CN107016669B

CN107016669B - A kind of dead pixel points of images detection method and device

Info

Publication number: CN107016669B
Application number: CN201710188591.3A
Authority: CN
Inventors: 罗宁; 朱祖建; 武继瑞; 戴正展; 郑天翼
Original assignee: Fuzhou Rockchip Electronics Co Ltd
Current assignee: Rockchip Electronics Co Ltd
Priority date: 2017-03-27
Filing date: 2017-03-27
Publication date: 2019-08-23
Anticipated expiration: 2037-03-27
Also published as: CN107016669A

Abstract

The invention discloses a kind of dead pixel points of images detection method and devices, the method passes through the block of pixels for obtaining NxM size on image first, and a sequence of pixel values will be obtained after the arrangement of all pixels dot sequency in block of pixels, and calculate the median of sequence of pixel values, obtain pixel median；It then determines that a specified small pixel value and one specify big pixel value from sequence of pixel values, and calculates the first difference, and size relation is obtained according to current pixel point and pixel median, determine the type of pixel of current pixel point and calculate the second difference；And then by judging whether the second difference and the quotient of the first difference are greater than the first default error, to determine whether current pixel point is doubtful bad point.Bad point is searched by being then based on image bad point attribute, compared to existing dead pixel detection method, reduces hardware area.The pixel on image is checked one by one simultaneously, is conducive to find more doubtful bad points, improves the efficiency of bad point detection.

Description

A kind of dead pixel points of images detection method and device

Technical field

The present invention relates to computer technology security fields, in particular to a kind of dead pixel points of images detection method and device.

Background technique

With the progress of science and technology, the resolution ratio of existing camera sensing device is continuously increased.Pervious bad point detection Algorithm, primarily directed to the bad point detection of the sensor of medium and small resolution ratio, for the sensor of high resolution, many algorithms Bad point detection speed is slow, can not accomplish on-line checking.Meanwhile existing dead pixel detection method (such as based on the method for LUT) needs MEM, consumption chip area are occupied, with the continuous improvement of ISP input resolution ratio, area consumption rises at tens times.Meanwhile With the improvement of living standards, people have a higher requirement to picture quality, the eyes of user are to having protrusion on a picture Bright spot or dim spot be it is very sensitive, the bad point on image will directly influence the sensory experience of user.

Summary of the invention

For this reason, it may be necessary to a kind of technical solution of dead pixel points of images detection be provided, to solve existing bad point detection algorithm core Piece consumption area, bad point detection rate is low, is unable to satisfy the problems such as demand sensor of big resolution ratio.

To achieve the above object, a kind of dead pixel points of images detection method is inventor provided, the described method comprises the following steps:

Using current pixel point as center pixel, the block of pixels of NxM size on image is obtained；

The pixel value of all pixels point in the block of pixels of NxM size is obtained, and will be acquired according to the size of pixel value All pixels point carry out sequence arrangement, obtain a sequence of pixel values, the corresponding arrangement number of pixel after each arrangement；

The median for calculating sequence of pixel values, obtains pixel median；

According to preset boundary threshold value, determines a specified small pixel value from sequence of pixel values and one is specified big pixel Value, the specified small pixel value are that arrangement number is that number specifies the corresponding pixel value of the pixel of small value, and the number is specified Small value is the absolute value of the difference of the arrangement number and preset boundary threshold value of the smallest pixel of pixel value；It is described to specify big pixel value It is the specified corresponding pixel value of pixel being worth greatly of number for arrangement number, the specified big value of number is the maximum picture of pixel value The absolute value of the difference of the arrangement number and preset boundary threshold value of vegetarian refreshments；

The difference of big pixel value and specified small pixel value is specified in calculating, determines the first difference；

According to the size relation of current pixel point and pixel median, the type of pixel of current pixel point is determined, and according to working as The type of pixel of preceding pixel point determines the second difference；

First judgement is carried out to the first difference and the second difference, and records the first judging result, first judgement includes: Judge whether the second difference and the quotient of the first difference are greater than the first default error, if then determining that current pixel point is doubtful bad Otherwise point determines that current pixel point is non-doubtful bad point.

Further, the method also includes steps:

Second judgement is carried out to all pixels point in sequence of pixel values, and records the second judging result, second judgement It include: to determine in sequence of pixel values, arrangement number is located between the specified big value of number and number maximum value or is located at number most It is doubtful bad point that small value and number, which specify the pixel between small value, and determines that arrangement number is located at the pixel within the scope of other Point is non-doubtful bad point；The number maximum value is the corresponding arrangement number of the maximum pixel of pixel value, and the number is minimum Value is the corresponding arrangement number of the smallest pixel of pixel value.

Further, the method also includes steps:

To the first judging result, the second judging result carry out the first logical operation, if the first logic operation result if true, Determine that current pixel point is bad point, if the first logic operation result is if false, determine that current pixel is not bad point.

Further, the method also includes steps:

Calculate second order of all pixels point on different preset directions in presetted pixel block centered on current pixel point Gradient mean value, the corresponding second order gradient mean value of each preset direction；

All second order gradient mean values being calculated are minimized, minimum second order gradient mean value is obtained and are recorded；

The corresponding texture value of pixel in presetted pixel block is calculated, texture value is obtained；

Third judgement is carried out to minimum second order gradient mean value and texture value, and records third judging result, the third is sentenced Disconnected includes: to judge whether the difference of minimum second order gradient mean value and texture value is greater than the second default error, if then determining current picture Vegetarian refreshments is doubtful bad point, otherwise determines that current pixel point is non-doubtful bad point.

Further, the method also includes steps:

Second logical operation is carried out to the first judging result and third judging result, if the second logic operation result if true, Determine that current pixel point is bad point, if the second logic operation result is if false, determine that current pixel is not bad point.

Further, the method also includes steps:

Third logical operation is carried out to the first judging result, the second judging result and third judging result, if third logic Operation result is if true, determine that current pixel point is bad point, if third logic operation result is if false, determine that current pixel is not bad Point.

Further, it is further comprised the steps of: after step " determining that current pixel point is bad point "

Its original pixel value is replaced using pixel median to the pixel for being determined as bad point.

According to the type of pixel of current pixel point, the pixel for being determined as bad point is used and specifies small pixel value or specified big Pixel value replaces its original pixel value.

Further, the type of pixel includes max type and min type, in step " according to the pixel class of current pixel point Type uses the pixel for being determined as bad point and specifies small pixel value or big pixel value is specified to replace its original pixel value " it is specific Include:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, to judgement Big pixel value is specified to replace its original pixel value for the pixel use of bad point；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, to judgement Its original pixel value is replaced using specified small pixel value for the pixel of bad point.

Further, step " difference of big pixel value and specified small pixel value is specified in calculating, determines the first difference " packet It includes:

The difference of big pixel value and specified small pixel value is specified in calculating, obtains the first intermediate difference；

Judge whether the first intermediate difference is greater than default first difference, if then determining that the first intermediate difference is first poor Otherwise value determines that default first difference is the first difference.

Further, the type of pixel includes max type and min type, and step is " according to current pixel point and pixel median Size relation determines the type of pixel of current pixel point, and determines the second difference according to the type of pixel of current pixel point " packet It includes:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, described the Two differences are the pixel value of current pixel point and the difference of specified small pixel value；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, described the Two differences are to specify the difference of the pixel value of big pixel value and current pixel point.

