CN111800592B - Dead pixel correction method, device and storage medium capable of suppressing pixel fluctuation - Google Patents
Dead pixel correction method, device and storage medium capable of suppressing pixel fluctuation Download PDFInfo
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Abstract
本发明公开了一种可以抑制像元波动的坏点校正方法及装置、存储介质，包括：基于待检测像素的同通道m*m邻域矩阵，根据像素亮度值将邻域矩阵的像素分到亮点坏点分析序列和暗点坏点分析序列；判断待检测像素所在坏点分析序列中像素的亮度值分布是否有第一断层，若是则进入第一次校正，否则进入第二次校正条件的判断，判断待检测像素所在坏点候选点序列中像素的亮度值分布是否有第二断层，若是则进入第二次校正，本发明通过对待检测像素所在坏点分析序列中像素的亮度值分布第一断层和第二断层的分布情况进行分析判断，进行两次校正过程，同时实现了图像传感器坏点校正和抑制像元波动。
The invention discloses a bad pixel correction method, device and storage medium capable of suppressing pixel fluctuation, comprising: based on the same-channel m*m neighborhood matrix of the pixels to be detected, dividing the pixels of the neighborhood matrix into groups according to the pixel brightness values Bright spot and dark spot analysis sequence and dark spot and dark spot analysis sequence; determine whether the brightness value distribution of the pixel in the dead spot analysis sequence where the pixel to be detected is located has the first fault, if so, enter the first correction, otherwise enter the second correction condition Judging, judging whether there is a second fault in the brightness value distribution of the pixels in the bad point candidate point sequence where the pixel to be detected is located, and if so, the second correction is entered. The distribution of the first fault and the second fault is analyzed and judged, and the correction process is carried out twice, and at the same time, the correction of the dead pixels of the image sensor and the suppression of pixel fluctuations are realized.
Description
Technical Field
The invention relates to the field of image processing, in particular to a dead pixel correction method and device capable of inhibiting pixel fluctuation and a storage medium.
Background
The existing image sensor dead pixel correction algorithm takes a pixel to be detected as a center, considers the processing of a Bayer color matrix of 5X5 around the pixel, compares surrounding pixels with the center pixel, judges as a dead pixel if a difference value exceeds a threshold value, and then takes a median value or an average value or a probability estimation result as a correction value of the dead pixel. The method is characterized in that the processing of judging and correcting the dead pixel is single, the processing of a single image can obtain an ideal effect, but the flicker of pixels caused by pixels with fluctuation is not considered, when the dead pixel fluctuates, the pixel is judged to be dead pixel at the previous moment and corrected to be a median value or other values, but the gray value change generated by fluctuation at the next moment does not meet the dead pixel judgment condition and is not corrected, and when a large difference exists between the corrected value and the original value, the pixel values of two frames before and after the pixel represented on the image at the position are changed greatly, so that the flicker phenomenon is formed. The flicker is not the pixel flicker of the sensor, but the flicker caused by the pixel fluctuation amplification of the dead pixel correction algorithm, namely the dead pixel correction algorithm of the existing image sensor solves the dead pixel problem and simultaneously brings a new flicker problem.
To solve this problem, it can be handled by the following method: and performing time domain filtering again, independently suppressing the fluctuation of the image pixels in the time domain, or adopting time-space domain filtering to reduce the traversal times, and simultaneously performing dead pixel correction in the space domain and flicker suppression in the time domain.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a dead pixel correction method and a device and a storage medium which can inhibit pixel fluctuation, and a dead pixel correction algorithm is improved, so that the amplification effect of the dead pixel correction algorithm on the pixel fluctuation is reduced, and the problem of image flicker is weakened or inhibited.
Specifically, the dead pixel correction method capable of suppressing the pixel fluctuation of the present invention includes the following steps:
(11) based on a same-channel m × m neighborhood matrix of a pixel to be detected, dividing pixels of the neighborhood matrix into a bright dot dead pixel analysis sequence and a dark dot dead pixel analysis sequence according to pixel brightness values;
(12) judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, entering a step (13), and otherwise, entering a step (14);
(13) correcting the brightness value of the pixel to be detected to a position crossing over a nearest first fault;
(14) judging whether the brightness value distribution of the pixels in the dead pixel candidate point sequence of the pixel to be detected has a second fault, if so, entering the step (15), and otherwise, finishing the correction process of the pixel to be detected;
(15) correcting the brightness value of the pixel to be detected to reach or cross the position of the nearest second fault;
the first/second fault is an interval larger than a preset first/second segmentation threshold, and the first segmentation threshold is larger than the second segmentation threshold.
