An adaptive brightness adjustment method and system for a display device

Abstract

This invention relates to the field of display control and image processing technology, specifically to an adaptive brightness adjustment method and system for a display device. The method includes: first, acquiring ambient light data, user brightness preferences, and power status to determine a target display brightness command; then, acquiring the content frame sequence of the foreground focus task, extracting brightness statistics and brightness changes, and determining a brightness tolerance window and an upper limit for single-frame brightness change based on content type switching hysteresis parameters; subsequently, generating a backlight update sequence under a minimum backlight update cycle constraint, and generating a pixel domain compensation parameter sequence when single-frame changes exceed the limit; when power constraints are met, lowering the target display brightness command and smoothing the compensation parameter sequence; performing brightness adjustment based on the backlight update sequence and the compensation parameter sequence; and updating the brightness tolerance window and hysteresis parameters based on contrast fluctuation indicators. This invention achieves low-flicker, low-jitter, and power-controlled adaptive brightness display on a TFT LCD screen.

Description

Technical Field

[0001] This invention relates to the field of display control and image processing technology, and specifically to an adaptive brightness adjustment method and system for a display device. Background Technology

[0002] In applications such as mobile terminals, automotive displays, and industrial human-machine interfaces, screen readability, power consumption, and user experience directly impact the overall battery life, reliability, and product competitiveness. Current brightness control methods primarily rely on ambient light or user settings, lacking constraints on the characteristics of the screen content. This can easily lead to problems such as frequent brightness fluctuations, abrupt scene transitions, and loss of detail. Simultaneously, TFT LCD screens have a minimum update cycle and response lag in their backlight drive; if the control strategy does not consider the backlight drive boundaries, perceptible flicker may occur. On the other hand, image processors often participate in frame buffering, composition, and color processing, but traditional solutions rarely link pixel domain adjustment on the image processor side with backlight adjustment. This makes it difficult to balance brightness tracking and visual stability when power or backlight updates are limited, thus affecting industry requirements for low power consumption, low flicker, and consistent display. Summary of the Invention

[0003] This invention provides an adaptive brightness adjustment method and system for a display device, which at least solves the problem of how to balance brightness following speed and image stability while suppressing perceptible flicker under conditions of limited backlight update and power.

[0004] In a first aspect, the present invention provides an adaptive brightness adjustment method for a display device, the method comprising: Acquire ambient lighting data, user brightness preferences, and power status to determine the target display brightness command; Obtain the content frame sequence of the foreground focus task, extract brightness statistics and brightness change, and determine the brightness tolerance window and the upper limit of brightness change amplitude per frame based on the content type switching hysteresis parameter; Obtain the minimum backlight update cycle, generate a backlight update sequence based on the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit of the brightness change amplitude of a single frame. When the power condition meets the power limit, the target display brightness is reduced and the pixel domain compensation parameter sequence is smoothed. Brightness adjustment is performed based on the backlight update sequence and the pixel domain compensation parameter sequence. Contrast fluctuation index is obtained, and brightness tolerance window and content type switching hysteresis parameters are updated.

[0005] In one possible implementation, determining the target display brightness instruction includes: determining the ambient target brightness based on ambient light data through a preset brightness mapping relationship; determining the preferred target brightness based on the user's brightness preference; determining the initial display brightness instruction based on the ambient target brightness and the preferred target brightness; and limiting the initial display brightness instruction to a preset brightness range based on the power state to obtain the target display brightness instruction.

[0006] In one possible implementation, extracting luminance statistics includes: dividing each frame in the content frame sequence of the foreground focus task into multiple image blocks, and calculating the mean luminance and variance of each image block to obtain luminance statistics.

[0007] In one possible implementation, extracting the brightness change includes: calculating the global average brightness for adjacent content frames in the content frame sequence and determining the difference between the global average brightness values, and taking the difference between the global average brightness values ​​and the number of times the difference between the global average brightness values ​​exceeds a preset difference threshold as the brightness change.

[0008] In one possible implementation, the content type switching hysteresis parameter includes a consecutive frame count threshold; determining the brightness tolerance window and the upper limit of single-frame brightness variation based on the content type switching hysteresis parameter includes: determining a content type identifier based on brightness statistics and brightness variation, the content type identifier being used to characterize the content type of the foreground focus task; updating the content type identifier only when the content type identifier remains consistent in consecutive content frames corresponding to the consecutive frame count threshold; and determining the brightness tolerance window based on the updated content type identifier, the brightness tolerance window being used to characterize the allowed range of brightness variation in the content frame sequence, and the upper limit of single-frame brightness variation being the upper limit parameter within the brightness tolerance window.

[0009] In one possible implementation, generating the backlight update sequence includes: mapping the target display brightness command to a backlight drive value sequence, and determining the update time sequence of the backlight drive value sequence based on the minimum backlight update period, such that the time interval between adjacent update times is not less than the minimum backlight update period; the backlight update sequence includes the backlight drive value sequence and the update time sequence; and the brightness difference corresponding to adjacent backlight drive values ​​in the backlight drive value sequence does not exceed the upper limit of the brightness change amplitude of a single frame.

[0010] In one possible implementation, generating the pixel domain compensation parameter sequence includes: converting the backlight driving value sequence into a backlight brightness sequence according to a preset brightness mapping relationship, wherein the preset brightness mapping relationship is the correspondence between the backlight driving value and the display brightness; determining the brightness deviation according to the target display brightness command and the backlight brightness sequence; generating a pixel brightness mapping parameter sequence corresponding to the content frame sequence according to the brightness deviation; and performing cross-frame smoothing processing on the pixel brightness mapping parameter sequence to obtain the pixel domain compensation parameter sequence.

[0011] In one possible implementation, the power state satisfies the power limiting conditions, including the battery level being lower than a preset power threshold and the expected power consumption increment reaching a preset power threshold; the expected power consumption increment is a power consumption increment calculated based on the correspondence between the backlight drive value and the backlight power consumption; the target display brightness reduction instruction includes limiting the target display brightness instruction to below a preset maximum brightness.