Further, the step " using current pixel point as center pixel, obtains the pixel region of NxM size on image Block " includes:

Using current pixel point as center pixel, TxS sub-block is obtained from image, then obtain NxM from the TxS sub-block Block of pixels.

Further, the TxS sub-block is 5x5 sub-block, then the block of pixels of the NxM size is 3x3 sub-block.

Further, described image is bayer format-pattern, and the pixel access of pixel includes the channel Gr, the channel Gb, B Channel and the channel R, then the corresponding pixel value of each pixel is Gr channel components value, Gb channel components value, R channel components value, B One of channel components value.

Further, which comprises

Using next pixel of current pixel point as center pixel, and judge whether next pixel is doubtful bad point, And record judging result；It repeats the above steps, until all pixels point traverses completion in the block of pixels of NxM size.

Inventor additionally provides a kind of dead pixel points of images detection device, and described device includes acquiring unit, sequencing unit, specifies Pixel value determining unit, computing unit, judging unit；The acquiring unit includes that block of pixels acquiring unit and pixel obtain list Member；The computing unit includes difference computational unit and pixel median computing unit, and the difference computational unit includes first poor It is worth computing unit and the second difference computational unit；The judging unit includes the first judging unit；

The block of pixels acquiring unit is used to obtain NxM size on image using current pixel point as center pixel Block of pixels；

The pixel acquisition unit is used to obtain the pixel value of all pixels point in the block of pixels of NxM size, the row Sequence unit is used for the size according to pixel value for acquired all pixels point carry out sequence arrangement, obtains a sequence of pixel values, The corresponding arrangement number of pixel after each arrangement；

The pixel median computing unit is used to calculate the median of sequence of pixel values, obtains pixel median；

The specified pixel determination unit is used for according to preset boundary threshold value, and determination one is specified small from sequence of pixel values Pixel value and one specify big pixel value, and the specified small pixel value is that arrangement number is that number specifies the pixel of small value corresponding Pixel value, it is exhausted with the difference of preset boundary threshold value that the number specifies small value to be that the arrangement of the smallest pixel of pixel value is numbered To value；Described to specify big pixel value be arrangement number is the specified corresponding pixel value of pixel being worth greatly of number, and the number refers to Fixed big value is the absolute value of the difference of the arrangement number and preset boundary threshold value of the maximum pixel of pixel value；

First difference computational unit determines that first is poor for calculating the difference for specifying big pixel value and specified small pixel value Value；

Second difference computational unit is used for the size relation according to current pixel point and pixel median, determines current picture The type of pixel of vegetarian refreshments, and the second difference is determined according to the type of pixel of current pixel point；

First judging unit is used to carry out the first judgement to the first difference and the second difference, and records the first judgement knot Fruit, first judgement includes: to judge whether the second difference and the quotient of the first difference are greater than the first default error, if then determining Current pixel point is doubtful bad point, otherwise determines that current pixel point is non-doubtful bad point.

Further, the judging unit further includes second judgment unit；

The second judgment unit is used to carry out all pixels point in sequence of pixel values the second judgement, and records second and sentence Break as a result, second judgement includes: to determine in sequence of pixel values, arrangement number is positioned at the specified big value of number and number maximum value Between or to specify pixel between small value positioned at number minimum value and number be doubtful bad point, and determine arrangement number position In the pixel within the scope of other be non-doubtful bad point；The number maximum value is the corresponding arrangement of the maximum pixel of pixel value Number, the number minimum value are the corresponding arrangement number of the smallest pixel of pixel value.

Further, described device further includes logical unit；

The logical unit is used to carry out the first logical operation to the first judging result, the second judging result, if the One logic operation result is if true, determine that current pixel point is bad point, if the first logic operation result is if false, determine current pixel It is not bad point.

Further, the computing unit includes second order gradient mean value computing unit, minimum second order gradient mean value calculating list Member, texture value computing unit, the judging unit includes third judging unit；

The second order gradient mean value computing unit owns in presetted pixel block for calculating centered on current pixel point Second order gradient mean value of the pixel on different preset directions, the corresponding second order gradient mean value of each preset direction；

The minimum second order gradient mean value computing unit is used to be minimized all second order gradient mean values being calculated, It obtains minimum second order gradient mean value and records；

The texture value computing unit obtains texture for calculating the corresponding texture value of pixel in presetted pixel block Value；

The third judging unit is used to carry out third judgement to minimum second order gradient mean value and texture value, and records third Judging result, the third judgement include: to judge whether the difference of minimum second order gradient mean value and texture value is default greater than second to miss Otherwise difference determines that current pixel point is non-doubtful bad point if then determining that current pixel point is doubtful bad point.

Further, described device further includes logical unit；

The logical unit is used to carry out the second logical operation to the first judging result and third judging result, if the Two logic operation results are if true, determine that current pixel point is bad point, if the second logic operation result is if false, determine current pixel It is not bad point.

Further, described device further includes logical unit；

The logical unit is used to carry out third to the first judging result, the second judging result and third judging result Logical operation, if third logic operation result is if true, determine that current pixel point is bad point, if third logic operation result is false Then determine that current pixel is not bad point.

Further, described device further includes bad point replacement unit, and the bad point replacement unit is used for being determined as bad point Pixel its original pixel value is replaced using pixel median.

Further, described device further includes bad point replacement unit, and the bad point replacement unit is used for according to current pixel The type of pixel of point uses the pixel for being determined as bad point and specifies small pixel value or big pixel value is specified to replace its original picture Element value.

Further, the type of pixel includes max type and min type, and " bad point replacement unit is used for according to current pixel point Type of pixel, to being determined as the pixel of bad point using specified small pixel value or big pixel value specified to replace its original pixel Value " specifically includes:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, and bad point is replaced Unit is changed for being determined as the pixel of bad point using specifying big pixel value to replace its original pixel value；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, and bad point is replaced Unit is changed for being determined as that the pixel of bad point replaces its original pixel value using specified small pixel value.

Further, described " the first difference computational unit is used to calculate the difference for specifying big pixel value and specified small pixel value, Determine the first difference " include:

For first difference computational unit for calculating the difference for specifying big pixel value and specified small pixel value, it is poor among first to obtain Value, and judge whether the first intermediate difference is greater than default first difference, it is no if then determining that the first intermediate difference is the first difference Then determine that default first difference is the first difference.

Further, the type of pixel includes max type and min type, and " the second difference computational unit is used for according to current picture The size relation of vegetarian refreshments and pixel median determines the type of pixel of current pixel point, and according to the type of pixel of current pixel point Determine the second difference " include:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, and second is poor Value computing unit is used to calculate the pixel value of current pixel point and the difference of specified small pixel value, obtains the second difference；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, and second is poor Value computing unit is used to calculate the difference for the pixel value for specifying big pixel value and current pixel point, obtains the second difference.

It is further, described that " block of pixels acquiring unit is for obtaining using current pixel point as center pixel, image The block of pixels of NxM size " includes:

Block of pixels acquiring unit is used to obtain using current pixel point as the sub-block of TxS size on center pixel, image, NxM block of pixels is obtained from the TxS sub-block again.