As a further optimization of the above solution, the step (11) comprises:
(21) sequencing m pixels with the number of m including the pixels to be detected from high to low according to the brightness value to obtain a pixel sequence;
(22) according to the parity condition of the m value, dividing the pixel sequence:
when m is odd, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
The individual pixels are divided into a dark-spot dead-spot candidate point sequence
Determining each pixel as a non-dead pixel;
when m is even number, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
Dividing each pixel into a dark point dead point candidate point sequence;
(23) obtaining a dead pixel candidate of a pixel to be detectedSelecting a point sequence and adding the second one to the sequence
Each pixel forms either a bright spot dead pixel analysis sequence or a dark spot dead pixel analysis sequence.
As a further optimization of the above scheme, the step (13) includes determining whether the luminance value of the pixel to be detected needs to be corrected across a first fault according to whether the correction direction of the pixel to be detected has the first fault, and the specific steps include:
(31) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist below the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information;
when at least one first fault is arranged below the pixel position to be detected, the upper and lower limit positions of the first fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
correcting the brightness value of the pixel to be detected to the lower limit position of the nearest first fault downwards;
(32) when the sequence of the pixels to be detected is a dark point dead point analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist above the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information;
when at least one first fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the first fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
the luminance value of the pixel to be detected is corrected upward to the upper limit position of the nearest one of the first faults.
As a further optimization of the above scheme, in the step (15), according to whether the distance between the brightness value of the pixel to be detected and the nearest second fault is greater than a preset correction threshold, the brightness value of the pixel to be detected is selected to be corrected to reach or cross the position of the nearest second fault, and the correction threshold is greater than a second segmentation threshold and smaller than a first segmentation threshold.
As a further optimization of the above scheme, the step (15) includes determining whether a correction process needs to be performed according to whether the correction direction of the pixel to be detected has the second fault, and the specific steps include:
(51) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist below the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault is arranged below the pixel position to be detected, the upper and lower limit positions of the second fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the nearest second fault;
judging whether A2 is greater than a preset correction threshold value;
if so, correcting the brightness value of the pixel to be detected downwards to reach the position of the nearest second fault;
otherwise, correcting the brightness value of the pixel to be detected downwards to a position beyond the nearest second fault;
(52) when the sequence of the pixels to be detected is a dark point dead point analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist above the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the second fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the second fault;
judging whether A1 is greater than a preset correction threshold value;
if so, correcting the brightness value of the pixel to be detected upwards to reach the position of the nearest second fault;
otherwise, the pixel brightness value to be detected is corrected upward to a position beyond the nearest one of the second faults.
The invention relates to a dead pixel correction device capable of inhibiting pixel fluctuation, which comprises:
the neighborhood pixel classification module is used for classifying pixels of the neighborhood matrix into a bright spot dead pixel analysis sequence and a dark spot dead pixel analysis sequence according to pixel brightness values based on the same-channel m × m neighborhood matrix of the pixels to be detected;
the first correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, the first correction execution module is started, and if not, the second correction execution module is started;
a first correction execution module for correcting the brightness value of the pixel to be detected to a position crossing a first fault;
the second correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a second fault or not, if so, the second correction execution module is started, and if not, the correction process of the pixels to be detected is completed;
a second correction execution module for correcting the brightness value of the pixel to be detected to a position reaching or crossing a nearest one of the second faults;
the first/second fault is an interval larger than a preset first/second segmentation threshold, and the first segmentation threshold is larger than the second segmentation threshold.
As a further optimization of the above scheme, the second correction execution module includes:
the second fault position distribution acquisition unit is used for judging the position relation between the pixel position to be detected and all second faults in the dead pixel analysis sequence where the pixel to be detected is located;
the pixel fluctuation judging unit is used for judging whether at least one second fault exists below the pixel to be detected when the pixel to be detected is in the bright spot dead pixel analysis sequence, and whether at least one second fault exists above the pixel to be detected when the pixel to be detected is in the dark spot dead pixel analysis sequence, if so, the pixel to be detected generates pixel fluctuation and needs to be corrected, otherwise, the pixel fluctuation does not occur;
the correction candidate position acquisition unit is used for acquiring the upper and lower limit positions of a second fault which is above the position of the pixel to be detected and has the closest distance with the position of the pixel to be detected;
and the correction candidate position selection unit is used for judging whether the distance between the pixel position to be detected and the nearest second fault is greater than a preset correction threshold value or not, if so, the correction position is selected to reach the position of the nearest second fault, otherwise, the correction position is selected to cross the position of the nearest second fault, and the correction threshold value is greater than the second segmentation threshold value and smaller than the first segmentation threshold value.