[0012] In one possible implementation, updating the backlight drive value according to the backlight update sequence includes updating the backlight drive value corresponding to the backlight update sequence during the vertical blanking of the display frame; the contrast fluctuation index includes the global contrast difference between adjacent content frames in the content frame sequence; updating the brightness tolerance window and content type switching hysteresis parameter includes: lowering the upper limit of the brightness change amplitude of a single frame and increasing the content type switching hysteresis parameter when the global contrast difference exceeds a preset fluctuation threshold, and raising the upper limit of the brightness change amplitude of a single frame and decreasing the content type switching hysteresis parameter when the global contrast difference does not exceed the preset fluctuation threshold.

[0013] In a second aspect, the present invention provides an adaptive brightness adjustment system for a display device, used to implement an adaptive brightness adjustment method for a display device, the system comprising: The target determination module is used to acquire ambient light data, user brightness preferences, and power status to determine the target display brightness command; The window determination module is used to obtain the content frame sequence of the foreground focus task, extract brightness statistics and brightness change, and determine the brightness tolerance window and the upper limit of the brightness change amplitude of a single frame based on the content type switching hysteresis parameter. The sequence generation module is used to obtain the minimum backlight update cycle, generate a backlight update sequence according to the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit of the brightness change amplitude of a single frame. The adjustment and update module is used to reduce the target display brightness command and smooth the pixel domain compensation parameter sequence when the power state meets the power limit conditions. It performs brightness adjustment based on the backlight update sequence and the pixel domain compensation parameter sequence, obtains the contrast fluctuation index, and updates the brightness tolerance window and content type switching hysteresis parameters.

[0014] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: By employing a joint decision-making technique based on ambient lighting data, user brightness preferences, and power status, a self-consistent balance between readability and power consumption constraints for brightness targets is achieved. By extracting brightness statistics and brightness changes from content frame sequences and introducing content type switching hysteresis parameters, stable determination and jitter suppression of brightness strategies during content switching are achieved. By generating a backlight update sequence under the constraint of the minimum backlight update cycle and stepping with a single-frame brightness change amplitude limit constraint, executable timing and low-flicker control of backlight adjustment are achieved. By generating a pixel domain compensation parameter sequence when backlight changes are limited and smoothing it under power constraints, continuous brightness following is achieved in scenarios with limited backlight and power consumption on TFT LCD screens. Finally, by using contrast fluctuation index feedback to update the brightness tolerance window and hysteresis parameters, closed-loop adaptive viewing stability is achieved. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the execution flow of the method of the present invention; Figure 2 This is a structural block diagram of the system of the present invention. Detailed Implementation

[0016] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0017] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0018] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0019] Adaptive brightness adjustment typically refers to the dynamic determination of the desired screen brightness by a display device during operation, taking into account factors such as ambient light, user preferences, and power supply status. This desired brightness is then converted into an executable display control quantity, ensuring relatively stable visual appeal and readability under different usage environments and content presentation conditions. In TFT LCD screens, brightness adjustment involves both the output level and update rhythm of the backlight driver and the brightness mapping method of pixel signals in the display chain. Therefore, an image processor can be used to extract features and generate parameters from the foreground frame sequence, and, when necessary, coordinate with backlight adjustment to complete pixel domain compensation, ensuring that brightness changes conform to the timing constraints of the display hardware and avoiding abrupt jumps. Based on this approach, this invention proposes an adaptive brightness adjustment method for display devices, forming a closed loop that integrates brightness target generation, content-aware constraints, backlight update sequence generation, and pixel domain compensation and feedback updates to achieve executable and stable adaptive brightness control.

[0020] like Figure 1 As shown, an adaptive brightness adjustment method for a display device includes: Acquire ambient lighting data, user brightness preferences, and power status to determine the target display brightness command; In one embodiment, the display device simultaneously acquires ambient light data, user brightness preferences, and power status during the brightness adaptive control cycle, using these three as the basis for brightness decisions. Ambient light data reflects current external lighting conditions, user brightness preferences reflect the user's subjective setting of screen brightness, and power status reflects battery level and power supply limitations. Based on these inputs, a target display brightness command is generated. This target display brightness command drives the backlight driver circuit or display driver link to complete the brightness setting and provides a unified brightness target benchmark for subsequent content perception and dynamic compensation.

[0021] Determining the target display brightness command includes: determining the ambient target brightness based on ambient light data through a preset brightness mapping relationship; determining the preferred target brightness based on the user's brightness preference; determining the initial display brightness command based on the ambient target brightness and the preferred target brightness; and limiting the initial display brightness command within a preset brightness range based on the power status to obtain the target display brightness command.

[0022] In one embodiment, the generation of the target display brightness instruction adopts the process of "ambient target brightness - preferred target brightness - initial display brightness instruction - limiting output", so that the brightness target changes with the environment and is constrained by user preferences and power supply capabilities, avoiding situations where excessive brightness leads to power consumption limitation or excessive brightness affects readability.

[0023] First, the target ambient brightness is determined based on ambient light data using a preset brightness mapping relationship. This preset brightness mapping relationship can be stored in memory as a lookup table, with entries configured to correspond to screen brightness ranges based on ambient illuminance ranges, and remaining monotonically constant as ambient illuminance increases. When ambient light data falls between adjacent entries, linear interpolation can be used to generate the target ambient brightness, ensuring continuous brightness changes. Ambient light data can be obtained from illuminance sampling values ​​from an ambient light sensor. After sampling, a time window smoothing process can be performed to suppress short-term flicker interference. The time window can be a moving average of several control cycles, thus avoiding frequent brightness fluctuations caused by instantaneous light spikes. Second, the preferred target brightness is determined based on the user's brightness preferences.

[0024] User brightness preferences can be derived from the current setting of the system brightness slider or from the user's most recent manual adjustment record. When continuous manual adjustments are detected within a short period, the preferred target brightness can prioritize following the manual setting to avoid the ambient target brightness overriding the user's intention. Then, the initial display brightness command is determined based on the ambient target brightness and the preferred target brightness. The initial display brightness command can be obtained through weighted fusion, with the fusion weight switching based on whether the user has recently made manual adjustments: increasing the weight of the preferred target brightness when the user has recently made manual adjustments, and increasing the weight of the ambient target brightness when the user has not made adjustments for a long time, thus balancing adaptability and controllability.