Further, described device further includes Traversal Unit；

The Traversal Unit is used for using next pixel of current pixel point as center pixel, and judges next pixel Whether it is doubtful bad point, and records judging result；It repeats the above steps, until all pixels point in the block of pixels of NxM size Traversal is completed.

The invention has the following advantages that based on the bad point attribute on image, (pixel value of bad point is typically much deeper than or remote small In the average pixel value of other pixels in the same block of pixels) search bad point, greatly reduce bad point detection device Hardware area.The pixel on image is checked one by one simultaneously, is conducive to find more doubtful bad points, and then in doubtful bad point In checked, effectively improve the efficiency of bad point detection.

Detailed description of the invention

Fig. 1 is the schematic diagram for the Bayer format image that an embodiment of the present invention is related to；

Fig. 2 is the schematic diagram of the corresponding relationship of the preset limit value that an embodiment of the present invention is related to and specified pixel point；

Fig. 3 is the schematic diagram for the minimum second order gradient mean value of calculating that an embodiment of the present invention is related to；

Fig. 4-A is comparison diagram before and after the bad point detection that an embodiment of the present invention is related to and replaced image；

Fig. 4-B is comparison diagram before and after the bad point detection that another embodiment of the present invention is related to and replaced image；

Fig. 4-C is comparison diagram before and after the bad point detection that another embodiment of the present invention is related to and replaced image；

Fig. 5 is the flow chart for the dead pixel points of images detection method that an embodiment of the present invention is related to；

Fig. 6 is the flow chart for the dead pixel points of images detection method that another embodiment of the present invention is related to；

Fig. 7 is the flow chart for the dead pixel points of images detection method that another embodiment of the present invention is related to；

Fig. 8 is the schematic diagram for the first logical operation process that an embodiment of the present invention is related to；

Fig. 9 is the schematic diagram for the second logical operation process that an embodiment of the present invention is related to；

Figure 10 is the schematic diagram for the third logical operation process that an embodiment of the present invention is related to；

Figure 11 is the schematic diagram for the dead pixel points of images detection device that an embodiment of the present invention is related to；

Description of symbols:

101, acquiring unit；111, block of pixels acquiring unit；121, pixel acquisition unit

102, judging unit；112, the first judging unit；122, second judgment unit；132, third judging unit；

103, computing unit；

113, pixel median computing unit；

123, second order gradient mean value computing unit；

133, minimum second order gradient mean value computing unit；

143, texture value computing unit；

153, difference computational unit；151, the first difference computational unit；152, the second difference computational unit；

104, recording unit；

105, logical unit；

106, sequencing unit；

107, bad point replacement unit；

108, specified pixel determination unit；

109, Traversal Unit.

Specific embodiment

Technology contents, construction feature, the objects and the effects for detailed description technical solution, below in conjunction with specific reality It applies example and attached drawing is cooperated to be explained in detail.

Referring to Fig. 1, the schematic diagram for the Bayer format image being related to for an embodiment of the present invention.In the present invention to The image of detection is bayer format-pattern, and the pixel access of pixel includes the channel Gr, the channel Gb, channel B and the channel R, then often The corresponding pixel value of a pixel is Gr channel components value, Gb channel components value, R channel components value, one in channel B component value Kind.From figure 1 it appears that Bayer format image is arranged according to certain rule, specifically using 2x2 window as base Plinth replicates repeated arrangement, includes 4 pixels in every 2x2 window, the channel components value of 4 pixels is in 2x2 window Arrangement mode can be different, but Gr channel components value and Gb channel components value necessarily are in relative position (i.e. in 2x2 window Diagonally opposing corner position).

Referring to Fig. 5, the described method comprises the following steps:

Step S501 is initially entered using current pixel point as center pixel, obtains the block of pixels of NxM size on image. In the present embodiment, step S501 includes: the acquisition TxS sub-block from image using current pixel point as center pixel, then from NxM block of pixels is obtained in the TxS sub-block.Further, the TxS sub-block is 5x5 sub-block, then the picture of the NxM size Plain block is 3x3 sub-block.In the domain RAW, the sub-block of 5x5 size first can be first obtained from whole image, from 5x5 sub-block 3x3 is extracted with the window in channel.In other embodiments, TxS and NxM can also be the sub-block of other numerical values reciteds, such as TxS For the sub-block of 9x9 size, then NxM can be the 5x5 sub-block extracted in the 9x9 size sub-block；TxS is 5x9 size for another example Sub-block, then NxM can be the 3x5 sub-block extracted in the 5x9 sub-block and the sub-block that TxS is 9x5 size, then NxM can be to be somebody's turn to do 5x3 sub-block extracted in 9x5 sub-block etc..If current pixel point is located at the marginal position of image, available current pixel Point the right and following pixel sub-block, such as sub-block only account for the 1/4 of the block of pixels of default size, can will be acquired The pixel of sub-block is symmetric to the left side and top, to constitute complete NxM block of pixels, current pixel point is still entire The central pixel point of block of pixels.In short, the selection of block of pixels size can determine according to actual needs.For the ease of Illustrate, the present invention is described further the method in Fig. 5 so that NxM is 3x3 as an example.

The pixel value that S502 obtains all pixels point in the block of pixels of NxM size is then entered step, and according to pixel Acquired all pixels point carry out sequence arrangement is obtained a sequence of pixel values, the pixel after each arrangement by the size of value Corresponding arrangement number.

The median that S503 calculates sequence of pixel values is then entered step, pixel median is obtained；

S504 is then entered step according to preset boundary threshold value, determined from sequence of pixel values a specified small pixel value and One is specified big pixel value, and the specified small pixel value is that arrangement number is that number specifies the corresponding pixel of the pixel of small value Value, the number specify the absolute value of the difference for the arrangement number and preset boundary threshold value that small value is the smallest pixel of pixel value； Described to specify big pixel value be arrangement number is the specified corresponding pixel value of pixel being worth greatly of number, the specified big value of number For the absolute value of the difference of the arrangement number and preset boundary threshold value of the maximum pixel of pixel value.

As shown in Fig. 2, by the block of pixels of NxM size be 3x3 sub-block for, in figure serial number 0-8 indicate according to from it is small to The corresponding arrangement number of pixel after longer spread, when preset limit value is 0, specified small pixel value is the pixel that number is 0 Corresponding pixel value is put, i.e., the minimum value in entire sequence of pixel values, specifying big pixel value is that the pixel that number is 8 is corresponding Pixel value, i.e., the maximum value in entire sequence of pixel values；When preset limit value is 1, specified small pixel value is the picture that number is 1 The corresponding pixel value of vegetarian refreshments, i.e., the second small pixel value in entire sequence of pixel values, specifying big pixel value is the picture that number is 7 The corresponding pixel value of vegetarian refreshments, i.e., second largest pixel value in entire sequence of pixel values；When preset limit value is 2, specify small Pixel value is the corresponding pixel value of pixel that number is 2, i.e., the small pixel value of the third in entire sequence of pixel values is specified big Pixel value is the corresponding pixel value of pixel that number is 6, i.e., the third-largest pixel value in entire sequence of pixel values；With such It pushes away.

It then enters step S505 and calculates the difference for specifying big pixel value and specified small pixel value, determine the first difference.At this In embodiment, step S505 includes: the difference that big pixel value and specified small pixel value are specified in calculating, obtains the first intermediate difference； Judge whether the first intermediate difference is greater than default first difference, if then determining that the first intermediate difference is the first difference, otherwise really Surely default first difference is the first difference.

