.

[0120] The electronic device provided by the present disclosure can be included in any of the following: image data acquisition equipment, audio / video player, navigation equipment, entertainment equipment, communication equipment, roadside traffic facilities, equipment in motor vehicles, industrial inspection equipment, flight equipment, medical equipment, security equipment, etc.

[0121] The electronic device provided by the present disclosure can be applied to any of the following: image data acquisition equipment, audio / video players, navigation equipment, entertainment equipment, communication equipment, roadside traffic facilities, equipment in motor vehicles, industrial inspection equipment, flight equipment, medical equipment, security equipment, etc.

[0122] Figure 6 This is a schematic diagram of the structure of an application embodiment of the electronic device disclosed in the present invention. Figure 6 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.

[0123] like Figure 6 As shown, the electronic device includes one or more processors and memory.

[0124] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0125] 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 run the computer program product to implement the signal reading method of the pixel unit of each embodiment of the present disclosure described above and / or other desired functions.

[0126] In one example, the electronic device may further include: an input device and an output device, and these components are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0127] In addition, the input device may also include, for example, a keyboard, a mouse, and the like.

[0128] The output device can output various information to the outside, including determined distance information, direction information, etc. The output device can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, and the like.

[0129] Of course, to simplify, Figure 6 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.

[0130] 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 in the signal reading method of the pixel unit according to various embodiments of the present disclosure described in the above part of this specification.

[0131] 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.

[0132] In addition, an embodiment of the present disclosure may also be a computer-readable storage medium on which computer program instructions are stored. When the computer program instructions are executed by a processor, the processor executes the steps in the signal reading method of the pixel unit according to various embodiments of the present disclosure described in the above part of this specification.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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 reading method for a pixel unit, characterized in that: include: At the initial moment of the first exposure period, the pixel unit is controlled to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge and accumulates the photoelectric charge before receiving a readout signal; the first exposure period is a time period determined based on the initial moment and the end moment; At least one time in the first exposure period, by controlling the readout signal, an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit is read out at least once to obtain at least one intermediate signal; At the end of the first exposure period, reading out an output signal determined based on all photoelectric charges accumulated by the pixel unit during the first exposure period by controlling a readout signal; An image signal corresponding to the pixel unit in the first exposure period is determined based on the at least one intermediate signal and the output signal.

2. The method according to claim 1, characterized in that The determining, based on the at least one intermediate signal and the output signal, an image signal corresponding to the pixel unit comprises: A weighted addition is performed on the at least one intermediate signal and the output signal, and a sum value obtained by the weighted addition is used as an image signal corresponding to the pixel unit.

3. The method according to claim 1 or 2, characterized in that: The at least one moment includes: a first moment and a second moment; the at least one intermediate signal includes a first intermediate signal and a second intermediate signal; The method of reading out an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit at least once at least once during at least one moment in the first exposure period to obtain at least one intermediate signal comprises: At the first moment, a first intermediate signal determined by the photoelectric charge accumulated by the pixel unit from the initial moment to the first moment is controlled by a readout signal; At the second moment, a second intermediate signal determined by the photoelectric charge accumulated by the pixel unit from the initial moment to the first moment is controlled by a readout signal.

4. The method according to any one of claims 1 to 3, characterized in that: The pixel unit comprises a photodiode and a reset transistor, the drain terminal of the reset transistor is connected to the photodiode, the source terminal of the reset transistor is connected to a power supply signal, and the gate terminal of the reset transistor receives the reset signal; At the initial moment of the first exposure period, the pixel unit is controlled to perform a reset operation through a reset signal, and after the reset operation, the pixel unit converts the light signal into a photoelectric charge and accumulates the photoelectric charge before receiving a readout signal, including: At the initial moment of the first exposure period, the reset signal is input into the gate terminal of the reset transistor to control the reset transistor to be turned on, and the photodiode is reset to a high level; After the reset operation, the reset transistor is turned off by controlling the reset signal, the optical signal is converted into photoelectric charge by the photodiode, and the photoelectric charge is accumulated before receiving the readout signal.