[0025] Finally, based on the power state, the initial display brightness command is limited to a preset brightness range to obtain the target display brightness command. The preset brightness range includes at least a maximum brightness upper limit and a minimum brightness lower limit. The maximum brightness upper limit can be adjusted according to changes in the power state. For example, when the battery level is below a preset power threshold or in a power-limited state, the maximum brightness upper limit is lowered, and when powered by an external power source or with sufficient battery power, a higher upper limit is restored. The minimum brightness lower limit is used to ensure basic readability in dark environments and prevent the backlight driver from entering an unstable range. To further stabilize the output, the target display brightness command can be set with an update threshold. When the difference between the target display brightness command and the current display brightness command is less than a preset brightness difference threshold, it remains unchanged, or the update is delayed when the interval between adjacent updates is less than a preset time threshold, thereby reducing meaningless micro-jitter and reducing the load on the control link.

[0026] Obtain the content frame sequence of the foreground focus task, extract brightness statistics and brightness change, and determine the brightness tolerance window and the upper limit of brightness change amplitude per frame based on the content type switching hysteresis parameter; In one embodiment, the display device determines the foreground focus task from the window management and composition output link, and obtains the content frame sequence corresponding to the foreground focus task according to the display refresh rate. Brightness statistics and brightness variation are extracted frame by frame from the content frame sequence. The brightness statistics characterize the local brightness distribution, and the brightness variation characterizes the intensity of brightness fluctuations between adjacent frames. Combined with a content type switching hysteresis parameter, the content frame sequence is used to determine content type stability, thereby determining a brightness tolerance window. An upper limit for the brightness variation amplitude of a single frame is then determined from the brightness tolerance window, ensuring that subsequent brightness adjustments remain continuous and controllable within the perceptible range of the content.

[0027] Extracting luminance statistics involves dividing each frame in the content frame sequence of the foreground focus task into multiple image blocks, and calculating the mean luminance and variance of each image block to obtain luminance statistics.

[0028] In one embodiment, the key to defining the luminance statistics lies in dividing the image into blocks and calculating the mean and variance of the luminance of each block, thereby characterizing the local luminance distribution boundary of the foreground focus task in a computationally calculable and storable manner. The extraction of luminance statistics can be performed directly on the frame buffer data after image compositing or on intermediate frames output by the image processor; regardless of the approach, each frame in the content frame sequence is used as input. First, each frame is divided into image blocks. The image block size can be configured to a fixed pixel size, such as 16×16 pixels or 32×32 pixels, to achieve a balance between statistical accuracy and computational overhead; when the frame resolution changes, the image block size can remain unchanged or be scaled proportionally.

[0029] Then, a luminance value sequence is calculated for each image block. The luminance value can be obtained by converting the color components of the pixels. The conversion method can adopt the industry-standard luminance component calculation, such as weighted summation of the red, green and blue components to obtain the luminance component. When the image source is in YUV format, the Y component can be directly used as the luminance value. The average luminance values ​​of all pixels in each image block are calculated to obtain the average luminance of the image block, and the luminance variance of the image block is further calculated to reflect the degree of luminance dispersion within the image block.

[0030] To reduce computational load, the calculation of image patch brightness variance can be performed using either two-pass or one-pass statistics: two-pass statistics first calculate the mean brightness of the image patch and then calculate the variance; one-pass statistics can simultaneously accumulate brightness and brightness squares and convert the variance at the end of the patch. When using fixed-point arithmetic, bit width expansion can be performed during the accumulation process and uniformly scaled during the final conversion. To ensure the stability of statistical results, areas with insufficient pixels at the image patch boundaries can be cropped or padded. The padding method can use repeated edge pixels or mirrored pixels to avoid introducing abrupt low or high brightness values.

[0031] The output of brightness statistics can be organized into a two-dimensional array that corresponds one-to-one with the image patch grid. The array elements contain the mean and variance of the image patch brightness. To facilitate subsequent calculations of brightness variation and content type identification, the brightness statistics can also include a frame timestamp or frame number to ensure clear cross-frame alignment. When a foreground focus task switch is detected, the extraction of brightness statistics restarts from the first frame after the switch to avoid statistical offset caused by cross-task aliasing.

[0032] Extracting brightness variation includes: calculating the global average brightness for adjacent content frames in the content frame sequence and determining the difference between the global average brightness values, and taking the difference between the global average brightness values ​​and the number of times the difference between the global average brightness values ​​exceeds a preset difference threshold as the brightness variation.

[0033] In one embodiment, the limiting point of the brightness change is that the brightness fluctuation intensity is characterized by the difference between the global average brightness and the number of threshold overruns, so that the brightness change can reflect both the change amplitude between single frames and the change frequency boundary over a period of time.

[0034] The extraction of brightness changes uses adjacent content frames in the content frame sequence as input. First, the global average brightness is calculated for each frame. The global average brightness can be obtained by directly averaging the pixel brightness of the entire frame; to reduce computational overhead, it can also be calculated based on brightness statistics, such as by weighting and summing the average brightness of each image block according to the number of pixels in the image block and dividing by the total number of pixels to obtain the global average brightness, thus reusing the image block statistical results and ensuring consistency. Subsequently, the difference between the global average brightness of two adjacent frames is obtained as the global average brightness difference. The global average brightness difference can be taken as the absolute value to ignore the direction of brightening and darkening, or the sign can be retained for subsequent trend differentiation. A preset difference threshold is used to define "perceptible inter-frame brightness change events". The preset difference threshold can be configured as a fixed threshold according to the display brightness scale, or it can be adaptively adjusted according to the current value of the target display brightness command. For example, the threshold can be appropriately reduced in the low brightness range to improve sensitivity, and the threshold can be appropriately increased in the high brightness range to suppress noise triggering.