S506 is then entered step according to the size relation of current pixel point and pixel median, determines the picture of current pixel point Plain type, and the second difference is determined according to the type of pixel of current pixel point.In the present embodiment, the type of pixel includes Max type and min type, when step S506 includes: that the value of current pixel point is greater than pixel median, it is determined that the pixel of current pixel point Type is max type, and second difference is the pixel value of current pixel point and the difference of specified small pixel value；The value of current pixel point When less than pixel median, it is determined that the type of pixel of current pixel point be min type, second difference be specify big pixel value with The difference of the pixel value of current pixel point.

The 3x3 of (bad point is not present) normal for a pixel is preset for block, most of pixel in block There is associations, and the pixel between them will not differ too big.When block range is smaller, block can be indicated with cluster Interior all pixels point, specified small pixel value and the upper and lower bound for specifying big pixel value to identify the cluster respectively.First difference Indicate that the height of this cluster, the second difference indicate the departure degree of current pixel point (central pixel point).If current pixel Point is bad point, then the second difference will be much larger than the first difference, thus can be compared by the way that preset value is arranged, to judge to work as Whether preceding pixel point is doubtful bad point.

Thus the first judgement can be carried out to the first difference and the second difference after step S506, and record the first judgement knot Fruit.First judgement includes: that step S507 judges whether the second difference and the quotient of the first difference are greater than the first default error, if It is to enter step S508 to determine that current pixel point is doubtful bad point, otherwise enters step S509 and determine that current pixel point is non-doubts Like bad point.

The selection of first default error can be adjusted according to actual needs, such as can be according to current pixel point pixel The difference in channel configures the first different preset error values, specifically: the pixel access of current pixel point is the channel R or channel B When, the first preset error value chooses the upper pixel access than current pixel point when being the channel G (including the channel Gr and the channel Gb) Must be small, because human eye is not so good as the channel G to the sensitivity in the channel R or channel B.It is different by being arranged for different pixels channel First preset error value can effectively improve the accuracy rate of bad point detection.If the quotient of the second difference and the first difference is much larger than the One preset difference value illustrates that the pixel value of current pixel point is greater or comes small more than the pixel value of other pixels in block, It thus can be determined that current pixel point is doubtful bad point.

As shown in fig. 6, the method also includes steps: the second judgement is carried out to all pixels point in sequence of pixel values, and Record the second judging result.Second judgement includes: that step S601 determines in sequence of pixel values, and the arrangement number of pixel is It is no to be located between the specified big value of number and number maximum value or specified between small value positioned at number minimum value and number, if then It enters step S602 and determines that the pixel is doubtful bad point, otherwise enter step S603 and determine that the pixel is non-doubtful bad point. The number maximum value is the corresponding arrangement number of the maximum pixel of pixel value, and the number minimum value is that pixel value is the smallest The corresponding arrangement number of pixel.

For a bad point may be only existed in a block of pixels, it is also possible to which there is multiple bad points, thus need It to be checked by method shown in fig. 6.Specific practice be exactly all pixels point in block is arranged in sequence (from greatly to Small or arrangement from small to large) after, default determines that the pixel for being located at both ends point is doubtful bad point.With NxM pixel region in Fig. 2 Block is for 3x3 sub-block, serial number 0-8 indicates to number in figure from small to large according to the corresponding arrangement of pixel after arranging.When pre- If boundary value is 1, specified small pixel value is to number the corresponding pixel value of pixel for being 1, i.e., in entire sequence of pixel values Second small pixel value, specifying big pixel value is to number the corresponding pixel value of pixel for being 7, i.e., in entire sequence of pixel values Second largest pixel.It is doubtful bad point by the pixel for determining that arrangement number is 0,1,7,8 according to the 4th deterministic process.Similarly, It is doubtful bad point by the pixel for determining that arrangement number is 0,1,2,6,7,8 when preset limit value is 2.Preset limit value is The case where other numerical value, and so on.

As shown in figure 8, the method also includes steps: carrying out the first logic to the first judging result, the second judging result Operation, if the first logic operation result is if true, determine that current pixel point is bad point, if the first logic operation result is if false, sentence Settled preceding pixel is not bad point.First logical operation can be AND operation, i.e. the first judging result and the second judging result are equal When judging current pixel point for doubtful bad point, just assert that current pixel point is bad point, otherwise assert that current pixel point is not bad point.

In certain embodiments, it for the same pixel, can repeatedly be calculated using the method for Fig. 5 and Fig. 6, and The each judging result Jing Guo both methods of record, it is equal for the first judging result and the second judging result that record each time The first logical operation is carried out, final first logical consequence is then counted.When the first logical operation determines that current pixel point is bad point Number account for the first logical operation total degree ratio be greater than preset ratio when, just assert current pixel point be bad point.Preferably, In calculating process each time, adjustable correlation parameter preset, such as the value of preset boundary threshold value, the first default error, lead to Repeated multiple times calculating is crossed, can effectively improve the precision of bad point detection.

As shown in fig. 7, in certain embodiments, the method also includes steps:

It initially enters step S701 to calculate centered on current pixel point, all pixels point is in difference in presetted pixel block Second order gradient mean value on preset direction, the corresponding second order gradient mean value of each preset direction.For ease of description, below It is to be described further centered on current pixel point, for the sub-block of 3x3 size to step S701 by presetted pixel block. In further embodiments, the size of presetted pixel block can also be of different sizes with NxM block of pixels, with specific reference to practical need It is chosen.

As shown in figure 3,3x3 sub-block is divided into 4 preset directions (including horizontal direction, vertical direction, 135 degree of directions With 45 degree of directions).By taking horizontal direction as an example, it includes this three groups of pixels, pixel C1, C2, C3 are one group, pixel C4, C5, C6 are one group, and pixel C7, C8, C9 are one group, and each group of pixel all corresponds to a second order gradient value.Second order gradient is Field of image processing one kind is most effective to look for side method, and by taking this group of pixel C1, C2, C3 as an example, second order gradient value can pass through Following formula is calculated: A1=2*C2-C1-C3, wherein A1 be second order gradient value, C1, C2, C3 be respectively pixel C1, The corresponding pixel value of C2, C3, pixel C1, C2, C3 are located on the same line, and pixel C2 is located at pixel C1 and pixel Between C3.Similarly, corresponding second order gradient can also be calculated for pixel C4, C5, C6 and pixel C7, C8, C9 Value A2 and A3, then A1, A2, A3 are averaged, second order gradient mean value in the horizontal direction can be obtained.In vertical direction similarly It can obtain, the same available one second order gradient mean value in vertical direction.

For 135 degree of directions, when calculating the second order gradient mean value of the direction, due to the straight line on 135 degree of directions C4, C8 are only covered, for ease of calculation, thus pixel C7 is collectively incorporated into the grouping of C4, C8.I.e. by pixel C1, C5, C9 points are one group, and pixel C4, C7, C8 points are one group, and pixel C2, C3, C6 points are one group.With pixel C4, C7, C8 For, second order gradient value can be calculated by the following formula and obtain: A4=2*C7-C4-C8.Other two groups can also equally be calculated Corresponding second order gradient value A5 and A6, then A4, A5, A6 are averaged, the second order gradient that can be obtained in 135 degree of directions is equal Value.It can similarly be obtained on 45 degree, the same available one second order gradient mean value in 45 degree of directions.

