Image output method, device, program product, and storage medium

Abstract

The application discloses an image output method and device, a program product and a storage medium, and relates to the technical field of image processing. The method comprises the following steps: determining a target average pixel value of a reference pixel array; in the case that the target average pixel value is out of a preset threshold range, adjusting a bias voltage applied to a readout circuit to a target bias voltage, wherein the average pixel value of the reference pixel array determined by using an analog voltage signal read by the readout circuit to which the target bias voltage is applied is within the preset threshold range; reading analog voltage signals output by the plurality of target pixels by using the readout circuit to which the target bias voltage is applied, and outputting a target image based on the reading result. Through the application, the technical problem that the quality of the output image is poor due to the difficulty in accurately adjusting the bias voltage in the related art is solved, and the technical effect of accurately adjusting the bias voltage to improve the quality of the generated image is achieved.

Description

Technical Field

[0001] This application relates to the field of computers, and more specifically, to an image output method, apparatus, program product, and storage medium. Background Technology

[0002] Infrared imaging technology is widely used in security monitoring, industrial temperature measurement, vehicle night vision, and aerospace. In the readout circuit that acquires pixel values, the bias voltage of the readout circuit has a decisive impact on the baseline stability and system noise performance of the entire link. The signal quality of the pixel output directly depends on the bias voltage applied to the readout circuit. To ensure that the readout circuit can still operate normally under different temperatures, process deviations, and power supply fluctuations, the bias voltage usually needs to be adjusted to suppress baseline drift and fixed pattern noise.

[0003] In related technologies, a fixed bias voltage value is determined during power-on initialization using empirical parameters or a one-time calibration, and this value is maintained unchanged during subsequent operation. However, pixels are extremely sensitive to changes in environmental factors such as temperature. As the operating environment temperature changes or the components age, the readout baseline of the readout circuit will drift significantly. The fixed bias cannot adapt to this dynamic change, resulting in severe fixed pattern noise in the pixel output image, reducing image contrast and temperature measurement accuracy, and failing to generate images that meet the requirements.

[0004] There is currently no effective solution to the above problems in the relevant technologies. Summary of the Invention

[0005] This application provides an image output method, apparatus, program product, and storage medium to at least solve the technical problem in the related art of poor image quality caused by the difficulty in accurately adjusting the bias voltage.

[0006] According to one aspect of the embodiments of this application, an image output method is provided, comprising: determining a target average pixel value of a reference pixel array, wherein the target average pixel value is used to indicate the average value of analog voltage signals output by a plurality of reference pixels included in the reference pixel array, each of the analog voltage signals output by the reference pixels is read by a readout circuit, the readout circuit is further used to read the analog voltage signals output by the plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under target imaging conditions, and the plurality of target pixels output... The analog voltage signal changes with the target imaging conditions, while the analog voltage signal output by the plurality of reference pixels is not affected by the target imaging conditions. When the average pixel value of the target exceeds a preset threshold range, the bias voltage applied to the readout circuit is adjusted to the target bias voltage. The average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range. The readout circuit with the target bias voltage applied reads the analog voltage signal output by the plurality of target pixels and outputs the target image based on the reading result.

[0007] In one exemplary embodiment, when the target average pixel value exceeds a preset threshold range, adjusting the bias voltage applied to the readout circuit to a target bias voltage includes: repeatedly performing the following target operation until the determined average pixel value of the reference pixel array is within the preset threshold range; when the target average pixel value exceeds the preset threshold range, generating a control signal including an adjusted bias parameter based on a comparison result between the target average pixel value and the preset threshold range, and adjusting the bias voltage using the bias parameter included in the control signal; reading a first analog voltage signal of the plurality of reference pixels using the readout circuit with the adjusted bias voltage applied; redetermining the average pixel value of the reference pixel array based on the read first analog voltage signal, and determining the redetermined average pixel value of the reference pixel array as the target average pixel value.

[0008] In an exemplary embodiment, when the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range. This includes: comparing the target average pixel value with a first threshold, wherein the first threshold is the smallest value included in the preset threshold range; when the target average pixel value is less than the first threshold, determining that the target average pixel value exceeds the preset threshold range, calculating the sum of an initial bias parameter and a preset step value of the bias voltage currently applied to the readout circuit to obtain a first bias parameter, wherein the first bias parameter is used to control the bias voltage to change in a first direction to increase the target average pixel value; and generating the control signal including the first bias parameter.

[0009] In one exemplary embodiment, when the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range. The method further includes: comparing the target average pixel value with a second threshold, wherein the second threshold is the largest value included in the preset threshold range; when the target average pixel value is greater than the second threshold, determining that the target average pixel value exceeds the preset threshold range, calculating the difference between an initial bias parameter and a preset step value of the bias voltage currently applied to the readout circuit to obtain a second bias parameter, wherein the second bias parameter is used to control the bias voltage to change in a second direction to reduce the target average pixel value; and generating the control signal including the second bias parameter.

[0010] In an exemplary embodiment, determining a target average pixel value for a reference pixel array includes: sequentially turning on each row of reference pixels in the reference pixel array, and for each row of reference pixels that is turned on, performing the following operations: acquiring the pixel value of each reference pixel in the currently turned-on row using the readout circuit to obtain a plurality of first pixel values; calculating a first average pixel value of the reference pixels in the currently turned-on row using the plurality of first pixel values; whenever the number of the calculated first average pixel values ​​reaches a preset number of rows, calculating a second average pixel value of the reference pixels in the preset number of rows using the preset number of first average pixel values, until the pixel values ​​of the reference pixels in all rows of the reference pixel array are calculated, obtaining one or more of the second average pixel values; and determining the target average pixel value using the one or more of the second average pixel values.

[0011] In an exemplary embodiment, the readout circuit is configured to acquire the pixel value of a first pixel in the following manner, wherein the first pixel is any reference pixel included in the currently active row: acquiring a current signal passing through the first pixel; converting the current signal into a second analog voltage signal; performing an amplification operation on the second analog voltage signal to obtain a first voltage signal; performing a second operation on the first voltage signal to obtain a second voltage signal, wherein the signal fluctuation of the second voltage signal within a target time period is within a preset fluctuation range; and performing an analog-to-digital conversion operation on the second voltage signal within the target time period to generate the pixel value of the first pixel.

[0012] In an exemplary embodiment, the readout circuit includes: a transistor, a column amplifier, a sample-and-hold unit, an analog-to-digital converter, and a digital signal output unit connected in sequence, wherein: the transistor is used to connect to the pixel under test and to convert the current signal passing through the pixel under test into an analog voltage signal; the column amplifier is used to amplify the analog voltage signal; the sample-and-hold unit is used to perform a second operation on the amplified analog voltage signal to obtain a third voltage signal, wherein the signal fluctuation of the third voltage signal within a target time period is within a preset fluctuation range; the analog-to-digital converter is used to perform an analog-to-digital conversion operation on the third voltage signal within the target time period to generate the pixel value of the pixel under test; and the digital signal output unit is used to output the pixel value of the pixel under test.

[0013] According to another aspect of the embodiments of this application, an image output device is also provided, comprising: a determining module, configured to determine a target average pixel value of a reference pixel array, wherein the target average pixel value is used to indicate the average value of analog voltage signals output by a plurality of reference pixels included in the reference pixel array, each of the analog voltage signals output by the reference pixels is read by a readout circuit, the readout circuit is further configured to read the analog voltage signals output by a plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under target imaging conditions, and the analog voltage signals output by the plurality of target pixels are... The analog voltage signal changes with the target imaging conditions, while the analog voltage signals output by the plurality of reference pixels are not affected by the target imaging conditions. The adjustment module is used to adjust the bias voltage applied to the readout circuit to the target bias voltage when the average pixel value of the target exceeds a preset threshold range. The average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range. The reading module is used to read the analog voltage signals output by the plurality of target pixels using the readout circuit with the target bias voltage applied, and output the target image based on the reading result.

[0014] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, wherein a computer program is stored therein, wherein the computer program is configured to perform the steps in any of the above method embodiments when executed by a processor.

[0015] According to another aspect of the embodiments of this application, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, causing the computer device to perform the steps in any of the method embodiments described above.

[0016] According to another aspect of the embodiments of this application, an electronic device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor is configured to perform the steps of any of the above method embodiments through the computer program.