As a further optimization of the above solution, the first correction execution module includes:
the first fault position distribution acquisition unit is used for judging the position relation between the position of the pixel to be detected and all first faults in the dead pixel analysis sequence where the pixel to be detected is located;
the correction condition judging unit is used for judging whether at least one first fault exists below the pixel to be detected when the pixel to be detected is in the bright spot dead pixel analysis sequence, and whether at least one first fault exists above the pixel to be detected when the pixel to be detected is in the dark spot dead pixel analysis sequence;
and the correction position acquisition unit is used for acquiring the upper and lower limit positions of the first fault which is above the position of the pixel to be detected and is closest to the position of the pixel to be detected, and correcting the brightness value of the pixel to be detected to the upper limit position crossing the closest first fault.
The invention also provides a storage medium on which computer instructions are stored, wherein the computer instructions execute the steps of the bad pixel correction method capable of inhibiting the pixel fluctuation when running.
The invention also provides a terminal based on the above dead pixel correction method capable of inhibiting pixel fluctuation, which comprises a memory and a processor, wherein the memory is stored with a computer instruction capable of running on the processor, and the processor executes the steps of the dead pixel correction method capable of inhibiting pixel fluctuation when running the computer instruction.
The invention discloses a dead pixel correction method and device capable of inhibiting pixel fluctuation, a storage medium and a terminal, and has the following beneficial effects:
1. according to the invention, through setting the first/second segmentation threshold values respectively, the brightness value of the pixel to be detected is corrected to the position crossing a first fault according to the position relationship between the first fault and the pixel to be detected in the analysis sequence of the pixel to be detected, the first fault which enables the pixel to be detected to be a dead pixel is eliminated, then the brightness value of the pixel to be detected is corrected to the position reaching or crossing a nearest second fault according to the position relationship between the second fault and the pixel to be detected in the analysis sequence of the pixel to be detected, the second fault which enables the pixel to be detected to generate pixel fluctuation is eliminated, the dead pixel correction and the pixel fluctuation inhibition of the image sensor are simultaneously realized through two correction processes, and the single pixel point flicker phenomenon caused by photosensitive fluctuation of some pixels on the image sensor is avoided.
2. In the first correction process, the brightness value of the pixel to be detected is corrected to the position crossing a first fault, namely the correction amplitude only crosses the first fault closest to the pixel to be detected, and the brightness value of the pixel to be detected is only jumped by one fault, so that the fluctuation of the brightness value of the pixel in the time domain in the correction process is reduced.
3. In the second correction process, the brightness value of the pixel to be detected is corrected to reach or cross the position of the nearest second fault, on one hand, the correction amplitude is only related to the position of the nearest second fault, the fluctuation of the brightness value of the pixel in the time domain in the correction process is reduced, meanwhile, through the setting of the preset correction threshold value, the correction amplitude is judged to reach the position of the nearest second fault or cross the position of the nearest second fault, the condition that the correction amplitude exceeds the preset correction threshold value when the pixel to be detected fluctuates is avoided, and the fluctuation of the brightness value of the pixel in the time domain in the correction process is further reduced.
Drawings
FIG. 1 is a block diagram of the overall process of the bad pixel correction method of the present invention for suppressing pixel fluctuation;
FIG. 2 is a block diagram of a first correction flow of the method for correcting a dead pixel capable of suppressing pixel fluctuation according to the present invention;
FIG. 3 is a block diagram of a second correction process when a sequence of a pixel to be detected is a bright dot dead pixel analysis sequence in the dead pixel correction method capable of suppressing pixel fluctuation of the present invention;
FIG. 4 is a block diagram of a second correction process when a sequence of a pixel to be detected is a dark-pixel dead pixel analysis sequence in the dead pixel correction method capable of suppressing pixel fluctuation according to the present invention;
FIG. 5 is a block diagram of a module structure of the bad pixel correction apparatus capable of suppressing pixel fluctuation according to the present invention.
Detailed Description
The technical solution of the present invention is further explained below with reference to the specific embodiments and the accompanying drawings.