In certain embodiments, presetted pixel block can also be other sizes, such as 5x5 sub-block, 3x5 sub-block, 7x7 sub-block Deng.For 5x5 sub-block, for calculating the second order gradient mean value in horizontal direction, the second order gradient in horizontal direction is equal Value is the average value of second order gradient value in 5 horizontal directions, it is assumed that the from left to right pixel in some horizontal direction is successively For C1, C2, C3, C4, C5, then the second order gradient value in the horizontal direction can obtain in the following manner: first calculate C1, C2 The average value of pixel value, obtains C1 '；The average value for then calculating C4, C5 pixel value, obtains C2 '；Pass through formula 2C3-C1 '-again C2 ' obtains the second order gradient value of the horizontal direction.The second order gradient value of remaining 4 horizontal direction asks method that can similarly obtain, and takes 5 The average value of second order gradient value is the second order gradient mean value in the corresponding horizontal direction of 5x5 sub-block pixel.Remaining direction two Rank gradient mean value ask method can the second order gradient mean value with the horizontal second order gradient mean value of 5x5 and 3x3 in remaining direction seek method, Details are not described herein again.

For 7x7 sub-block, equally for calculating the second order gradient mean value in horizontal direction, in horizontal direction two Rank gradient mean value is the average value of second order gradient value in 7 horizontal directions, it is assumed that in some horizontal direction from left to right as Vegetarian refreshments is followed successively by C1, C2, C3, C4, C5, C6, C7, then the second order gradient value in the horizontal direction can obtain in the following manner It arrives: first calculating the average value of C1, C2, C3 pixel value, obtain C3 '；The average value for calculating C3, C4, C5 pixel value again, obtains C4 '； The average value for then calculating C5, C6, C7 pixel value, obtains C5 '；The horizontal direction is obtained by formula 2C4 '-C3 '-C5 ' again Second order gradient value.The second order gradient value of remaining 4 horizontal direction asks method that can similarly obtain, and takes the average value of 7 second order gradient values Second order gradient mean value as in the corresponding horizontal direction of 7x7 sub-block pixel.Remaining direction second order gradient mean value asks method can Second order gradient mean value with the horizontal second order gradient mean value of 7x7 and 3x3 in remaining direction seeks method, and details are not described herein again.

S702 can then be entered step to be minimized all second order gradient mean values being calculated, obtain minimum second order Gradient mean value simultaneously records.Equally by taking presetted pixel block is 3x3 sub-block as an example, minimum second order gradient mean value is on 4 directions The minimum value in 4 second order gradient mean values being calculated.Minimum second order gradient mean value is " side ", if current pixel point is Bad point, then minimum second order gradient mean value is often larger, thus can be by being determined in advance a preset threshold, then by minimum second order Gradient mean value is compared with preset threshold, and then judges whether current pixel point is bad point.

S703 can then be entered step and calculate the corresponding texture value of pixel in presetted pixel block, obtain texture value. The texture value of block of pixels reflects the abundant degree for the high-frequency information having in the block of pixels, and texture value is abundanter, Corresponding gradient value is also bigger.As the texture value of the 3x3 sub-block of Fig. 3 can be calculated in the following manner: texture= (|△31|+|△64|+|△97|+|△71|+|△82|+|△93|+|△91|)/7.Wherein, texture indicates texture value, △ 31=C3-C1 (C3, C1 are respectively the corresponding pixel value of pixel C3, C1).It calculates separately in 3x3 sub-block, in addition to center Except pixel, the gradient mean value between non-conterminous pixel two-by-two in rest of pixels point.For the sub-block of other sizes, together Li Ke get, details are not described herein again.

Third judgement then is carried out to minimum second order gradient mean value and texture value, and records third judging result.Described Three judgements include: step S704 judge the difference of minimum second order gradient mean value and texture value whether greater than the second default error, if It then enters step S705 and determines that current pixel point is doubtful bad point, otherwise enter step S706 and determine that current pixel point is non-doubtful Bad point.The choosing value of second default error can be customized according to actual needs, in the present embodiment, the second default error It is determined according to the channel type of current pixel point, the choosing value of the default error of reason such as first.

As shown in figure 9, the method also includes steps: carrying out the second logic to the first judging result and third judging result Operation, if the second logic operation result is if true, determine that current pixel point is bad point, if the second logic operation result is if false, sentence Settled preceding pixel is not bad point.Second logical operation can be AND operation, i.e. the first judging result and third judging result are equal When judging current pixel point for doubtful bad point, just assert that current pixel point is bad point, otherwise assert that current pixel point is not bad point.

As shown in Figure 10, the method also includes steps: judging to tie to the first judging result, the second judging result and third Fruit carries out third logical operation, if third logic operation result is if true, determine that current pixel point is bad point, if third logic is transported Result is calculated if false, determining that current pixel is not bad point.Third logical operation can be AND operation, i.e. the first judging result, the When two judging results, third judging result judge current pixel point for doubtful bad point, just assert that current pixel point is bad point, it is no Then assert that current pixel point is not bad point.The protection for being conducive to image border high-frequency information in this way reaches better protecting effect, Improve the accuracy rate of bad point detection.Certainly, in other embodiments, third logical operation can also be other operations, such as three It is a judge in there are two judging result determine current pixel point be doubtful bad point when, third logic operation result be very, otherwise for It is false.

When any one of the first logical operation, the second logical operation, third logical operation result judgement current pixel point When for bad point, so that it may be replaced to current pixel point.In certain embodiments, being replaced to bad point can be by following Mode is realized: to be determined as bad point pixel use, pixel median replace its original pixel value.Pixel median, that is, NxM is big Median after all pixels point arranges in sequence in small block of pixels is replaced bad point using the value, can effectively be reduced Difference in current pixel point and block between other pixels achievees the purpose that repair bad point, keeps image detail.

In certain embodiments, being replaced to bad point can be realized by also following manner: according to current pixel point Type of pixel uses the pixel for being determined as bad point and specifies small pixel value or big pixel value is specified to replace its original pixel Value.It specifically includes: when the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, right Being determined as that the pixel of bad point uses specifies big pixel value to replace its original pixel value；The value of current pixel point is less than in pixel When value, it is determined that the type of pixel of current pixel point is min type, is replaced to the pixel for being determined as bad point using specified small pixel value Change its original pixel value.For bad point, itself can may also carry some image informations, if using pixel median It is replaced completely, is unfavorable for retaining these image informations, and use this scheme bad compared to being replaced using pixel median The scheme of point, can be better maintained image detail.

So far, just complete a pixel (current pixel point) whether be bad point detection, for piece image, Which contain many pixels to need to start the detection of next pixel, thus the side after current pixel point detection Method include: and judge whether next pixel is doubtful bad point using next pixel of current pixel point as center pixel, and Record judging result；It repeats the above steps, until all pixels point traverses completion in the block of pixels of NxM size.In reality In application process, judgement for each pixel can judge current picture according to any one method of Fig. 8 into Figure 10 Vegetarian refreshments is bad point, and the combination of these types of method can also be selected to carry out comprehensive judgement, can also execute repeatedly it is multiple this The combination of several method judges.In short, dead pixel detection method selection is upper there are many selection, testing staff can be according to reality It needs to select.For detection effect as shown in Fig. 5-A, Fig. 5-B, Fig. 5-C, the left side in every width figure indicates original image, middle table Show the bad point detected, the right indicates the image repaired by bad point replacement, it can be clearly seen that the image on the right is than left side figure As whole more smooth, the sensory experience of user is more preferable.