[0017] This application achieves a separation between the bias voltage control logic and the image imaging process. Since the reference pixel array and the target pixel array are under the same target imaging conditions and have the same readout circuit structure, the reference pixel array is independent of the target pixel array. The reference pixels included in the reference pixel array are unaffected by the target imaging conditions, and the output analog voltage signal only reflects the influence of certain factors within the circuit itself on the analog voltage signal. By calculating the average pixel value of the reference pixels in real time and comparing it with a preset threshold range, when the average pixel value exceeds the preset threshold range, the bias voltage applied to the readout circuit is dynamically adjusted to ensure that the average pixel value of the reference pixels is within the preset threshold range, effectively suppressing pattern noise. Based on this, the corrected readout circuit reads the analog voltage signal output by the target pixels and outputs the image. This ensures that the final generated image maintains a high signal-to-noise ratio while eliminating image artifacts and distortion caused by inappropriate bias voltage. This solves the technical problem in related technologies where the difficulty in accurately adjusting the bias voltage leads to poor image quality, achieving the technical effect of accurately adjusting the bias voltage to improve the quality of the generated image. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating an application scenario of an image output method according to an embodiment of this application;

[0019] Figure 2 This is a schematic flowchart of an image output method according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a pixel array structure according to an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of a correction module according to an embodiment of this application;

[0022] Figure 5 This is a schematic flowchart of a bias voltage adjustment method according to an embodiment of this application;

[0023] Figure 6 This is a schematic diagram of a mean calculation module according to an embodiment of this application;

[0024] Figure 7 This is a flowchart illustrating a method for calculating the average pixel value of a target according to an embodiment of this application;

[0025] Figure 8 This is a schematic diagram of a readout circuit according to an embodiment of this application;

[0026] Figure 9This is a timing diagram of the operation of an image output device according to one embodiment of this application;

[0027] Figure 10 This is a flowchart illustrating an adaptive control method for the gate bias node of an infrared readout circuit based on a reference pixel, according to an embodiment of this application.

[0028] Figure 11 This is a structural block diagram of an image output device according to an embodiment of this application. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. Furthermore, in the absence of conflict, the various embodiments and features in the embodiments of the present application can be arbitrarily combined with each other in principle.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] According to one aspect of the embodiments of this application, an image output method is provided. Optionally, in this embodiment, the above-described image output method may be applied to, but is not limited to, [examples of image output methods]. Figure 1 The hardware environment shown includes terminal device 102 and server 104. Server 104 can be connected to terminal device 102 via a network and can be used to provide services (e.g., application services, etc.) to terminal device 102 or clients installed on terminal device 102. A database can be set up on server 104 or independently of server 104 to provide data storage services for server 104.

[0032] The aforementioned network may include, but is not limited to, at least one of the following: wired network and wireless network. The aforementioned wired network may include, but is not limited to, at least one of the following: wide area network (WAN), metropolitan area network (MAN), and local area network (LAN). The aforementioned wireless network may include, but is not limited to, at least one of the following: Wireless Fidelity (WIFI) and Bluetooth. Terminal device 102 may be, but is not limited to, a personal computer (PC), mobile phone, tablet computer, etc. Server 104 may be, but is not limited to, a cloud server, server cluster, or other server types.

[0033] The image output method of this application embodiment can be executed by server 104, terminal device 102, or jointly by server 104 and terminal device 102. Alternatively, the image output method of this application embodiment can be executed by a client installed on the terminal device 102.

[0034] Taking the image output method in this embodiment executed by terminal device 102 (server 104) as an example, Figure 2 This is a flowchart illustrating an image output method according to an embodiment of this application, such as... Figure 2 As shown, the process of this method may include the following steps:

[0035] Step S202: Determine the target average pixel value of the reference pixel array, wherein the target average pixel value is used to indicate the average value of the analog voltage signals output by the plurality of reference pixels included in the reference pixel array, the analog voltage signal output by each of the reference pixels is read by a readout circuit, the readout circuit is also used to read the analog voltage signals output by the plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under the target imaging conditions, and the analog voltage signals output by the plurality of target pixels change with the change of the target imaging conditions, while the analog voltage signals output by the plurality of reference pixels are not affected by the target imaging conditions;

[0036] Optionally, the image output method in this embodiment can be applied to scenarios such as security monitoring, industrial online temperature measurement, vehicle-mounted night vision systems, and aerospace exploration. In these scenarios, the target pixel array is exposed to environments with drastic temperature fluctuations, long-term continuous operation, or complex background radiation interference. This method utilizes fixed reference pixels, which are unaffected by the scene content, to monitor the bias voltage of the readout circuit in real time and dynamically adjusts the bias voltage to eliminate fixed pattern noise caused by factors such as process deviations. This ensures that in application scenarios with extremely high image stability requirements, such as dynamic target tracking or nighttime monitoring, the imaging pixels (i.e., target pixels) can still continuously output clear images with high signal-to-noise ratio and high consistency, improving the practical value and availability of the images.

[0037] Optionally, the reference pixel array in this embodiment is a set of special pixels set at the edge of the infrared focal plane array (FPA) or in a specific non-imaging area. It is mainly used to monitor the working status inside the readout circuit.

[0038] Optionally, the reference pixel in this embodiment is similar in physical structure to the effective pixel (i.e., the target pixel), but is typically made unaffected by the target imaging conditions through methods such as a light-shielding layer, grounding connection, or fixed bias circuit. In practical use, the reference pixel includes, but is not limited to: a completely light-shielding reference pixel, a blind-end pixel connected to a fixed reference voltage, and a shielded pixel used for calibrating dark current.

[0039] Optionally, in this embodiment, the target average pixel value refers to a value obtained by statistically processing (e.g., averaging) the analog voltage signals output by multiple reference pixels in the reference pixel array. This value characterizes the overall DC operating point or baseline level of the current readout circuit at a specific moment. This value does not represent the temperature or brightness of any actual scene, but is used as a value for subsequent comparison with a preset threshold range to indicate whether the bias voltage applied to the readout circuit needs to be adjusted.

[0040] Optionally, the analog voltage signal in this embodiment can be either the analog voltage signal obtained by the target pixel array converting the received infrared radiation energy into an electrical signal under target imaging conditions, amplified by a column amplifier circuit, and stabilized by a sample-and-hold circuit; or it can be the analog level signal obtained by amplifying the electrical signal generated by the reference pixel in a fixed state, amplifying it by a column amplifier circuit, and stabilizing it by a sample-and-hold circuit. Optionally, the amplitude of the analog voltage signal in this embodiment directly corresponds to the response intensity of the pixel or the bias state of the circuit.

[0041] Optionally, the readout integrated circuit (ROIC) in this embodiment is a dedicated integrated circuit responsible for performing preliminary signal processing operations such as gating, amplification, sampling, holding, and analog-to-digital conversion of pixel signals. The readout circuit converts the weak electrical signals generated by the pixels into digital image data that can be processed by an external processor, while providing the necessary bias voltage. In practical applications, the types of readout circuits include, but are not limited to: uncooled microbolometer readout circuits, cooled photon detector readout circuits, hybrid readout circuits based on charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology, and intelligent readout circuits integrating on-chip non-uniformity correction (NUC) functionality.

[0042] Optionally, in this embodiment, the target pixel array is the core area used for actual imaging. The pixel values ​​output by the target pixels carry spatial distribution information of the environmental scene, which is used to generate an image. In actual use, the target pixel array can be composed of a large number of thermistors or photodiodes sensitive to infrared radiation. Each target pixel generates a corresponding electrical signal according to the received scene infrared radiation intensity. The output value of the target pixel changes with the scene temperature, thereby constituting the final infrared image. Target pixels include, but are not limited to: ordinary imaging pixels for monitoring, radiation measurement pixels for temperature measurement, and effective pixels that still participate in imaging after being shielded by a bad pixel mask.

[0043] Optionally, the identical operating conditions in this embodiment mean that the reference pixel array and the target pixel array are identical in physical structure and electrical connection. They have the same readout circuit parameters, such as the same column amplifier gain, the same analog-to-digital converter (ADC) quantization characteristics, the same supply voltage, the same temperature field distribution, and the same bias voltage (such as the High-Speed ​​Source Node (HSSD) voltage). These identical operating conditions ensure that the analog voltage signal output by the reference pixel can accurately represent the interference experienced by the target pixel.

[0044] Optionally, in this embodiment, the target imaging conditions refer to the external environment that affects the output signal intensity of the target pixel, including but not limited to the infrared radiation distribution in the target scene, ambient temperature, object temperature, and exposure time. Changes in the target imaging conditions will cause significant fluctuations in the analog voltage signal output by the target pixel, thereby degrading the image quality output by the target pixel.

[0045] Step S204: When the target average pixel value exceeds the preset threshold range, the bias voltage applied to the readout circuit is adjusted to the target bias voltage, wherein the average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range.