[0035] To obtain the number of threshold violations, the display device counts events based on the difference in the global average brightness within a sliding time window: when the difference in the global average brightness exceeds a preset difference threshold, it is counted as an inter-frame event, and the number of inter-frame events is accumulated within the frame number range corresponding to the window length; the sliding window can take several frames, for example, covering a display duration of 0.5 seconds to 2 seconds, to match the time scale of human eye sensitivity to flicker and jumps. To avoid miscounting due to occasional noise, the difference in the global average brightness can be smoothed in first order or filtered by median before threshold comparison; when smoothing is used, the smoothing coefficient can be fixed or adaptively adjusted according to the noise level of the content frame sequence. The output of brightness change includes the difference in the global average brightness corresponding to the current frame pair and the number of inter-frame events within the sliding window, both of which can be used as inputs for subsequent content type identification and brightness tolerance window determination; when the frame rate changes, the number of frames in the sliding window can be adjusted with the frame rate to maintain a consistent time length, thereby maintaining statistical stability.

[0036] The content type switching hysteresis parameter includes a consecutive frame count threshold. Determining the brightness tolerance window and the upper limit of single-frame brightness variation based on the content type switching hysteresis parameter includes: determining the content type identifier based on brightness statistics and brightness variation, which is used to characterize the content type of the foreground focus task; updating the content type identifier only when it remains consistent in consecutive content frames corresponding to the consecutive frame count threshold; and determining the brightness tolerance window based on the updated content type identifier, which is used to characterize the allowed range of brightness variation in the content frame sequence, with the upper limit of single-frame brightness variation being the upper limit parameter within the brightness tolerance window.

[0037] In one embodiment, the limiting point of the content type switching hysteresis parameter is the introduction of a consecutive frame count threshold as a condition for updating the content type identifier. This suppresses repeated content type switching caused by short-term fluctuations and ensures stable temporal consistency between the brightness tolerance window and the upper limit of brightness variation in a single frame. The content type switching hysteresis parameter includes at least a consecutive frame count threshold, which specifies that the content type identifier must remain consistent across consecutive content frames before updating is allowed.

[0038] The content type identifier is determined based on brightness statistics and brightness variation. The display device can use a rule-based determination method: for example, when the number of inter-frame events in brightness variation is high and the global average brightness difference frequently exceeds the limit, the content type identifier is determined to be dynamic content type; when the number of inter-frame events in brightness variation is low and the global average brightness difference is consistently below the preset difference threshold, and there are many low-variance image blocks in the brightness statistics, the content type identifier is determined to be static content type; when the proportion of high-variance image blocks in the brightness statistics is high and the brightness variation is at a medium level, the content type identifier is determined to be high-detail content type.

[0039] To ensure feasibility, the rule thresholds can be fixed through configuration files or determined during factory calibration, and can be configured separately for different display panels and backlight driving capabilities. Content type identifier updates follow the principle of continuous frame consistency: the display device caches the content type identifier calculated for each frame, and only updates it to a stable content type identifier when the same content type identifier remains consistent across consecutive content frames corresponding to the continuous frame count threshold; if continuity is interrupted, the counting restarts. The brightness tolerance window is determined based on the stable content type identifier. The brightness tolerance window characterizes the allowable brightness variation range of the content frame sequence and can be obtained through a lookup table. The lookup table entry uses the content type identifier as an index and outputs a set of allowable range parameters; the allowable range parameters can be defined as a range of brightness variation amplitudes or as a combination of constraints for single-frame and multi-frame variations.

[0040] The upper limit of single-frame brightness variation is obtained by taking the upper limit parameter from the brightness tolerance window, and can be further fine-tuned in conjunction with the brightness variation amount: when the brightness variation amount indicates that the number of recent inter-frame events is consistently high, the upper limit of single-frame brightness variation can be appropriately lowered to reduce the risk of perceptible jumps; when the brightness variation amount is consistently low, the upper limit of single-frame brightness variation can be appropriately raised to improve the brightness following speed. To avoid frequent changes in the brightness tolerance window, the update of the brightness tolerance window is also constrained by the principle of consistency across consecutive frames, and the update time is aligned with the update time of the content type identifier. Through the above mechanism, the brightness statistics and brightness variation amount form a stable basis for content type determination on the time axis, the consecutive frame number threshold forms a verifiable hysteresis boundary, and the brightness tolerance window and the upper limit of single-frame brightness variation provide clear and executable constraints for subsequent backlight update sequences and pixel domain compensation parameter sequences.

[0041] Obtain the minimum backlight update cycle, generate a backlight update sequence based on the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit of the brightness change amplitude of a single frame. The display device obtains the minimum backlight update cycle and uses the target display brightness command as the brightness convergence target to generate a backlight update sequence. This backlight update sequence constrains the update rhythm of the backlight drive value over time, ensuring that the update interval of the backlight drive value is not less than the minimum backlight update cycle and that the brightness variation in a single frame caused by changes in the backlight drive value is controlled. Based on a preset brightness mapping relationship, the brightness changes corresponding to the backlight update sequence are converted into single-frame brightness variation amplitudes. When the single-frame brightness variation amplitude exceeds the upper limit of the single-frame brightness variation amplitude, a pixel domain compensation parameter sequence is generated to ensure brightness convergence while simultaneously satisfying the constraint of the upper limit of the single-frame brightness variation amplitude.

[0042] The process of generating a backlight update sequence includes: mapping the target display brightness command to a backlight drive value sequence, and determining the update time sequence of the backlight drive value sequence based on the minimum backlight update period, such that the time interval between adjacent update times is not less than the minimum backlight update period; the backlight update sequence includes the backlight drive value sequence and the update time sequence; and ensuring that the brightness difference between adjacent backlight drive values ​​in the backlight drive value sequence does not exceed the upper limit of the brightness change amplitude in a single frame.

[0043] In one embodiment, the additional constraint of the backlight update sequence is that the backlight update sequence is composed of a backlight driving value sequence and an update time sequence, and simultaneously satisfies the minimum backlight update cycle constraint and the upper limit constraint of the brightness change amplitude of a single frame.