Figure 11 is please referred to, for the schematic diagram for the dead pixel points of images detection device that an embodiment of the present invention is related to.Described image For bayer format-pattern, the pixel access of pixel includes the channel Gr, the channel Gb, channel B and the channel R, then each pixel pair The pixel value answered is that pixel value is Gr channel components value, Gb channel components value, R channel components value, one in channel B component value Kind.Described device includes acquiring unit 101, sequencing unit 106, specified pixel determination unit 108, computing unit 103, judgement list First 102, recording unit 104；The acquiring unit 101 includes block of pixels acquiring unit 111 and pixel acquisition unit 121；Institute Stating computing unit 103 includes difference computational unit 153 and pixel median computing unit 113, and the difference computational unit 153 includes First difference computational unit 151 and the second difference computational unit 152；The judging unit 102 includes the first judging unit 112；

The block of pixels acquiring unit 111 is used to obtain NxM size on image using current pixel point as center pixel Block of pixels；

The pixel acquisition unit 121 is used to obtain the pixel value of all pixels point in the block of pixels of NxM size, described Sequencing unit is used for the size according to pixel value for acquired all pixels point carry out sequence arrangement, obtains a pixel value sequence Column, the corresponding arrangement number of pixel after each arrangement；

The pixel median computing unit 113 is used to calculate the median of sequence of pixel values, obtains pixel median；

The specified pixel determination unit 108 is used for according to preset boundary threshold value, and a finger is determined from sequence of pixel values Determine small pixel value and one is specified big pixel value, the specified small pixel value is that arrangement number is the pixel that number specifies small value Corresponding pixel value, the number specify the difference for the arrangement number and preset boundary threshold value that small value is the smallest pixel of pixel value Absolute value；It is described that specify big pixel value be arrangement number is the specified corresponding pixel value of pixel being worth greatly of number, the volume Number specified big value is the absolute value of the difference of the arrangement number and preset boundary threshold value of the maximum pixel of pixel value；

First difference computational unit 151 determines for calculating the difference for specifying big pixel value and specified small pixel value One difference；

Second difference computational unit 152 is used for the size relation according to current pixel point and pixel median, and determination is worked as The type of pixel of preceding pixel point, and the second difference is determined according to the type of pixel of current pixel point；

First judging unit 112 is used to carry out the first judgement, the recording unit to the first difference and the second difference 104 for recording the first judging result, and first judgement includes: judge whether the quotient of the second difference and the first difference is greater than the Otherwise one default error determines that current pixel point is non-doubtful bad point if then determining that current pixel point is doubtful bad point.

When using dead pixel points of images detection device, the picture centered on current pixel point of block of pixels acquiring unit 111 first Vegetarian refreshments obtains the block of pixels of NxM size on image.In the present embodiment, block of pixels acquiring unit 111 is with current pixel Point is center pixel, and TxS sub-block is obtained from image, then NxM block of pixels is obtained from the TxS sub-block.Further, The TxS sub-block is 5x5 sub-block, then the block of pixels of the NxM size is 3x3 sub-block.It, can be first from whole in the domain RAW The sub-block that 5x5 size is first obtained in image is extracting 3x3 with the window in channel from 5x5 sub-block.In other embodiments, TxS It can also be the sub-block of other numerical values reciteds with NxM, such as TxS is the sub-block of 9x9 size, then NxM can be the big boy of the 9x9 The 5x5 sub-block extracted in block；TxS is the sub-block of 5x9 size for another example, then NxM can be 3x5 extracted in the 5x9 sub-block Block and TxS are the sub-block of 9x5 size, then NxM can be the 5x3 sub-block etc. extracted in the 9x5 sub-block.In short, pixel The selection of block size can determine that for ease of description, the present invention makees so that NxM is 3x3 as an example into one according to actual needs Walk explanation.

Pixel acquisition unit 121 obtains the pixel value of all pixels point in the block of pixels of NxM size, the sequencing unit For the size according to pixel value by acquired all pixels point carry out sequence arrangement, a sequence of pixel values, Mei Yipai are obtained The corresponding arrangement number of pixel after column.

Pixel median computing unit 113 calculates the median of sequence of pixel values, obtains pixel median.

Specified pixel determination unit 108 determines a specified small pixel according to preset boundary threshold value from sequence of pixel values Value and one specify big pixel value.The specified small pixel value is that arrangement number is that number specifies the corresponding picture of the pixel of small value Plain value, it is absolute with the difference of preset boundary threshold value that the number specifies small value to number for the arrangement of the smallest pixel of pixel value Value；Described to specify big pixel value be arrangement number is the specified corresponding pixel value of pixel being worth greatly of number, and the number is specified Big value is the absolute value of the difference of the arrangement number and preset boundary threshold value of the maximum pixel of pixel value；

First difference computational unit 151 calculates the difference for specifying big pixel value and specified small pixel value, determines the first difference.Tool Body includes: the first difference computational unit for calculating the difference for specifying big pixel value and specified small pixel value, and it is poor among first to obtain Value, and judge whether the first intermediate difference is greater than default first difference, it is no if then determining that the first intermediate difference is the first difference Then determine that default first difference is the first difference.

Second difference computational unit 152 determines current pixel point according to the size relation of current pixel point and pixel median Type of pixel, and the second difference is determined according to the type of pixel of current pixel point.In the present embodiment, the type of pixel Including max type and min type, the second difference can specifically determine in the following manner: the value of current pixel point is greater than pixel median When, it is determined that the type of pixel of current pixel point is max type, and the second difference computational unit is used to calculate the pixel of current pixel point The difference of value and specified small pixel value, obtains the second difference；When the value of current pixel point is less than pixel median, it is determined that current pixel The type of pixel of point is min type, and the second difference computational unit is for calculating the pixel value for specifying big pixel value and current pixel point Difference, obtain the second difference.

Thus the first judging unit 112 carries out the first judgement to the first difference and the second difference, and the recording unit 104 is remembered The first judging result is recorded, first judgement includes: to judge whether the quotient of the second difference and the first difference is greater than the first default mistake Otherwise difference determines that current pixel point is non-doubtful bad point if then determining that current pixel point is doubtful bad point.

In certain embodiments, the judging unit 102 further includes second judgment unit 122, the second judgment unit 122 for carrying out the second judgement to all pixels point in sequence of pixel values, and the recording unit is used to record the second judging result, Second judgement includes: to determine in sequence of pixel values, arrangement number be located between the specified big value of number and number maximum value or Person is located at number minimum value and number specifies the pixel between small value for doubtful bad point, and determines that arrangement number is located at other Pixel in range is non-doubtful bad point；The number maximum value is the corresponding arrangement number of the maximum pixel of pixel value, The number minimum value is the corresponding arrangement number of the smallest pixel of pixel value.

In certain embodiments, described device further includes logical unit 105, and the logical unit 105 is used for First logical operation is carried out to the first judging result, the second judging result, if the first logic operation result is if true, determine current Pixel is bad point, if the first logic operation result is if false, determine that current pixel is not bad point.First logical operation can be When AND operation, i.e. the first judging result and the second judging result judge current pixel point for doubtful bad point, just assert current Pixel is bad point, otherwise assert that current pixel point is not bad point.