[0046] Optionally, the preset threshold range in this embodiment is a numerical limit preset within an allowable deviation range, used to determine whether the bias voltage of the readout circuit is in a stable state. This range is typically determined by the dynamic range, noise margin, and accuracy requirements of the target image in the system design. When the average pixel value of the target is within the preset threshold range, the bias voltage is considered appropriate; if it exceeds the preset threshold range, an adjustment mechanism is triggered. The preset threshold range includes, but is not limited to: an interval extending above and below the ideal baseline voltage by a certain voltage value (e.g., ±10mV); upper and lower limits expressed in digital code values ​​(e.g., in units of the least significant bit (LSB)); and an adaptive threshold window dynamically adjusted according to temperature or time. For example, the preset threshold range is [A, B], where A is the first threshold and B is the second threshold.

[0047] Optionally, the bias voltage in this embodiment is a DC control voltage applied to key analog nodes (such as the gate of a transistor, the input of an integrator, etc.) inside the readout circuit. Adjusting the bias voltage can change the on-state current of the transistors included in the readout circuit, thereby adjusting the current passing through the target pixel and suppressing fixed pattern noise and baseline drift.

[0048] Optionally, the target bias voltage in this embodiment refers to the latest bias voltage value that, after the above adjustments, enables the average pixel value of the reference pixel to be within a preset threshold range. It represents the bias setting required for the readout circuit to achieve optimal stability in the current state.

[0049] Step S206: The readout circuit with the target bias voltage applied is used to read the analog voltage signal output by the plurality of target pixels, and the target image is output based on the reading result.

[0050] Optionally, in this embodiment, the target image refers to the final output image data generated based on the corrected bias voltage after being processed by the readout circuit. Because the bias voltage is adaptively adjusted in real time, the image output by the target pixel has low fixed pattern noise, and the quality of the target image meets the preset standard.

[0051] The following example illustrates the solution in this embodiment. A vehicle-mounted infrared night vision camera is driving on a highway at night, with an ambient temperature of -10°C. At this time, the system needs to output clear infrared images in real time to assist the driver in observing pedestrians or obstacles ahead. The system first calculates the target average pixel value to be 3500 LSB based on the analog voltage signals output by multiple reference pixels in the reference pixel array located on both sides of the focal plane array. These reference pixels are covered by light-shielding plates and do not receive any external infrared radiation; therefore, their output analog voltage signals only reflect the internal electrical state of the readout circuit (such as the current magnitude affected by the HSSD bias voltage) and are completely unaffected by target imaging conditions (such as headlights from vehicles ahead or the body temperature of pedestrians). The above target average pixel value is compared with a preset threshold range [3200, 3300] LSB, determining that the current target average pixel value exceeds the preset threshold range. Based on this comparison result, the bias voltage applied to the readout circuit is adjusted so that the average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the adjusted bias voltage is within a preset threshold range. Finally, the analog voltage signal output by the target pixel array is reread using the readout circuit, which has stabilized at its optimal operating point. At this point, the output signal of the target pixel no longer contains noise caused by improper bias voltage. The system then processes the output signal of the target pixel to obtain the final target image, which includes low noise and clearly presents a nighttime road scene.

[0052] In this embodiment, since the reference pixel array and the target pixel array are under the same target imaging conditions and have the same readout circuit structure, the reference pixel array is independent of the target pixel array. The reference pixels included in the reference pixel array are not affected by the target imaging conditions, and the output analog voltage signal only reflects the influence of certain factors of the circuit itself on the analog voltage signal, thus achieving the separation of the bias voltage control logic and the image imaging process. By calculating the target average pixel value of the reference pixel in real time and comparing it with a preset threshold range, when the target average pixel value is detected to exceed the preset threshold range, the bias voltage applied to the readout circuit is dynamically adjusted so that the average pixel value of the reference pixel is within the preset threshold range, effectively suppressing pattern noise. On this basis, the corrected readout circuit reads the analog voltage signal output by the target pixel and outputs the image, so that the final generated image maintains a high signal-to-noise ratio while eliminating image artifacts and distortions caused by applying an inappropriate bias voltage. This solves the technical problem in related technologies where the output image quality is poor due to the difficulty in accurately adjusting the bias voltage, achieving the technical effect of accurately adjusting the bias voltage to improve the quality of the generated image.

[0053] In one exemplary embodiment, when the target average pixel value exceeds a preset threshold range, adjusting the bias voltage applied to the readout circuit to a target bias voltage includes: repeatedly performing the following target operation until the determined average pixel value of the reference pixel array is within the preset threshold range; when the target average pixel value exceeds the preset threshold range, generating a control signal including an adjusted bias parameter based on a comparison result between the target average pixel value and the preset threshold range, and adjusting the bias voltage using the bias parameter included in the control signal; reading a first analog voltage signal of the plurality of reference pixels using the readout circuit with the adjusted bias voltage applied; redetermining the average pixel value of the reference pixel array based on the read first analog voltage signal, and determining the redetermined average pixel value of the reference pixel array as the target average pixel value.

[0054] Optionally, the target operation in this embodiment is an operation that is continuously performed during the iterative adjustment of the bias voltage. The target operation includes "monitoring the analog voltage signal output by the reference pixel, calculating the average pixel value of the reference pixels included in the reference pixel array, determining whether the calculated average pixel value is within a preset threshold range, and adjusting the bias voltage applied to the readout circuit when the average pixel value exceeds the preset threshold range", so as to gradually bring the average pixel value of the reference pixel array within the preset threshold range.

[0055] Optionally, the first analog voltage signal in this embodiment refers to the analog voltage signal re-output by the reference pixel array in the current working state after a specific bias voltage (i.e., the adjusted bias voltage) is specified. It can intuitively represent the change in current flowing through the reference pixel array after the last bias voltage adjustment, and is used to verify whether the current bias voltage has made the average pixel value of the reference pixel array within the preset threshold range.

[0056] Optionally, in this embodiment, the adjusted bias parameter refers to a new digital control word or control quantity, calculated using a specific algorithm (such as adding or subtracting step values), based on a comparison between the current target average pixel value and a preset threshold range, to replace the old bias parameter. This parameter directly determines the specific value of the bias voltage applied to the readout circuit.

[0057] Optionally, the control signal in this embodiment carries specific parameter information for updating the bias voltage. This includes not only the numerical value itself, but may also include a validity flag, an update enable signal, or timing control information to ensure that the bias voltage is updated at the correct time.

[0058] Figure 3 This is a schematic diagram of a pixel array structure according to an embodiment of this application, such as... Figure 3 As shown, in practical use, the focal plane array (i.e., the aforementioned pixel array) includes a reference pixel array composed of reference pixels and an effective pixel array (i.e., the aforementioned target pixel array) composed of effective pixels (i.e., the aforementioned target pixels). The pixel array structure mainly consists of a row scanning module, a focal plane array including effective pixels and reference pixels, a column amplifier, an analog-to-digital converter circuit, a serial-to-parallel converter module, a mean statistics module, a column processing module, a row scanning module, and a correction module. The row scanning module controls the gating timing of each row of pixels in the focal plane array, enabling row-by-row readout; the column processing circuit performs column gating control and data management of the reference pixels and effective pixels. The infrared focal plane array consists of an effective pixel area and a reference pixel area. The reference pixels are respectively set on both sides of the array to acquire reference signals reflecting the working status of the readout circuit in real time, such as... Figure 3As shown, in the infrared focal plane array, columns P to 9 (512 rows) on the left are deployed as reference pixels, columns 1 to 8 (512 rows) on the right are also deployed as reference pixels, and columns 1 to M (512 rows) in the middle are deployed as effective pixels. Effective pixels are used to acquire infrared image information, while reference pixels do not participate in image imaging and are only used for subsequent statistics and control. Under the control of the row scanning module, the analog voltage signal output by the pixel is amplified by the column amplifier and then sent to the analog-to-digital converter circuit and the serial-to-parallel converter circuit to realize the data reconstruction and output of analog signals to digital signals. Simultaneously, the pixel values ​​output by the converted pixels are extracted separately and sent to the mean calculation module. The mean calculation module performs multi-level statistical processing on the pixel values ​​output by the reference pixels in the column and row directions. By accumulating and averaging the data from multiple reference pixels, multiple scan rows, and multiple sampling periods, it obtains a statistical result that characterizes the current readout circuit bias state. The target average pixel value calculated by the mean calculation module is further input to the correction module. The correction module generates corresponding bias parameters based on the deviation between the target average pixel value and the preset threshold range. The new bias parameters output by the correction algorithm are fed back to the bias control node in the column processing module and the readout circuit to adjust the operating state of the key analog units. In this embodiment, the bias control node is the HSSD control node in the readout circuit. The HSSD dynamically adjusts the operating point of the column-level readout link by controlling the gate bias voltage of the transistor, thereby suppressing temperature drift, process deviation, and baseline drift caused by long-term operation. Through the above structure, this embodiment constructs a reference pixel statistics and bias adaptive control path independent of the image data path, realizing real-time monitoring, real-time calibration, and closed-loop control during the operation of the readout circuit, improving the stability, consistency, and long-term reliability of the system without affecting normal image output. It should be noted that the above design of setting the reference pixels on both sides of the array is only an illustrative example. The layout relationship between the reference pixels and the target pixels can be set according to actual needs, and this application does not limit it.