The invention provides a dead pixel correction method capable of inhibiting pixel fluctuation, which can simultaneously process the problems of an image in a space domain and a time domain, not only effectively corrects dead pixels in image pixels in the space domain of the image, but also can inhibit large-amplitude fluctuation of the pixels in the time domain through two correction processes, and avoids the phenomenon of single-pixel-point flicker caused by photosensitive fluctuation of some pixels on an image sensor, and comprises the following steps:
(11) establishing a Bayer color matrix by taking the pixel points to be detected as central pixel points, and acquiring an m × m single-channel matrix of the same channel;
based on a same-channel m × m neighborhood matrix of a pixel to be detected, dividing pixels of the neighborhood matrix into a bright dot dead pixel analysis sequence and a dark dot dead pixel analysis sequence according to pixel brightness values;
specifically, m × m pixels including the pixel to be detected are sequenced from high to low according to the brightness value, and a pixel sequence is obtained; it is easy to understand that, in the pixel sequence of the m × m neighborhood matrix, when the pixel to be detected is at the first half position, it is most likely to be a bright dot dead pixel as a bright dot dead pixel candidate, the luminance value of the pixel to be detected needs to be corrected downward, i.e., the correction direction is downward, when the pixel to be detected is at the second half position, it is most likely to be a dark dot dead pixel as a dark dot dead pixel candidate, and the luminance value of the pixel to be detected needs to be corrected upward, i.e., the correction direction is upward.
(22) Considering the condition that more than one dead pixel exists in the neighborhood matrix, dividing the pixel sequence according to the parity condition of the m value, and taking more than half of the pixels including the pixel to be detected as a dead pixel analysis sequence:
when m is odd, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
The individual pixels are divided into a dark-spot dead-spot candidate point sequence
Determining each pixel as a non-dead pixel;
when m is even number, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
Each pixel is divided into darkA candidate point sequence of the point dead points;
(23) obtaining a dead pixel candidate point sequence of a pixel to be detected, and adding a second point into the sequence
Each pixel forms either a bright spot dead pixel analysis sequence or a dark spot dead pixel analysis sequence.
When the pixel to be detected is in the bright spot dead spot candidate point sequence, the pixel to be detected is in the bright spot dead spot candidate point sequence
Adding each pixel in the front of the bright spot dead spot candidate point sequence to form a bright spot dead spot analysis sequence, and when the pixel to be detected is in the dark spot dead spot candidate point sequence, adding the first pixel in the bright spot dead spot candidate point sequence to form a bright spot dead spot analysis sequence
And adding the pixels to the rearmost part of the dark point dead point candidate point sequence to form a dark point dead point analysis sequence, so that all the pixels in the dark point dead point analysis sequence are sorted from high to low according to the brightness value.
Then, sequentially acquiring the brightness value gradients of two adjacent pixels according to the dead pixel analysis sequence of the pixel to be detected;
setting an interval larger than a preset first/second segmentation threshold value as a first/second fault, wherein the first segmentation threshold value is larger than the second segmentation threshold value.
Recording the interval with the brightness value gradient larger than a first preset segmentation threshold as a first fault position;
(12) judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, entering a step (13), and otherwise, entering a step (14);
(13) correcting the brightness value of the pixel to be detected to a position crossing a first fault; the step comprises the steps of judging whether a correction process is needed or not according to whether the correction direction of the pixel to be detected has a first fault or not, specifically:
(31) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist below the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information; at this time, in the bright dot dead pixel analysis sequence, all pixels are sorted from high to low according to the brightness values, and there is no first fault below the position of the pixel to be detected, which indicates that the brightness value of the pixel to be detected is closer to the middle brightness in the whole m × m neighborhood matrix, and no large abnormal jump occurs, and no correction is needed.
When at least one first fault is arranged below the pixel position to be detected, correction is needed at the moment, and the upper and lower limit positions of the first fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
correcting the brightness value of the pixel to be detected to the lower limit position of the nearest first fault downwards;
there may be a plurality of first faults below the pixel position to be detected, and in this embodiment, the selection of the correction position only relates to one first fault below the pixel position to be detected which is closest to the pixel position to be detected; that is, the correction amplitude is only skipped by one slice (the difference between the pixel value after the pixel to be detected is corrected and the original value is defined as the correction amplitude or the skipping amplitude), so that the large fluctuation of the brightness value of the pixel to be detected in the time domain in the first correction process is avoided.