In certain embodiments, the computing unit 103 includes second order gradient mean value computing unit 123, minimum two ladders Average calculation unit 133, texture value computing unit 143 are spent, the judging unit 102 includes third judging unit 132；

The second order gradient mean value computing unit 123 is for calculating centered on current pixel point, in presetted pixel block Second order gradient mean value of all pixels point on different preset directions, the corresponding second order gradient mean value of each preset direction；

The minimum second order gradient mean value computing unit 133 is used to take minimum to all second order gradient mean values being calculated Value, obtains minimum second order gradient mean value and records；

The texture value computing unit 143 obtains line for calculating the corresponding texture value of pixel in presetted pixel block Reason value；

The third judging unit 132 is used to carry out third judgement, the note to minimum second order gradient mean value and texture value For record unit for recording third judging result, the third judgement includes: to judge the difference of minimum second order gradient mean value and texture value Whether it is greater than the second default error, if then determining that current pixel point is doubtful bad point, otherwise determines that current pixel point is non-doubts Like bad point.

In certain embodiments, described device further includes logical unit 105, and the logical unit 105 is used for Second logical operation is carried out to the first judging result and third judging result, if the second logic operation result is if true, determine current Pixel is bad point, if the second logic operation result is if false, determine that current pixel is not bad point.Second logical operation can be When AND operation, i.e. the first judging result and third judging result judge current pixel point for doubtful bad point, just assert current Pixel is bad point, otherwise assert that current pixel point is not bad point.

In certain embodiments, the logical unit 105 is used for the first judging result, the second judging result and the Three judging results carry out third logical operation, if third logic operation result if true, determine that current pixel point is bad point, if the Three logic operation results are if false, determine that current pixel is not bad point.Third logical operation can be AND operation, i.e., first sentences When disconnected result, the second judging result, third judging result judge current pixel point for doubtful bad point, current pixel point is just assert For bad point, otherwise assert that current pixel point is not bad point.The protection for being conducive to image border high-frequency information in this way reaches better Protecting effect improves the accuracy rate of bad point detection.Certainly, in other embodiments, third logical operation can also be other fortune Calculate, for example, three judge in when there are two judging result judgement current pixel points as doubtful bad point, third logic operation result is It very, is otherwise false.

When logical unit carries out any one of the first logical operation, the second logical operation, third logical operation simultaneously When determining current pixel point for bad point, so that it may be replaced to current pixel point.

In certain embodiments, described device further includes bad point replacement unit 107, and the bad point replacement unit 107 is used for Its original pixel value is replaced using pixel median to the pixel for being determined as bad point.Pixel median, that is, NxM size pixel region Median after all pixels point arranges in sequence in block replaces bad point using the value, can effectively reduce current pixel point With the difference in block between other pixels, achievees the purpose that repair bad point, keeps image detail.

In further embodiments, the bad point replacement unit 107 is used for according to the type of pixel of current pixel point, to sentencing It is set to the pixel of bad point using specified small pixel value or big pixel value is specified to replace its original pixel value.The type of pixel Including max type and min type, " bad point replacement unit is used for the type of pixel according to current pixel point, to the pixel for being determined as bad point Point is using specified small pixel value or big pixel value is specified to replace its original pixel value " it specifically includes: the value of current pixel point is big When pixel median, it is determined that the type of pixel of current pixel point is max type, and bad point replacement unit is used for being determined as bad point Pixel, which uses, specifies big pixel value to replace its original pixel value；When the value of current pixel point is less than pixel median, it is determined that The type of pixel of current pixel point is min type, and bad point replacement unit is used for the specified statuette of pixel use for being determined as bad point Element value replaces its original pixel value.For bad point, itself can may also carry some image informations, if using picture Plain intermediate value is replaced completely, is unfavorable for retaining these image informations, and this scheme is used to carry out compared to using pixel median The scheme for replacing bad point, can be better maintained image detail.

So far, just complete a pixel (current pixel point) whether be bad point detection, for piece image, Which contain many pixels to need to start the detection of next pixel after current pixel point detection.The thus dress Setting further includes Traversal Unit 109, and the Traversal Unit 109 is used for using next pixel of current pixel point as center pixel, And judge whether next pixel is doubtful bad point, and record judging result；It repeats the above steps, until the pixel of NxM size All pixels point traverses completion in block.It in actual application, can be according to Fig. 8 for the judgement of each pixel Any one method into Figure 10 judges that current pixel point is bad point, can also select the combination of these types of method into The comprehensive judgement of row can also execute repeatedly the combination of these types of method repeatedly to judge.In short, dead pixel detection method selects Selection, testing staff can select according to actual needs there are many upper.Detection effect as shown in Fig. 5-A, Fig. 5-B, Fig. 5-C, The left side in every width figure indicates original image, the bad point that intermediate representation detects, the right indicates the figure repaired by bad point replacement Picture, it can be clearly seen that the image on the right is more whole than left image more smooth, and the sensory experience of user is more preferable.

It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to Non-exclusive inclusion, so that the process, method, article or the terminal device that include a series of elements not only include those Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or end The intrinsic element of end equipment.In the absence of more restrictions, being limited by sentence " including ... " or " including ... " Element, it is not excluded that there is also other elements in process, method, article or the terminal device for including the element.This Outside, herein, " being greater than ", " being less than ", " being more than " etc. are interpreted as not including this number；" more than ", " following ", " within " etc. understand Being includes this number.

It should be understood by those skilled in the art that, the various embodiments described above can provide as method, apparatus or computer program production Product.Complete hardware embodiment, complete software embodiment or embodiment combining software and hardware aspects can be used in these embodiments Form.The all or part of the steps in method that the various embodiments described above are related to can be instructed by program relevant hardware come It completes, the program can store in the storage medium that computer equipment can be read, for executing the various embodiments described above side All or part of the steps described in method.The computer equipment, including but not limited to: personal computer, server, general-purpose computations It is machine, special purpose computer, the network equipment, embedded device, programmable device, intelligent mobile terminal, smart home device, wearable Smart machine, vehicle intelligent equipment etc.；The storage medium, including but not limited to: RAM, ROM, magnetic disk, tape, CD, sudden strain of a muscle It deposits, USB flash disk, mobile hard disk, storage card, memory stick, webserver storage, network cloud storage etc..

The various embodiments described above are referring to the method according to embodiment, equipment (system) and computer program product Flowchart and/or the block diagram describes.It should be understood that can be realized by computer program instructions every in flowchart and/or the block diagram The combination of process and/or box in one process and/or box and flowchart and/or the block diagram.It can provide these computers Program instruction generates a machine to the processor of computer equipment, so that the finger executed by the processor of computer equipment It enables and generates to specify in one or more flows of the flowchart and/or one or more blocks of the block diagram The device of function.

These computer program instructions, which may also be stored in, to be able to guide computer equipment computer operate in a specific manner and sets In standby readable memory, so that the instruction being stored in the computer equipment readable memory generates the manufacture including command device Product, command device realization refer in one or more flows of the flowchart and/or one or more blocks of the block diagram Fixed function.