[0059] In this embodiment, when the average pixel value is detected to exceed the preset threshold range, the adjustment is not completed all at once. Instead, the average pixel value is recalculated based on the analog voltage signal output from the reference pixel in real time, and a new control signal is generated accordingly for fine-tuning until the average pixel value of the reference pixel stabilizes within the preset threshold range. This iterative adjustment method ensures that the bias voltage can ultimately be precisely locked at the optimal operating point.

[0060] In an exemplary embodiment, when the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range. This includes: comparing the target average pixel value with a first threshold, wherein the first threshold is the smallest value included in the preset threshold range; when the target average pixel value is less than the first threshold, determining that the target average pixel value exceeds the preset threshold range, calculating the sum of an initial bias parameter and a preset step value of the bias voltage currently applied to the readout circuit to obtain a first bias parameter, wherein the first bias parameter is used to control the bias voltage to change in a first direction to increase the target average pixel value; and generating the control signal including the first bias parameter.

[0061] Optionally, in this embodiment, the first threshold refers to the lower boundary value of a preset threshold range, that is, the minimum allowed value within the preset threshold range. When the target average pixel value is lower than this threshold, it indicates that the bias voltage needs to be adjusted, and the bias voltage needs to be compensated in the direction of increasing the pixel value output by the reference pixel. The first threshold includes, but is not limited to: the minimum LSB (i.e., least significant bit) value of a preset digital range, the minimum number of volts in the analog voltage window, or a lower limit warning line dynamically calculated based on the system noise floor.

[0062] Optionally, the initial bias parameter in this embodiment refers to the specific control value currently in effect for setting the bias voltage. It is the bias parameter calculated when the bias voltage was last adjusted or the default bias parameter set during system power-on initialization. When calculating new parameters, it serves as a reference starting point, and fine-tuning is performed by adding step values.

[0063] Optionally, the preset step value in this embodiment refers to the fixed increment by which the bias parameter changes during a single adjustment operation. This value determines the step size of the bias voltage adjustment. A smaller step value can improve accuracy but increases the adjustment time of the bias voltage, while a larger step value can speed up the response but may cause oscillations in the pixel output signal. In actual use, it needs to be set reasonably according to the situation.

[0064] Optionally, in this embodiment, the first bias parameter refers to a new control parameter obtained after calculation, used to increase the target average pixel value. It is obtained by adding the initial bias parameter to a preset step value, aiming to pull the bias voltage in the positive direction, thereby increasing the target average pixel value and bringing it within a preset threshold range.

[0065] Optionally, in this embodiment, since the target average pixel value is low, the system determines that the bias parameter needs to be increased to increase the target average pixel value. Therefore, the "first direction" corresponds to the positive adjustment of the bias voltage (e.g., increasing the bias current or increasing the gate voltage).

[0066] This embodiment uses a preset threshold range's minimum value (i.e., the first threshold) as a criterion to determine that when the average pixel value is low, the target average pixel value is increased by adding the bias parameter. This threshold-based adjustment method avoids signal oscillations in the pixel output caused by blindly adjusting the bias voltage, thus improving the response speed and adjustment accuracy of the bias control while ensuring the correctness of the adjustment direction.

[0067] In one exemplary embodiment, when the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range. The method further includes: comparing the target average pixel value with a second threshold, wherein the second threshold is the largest value included in the preset threshold range; when the target average pixel value is greater than the second threshold, determining that the target average pixel value exceeds the preset threshold range, calculating the difference between an initial bias parameter and a preset step value of the bias voltage currently applied to the readout circuit to obtain a second bias parameter, wherein the second bias parameter is used to control the bias voltage to change in a second direction to reduce the target average pixel value; and generating the control signal including the second bias parameter.

[0068] Optionally, in this embodiment, the second threshold refers to the upper boundary value of a preset threshold range, i.e., the maximum value allowed within that range. When the target average pixel value is higher than this threshold, it indicates that the bias voltage needs to be adjusted, and the bias voltage needs to be compensated in the direction of reducing the pixel value output by the reference pixel. The first threshold includes, but is not limited to: the maximum LSB (i.e., most significant bit) value of a preset digital range, the highest volt value of the analog voltage window, or the upper limit warning line dynamically calculated based on the upper limit of the system's dynamic range.

[0069] Optionally, the initial bias parameter in this embodiment refers to the specific control value currently in effect for setting the bias voltage. It is the bias parameter calculated when the bias voltage was last adjusted or the default bias parameter set during system power-on initialization. When calculating new parameters, it serves as a reference starting point, and fine-tuning is performed by subtracting the step value.

[0070] Optionally, the preset step value in this embodiment refers to the fixed decrease in the amount by which the bias parameter changes during a single adjustment operation. This value determines the step size of the bias voltage adjustment. A smaller step value can improve accuracy but increases the adjustment time of the bias voltage, while a larger step value can speed up the response but may cause oscillations in the pixel output signal. In actual use, it needs to be set reasonably according to the situation.

[0071] Optionally, in this embodiment, the second bias parameter refers to a new control parameter obtained after calculation that reduces the target average pixel value. It is obtained by subtracting the initial bias parameter from the preset step value, aiming to pull the bias voltage in the negative direction, thereby reducing the target average pixel value and bringing it within the preset threshold range.

[0072] Optionally, in this embodiment, since the target average pixel value is too high, the system determines that the bias parameter needs to be reduced to reduce the target average pixel value. Therefore, the "second direction" corresponds to the negative adjustment of the bias voltage (e.g., reducing the bias current or lowering the gate voltage).

[0073] In this embodiment, by setting the maximum value of the preset threshold range (i.e., the second threshold) as the judgment benchmark, it is clear that when the average pixel value is too high, the bias voltage is adjusted by reducing the bias parameter. This prevents the average pixel value from exceeding the preset threshold range due to excessive bias voltage, and avoids the oscillation of the pixel output signal caused by blindly adjusting the bias voltage. Thus, while ensuring the correctness of the adjustment direction, the response speed and adjustment accuracy of the bias control are improved.

[0074] Figure 4 This is a schematic diagram of a correction module according to an embodiment of this application, as shown below. Figure 4As shown, in practical use, the correction module is used to compare the target average pixel value with the preset threshold range and generate the corresponding bias parameters. The correction module consists of an input interface, comparison and control logic, and a register group. It receives the 16-bit average pixel value (average) and the validity flag (average_valid) from the mean statistics module. Driven by the clock clk, reset rst_n, and enable signals clk_en and stc_cal_en, it compares average with the preset upper threshold stc_thres_up (i.e., the second threshold mentioned above) and lower threshold stc_thres_down (i.e., the first threshold mentioned above) through an internal comparator; and determines whether the average pixel value is greater than the second threshold or less than the first threshold. In this case, based on the input feedback direction selection signal stc_cal_trend (1 bit, 1 for negative feedback, 0 for positive feedback) and the configurable adjustment step size stc_step, if the average is higher than the upper limit, a subtraction or addition operation is performed (e.g., subtraction for negative feedback), and the calculate_done flag is cleared. If it is lower than the lower limit, the opposite operation is performed and the calculate_done flag is cleared. If it falls within the preset threshold range, the bias parameter value remains unchanged and calculate_done=1 is output, indicating that the current round of bias voltage adjustment is complete. Internally, the correction module stores the current bias compensation amount through a 7-bit register skim_hssd_adj, and finally outputs the updated 7-bit bias parameter skim_hssd_adj, the validity flag hssd_valid, and the status flag calculate_done for use by subsequent structures, thereby realizing adaptive and stable control of the readout circuit baseline. The bias parameter adjustment logic described above, based on the comparison between the average pixel value and preset upper threshold stc_thres_up (i.e., the second threshold) and lower threshold stc_thres_down (i.e., the first threshold), is shown in Table 1. Simultaneously, the module generates an hssd_valid output signal to indicate that the current HSSD parameter update is valid. The final output 7-bit adjustment value (i.e., the bias parameter) skim_hssd_adj can be directly used to adjust the bias voltage. The correction module employs a digital closed-loop control structure combining dual threshold comparison and step-by-step feedback adjustment. Through simple addition and subtraction operations, it can ensure that the average pixel value of the reference pixel is within the preset threshold range. This approach offers advantages such as low logic resource consumption, fast response speed, and ease of digital implementation, making it particularly suitable for applications such as temperature drift compensation, scene adaptive control, and automatic gain adjustment in infrared detector readout circuits.