(32) Similar to the first correction process of the bright dot dead pixel analysis sequence, when the sequence of the pixels to be detected is the dark dot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist above the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information;
when at least one first fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the first fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
the luminance value of the pixel to be detected is corrected upward to the upper limit position of the nearest one of the first faults.
Then, according to the brightness value gradients of two adjacent pixels in the dead pixel analysis sequence of the pixel to be detected, recording the interval with the brightness value gradient larger than a second preset segmentation threshold as a second fault position;
(14) judging whether the brightness value distribution of the pixels in the dead pixel candidate point sequence of the pixel to be detected has a second fault, if so, entering the step (15), and otherwise, finishing the correction process of the pixel to be detected;
(15) correcting the brightness value of the pixel to be detected to reach or cross the position of the nearest second fault; the step includes judging whether a correction process needs to be performed according to whether the correction direction of the pixel to be detected has a second fault, and selecting whether the luminance value of the pixel to be detected reaches or crosses the position of the nearest second fault according to whether the distance between the luminance value of the pixel to be detected and the nearest second fault is greater than a preset correction threshold, wherein the correction threshold is greater than a second segmentation threshold and smaller than a first segmentation threshold, specifically:
(51) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist below the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault is arranged below the pixel position to be detected, the upper and lower limit positions of the second fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the nearest second fault;
judging whether A2 is larger than a preset correction threshold value or not, if so, correcting the brightness value of the pixel to be detected downwards to reach the position of the nearest second fault;
otherwise, correcting the brightness value of the pixel to be detected downwards to a position beyond the nearest second fault;
(52) when the sequence of the pixels to be detected is a dark point dead point analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist above the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the second fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the second fault;
judging whether A1 is greater than a preset correction threshold value;
if so, correcting the brightness value of the pixel to be detected upwards to reach the position of the nearest second fault;
otherwise, the brightness value of the pixel to be detected is corrected upwards to the position of crossing the nearest second fault.
Aiming at the process, taking 3 as an example of a neighborhood matrix m, taking a pixel point to be detected as a central pixel point, establishing a 5x 5Bayer color matrix, and obtaining a 3 x 3 single-channel matrix of the same channel;
and analyzing 9 pixels in a 3-by-3 neighborhood matrix of the same channel, and setting a preset first segmentation threshold TH1 to be 25, a preset second segmentation threshold TH2 to be 10 and a preset correction threshold TH _ C to be 15.
The method comprises the steps of sequencing the brightness values of 9 pixels in a channel image from high to low, judging whether a pixel to be detected is one of brightest 4 pixels or one of darkest 4 pixels, wherein when the brightness value of the pixel to be detected is located at the 5 th bit in the sequence, the pixel to be detected is a non-dead pixel, when the pixel to be detected is located at other positions, further judging whether the pixel to be detected is a dead pixel or not is needed, analyzing by taking one of the darkest 4 pixels as an example, performing double-threshold judgment on the brightness gradient value of the sequenced last 5 pixels, judging whether the brightness gradient value exceeds a first segmentation threshold value or not for the first time, and judging whether the brightness gradient value exceeds a second segmentation threshold value or not for the second time.
The difference value of 5 pixels forms 4 gradients, first, judgment of a first segmentation threshold is carried out, whether first faults exist in the 4 gradients or not is detected, and a plurality of first faults exist;
if the first fault exists, the position relation between the pixel to be detected and the first fault is continuously judged, taking the first fault as an example, if the pixel to be detected is positioned above the first fault, the brightness value of the pixel to be detected is in the middle of the whole neighborhood matrix and cannot be a dead pixel, and the original value is reserved; if the pixel to be detected is located below the first fault, the pixel to be detected belongs to a dead pixel, namely the pixel to be detected is determined to be the dead pixel as long as the gray value of the pixel to be detected is located below the first fault, the dead pixel enters a first dead pixel correction process, and after the first correction process is completed, the pixel to be detected enters a second segmentation threshold value.
If the first fault does not exist, directly judging a second segmentation threshold, and detecting whether the 4 gradients have second faults or not, wherein a plurality of second faults exist; similarly, as long as the brightness value of the pixel to be detected is positioned below the second fault, the pixel is judged to be a dead pixel, and the second dead pixel correction process is carried out.
For the first correction process, it is corrected to the pixel value that is closest above its adjacent first slice, i.e. the corrected pixel value variation jumps by only one slice no matter how many slices are actually distributed.