[0044] By using this limiting point, the change in the backlight drive value is no longer solely determined by the target display brightness command, but is discretized on the time axis and limited by the backlight drive capability boundary. This prevents flickering caused by excessively rapid backlight updates or perceptible jumps caused by excessively large step sizes. The minimum backlight update cycle can be determined by the specifications of the backlight drive circuit, register read results, or calibration values ​​during drive initialization, or it can be configured by the display controller based on the minimum refresh interval of the backlight drive interface.

[0045] When the target display brightness command is converted into a backlight drive value sequence, a preset brightness mapping relationship can be used for mapping. This preset brightness mapping relationship is stored in a lookup table, with each table entry establishing a correspondence between the backlight drive value and the display brightness. When the target display brightness command is between adjacent entries, interpolation is used to obtain the backlight drive value to ensure the continuity of the backlight drive value as it changes with the target display brightness command. The generation of the update time sequence is based on the minimum backlight update cycle: first, the minimum interval from the current time to the next allowed update time is determined, and this minimum interval is used as the step unit of the update time sequence; then, the required number of backlight drive value updates is determined based on the difference between the current backlight drive value and the target backlight drive value, and the number of updates is expanded onto the update time sequence so that the time interval between adjacent update times is not less than the minimum backlight update cycle.

[0046] To meet the upper limit of brightness variation in a single frame, the display device constrains adjacent backlight drive values ​​when generating the backlight drive value sequence: based on a preset brightness mapping relationship, the difference in backlight drive values ​​is converted into a brightness difference. When the brightness difference exceeds the upper limit of brightness variation in a single frame, the difference in backlight drive values ​​is split into multiple smaller steps, and the length of the backlight drive value sequence is increased or the convergence time is extended accordingly, so that the brightness difference caused by each step does not exceed the upper limit of brightness variation in a single frame. If the minimum backlight update cycle results in insufficient available update times to complete the splitting, the minimum backlight update cycle constraint is maintained first, and the update time sequence is adjusted by "extending the convergence time" to ensure that the backlight update sequence is executable within the driving capability boundary.

[0047] To avoid frequent minor fluctuations in the target display brightness command causing repeated recalculation of the backlight drive value sequence, an update threshold can be introduced into the backlight update sequence. When the difference between the target backlight drive value and the current backlight drive value is lower than a preset drive difference threshold, the backlight drive value sequence remains unchanged. Only after the accumulated difference exceeds the preset drive difference threshold is the backlight drive value sequence and update time sequence regenerated. The final output of the backlight update sequence is a set of backlight drive value update plans sorted by time. Subsequent stages can trigger backlight drive value writing according to the update time sequence, achieving dual control over the backlight update rhythm and the amplitude of brightness changes per frame.

[0048] The generation of the pixel domain compensation parameter sequence includes: converting the backlight driving value sequence into a backlight brightness sequence according to a preset brightness mapping relationship, where the preset brightness mapping relationship is the correspondence between the backlight driving value and the display brightness; determining the brightness deviation according to the target display brightness command and the backlight brightness sequence; generating a pixel brightness mapping parameter sequence corresponding to the content frame sequence according to the brightness deviation; and performing cross-frame smoothing processing on the pixel brightness mapping parameter sequence to obtain the pixel domain compensation parameter sequence.

[0049] In one embodiment, the newly added constraint on the pixel domain compensation parameter sequence is that when the backlight update sequence is constrained by both the minimum backlight update cycle and the upper limit of the brightness change amplitude per frame, and thus cannot quickly approach the target display brightness command, the insufficient or excessive backlight brightness is compensated by mapping pixel brightness in the pixel domain. This constraint decomposes brightness adjustment into a "slow-change main channel" in the backlight domain and a "fast compensation channel" in the pixel domain, ensuring that the backlight drive maintains an executable update rhythm while maintaining the perceived brightness's adherence to the target display brightness command.

[0050] The generation of the pixel domain compensation parameter sequence first relies on the conversion from the backlight drive value sequence to the backlight brightness sequence: according to the preset brightness mapping relationship, the backlight drive value sequence is converted into a backlight brightness sequence item by item. The backlight brightness sequence is used to characterize the backlight output brightness level corresponding to each update time. Then, the brightness deviation is determined. The brightness deviation is obtained by the difference between the target display brightness command and the backlight brightness sequence. The brightness deviation can be aligned frame by frame, that is, the backlight brightness corresponding to each frame is compared with the expected brightness corresponding to the target display brightness command to obtain the frame-level brightness deviation.

[0051] To ensure feasibility, the alignment method for frame-level brightness deviation can adopt the nearest principle: the backlight brightness corresponding to the most recent backlight update at the start time of each frame is used as the backlight brightness of that frame; when the backlight update occurs between frames, the average backlight brightness within the time range of that frame can also be used as the backlight brightness of that frame. When generating the pixel brightness mapping parameter sequence based on the frame-level brightness deviation, a linear mapping method can be used to adjust the pixel brightness of the content frame sequence: when the frame-level brightness deviation is positive, the pixel brightness of the content frame sequence is increased to compensate for insufficient backlight brightness; when the frame-level brightness deviation is negative, the pixel brightness of the content frame sequence is decreased to suppress excessive backlight brightness. The pixel brightness mapping parameter sequence can include two types of parameters: gain parameters and bias parameters. The gain parameters are used to stretch the overall pixel brightness range, and the bias parameters are used to shift the overall pixel brightness baseline; to avoid introducing color shift, pixel brightness mapping is preferentially performed on the luminance component, and after mapping, the luminance component is recombined with the original chrominance component for output.

[0052] The mapping process requires saturation and quantization constraints: the pixel brightness mapping result is limited to the brightness range allowed by the display pipeline, and truncation is performed when the value exceeds the range; when fixed-point arithmetic is used, the gain and bias parameters are set with quantization bit widths and rounded to ensure hardware stability. To suppress flickering caused by inter-frame transitions in compensation parameters, the pixel brightness mapping parameter sequence also needs to undergo cross-frame smoothing. Cross-frame smoothing can use first-order low-pass smoothing or moving average smoothing to limit the changes in gain and bias parameters between adjacent frames, and to ensure that the amplitude of parameter changes after smoothing is consistent with the upper limit of brightness change amplitude in a single frame.