[0075] Table 1:

[0076]

[0077] Figure 5 This is a schematic flowchart of a bias voltage adjustment method according to an embodiment of this application, as shown below. Figure 5 As shown, in practical use, the bias voltage is adjusted by performing the following steps:

[0078] Step S502: Acquire the first pixel value of the reference pixel array;

[0079] Step S504: Using the first pixel value of the collected reference pixel array, calculate the average pixel value of the reference pixels included in the reference pixel array.

[0080] Step S506: Compare the average pixel value with the second threshold. If the average pixel value is greater than the second threshold, proceed to step S508. If the average pixel value is less than or equal to the second threshold, proceed to step S510.

[0081] Step S508: Set the adjusted initial bias parameter = initial bias parameter - step value;

[0082] Step S510: Compare the average pixel value with the first threshold. If the average pixel value is less than the first threshold, proceed to step S514. If the average pixel value is greater than or equal to the first threshold, proceed to step S512.

[0083] Step S512: Do not adjust the initial bias parameters;

[0084] Step S514: Set the adjusted initial bias parameter = initial bias parameter + step value;

[0085] Step S516: Adjust the bias voltage using the initial bias parameters and execute step S502 again.

[0086] It should be noted that in practical use, the average pixel value can be compared with the first threshold first. If the average pixel value is less than the first threshold, the adjusted initial bias parameter is set to the initial bias parameter plus the step value. If the average pixel value is greater than or equal to the first threshold, the average pixel value is then compared with the second threshold. If the average pixel value is greater than the second threshold, the adjusted initial bias parameter is set to the initial bias parameter minus the step value. If the average pixel value is less than or equal to the second threshold, the initial bias parameter is not adjusted. The bias voltage is then adjusted using the initial bias parameter, and the pixel values ​​of the reference pixel array continue to be acquired.

[0087] In an exemplary embodiment, determining a target average pixel value for a reference pixel array includes: sequentially turning on each row of reference pixels in the reference pixel array, and for each row of reference pixels that is turned on, performing the following operations: acquiring the pixel value of each reference pixel in the currently turned-on row using the readout circuit to obtain a plurality of first pixel values; calculating a first average pixel value of the reference pixels in the currently turned-on row using the plurality of first pixel values; whenever the number of the calculated first average pixel values ​​reaches a preset number of rows, calculating a second average pixel value of the reference pixels in the preset number of rows using the preset number of first average pixel values, until the pixel values ​​of the reference pixels in all rows of the reference pixel array are calculated, obtaining one or more of the second average pixel values; and determining the target average pixel value using the one or more of the second average pixel values.

[0088] Optionally, in this embodiment, row-by-row pass-through refers to the readout circuit sequentially selecting each row of pixels in the reference pixel array according to a specific timing control signal, activating it to output an analog voltage signal. This is a serial readout mechanism that ensures that only one row of pixels is in an active output state at any given time, thereby avoiding signal interference caused by simultaneous output from multiple rows of pixels. Row-by-row pass-through includes, but is not limited to, implementation through: pulse triggering of the row selection signal, level switching based on the row driver, and selection operations following an alternating odd-even row scanning strategy.

[0089] Optionally, in this embodiment, the first pixel value refers to the quantized value of the analog voltage signal output by a single reference pixel in the currently active row after processing when the readout circuit is in an active state. The first pixel value is used to represent the analog voltage signal of the instantaneous response of the specific reference pixel at a specific moment, directly reflecting the local electrical state and noise characteristics of the pixel.

[0090] Optionally, in this embodiment, the first average pixel value refers to the statistical result obtained by taking the arithmetic average (or weighted average) of the pixel values ​​of all reference pixels in the currently active row of reference pixels. This value is used to eliminate random noise or minor process deviations in individual pixels within a single row, and represents an average value of the analog voltage signal output by the reference pixels included in the row.

[0091] Optionally, the preset number of rows in this embodiment refers to the number of rows used to aggregate the average value of a single row when performing multi-level calculations of average pixel values. This is a configurable parameter used to balance the stability of statistical results with computational latency. By accumulating the average data of multiple rows, random noise can be further suppressed to obtain a more representative average pixel value. The preset number of rows includes, but is not limited to: a fixed number of rows (such as 4 rows, 8 rows, 16 rows, 256 rows, 512 rows, etc.), a dynamically adjusted row window, or the number of rows corresponding to a complete frame or a portion of a frame.

[0092] Optionally, the second average pixel value in this embodiment refers to the second statistical average value calculated using a preset number of first average pixel values.

[0093] Figure 6 This is a schematic diagram of a mean calculation module according to an embodiment of this application, as shown below. Figure 6As shown, in practical use, this mean calculation module is a multi-stage statistical processing circuit based on a pipeline architecture, designed to calculate the average pixel value of reference pixels in real time with low hardware overhead. The mean calculation module consists of a column, row, and four-row three-stage accumulator. A 5-bit column counter `pcnt` filters the data output from the 4th to 11th columns (accumulation only occurs when `pcnt` = 4~11). At the end of each row (`pcnt` == 15), the 12-bit `ADC_OUT` data is shifted left by 5 bits and input into the column accumulator. The accumulated result is shifted right by 3 bits (divided by 8) and sent to the 12-bit row accumulator. Simultaneously, a 12-bit row counter `rcnt` is used in conjunction with the `full4` signal (when `rcnt` != 0 and `rcnt`... When [1:0]==0 and pcnt==0, the process is triggered, that is, every 4 rows are accumulated, the row accumulation result is shifted right by 2 bits (divided by 4) and sent to a 29-bit 4-row accumulator, so as to gradually reduce the data bit width and achieve graded averaging during the accumulation process; finally, when the window end signal H_end (generated by rcnt==reg_Y_WIN_SIZE) and pcnt==0, the dividend generation module combines sum_4rows (takes the high 24 bits dividen[28:5], where dividen=sum_ The 29-bit dividend (dividen) formed by 4rows + (sum_rows / 4) and sum_rows (taking the [11:0] part of the lower 24 bits, i.e., sum_rows>>2) and the 10-bit divisor (divisor[9:0]=reg_Y_WIN_SIZE[11:2]) generated by right-shifting the window height register reg_Y_WIN_SIZE by 2 bits are fed into a 24-bit pipelined divider (PIPELINE=4) for division. The lower 16 bits of the quotient [15:0] are aligned with the dividen_valid signal by the control delay module (ctl_delay) for 3 clock cycles and then latched into the final 16-bit average output AVERAGE, accompanied by a 1-bit AVERAGE_valid valid flag, thereby realizing a stable statistical representation of the bias state of the readout circuit. The calculation logic is: AVERAGE=Sum(ADC_OUT) / (reg_Y_WIN_SIZE×8). The mean calculation module provided in this embodiment adopts a hierarchical statistical structure of column average, row average, 4-row average, and window average. While ensuring calculation accuracy, it significantly reduces hardware resource consumption. It is suitable for application scenarios such as scene temperature statistics, background mean calculation, and non-uniformity correction reference value generation in infrared detector readout circuits. It avoids the hardware overhead caused by large bit-width full-frame accumulators and real-time division operations, reduces logic area and power consumption while ensuring statistical accuracy, and improves data processing efficiency.

[0094] Figure 7 This is a flowchart illustrating a method for calculating the average pixel value of a target according to an embodiment of this application, as shown below. Figure 7 As shown, in practical use, the target average pixel value of the reference pixels included in the reference pixel array is calculated by performing the following steps:

[0095] Step S702: Collect the second pixel value of the reference pixel included in the reference pixel array row by row;

[0096] Step S704: After determining that the acquisition of the second pixel value of a row of reference pixels has been completed, calculate the first average pixel value of the reference pixels included in this row.

[0097] Step S706: When 16 first average pixel values ​​are calculated, the second average pixel values ​​of the reference pixels included in these 16 rows are calculated using the first average pixel values ​​of these 16 rows of reference pixels.

[0098] Step S708: When 16 second average pixel values ​​are calculated, the third average pixel value of the reference pixels included in these 256 rows is calculated using these 16 second average pixel values.

[0099] In step S710, for every two third average pixel values ​​obtained, the fourth average pixel value of the reference pixels included in these 512 rows is calculated using these two third average pixel values.