And when the first fault does not exist, firstly judging the threshold value of the second fault, detecting the distribution of the second fault, and correcting the pixel to be detected below the second fault by comparing the threshold value with a preset correction threshold value again, namely, correcting the pixel to be detected to the nearest pixel value above the second fault, namely jumping by one second fault, if the pixel to be detected is smaller than the correction threshold value, and correcting the pixel to be detected to the nearest pixel value below the second fault.
The dead pixel judgment mode of the double thresholds prevents the singularity of dead pixel judgment, and the correction threshold judgment during the second fault correction processing limits the correction jitter of the pixel to be detected and reduces the pixel value fluctuation of the pixel to be detected in the time domain.
Experiments show that when the first segmentation threshold TH1 is 25, the second segmentation threshold TH2 is 10, and the correction threshold TH _ C is 15, not only static dead pixels in an image can be effectively corrected, but also a good flicker suppression effect can be achieved for dynamic flickering dead pixels, and the fluctuation range can be within 20 gray values.
The embodiment of the invention also provides a dead pixel correction device capable of inhibiting pixel fluctuation, which comprises:
the neighborhood pixel classification module is used for classifying pixels of the neighborhood matrix into a bright spot dead pixel analysis sequence and a dark spot dead pixel analysis sequence according to pixel brightness values based on the same-channel m × m neighborhood matrix of the pixels to be detected;
the first correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, the first correction execution module is started, and if not, the second correction execution module is started;
a first correction execution module for correcting the brightness value of the pixel to be detected to a position crossing a first fault;
the second correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a second fault or not, if so, the second correction execution module is started, and if not, the correction process of the pixels to be detected is completed;
a second correction execution module for correcting the brightness value of the pixel to be detected to a position reaching or crossing a nearest one of the second faults;
the first/second fault is an interval larger than a preset first/second segmentation threshold, and the first segmentation threshold is larger than the second segmentation threshold.
Wherein the second correction execution module includes:
the second fault position distribution acquisition unit is used for judging the position relation between the pixel position to be detected and all second faults in the dead pixel analysis sequence where the pixel to be detected is located;
the pixel fluctuation judging unit is used for judging whether a second fault exists below the pixel to be detected when the pixel to be detected is in the bright spot dead pixel analysis sequence, and whether a second fault exists above the pixel to be detected when the pixel to be detected is in the dark spot dead pixel analysis sequence, if so, the pixel to be detected generates pixel fluctuation and needs to be corrected, otherwise, the pixel fluctuation does not occur;
the correction candidate position acquisition unit is used for acquiring the upper and lower limit positions of a second fault which is above the position of the pixel to be detected and has the closest distance with the position of the pixel to be detected;
and the correction candidate position selection unit is used for judging whether the distance between the pixel position to be detected and the nearest second fault is greater than a preset correction threshold value or not, if so, the correction position is selected to reach the position of the nearest second fault, otherwise, the correction position is selected to cross the position of the nearest second fault, and the correction threshold value is greater than the second segmentation threshold value and smaller than the first segmentation threshold value.
Wherein, the first correction execution module comprises:
the first fault position distribution acquisition unit is used for judging the position relation between the position of the pixel to be detected and all first faults in the dead pixel analysis sequence where the pixel to be detected is located;
the correction condition judging unit is used for judging whether a first fault exists below the pixel to be detected when the pixel to be detected is in the bright spot dead pixel analysis sequence or not, and whether a first fault exists above the pixel to be detected when the pixel to be detected is in the dark spot dead pixel analysis sequence or not, if yes, the pixel to be detected is a dead pixel and needs to be corrected, and if not, the pixel to be detected is a non-dead pixel;
and the correction position acquisition unit is used for acquiring the upper and lower limit positions of the first fault which is above the position of the pixel to be detected and is closest to the position of the pixel to be detected, and correcting the brightness value of the pixel to be detected to the upper limit position crossing the closest first fault.
The embodiment of the invention also provides a storage medium, wherein a computer instruction is stored on the storage medium, and when the computer instruction runs, the steps of the bad pixel correction method capable of inhibiting pixel fluctuation are executed. The storage medium may include ROM, RAM, magnetic or optical disks, etc. The storage medium may further include a non-volatile memory (non-volatile) or a non-transitory memory (non-transient) or the like.
The embodiment of the invention also provides a terminal, which comprises a memory and a processor, wherein the memory is stored with computer instructions capable of running on the processor, and the processor executes the steps of the dead pixel correction method capable of inhibiting pixel fluctuation when running the computer instructions.
The present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make various modifications without creative efforts from the above-described conception, and fall within the scope of the present invention.