[0053] After generation, the pixel domain compensation parameter sequence is aligned and stored frame by frame with the content frame sequence. In the subsequent brightness adjustment stage, the corresponding pixel brightness mapping parameters are read and pixel brightness mapping is completed before each frame is output. Thus, even under the condition of limited backlight update rhythm, the target display brightness command can still be controlled and followed.

[0054] When the power condition meets the power limit, the target display brightness is reduced and the pixel domain compensation parameter sequence is smoothed. Brightness adjustment is performed based on the backlight update sequence and the pixel domain compensation parameter sequence. Contrast fluctuation index is obtained, and brightness tolerance window and content type switching hysteresis parameters are updated.

[0055] When the power supply meets the power limit conditions, the display device lowers the target display brightness command and smooths the pixel domain compensation parameter sequence to limit the impact of brightness adjustment on backlight power consumption and image quality. Subsequently, the display device updates the backlight drive value at allowed update times according to the backlight update sequence, and performs pixel brightness mapping processing on the content frame sequence according to the pixel domain compensation parameter sequence to complete the brightness adjustment. During the brightness adjustment process, the display device simultaneously acquires the contrast fluctuation index to characterize the degree of contrast change between adjacent content frames, and updates the brightness tolerance window and content type switching hysteresis parameters accordingly. This allows the subsequent brightness tolerance window and the upper limit of single-frame brightness change to adaptively adjust with image stability, forming a closed-loop control.

[0056] The power status meets the power limiting conditions, including the battery level being lower than the preset power threshold and the expected power consumption increment reaching the preset power threshold; the expected power consumption increment is the power consumption increment calculated based on the correspondence between the backlight drive value and the backlight power consumption; the target display brightness reduction instruction includes limiting the target display brightness instruction to below the preset maximum brightness.

[0057] In one embodiment, the new limiting point for the power limiting condition and the target display brightness command reduction is that the joint determination of the battery power threshold and the expected power consumption increment threshold is used as the trigger condition, and the target display brightness command is limited by a preset maximum brightness, so that the power consumption constraint has a clear and verifiable boundary.

[0058] The power status can be provided by the battery management unit, including at least battery level and power supply mode information. A battery level below a preset threshold indicates increased battery life pressure, and an expected power consumption increment reaching a preset power threshold indicates that brightness adjustment will cause power consumption to exceed the allowable range. The calculation of the expected power consumption increment is based on the correspondence between backlight drive value and backlight power consumption. This correspondence can be obtained through factory calibration and stored in a lookup table, where each lookup entry corresponds to a backlight drive value range and a backlight power consumption range. When the backlight drive value is between adjacent entries, interpolation is used to obtain the backlight power consumption. The expected power consumption increment can be determined by subtracting the backlight power consumption corresponding to the current backlight drive value from the backlight power consumption corresponding to the target backlight drive value. The target backlight drive value can be calculated from the target display brightness command through a preset brightness mapping relationship, and the current backlight drive value can be read from the backlight drive circuit register or cached by the brightness control module.

[0059] When the power limit condition is met, the display device performs target display brightness command limiting processing, restricting the target display brightness command to below the preset maximum brightness. The preset maximum brightness can be configured in stages according to the power supply mode; for example, a higher value is used when powered by an external power source, and a lower value is used when powered by battery and the battery level is below a preset power threshold. To avoid sudden brightness changes caused by limiting, the reduction of the target display brightness command can adopt a segmented convergence method. First, the target display brightness command is reduced to the preset maximum brightness, and then smooth convergence is completed by the backlight update sequence and the pixel domain compensation parameter sequence.

[0060] When smoothing the pixel domain compensation parameter sequence, the smoothing object can be the gain and bias parameters in the pixel brightness mapping parameter sequence. The smoothing method can be first-order low-pass smoothing or moving average smoothing, making the changes in compensation parameters after power limiting trigger more gradual and avoiding flickering caused by instantaneous changes in compensation parameters. To ensure the stability of power limiting triggering and release, a power limiting exit hysteresis condition can be set. For example, the power limiting can be released after the battery level is higher than a preset power threshold and the expected power consumption increment is lower than a preset power threshold for several control cycles, thereby avoiding brightness strategy jitter caused by frequent switching near the threshold.

[0061] Updating the backlight drive value according to the backlight update sequence includes updating the backlight drive value corresponding to the backlight update sequence during the vertical blanking of the display frame; the contrast fluctuation index includes the global contrast difference between adjacent content frames in the content frame sequence; updating the brightness tolerance window and content type switching hysteresis parameter includes: lowering the upper limit of the brightness change amplitude of a single frame and increasing the content type switching hysteresis parameter when the global contrast difference exceeds the preset fluctuation threshold, and raising the upper limit of the brightness change amplitude of a single frame and decreasing the content type switching hysteresis parameter when the global contrast difference does not exceed the preset fluctuation threshold.

[0062] In one embodiment, the added limitation of brightness adjustment execution and feedback update is that the backlight drive value is updated during vertical blanking to reduce visible flicker, and the global contrast difference is used as a contrast fluctuation index to drive the adaptive update of the brightness tolerance window and content type switching hysteresis parameters, thereby transforming visual stability into a calculable closed-loop parameter tuning basis.

[0063] During the brightness adjustment execution phase, the display device updates the backlight drive value according to the backlight update sequence. The timing of updating the backlight drive value is synchronized with the display scan. During the vertical blanking period of each display frame, the backlight drive value corresponding to the backlight update sequence is written to avoid stripes or flickering caused by sudden changes in backlight brightness within the effective display range. When there is a write delay in the backlight drive interface, a safe write window can be reserved after the start of vertical blanking to ensure that the write is completed before the start of the next effective display frame.