[0100] Step S712: Determine the target average pixel value of the reference pixels included in the reference pixel array based on the fourth average pixel value.

[0101] This embodiment achieves high-precision average pixel value detection while reducing hardware complexity by using row averaging, column averaging, and global averaging. Compared to directly accumulating all reference pixel data at once, this scheme first performs local averaging on each row of data, and then performs secondary averaging on the results of multiple rows. This effectively filters out single-row noise and transient interference. At the same time, by using a preset number of rows as a statistical window, representative statistical results can be obtained in a shorter time. This allows the system to quickly and accurately calculate the average pixel value of the reference pixel array without affecting the normal imaging frame rate.

[0102] In an exemplary embodiment, the readout circuit is configured to acquire the pixel value of a first pixel in the following manner, wherein the first pixel is any reference pixel included in the currently active row: acquiring a current signal passing through the first pixel; converting the current signal into a second analog voltage signal; performing an amplification operation on the second analog voltage signal to obtain a first voltage signal; performing a second operation on the first voltage signal to obtain a second voltage signal, wherein the signal fluctuation of the second voltage signal within a target time period is within a preset fluctuation range; and performing an analog-to-digital conversion operation on the second voltage signal within the target time period to generate the pixel value of the first pixel.

[0103] Optionally, the current signal in this embodiment is a weak electrical signal generated by a reference pixel (such as a microbolometer photodiode or thermistor) in the reference pixel array. For the reference pixel, since it is usually in a light-shielded or fixed potential state, the current mainly reflects the dark current, leakage current or bias current of the readout circuit itself, and does not contain scene infrared radiation information.

[0104] Optionally, the second analog voltage signal in this embodiment is a voltage signal corresponding to the aforementioned current signal obtained after a conversion operation. This signal is typically a raw voltage form with high impedance, low amplitude, and may contain high-frequency noise. It has not been sufficiently amplified or stabilized, and direct input to subsequent circuits may be subject to noise interference or fail to match the input range of the ADC.

[0105] Optionally, in this embodiment, the first voltage signal is a voltage signal obtained by amplifying the second analog voltage signal (e.g., through a column amplifier, programmable gain amplifier, or differential amplifier). The purpose of amplification is to increase the signal amplitude so that it covers the optimal dynamic range of the analog-to-digital converter (ADC), thereby improving the signal-to-noise ratio.

[0106] Optionally, the second operation in this embodiment refers to performing sample-and-hold processing on the amplified first voltage signal. The core function of this operation is to freeze the analog voltage value within a specific time window (i.e., the target time period), so that it remains constant during the subsequent analog-to-digital conversion process, thereby eliminating signal fluctuations caused by sampling switch on-resistance, charge injection, or holding capacitor leakage, and ensuring the accuracy of ADC conversion.

[0107] Optionally, the target time period in this embodiment refers to the time window during which the sample-and-hold circuit is in the hold state, i.e., the period from when the sampling switch is turned off to when the analog-to-digital conversion is completed and valid data is output. During this period, the second voltage signal should remain constant, and its fluctuations (such as voltage drops or ripples) must be controlled within the preset accuracy requirements to ensure the effectiveness of ADC sampling.

[0108] Optionally, the preset fluctuation range in this embodiment refers to the maximum permissible deviation of the second voltage signal during the holding phase, which is typically determined by the system's noise budget, the ADC's resolution, and the required measurement accuracy. If the signal fluctuation exceeds this range, it will lead to significant errors in the conversion result or fixed pattern noise in the image. The preset fluctuation range differs from the preset threshold range mentioned above. The preset fluctuation range defines the stability index of the analog voltage signal itself during the holding phase of the sample-and-hold circuit, ensuring the accuracy and signal-to-noise ratio of the analog-to-digital conversion process, focusing on the instantaneous physical characteristics during signal transmission; while the preset threshold range defines the effective range allowed by the statistically processed digital quantity (such as the average pixel value of the reference pixel).

[0109] Optionally, in this embodiment, the pixel value of the first pixel refers to the final digital value output after complete processing. It represents the magnitude of the analog voltage signal output by the reference pixel during the current readout cycle and serves as the basis for subsequent calculation of the average pixel value and bias voltage adjustment.

[0110] This embodiment further clarifies how to generate the final digital pixel value from the original current signal, how to increase the signal amplitude through amplification, and how to stabilize the signal through specific operations (such as sample-and-hold) to suppress the effects of timing jitter. This ensures that the acquired first pixel value can accurately and stably reflect the analog state of the reference pixel, eliminating quantization errors caused by insufficient amplification and sampling errors caused by timing inconsistencies.

[0111] In an exemplary embodiment, the readout circuit includes: a transistor, a column amplifier, a sample-and-hold unit, an analog-to-digital converter, and a digital signal output unit connected in sequence, wherein: the transistor is used to connect to the pixel under test and to convert the current signal passing through the pixel under test into an analog voltage signal; the column amplifier is used to amplify the analog voltage signal; the sample-and-hold unit is used to perform a second operation on the amplified analog voltage signal to obtain a third voltage signal, wherein the signal fluctuation of the third voltage signal within a target time period is within a preset fluctuation range; the analog-to-digital converter is used to perform an analog-to-digital conversion operation on the third voltage signal within the target time period to generate the pixel value of the pixel under test; and the digital signal output unit is used to output the pixel value of the pixel under test.

[0112] Optionally, in this embodiment, the transistor is a signal readout switch or source follower directly connected to the pixel under test (such as a microbolometer or photodiode). The transistor (typically corresponding to a readout transistor) functions to extract the weak current signal generated by the pixel and, under the control of a bias voltage node (such as HSSD), convert it into an analog voltage signal that can be processed by subsequent circuits.

[0113] Optionally, in this embodiment, the column amplifier refers to an analog signal amplification module integrated on the column path of the readout circuit (ROIC), used to receive weak analog voltage signals from the transistor output and amplify them to a range suitable for the input level of the analog-to-digital converter. Through amplification, the column amplifier can improve the signal-to-noise ratio, overcome noise introduced by subsequent circuits, and ensure that weak changes in infrared radiation can be accurately captured.

[0114] Optionally, the sample-and-hold unit in this embodiment refers to a circuit module that instantaneously captures and holds the amplified analog voltage signal, and the operation it performs is usually called sample-and-hold.

[0115] Optionally, in this embodiment, the third voltage signal refers to an analog voltage value that remains constant during the hold phase after being processed by the sample-and-hold unit. This signal represents the pre-quantization state of the current pixel at the sampling moment, and its stability directly determines the accuracy of the analog-to-digital conversion.

[0116] Optionally, in this embodiment, the analog-to-digital conversion unit refers to a circuit module, such as an ADC, that converts the third voltage signal in the analog domain into pixel values ​​in the digital domain. Within a window period that maintains signal stability, it quantizes the voltage to generate corresponding digital code values ​​(such as 12-bit or 16-bit data), thus obtaining the pixel value of the corresponding cell.

[0117] Optionally, the digital signal output unit in this embodiment is responsible for transmitting the pixel values ​​generated by the analog-to-digital conversion unit to the circuitry of subsequent processing modules or external interfaces. It may include a parallel-to-serial converter, a shift register, or a digital logic control module to ensure that the data is output in the correct timing and format so as to synchronize with the mean statistics module or other digital processing units.

[0118] Figure 8 This is a schematic diagram of a readout circuit according to an embodiment of this application, as shown below. Figure 8As shown, the readout circuit includes, in sequence, a transistor, a column amplifier, a sample-and-hold unit, an analog-to-digital converter (ADC), and a digital signal output unit. The transistor is connected to the infrared pixel and is connected to the power supply AVDD via a readout metal-oxide-semiconductor field-effect transistor (MOS), used to extract the electrical signal generated by the pixel. The gate of the readout MOS is connected to a bias voltage node, which can be called the HSSD. This bias voltage node is used to set the DC operating point of the high-speed analog readout circuit and has a significant impact on the baseline and stability of the column-level signal. The signal output from the pixel enters the column amplifier for analog amplification after passing through the bias node, in order to improve the signal-to-noise ratio and match the input range of the subsequent circuits. The amplified analog signal then enters the sample-and-hold unit, which samples the instantaneous analog voltage and stabilizes the output during the holding phase to eliminate the impact of timing jitter on the accuracy of the subsequent conversion. The sample-and-hold signal is then sent to the ADC to convert the analog signal to a digital signal, and finally outputs digital image data.