Claims (10)
1. A dead pixel correction method capable of suppressing fluctuation of a pixel is characterized in that: the method comprises the following steps:
(11) based on a same-channel m × m neighborhood matrix of a pixel to be detected, dividing pixels of the neighborhood matrix into a bright dot dead pixel analysis sequence and a dark dot dead pixel analysis sequence according to pixel brightness values;
(12) judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, entering a step (13), and otherwise, entering a step (14);
(13) correcting the brightness value of the pixel to be detected to a position crossing over a nearest first fault;
(14) judging whether the brightness value distribution of the pixels in the dead pixel candidate point sequence of the pixel to be detected has a second fault, if so, entering the step (15), and otherwise, finishing the correction process of the pixel to be detected;
(15) correcting the brightness value of the pixel to be detected to reach or cross the position of the nearest second fault;
the first/second fault is an interval larger than a preset first/second segmentation threshold, and the first segmentation threshold is larger than the second segmentation threshold;
the step (13) includes judging whether the luminance value of the pixel to be detected needs to be corrected across a first fault according to whether the correction direction of the pixel to be detected has the first fault;
the step (15) includes determining whether or not a correction process is required depending on whether or not the correction direction of the pixel to be detected has the second tomographic section.
2. The method of correcting a dead pixel that suppresses fluctuation of a pixel according to claim 1, wherein: the step (11) comprises:
(21) sequencing m pixels with the number of m including the pixels to be detected from high to low according to the brightness value to obtain a pixel sequence;
(22) according to the parity condition of the m value, dividing the pixel sequence:
when m is odd, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
The individual pixels are divided into a dark-spot dead-spot candidate point sequence
Determining each pixel as a non-dead pixel;
when m is even number, the pixel sequence is preceded by
Dividing each pixel into a bright spot and dead spot candidate point sequence, and then
Dividing each pixel into a dark point dead point candidate point sequence;
(23) obtaining a dead pixel candidate point sequence of a pixel to be detected, and adding a second point into the sequence
Each pixel forms either a bright spot dead pixel analysis sequence or a dark spot dead pixel analysis sequence.
3. The method of correcting a dead pixel that suppresses fluctuation of a pixel according to claim 2, wherein: the step (13) includes determining whether the luminance value of the pixel to be detected needs to be corrected across a first slice according to whether the correction direction of the pixel to be detected has the first slice, and the specific steps include:
(31) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist below the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information;
when at least one first fault is arranged below the pixel position to be detected, the upper and lower limit positions of the first fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
correcting the brightness value of the pixel to be detected to the lower limit position of the nearest first fault downwards;
(32) when the sequence of the pixels to be detected is a dark point dead point analysis sequence:
judging the position relation between the pixel position to be detected and all the first faults;
when the first fault does not exist above the position of the pixel to be detected, no correction is carried out, and the pixel to be detected is output as non-dead pixel information;
when at least one first fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the first fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
the luminance value of the pixel to be detected is corrected upward to the upper limit position of the nearest one of the first faults.
4. A method of correcting a dead pixel that suppresses fluctuation in a picture element according to claim 3, wherein: and (15) selecting to correct the brightness value of the pixel to be detected to reach or cross the position of the nearest second fault according to whether the distance between the brightness value of the pixel to be detected and the nearest second fault is larger than a preset correction threshold value, wherein the correction threshold value is larger than a second segmentation threshold value and smaller than a first segmentation threshold value.
5. The method of correcting a dead pixel according to claim 4, wherein: the step (15) includes judging whether a correction process needs to be performed according to whether the correction direction of the pixel to be detected has a second fault, and specifically includes:
(51) when the sequence of the pixels to be detected is a bright spot dead pixel analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist below the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault is arranged below the pixel position to be detected, the upper and lower limit positions of the second fault which is closest to the pixel position to be detected below the pixel position to be detected are obtained;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the nearest second fault;
judging whether A2 is greater than a preset correction threshold value;
if so, correcting the brightness value of the pixel to be detected downwards to reach the position of the nearest second fault;
otherwise, correcting the brightness value of the pixel to be detected downwards to a position beyond the nearest second fault;
(52) when the sequence of the pixels to be detected is a dark point dead point analysis sequence:
judging the position relation between the pixel position to be detected and all second faults;
when the second fault does not exist above the position of the pixel to be detected, no correction is carried out, and pixel fluctuation information of the pixel to be detected is output;
when at least one second fault exists above the pixel position to be detected, acquiring the upper and lower limit positions of the second fault which is above the pixel position to be detected and is closest to the pixel position to be detected;
calculating the distance A1 from the pixel position to be detected to the upper limit of the nearest second fault and the distance A2 from the pixel position to be detected to the lower limit of the second fault;
judging whether A1 is greater than a preset correction threshold value;
if so, correcting the brightness value of the pixel to be detected upwards to reach the position of the nearest second fault;
otherwise, the pixel brightness value to be detected is corrected upward to a position beyond the nearest one of the second faults.