[0064] Pixel luminance mapping and backlight updates are executed in parallel. Before outputting each frame, the display device reads the pixel domain compensation parameters aligned with that frame and performs pixel luminance mapping on the content frame sequence, ensuring that backlight domain and pixel domain brightness adjustments work synergistically within the same frame. To avoid color distortion, pixel luminance mapping prioritizes the luminance component while keeping the chrominance component unchanged. The mapped result is truncated to meet the value range of the display pipeline. The contrast fluctuation index is obtained by taking adjacent content frames in the content frame sequence as input. For each frame, the global contrast is calculated, and the difference in global contrast between adjacent frames is obtained. The global contrast can be calculated using the difference between the global maximum and minimum luminance values ​​or the quantile difference of the luminance distribution. The specific calculation method can be fixed to ensure index consistency. To suppress noise, the contrast fluctuation index can be averaged or taken as the maximum value within several frame windows as the current period index.

[0065] When updating the brightness tolerance window and content type switching hysteresis parameter, a preset fluctuation threshold is used as the judgment boundary: when the global contrast difference exceeds the preset fluctuation threshold, it indicates that the screen has a strong risk of contrast fluctuation under brightness adjustment. The display device lowers the upper limit of the single frame brightness change amplitude to slow down the single frame brightness change, and increases the content type switching hysteresis parameter to improve the stability of content type identifier updates, thereby reducing the frequent switching of the brightness tolerance window; when the global contrast difference does not exceed the preset fluctuation threshold, it indicates that the screen stability is good. The display device raises the upper limit of the single frame brightness change amplitude to improve the brightness following speed, and decreases the content type switching hysteresis parameter to improve the response of the content type identifier to the actual content changes.

[0066] The adjustment range of the upper limit of single-frame brightness variation can be configured in fixed steps, and the adjustment of the content type switching hysteresis parameter can be achieved by increasing or decreasing the threshold of consecutive frames, and remains unchanged when the preset upper or lower limit is reached to avoid failure caused by infinite increase or decrease. To ensure the continuity of updates, the brightness tolerance window is immediately used for the generation of the backlight update sequence and pixel domain compensation parameter sequence in the next control cycle after the update, and the content type switching hysteresis parameter is immediately used for the stability determination of the content type identifier in the next control cycle after the update, thus forming a closed-loop adjustment path with contrast fluctuation index as feedback, so that power consumption constraints, execution timing and visual stability converge synergistically under the same control framework.

[0067] like Figure 2 As shown, an adaptive brightness adjustment system for a display device is used to implement an adaptive brightness adjustment method for the display device. The system includes: The target determination module acquires ambient light data, user brightness preferences, and power status to determine the target display brightness command. This module can be implemented in hardware by a combination of an ambient light sensor, a system controller, and a power management unit. The ambient light sensor outputs illuminance sampling values, which are sent to the system controller via I2C or SPI bus. User brightness preferences are set by the touch controller or button controller and written to registers or shared memory via the operating system interface for the system controller to read. Power status is provided by the battery metering chip and the power management unit, including battery level, power supply mode, and power limit flags. After reading the above inputs, the system controller or application processor generates the target display brightness command in the firmware or driver and sends it to the backlight control register or brightness control register via the internal bus.

[0068] The window determination module is used to acquire the content frame sequence of the foreground focus task, extract brightness statistics and brightness changes, and determine the brightness tolerance window and the upper limit of brightness change amplitude per frame based on the content type switching hysteresis parameter. The window determination module is typically supported by an image processor, a display compositing unit, and a storage subsystem. The content frame sequence of the foreground focus task is output to the frame buffer by the graphics compositing unit, and the frame buffer is stored in external memory such as DDR or on-chip SRAM. The image processor reads the content frame data frame by frame through the DMA channel, performing pixel traversal, block statistics, and inter-frame comparison required for extracting brightness statistics and brightness changes. The content type switching hysteresis parameter can be stored in a register group or configuration memory area. The image processor or control processor generates the brightness tolerance window and the upper limit of brightness change amplitude per frame based on the statistical results and hysteresis parameter, and writes them back to the shared register for subsequent modules to call.

[0069] The sequence generation module is used to obtain the minimum backlight update cycle, generate a backlight update sequence based on the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit of the brightness change amplitude of a single frame. The sequence generation module is implemented in hardware by the backlight control unit, timing controller, and processor working together. The minimum backlight update cycle can be provided by the backlight driver chip specifications, the backlight control unit registers, or the timing controller, which the processor uses to determine the minimum allowable update interval for the backlight driver. The target display brightness command is mapped into a backlight driver value sequence within the processor or backlight control unit, and combined with the minimum backlight update cycle to generate an update time sequence, forming the backlight update sequence. The backlight driver value sequence can be output to the backlight driver chip via a PWM generator or current DAC. If the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit, the processor or image processor generates a pixel domain compensation parameter sequence and writes this parameter sequence into a register or parameter buffer for the pixel processing link to read, so as to perform mapping compensation on the pixel brightness before the display data is output.

[0070] The adjustment and update module is used to reduce the target display brightness command and smooth the pixel domain compensation parameter sequence when the power state meets the power limit conditions. It performs brightness adjustment based on the backlight update sequence and the pixel domain compensation parameter sequence, obtains the contrast fluctuation index, and updates the brightness tolerance window and content type switching hysteresis parameters. The adjustment and update module is implemented in hardware through the collaborative efforts of the power management unit, display timing controller, backlight drive link, and image processor feedback calculation unit. When the power management unit sets the power limit flag or reports a power consumption constraint state, the processor reduces the target display brightness command and writes the pixel domain compensation parameter sequence back to the parameter cache after smoothing. The update of the backlight drive value is triggered by the display timing controller during vertical blanking to ensure that the backlight register write and PWM duty cycle update are completed within a safe window. The pixel domain compensation parameters are applied to each frame by the image processor in the output link to achieve pixel brightness mapping. The contrast fluctuation index can be obtained by the image processor by quickly statistically analyzing adjacent frames and reported to the processor via a register. The processor or image processor updates the brightness tolerance window and content type switching hysteresis parameters based on the contrast fluctuation index and writes them into the configuration register, so that the window determination and sequence generation of the next control cycle form a closed-loop update.