[0119] Figure 9 This is a timing diagram of the operation of an image output device according to one embodiment of this application, such as... Figure 9 As shown, this timing diagram illustrates the complete data flow and control logic of the adaptive control of the gate bias node of the readout circuit based on the reference pixel array. Using the pixel clock (CLK) as the time base, the effective acquisition window for each frame and each row is first defined by the Frame_Valid and Line_Valid signals. After sampling of the imaging pixels (i.e., the target pixels mentioned above), the system digitally processes the ADC_Serial_Data of the fixed reference columns (e.g., 16 columns), accumulating it row by row and outputting Avg_Col (the average of 16 columns, i.e., the average of the reference signal in a single row) at the end of each row. Subsequently, the statistics module adopts a hierarchical accumulation strategy, calculating Avg_16Line (...) every 16 rows. The algorithm calculates Avg_256Line (single-frame mean) every 256 lines and Avg_512Line (long-term mean across multiple frames) every 512 lines to filter out transient noise and characterize the long-term baseline drift trend of the readout link. Finally, after receiving Avg_512Line, the correction module compares it with a preset threshold range to generate the HSSD compensation value HSSD_Result (i.e., skim_hssd_adj). At the beginning of the next frame (the N+1th frame), the module updates the gate bias of the readout circuit, thereby achieving frame-level adaptive closed-loop adjustment of HSSD independent of the imaging data path, ensuring the stability of the readout baseline under different operating conditions.

[0120] The above method is described below through a specific embodiment. In the dynamic temperature compensation scenario of the vehicle-mounted infrared night vision system, after the system is powered on, it enters the normal operating mode. At this time, the target pixels in the vehicle-mounted infrared focal plane array are acquiring the road conditions ahead to output the target image. Figure 10 This is a flowchart illustrating an adaptive control method for the gate bias node of an infrared readout circuit based on a reference pixel, according to an embodiment of this application, comprising the following steps:

[0121] In step S1002, the readout circuit reads the analog voltage signal output by the target pixel array line by line through the line scanning module. The target pixel receives infrared radiation from the vehicle in front, and its output analog voltage signal changes with the target temperature. The reference pixel is blocked from light, and its output analog voltage signal is only affected by the readout circuit's own operating point (such as HSSD bias voltage) and is not affected by external target imaging conditions.

[0122] In step S1004, the mean statistics module performs multi-level accumulation and average calculation on the read reference pixel data to determine the target average pixel value of the reference pixel array. The module filters out 8 fixed columns of reference data in the column direction and performs multi-window (e.g., 512 rows) accumulation and average in the row direction to obtain the digital average value reflecting the current readout link baseline status.

[0123] In step S1006, the correction algorithm module compares the above target average pixel value with the preset threshold range (defined by stc_thres_up and stc_thres_down). The current ambient temperature rise causes HSSD bias drift, resulting in an average value of 4500, which is higher than the upper limit threshold of 4000. Therefore, it is determined that the target average pixel value exceeds the preset threshold range.

[0124] In step S1008, the correction algorithm module adjusts the bias voltage applied to the gate bias node HSSD of the readout circuit according to the negative feedback logic (stc_cal_trend=1) and the preset step value (stc_step) to generate the target bias voltage parameter skim_hssd_adj.

[0125] In step S1010, the analog voltage signal of the target pixel array is reread using the readout circuit with the updated target bias voltage applied, and the target image is obtained. At this time, since the gate bias node HSSD of the readout circuit has been adjusted, the average pixel value of the reference pixel is within the range of the preset threshold, ensuring the stability of the target image baseline in the subsequent output and eliminating the fixed pattern noise caused by temperature changes.

[0126] Through the above embodiments, without changing the imaging window, the average pixel value of the reference pixel is calculated in real time and compared with a preset threshold range. When the average pixel value of the reference pixel is detected to exceed the preset threshold range, the bias voltage applied to the readout circuit is dynamically adjusted so that the average pixel value of the reference pixel is within the preset threshold range. This effectively suppresses pattern noise and significantly improves the quality of the image generated by the infrared imaging system in the target scene.

[0127] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / random access memory (RAM), magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0129] According to another aspect of the embodiments of this application, an image output device is also provided, which can be used to implement the image output method provided in the above embodiments, and will not be repeated hereafter. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0130] Figure 11 This is a structural block diagram of an image output device according to an embodiment of this application, such as... Figure 11 As shown, the device includes:

[0131] The determining module 112 is used to determine the target average pixel value of the reference pixel array, wherein the target average pixel value is used to indicate the average value of the analog voltage signals output by a plurality of reference pixels included in the reference pixel array, the analog voltage signal output by each of the reference pixels is read by a readout circuit, the readout circuit is also used to read the analog voltage signals output by a plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under target imaging conditions, and the analog voltage signals output by the plurality of target pixels change with the change of the target imaging conditions, while the analog voltage signals output by the plurality of reference pixels are not affected by the target imaging conditions.

[0132] The adjustment module 114 is used to adjust the bias voltage applied to the readout circuit to the target bias voltage when the target average pixel value exceeds the preset threshold range. The average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range.

[0133] The reading module 116 is used to read the analog voltage signal output by the plurality of target pixels using the readout circuit with the target bias voltage applied thereon, and output the target image based on the reading result.

[0134] The readout circuit includes a transistor, a column amplifier, a sample-and-hold unit, an analog-to-digital converter, and a digital signal output unit connected in sequence. The transistor is connected to the pixel under test and converts the current signal passing through the pixel into an analog voltage signal. The column amplifier amplifies the analog voltage signal. The sample-and-hold unit performs a second operation on the amplified analog voltage signal to obtain a third voltage signal, wherein the signal fluctuation of the third voltage signal within a target time period is within a preset fluctuation range. The analog-to-digital converter performs an analog-to-digital conversion operation on the third voltage signal within the target time period to generate the pixel value of the pixel under test. The digital signal output unit outputs the pixel value of the pixel under test.

[0135] It should be noted that the determining module 112 in this embodiment can be used to perform the above step S202, the adjusting module 114 in this embodiment can be used to perform the above step S204, and the reading module 116 in this embodiment can be used to perform the above step S206.

[0136] In this embodiment, since the reference pixel array and the target pixel array are under the same target imaging conditions and have the same readout circuit structure, the reference pixel array is independent of the target pixel array. The reference pixels included in the reference pixel array are not affected by the target imaging conditions, and the output analog voltage signal only reflects the influence of certain factors of the circuit itself on the analog voltage signal, thus achieving the separation of the bias voltage control logic and the image imaging process. By calculating the target average pixel value of the reference pixel in real time and comparing it with a preset threshold range, when the target average pixel value is detected to exceed the preset threshold range, the bias voltage applied to the readout circuit is dynamically adjusted so that the average pixel value of the reference pixel is within the preset threshold range, effectively suppressing pattern noise. On this basis, the corrected readout circuit reads the analog voltage signal output by the target pixel and outputs the image, so that the final generated image maintains a high signal-to-noise ratio while eliminating image artifacts and distortions caused by inappropriate applied bias voltage. This solves the technical problem in related technologies where the output image quality is poor due to the difficulty in accurately adjusting the bias voltage, achieving the technical effect of real-time and accurate adjustment of the bias voltage to improve the quality of the generated image.

[0137] In an exemplary embodiment, the adjustment module 114 is further configured to adjust the bias voltage applied to the readout circuit to a target bias voltage when the target average pixel value exceeds a preset threshold range by repeatedly performing the following target operation until the determined average pixel value of the reference pixel array is within the preset threshold range: when the target average pixel value exceeds the preset threshold range, generating a control signal including the adjusted bias parameter based on the comparison result between the target average pixel value and the preset threshold range, and adjusting the bias voltage using the bias parameter included in the control signal; reading the first analog voltage signal of the plurality of reference pixels using the readout circuit with the adjusted bias voltage applied; redetermining the average pixel value of the reference pixel array based on the read first analog voltage signal, and determining the redetermined average pixel value of the reference pixel array as the target average pixel value.

[0138] In an exemplary embodiment, the adjustment module 114 is further configured to generate a control signal including an adjusted bias parameter based on a comparison result between the target average pixel value and the preset threshold range when the target average pixel value exceeds the preset threshold range: comparing the target average pixel value with a first threshold, wherein the first threshold is the smallest value included in the preset threshold range; determining that the target average pixel value exceeds the preset threshold range when the target average pixel value is less than the first threshold, calculating the sum of an initial bias parameter and a preset step value of the bias voltage currently applied to the readout circuit to obtain a first bias parameter, wherein the first bias parameter is used to control the bias voltage to change in a first direction to increase the target average pixel value; and generating the control signal including the first bias parameter.