6. A dead pixel correction device capable of suppressing fluctuation of a pixel, characterized in that: the method comprises the following steps:
the neighborhood pixel classification module is used for classifying pixels of the neighborhood matrix into a bright spot dead pixel analysis sequence and a dark spot dead pixel analysis sequence according to pixel brightness values based on the same-channel m × m neighborhood matrix of the pixels to be detected;
the first correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a first fault or not, if so, the first correction execution module is started, and if not, the second correction execution module is started;
a first correction execution module for correcting the brightness value of the pixel to be detected to a position crossing a first fault;
the second correction condition judgment module is used for judging whether the brightness value distribution of the pixels in the dead pixel analysis sequence of the pixels to be detected has a second fault or not, if so, the second correction execution module is started, and if not, the correction process of the pixels to be detected is completed;
a second correction execution module for correcting the brightness value of the pixel to be detected to a position reaching or crossing a nearest one of the second faults;
the first/second fault is an interval larger than a preset first/second segmentation threshold, and the first segmentation threshold is larger than the second segmentation threshold;
the first correction execution module comprises a correction condition judgment unit, a correction condition judgment unit and a correction condition judgment unit, wherein the correction condition judgment unit is used for judging whether at least one first fault exists below a pixel to be detected when the pixel to be detected is in a bright-spot dead-spot analysis sequence, whether at least one first fault exists above the pixel to be detected when the pixel to be detected is in a dark-spot dead-spot analysis sequence, if yes, the pixel to be detected is a dead spot and needs to be corrected, and if not, the pixel to be detected is a non-dead spot;
the second correction execution module comprises a pixel fluctuation judging unit used for judging whether at least one second fault exists below the pixel to be detected when the pixel to be detected is in the bright spot dead pixel analysis sequence, and whether at least one second fault exists above the pixel to be detected when the pixel to be detected is in the dark spot dead pixel analysis sequence, if so, the pixel to be detected generates pixel fluctuation and needs to be corrected, otherwise, the pixel fluctuation does not occur.
7. The device of claim 6, wherein the bad pixel correction device is configured to suppress fluctuation of pixels, and comprises: the second correction execution module includes:
the second fault position distribution acquisition unit is used for judging the position relation between the pixel position to be detected and all second faults in the dead pixel analysis sequence where the pixel to be detected is located;
the correction candidate position acquisition unit is used for acquiring the upper and lower limit positions of a second fault which is above the position of the pixel to be detected and has the closest distance with the position of the pixel to be detected;
and the correction candidate position selection unit is used for judging whether the distance between the pixel position to be detected and the nearest second fault is greater than a preset correction threshold value or not, if so, the correction position is selected to reach the position of the nearest second fault, otherwise, the correction position is selected to cross the position of the nearest second fault, and the correction threshold value is greater than the second segmentation threshold value and smaller than the first segmentation threshold value.
8. The device of claim 6, wherein the bad pixel correction device is configured to suppress fluctuation of pixels, and comprises: the first correction execution module includes:
the first fault position distribution acquisition unit is used for judging the position relation between the position of the pixel to be detected and all first faults in the dead pixel analysis sequence where the pixel to be detected is located;
and the correction position acquisition unit is used for acquiring the upper and lower limit positions of the first fault which is above the position of the pixel to be detected and is closest to the position of the pixel to be detected, and correcting the brightness value of the pixel to be detected to the upper limit position crossing the closest first fault.
9. A storage medium having stored thereon computer instructions, characterized in that: the computer instructions when executed perform the steps of the method for correcting the dead pixel capable of suppressing the fluctuation of the pixel according to any one of claims 1 to 5.
10. A terminal comprising a memory and a processor, the memory having stored thereon computer instructions executable on the processor, the terminal comprising: the processor executes the computer instructions to execute the steps of the method for correcting the dead pixel, which can suppress the fluctuation of the pixel, according to any one of claims 1 to 5.
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