[0071] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0072] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. An adaptive brightness adjustment method for a display device, characterized in that, The method includes: Acquire ambient lighting data, user brightness preferences, and power status to determine the target display brightness command; Obtain the content frame sequence of the foreground focus task, extract brightness statistics and brightness change, and determine the brightness tolerance window and the upper limit of brightness change amplitude per frame based on the content type switching hysteresis parameter; Obtain the minimum backlight update cycle, generate a backlight update sequence according to the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the single-frame brightness change amplitude of the backlight update sequence exceeds the upper limit of the single-frame brightness change amplitude. When the power state meets the power limit condition, the target display brightness instruction is reduced and the pixel domain compensation parameter sequence is smoothed. Brightness adjustment is performed according to the backlight update sequence and the pixel domain compensation parameter sequence. Contrast fluctuation index is obtained, and the brightness tolerance window and the content type switching hysteresis parameter are updated.

2. The method according to claim 1, characterized in that, The instruction to determine the target display brightness includes: The target ambient brightness is determined based on the ambient lighting data using a preset brightness mapping relationship. Determine the preferred target brightness based on the user's brightness preference; The initial display brightness command is determined based on the ambient target brightness and the preferred target brightness. Based on the power state, the initial display brightness command is limited to a preset brightness range to obtain the target display brightness command.

3. The method according to claim 1, characterized in that, The extracted brightness statistics include: Each frame in the content frame sequence of the foreground focus task is divided into multiple image blocks, and the mean brightness and variance of brightness of each image block are calculated to obtain the brightness statistics.

4. The method according to claim 1, characterized in that, The extracted brightness change includes: The global average brightness value is calculated for each adjacent content frame in the content frame sequence, and the difference between the global average brightness values ​​is determined. The difference between the global average brightness values ​​and the number of times the difference between the global average brightness values ​​exceeds a preset difference threshold are used as the brightness change amount.

5. The method according to claim 1, characterized in that, The content type switching hysteresis parameter includes a consecutive frame count threshold; determining the brightness tolerance window and the upper limit of single-frame brightness variation based on the content type switching hysteresis parameter includes: A content type identifier is determined based on the brightness statistics and the brightness change, and the content type identifier is used to characterize the content type of the foreground focus task; The content type identifier is updated only if it remains consistent across consecutive content frames corresponding to the consecutive frame number threshold. The brightness tolerance window is determined based on the updated content type identifier. The brightness tolerance window is used to characterize the range of brightness variation allowed in the content frame sequence, and the upper limit of the brightness variation amplitude of a single frame is the upper limit parameter of the brightness tolerance window.

6. The method according to claim 1, characterized in that, The generation of the backlight update sequence includes: The target display brightness command is mapped to a backlight drive value sequence, and the update time sequence of the backlight drive value sequence is determined based on the backlight minimum update cycle, so that the time interval between adjacent update times is not less than the backlight minimum update cycle. The backlight update sequence includes the backlight drive value sequence and the update time sequence; And ensure that the brightness difference between adjacent backlight drive values ​​in the backlight drive value sequence does not exceed the upper limit of the brightness change range of a single frame.

7. The method according to claim 6, characterized in that, The generated pixel domain compensation parameter sequence includes: The backlight driving value sequence is converted into a backlight brightness sequence according to a preset brightness mapping relationship, wherein the preset brightness mapping relationship is the correspondence between the backlight driving value and the display brightness; The brightness deviation is determined based on the target display brightness command and the backlight brightness sequence; Generate a pixel brightness mapping parameter sequence corresponding to the content frame sequence based on the brightness deviation; The pixel brightness mapping parameter sequence is then subjected to cross-frame smoothing to obtain the pixel domain compensation parameter sequence.

8. The method according to claim 1, characterized in that, The power state satisfies the power limiting condition if the battery level is lower than a preset power threshold and the expected power consumption increment reaches a preset power threshold. The expected power consumption increment is a power consumption increment calculated based on the correspondence between the backlight drive value and the backlight power consumption; The instruction to reduce the target display brightness includes limiting the target display brightness to below a preset maximum brightness.

9. The method according to claim 1, characterized in that, Updating the backlight drive value according to the backlight update sequence includes updating the backlight drive value corresponding to the backlight update sequence during the vertical blanking of the display frame; the contrast fluctuation index includes the global contrast difference between adjacent content frames in the content frame sequence. Updating the brightness tolerance window and the content type switching hysteresis parameter includes: lowering the upper limit of the single-frame brightness change amplitude and increasing the content type switching hysteresis parameter when the global contrast difference exceeds a preset fluctuation threshold; and raising the upper limit of the single-frame brightness change amplitude and decreasing the content type switching hysteresis parameter when the global contrast difference does not exceed the preset fluctuation threshold.

10. An adaptive brightness adjustment system for a display device, used to implement the adaptive brightness adjustment method of the display device according to any one of claims 1-9, characterized in that, The system includes: The target determination module is used to acquire ambient light data, user brightness preferences, and power status to determine the target display brightness command; The window determination module is used to obtain the content frame sequence of the foreground focus task, extract brightness statistics and brightness change, and determine the brightness tolerance window and the upper limit of the brightness change amplitude of a single frame based on the content type switching hysteresis parameter. The sequence generation module is used to obtain the minimum backlight update cycle, generate a backlight update sequence according to the target display brightness command and the minimum backlight update cycle, and generate a pixel domain compensation parameter sequence when the brightness change amplitude of a single frame in the backlight update sequence exceeds the upper limit of the brightness change amplitude of a single frame. The adjustment and update module is used to reduce the target display brightness command and smooth the pixel domain compensation parameter sequence when the power state meets the power limit conditions. It performs brightness adjustment based on the backlight update sequence and the pixel domain compensation parameter sequence, obtains the contrast fluctuation index, and updates the brightness tolerance window and content type switching hysteresis parameters.

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