[0139] In an exemplary embodiment, the adjustment module 114 is further configured to generate a control signal including an adjusted bias parameter based on a comparison result between the target average pixel value and the preset threshold range when the target average pixel value exceeds the preset threshold range: comparing the target average pixel value with a second threshold, wherein the second threshold is the largest value included in the preset threshold range; determining that the target average pixel value exceeds the preset threshold range when the target average pixel value is greater than the second threshold, calculating the difference between the initial bias parameter and the preset step value of the bias voltage currently applied to the readout circuit to obtain a second bias parameter, wherein the second bias parameter is used to control the bias voltage to change in a second direction to reduce the target average pixel value; and generating the control signal including the second bias parameter.

[0140] In an exemplary embodiment, the determining module 112 is further configured to determine the target average pixel value of the reference pixel array by: sequentially turning on each row of reference pixels included in the reference pixel array, and performing the following operations for each row of reference pixels turned on: acquiring the pixel value of each reference pixel included in the currently turned-on row using the readout circuit to obtain a plurality of first pixel values; calculating the first average pixel value of the reference pixels included in the currently turned-on row using the plurality of first pixel values; whenever the number of the calculated first average pixel values ​​reaches a preset number of rows, calculating the second average pixel value of the reference pixels included in the preset number of rows using the preset number of first average pixel values, until the pixel values ​​of the reference pixels in all rows included in the reference pixel array are calculated, to obtain one or more of the second average pixel values; and determining the target average pixel value using one or more of the second average pixel values.

[0141] In an exemplary embodiment, the determining module 112 is further configured to use the readout circuit to acquire the pixel value of a first pixel in the following manner, wherein the first pixel is any reference pixel included in the currently active row: acquiring a current signal passing through the first pixel; converting the current signal into a second analog voltage signal; performing an amplification operation on the second analog voltage signal to obtain a first voltage signal; performing a second operation on the first voltage signal to obtain a second voltage signal, wherein the signal fluctuation of the second voltage signal within a target time period is within a preset fluctuation range; and performing an analog-to-digital conversion operation on the second voltage signal within the target time period to generate the pixel value of the first pixel.

[0142] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0143] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the steps in any of the above method embodiments when it is run.

[0144] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, ROMs, RAMs, portable hard drives, magnetic disks, or optical disks.

[0145] According to another aspect of the embodiments of this application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor is configured to perform the steps of any of the method embodiments described above via the computer program. In an exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0146] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0147] According to another aspect of the embodiments of this application, a computer program product is also provided, which includes a computer program / instructions containing program code for performing the methods shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network via a communication component, and / or installed from a removable medium. When the computer program is executed by a central processing unit, it performs various functions provided in the embodiments of this application. The sequence numbers of the embodiments of this application above are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0148] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0149] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for outputting an image, characterized in that, include: A target average pixel value is determined for a reference pixel array, wherein the target average pixel value is used to indicate the average value of analog voltage signals output by a plurality of reference pixels included in the reference pixel array, the analog voltage signal output by each reference pixel is read using a readout circuit, the readout circuit is also used to read the analog voltage signals output by a plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under target imaging conditions, and the analog voltage signals output by the plurality of target pixels change with the change of the target imaging conditions, while the analog voltage signals output by the plurality of reference pixels are not affected by the target imaging conditions; If the target average pixel value exceeds a preset threshold range, the bias voltage applied to the readout circuit is adjusted to the target bias voltage, wherein the average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range. The readout circuit, to which the target bias voltage is applied, reads the analog voltage signals output by the plurality of target pixels and outputs the target image based on the reading results.

2. The method according to claim 1, characterized in that, When the target average pixel value exceeds a preset threshold range, adjusting the bias voltage applied to the readout circuit to the target bias voltage includes: Repeat the following target operation until the average pixel value of the determined reference pixel array is within the preset threshold range: If the target average pixel value exceeds the preset threshold range, a control signal including the adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range, and the bias voltage is adjusted using the bias parameter included in the control signal. The readout circuit with an adjusted bias voltage is used to read the first analog voltage signal of the plurality of reference pixels; The average pixel value of the reference pixel array is re-determined based on the read first analog voltage signal, and the re-determined average pixel value of the reference pixel array is determined as the target average pixel value.

3. The method according to claim 2, characterized in that, If the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range, including: The target average pixel value is compared with a first threshold, wherein the first threshold is the smallest value included in the preset threshold range; If the target average pixel value is less than the first threshold, it is determined that the target average pixel value exceeds the preset threshold range. The sum of the initial bias parameter and the preset step value of the bias voltage currently applied to the readout circuit is calculated to obtain the first bias parameter. The first bias parameter is used to control the bias voltage to change in the first direction to increase the target average pixel value. The control signal including the first bias parameter is generated.

4. The method according to claim 2, characterized in that, If the target average pixel value exceeds the preset threshold range, a control signal including an adjusted bias parameter is generated based on the comparison result between the target average pixel value and the preset threshold range, and further includes: Compare the target average pixel value with a second threshold, wherein the second threshold is the largest value included in the preset threshold range; If the target average pixel value is greater than the second threshold, it is determined that the target average pixel value exceeds the preset threshold range. The difference between the initial bias parameter of the bias voltage currently applied to the readout circuit and the preset step value is calculated to obtain the second bias parameter. The second bias parameter is used to control the bias voltage to change in the second direction to reduce the target average pixel value. The control signal including the second bias parameter is generated.

5. The method according to claim 1, characterized in that, Determining the target average pixel value of the reference pixel array includes: Each row of reference pixels in the reference pixel array is sequentially turned on, and for each row of reference pixels that is turned on, the following operations are performed: the pixel value of each reference pixel in the currently turned on row is acquired using the readout circuit to obtain a plurality of first pixel values; the first average pixel value of the reference pixels in the currently turned on row is calculated using the plurality of first pixel values. Whenever the number of the first average pixel values ​​calculated reaches a preset number of rows, the second average pixel value of the reference pixels included in the preset number of rows is calculated using the preset number of first average pixel values, until the pixel values ​​of the reference pixels in all rows included in the reference pixel array are calculated, and one or more second average pixel values ​​are obtained. The target average pixel value is determined using one or more of the second average pixel values.

6. The method according to claim 5, characterized in that, The readout circuit is used to acquire the pixel value of the first pixel in the following manner, wherein the first pixel is any reference pixel included in the currently active row: Acquire the current signal passing through the first pixel; The current signal is converted into a second analog voltage signal; The second analog voltage signal is amplified to obtain the first voltage signal; Perform a second operation on the first voltage signal to obtain a second voltage signal, wherein the signal fluctuation of the second voltage signal within a target time period is within a preset fluctuation range; An analog-to-digital conversion operation is performed on the second voltage signal during the target time period to generate the pixel value of the first pixel.

7. The method according to claim 1, characterized in that, The readout circuit includes: a transistor, a column amplifier, a sample-and-hold unit, an analog-to-digital converter, and a digital signal output unit connected in sequence, wherein: The transistor is used to connect to the pixel under test and to convert the current signal passing through the pixel under test into an analog voltage signal; The column amplifier is used to amplify the analog voltage signal; The sample-and-hold unit is used to perform a second operation on the amplified analog voltage signal to obtain a third voltage signal, wherein the signal fluctuation of the third voltage signal within the target time period is within a preset fluctuation range; The analog-to-digital conversion unit is used to perform analog-to-digital conversion on the third voltage signal within the target time period to generate the pixel value of the pixel to be measured. The digital signal output unit is used to output the pixel value of the pixel to be measured.

8. An image output device, characterized in that, include: A determining module is used to determine the target average pixel value of a reference pixel array, wherein the target average pixel value is used to indicate the average value of the analog voltage signals output by a plurality of reference pixels included in the reference pixel array, the analog voltage signal output by each reference pixel is read by a readout circuit, the readout circuit is also used to read the analog voltage signals output by a plurality of target pixels included in the target pixel array, the reference pixel array and the target pixel array are under the same operating conditions, the target pixel array is used to output an image under target imaging conditions, and the analog voltage signals output by the plurality of target pixels change with the change of the target imaging conditions, while the analog voltage signals output by the plurality of reference pixels are not affected by the target imaging conditions; An adjustment module is used to adjust the bias voltage applied to the readout circuit to a target bias voltage when the target average pixel value exceeds a preset threshold range, wherein the average pixel value of the reference pixel array determined by the analog voltage signal read by the readout circuit with the target bias voltage applied is within the preset threshold range. The reading module is used to read the analog voltage signals output by the plurality of target pixels using the readout circuit with the target bias voltage applied, and output the target image based on the reading results.

9. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of the method according to any one of claims 1 to 7.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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