5. The method according to claim 4, characterized in that The pixel unit further includes a source follower transistor and a pixel selection transistor; the source follower transistor is used to follow the voltage change of the photodiode to generate a corresponding voltage signal; The method of reading out an intermediate signal determined based on the photoelectric charge accumulated in the pixel unit at least once at least once during at least one moment in the first exposure period to obtain at least one intermediate signal comprises: At at least one moment in the first exposure period, the pixel selection transistor is controlled to be turned on by the readout signal, and the voltage signal generated in the source follower transistor is output as the intermediate signal to obtain the at least one intermediate signal.

6. A signal reading device for a pixel unit, characterized in that: include: Pixel unit and signal processing module; The photoelectric conversion module in the pixel unit is used to perform a reset operation according to the control of the reset signal at the initial moment of the first exposure period, convert the light signal into a photoelectric charge after the reset operation, and accumulate the photoelectric charge before receiving the readout signal; the first exposure period is a time period determined based on the initial moment and the end moment; The signal readout module in the pixel unit is used to read out an intermediate signal determined based on the photoelectric charge accumulated in the photoelectric conversion module at least once at least at a time point in the first exposure period, according to the control of the readout signal, to obtain at least one intermediate signal; and to read out an output signal determined based on all the photoelectric charges accumulated by the photoelectric conversion module in the first exposure period at the end time point of the first exposure period, according to the control of the readout signal; The signal processing module is used to receive the at least one intermediate signal and the output signal output by the signal readout module, and determine the image signal corresponding to the pixel unit in the first exposure period based on the at least one intermediate signal and the output signal.

7. The device according to claim 6, characterized in that The signal processing module is specifically used to perform weighted addition on the at least one intermediate signal and the output signal, and use the sum value obtained by the weighted addition as the image signal corresponding to the pixel unit.

8. The device according to claim 6 or 7, characterized in that The photoelectric conversion module includes a photodiode and a reset transistor, the drain terminal of the reset transistor is connected to the photodiode, the source terminal of the reset transistor is connected to the power supply signal, and the gate terminal of the reset transistor receives the reset signal; At the initial moment of the first exposure period, the reset transistor receives the reset signal through the gate terminal, and the reset transistor is turned on according to the control of the reset signal; after the reset operation, the reset transistor is turned off according to the control of the reset signal; The photodiode is reset to a high level when the reset transistor is turned on; when the reset transistor is turned off, the photodiode converts the optical signal into photoelectric charge and accumulates the photoelectric charge before receiving a readout signal.

9. The device according to claim 8, characterized in that The signal readout module includes: a source follower transistor and a pixel selection transistor; The gate terminal of the source follower transistor is connected to the photodiode, the source terminal of the source follower transistor is connected to a power supply signal, the drain terminal of the source follower transistor is connected to the drain terminal of the pixel selection transistor, and the source follower transistor is used to generate a corresponding voltage signal according to a voltage change in the photodiode; The drain terminal of the pixel selection transistor is connected to the drain terminal of the source follower transistor, the source terminal of the pixel selection transistor is connected to the signal processing module as the output terminal of the pixel unit, the gate terminal of the pixel selection transistor receives the readout signal, and the voltage signal generated in the source follower transistor is read out as the intermediate signal or the output signal according to the control of the readout signal.

10. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor, further comprising a signal reading device for a pixel unit according to any one of claims 6 to 9; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to control the timing signal processing device to implement the signal reading method of the pixel unit described in any one of claims 1-5.

11. The device according to claim 10, characterized in that The electronic device is included in any of the following: image data acquisition equipment, audio / video player, navigation equipment, entertainment equipment, communication equipment, roadside traffic facilities, equipment in motor vehicles, industrial testing equipment, flight equipment, medical equipment, and security equipment.

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