These computer program instructions can also be loaded into computer equipment, so that executing on a computing device a series of Operating procedure is to generate computer implemented processing, so that the instruction executed on a computing device is provided for realizing in process The step of function of being specified in figure one process or multiple processes and/or block diagrams one box or multiple boxes.

Although the various embodiments described above are described, once a person skilled in the art knows basic wounds The property made concept, then additional changes and modifications can be made to these embodiments, so the above description is only an embodiment of the present invention, It is not intended to limit scope of patent protection of the invention, it is all to utilize equivalent structure made by description of the invention and accompanying drawing content Or equivalent process transformation, being applied directly or indirectly in other relevant technical fields, similarly includes in patent of the invention Within protection scope.

Claims

1. a kind of dead pixel points of images detection method, which is characterized in that the described method comprises the following steps:

The pixel value of all pixels point in the block of pixels of NxM size is obtained, and according to the size of pixel value by acquired institute There is pixel carry out sequence arrangement, obtains a sequence of pixel values, the corresponding arrangement number of the pixel after each arrangement；

The median for calculating sequence of pixel values, obtains pixel median；

According to preset boundary threshold value, determines a specified small pixel value from sequence of pixel values and one is specified big pixel value, institute It is that number specifies the corresponding pixel value of the pixel of small value that state specified small pixel value, which be arrangement number, and the number specifies the small value to be The absolute value of the difference of the arrangement number and preset boundary threshold value of the smallest pixel of pixel value；It is described to specify big pixel value for arrangement Number is the specified corresponding pixel value of pixel being worth greatly of number, and the specified big value of number is the maximum pixel of pixel value The absolute value of the difference of arrangement number and preset boundary threshold value；

According to the size relation of current pixel point and pixel median, the type of pixel of current pixel point is determined, and according to current picture The type of pixel of vegetarian refreshments determines the second difference；

First judgement is carried out to the first difference and the second difference, and records the first judging result, first judgement includes: judgement Whether the quotient of the second difference and the first difference is greater than the first default error, no if then determining that current pixel point is doubtful bad point Then determine that current pixel point is non-doubtful bad point.

2. dead pixel points of images detection method as described in claim 1, which is characterized in that the method also includes steps:

Second judgement is carried out to all pixels point in sequence of pixel values, and records the second judging result, second judgement includes: Determine in sequence of pixel values, arrangement number be located between the specified big value of number and number maximum value or be located at number minimum value and It is doubtful bad point that number, which specifies the pixel between small value, and it is non-for determining that arrangement number is located at the pixel within the scope of other Doubtful bad point；The number maximum value is the corresponding arrangement number of the maximum pixel of pixel value, and the number minimum value is picture Element is worth the corresponding arrangement number of the smallest pixel.

3. dead pixel points of images detection method as claimed in claim 2, which is characterized in that the method also includes steps:

First logical operation is carried out to the first judging result, the second judging result, if the first logic operation result is if true, determine Current pixel point is bad point, if the first logic operation result is if false, determine that current pixel is not bad point.

4. dead pixel points of images detection method as claimed in claim 1 or 2, which is characterized in that the method also includes steps:

Calculate second order gradient of all pixels point on different preset directions in presetted pixel block centered on current pixel point Mean value, the corresponding second order gradient mean value of each preset direction；

Third judgement is carried out to minimum second order gradient mean value and texture value, and records third judging result, the third judgement packet It includes: judging whether the difference of minimum second order gradient mean value and texture value is greater than the second default error, if then determining current pixel point For doubtful bad point, otherwise determine that current pixel point is non-doubtful bad point.

5. dead pixel points of images detection method as claimed in claim 4, which is characterized in that the method also includes steps:

Second logical operation is carried out to the first judging result and third judging result, if the second logic operation result is if true, determine Current pixel point is bad point, if the second logic operation result is if false, determine that current pixel is not bad point.

6. dead pixel points of images detection method as claimed in claim 4, which is characterized in that the method also includes steps:

Third logical operation is carried out to the first judging result, the second judging result and third judging result, if third logical operation As a result if true, determining that current pixel point is bad point, if third logic operation result is if false, determine that current pixel is not bad point.

7. the dead pixel points of images detection method as described in claim 3 or 5 or 6, which is characterized in that " determine current pixel in step Point is bad point " it further comprises the steps of: later

8. the dead pixel points of images detection method as described in claim 3 or 5 or 6, which is characterized in that " determine current pixel in step Point is bad point " it further comprises the steps of: later

According to the type of pixel of current pixel point, to the specified small pixel value of pixel use for being determined as bad point or big pixel is specified Value replaces its original pixel value.

9. dead pixel points of images detection method as claimed in claim 8, which is characterized in that the type of pixel includes max type and min Type " according to the type of pixel of current pixel point, uses the pixel for being determined as bad point and specifies small pixel value or specified in step Big pixel value replaces its original pixel value " it specifically includes:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, bad to being determined as The pixel of point, which uses, specifies big pixel value to replace its original pixel value；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, bad to being determined as The pixel of point replaces its original pixel value using specified small pixel value.

10. dead pixel points of images detection method as described in claim 1, which is characterized in that " big pixel value is specified in calculating to the step And the difference of specified small pixel value, determines the first difference " include:

Judge whether the first intermediate difference is greater than default first difference, it is no if then determining that the first intermediate difference is the first difference Then determine that default first difference is the first difference.

11. dead pixel points of images detection method as described in claim 1, which is characterized in that the type of pixel include max type and Min type, step " according to the size relation of current pixel point and pixel median, determine the type of pixel of current pixel point, and according to The type of pixel of current pixel point determines the second difference " include:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, and described second is poor Value is the pixel value of current pixel point and the difference of specified small pixel value；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, and described second is poor Value is to specify the difference of the pixel value of big pixel value and current pixel point.

12. dead pixel points of images detection method as described in claim 1, which is characterized in that the step " in being with current pixel point Imago vegetarian refreshments obtains the block of pixels of NxM size on image " include:

Using current pixel point as center pixel, TxS sub-block is obtained from image, then NxM pixel is obtained from the TxS sub-block Block.

13. dead pixel points of images detection method as claimed in claim 12, which is characterized in that the TxS sub-block is 5x5 sub-block, then The block of pixels of the NxM size is 3x3 sub-block.

14. dead pixel points of images detection method as described in claim 1, which is characterized in that described image is bayer format-pattern, The pixel access of pixel includes the channel Gr, the channel Gb, channel B and the channel R, then the corresponding pixel value of each pixel is pixel Value is one of Gr channel components value, Gb channel components value, R channel components value, channel B component value.

15. the dead pixel points of images detection method as described in claim 1 or 14, which is characterized in that the described method includes:

Using next pixel of current pixel point as center pixel, and judge whether next pixel is doubtful bad point, and remembers Record judging result；It repeats the above steps, until all pixels point traverses completion in the block of pixels of NxM size.

16. a kind of dead pixel points of images detection device, which is characterized in that described device includes acquiring unit, sequencing unit, specified pixel Determination unit, computing unit, judging unit, recording unit；The acquiring unit includes that block of pixels acquiring unit and pixel obtain Take unit；The computing unit includes difference computational unit and pixel median computing unit, and the difference computational unit includes the One difference computational unit and the second difference computational unit；The judging unit includes the first judging unit；

The block of pixels acquiring unit is used to obtain the pixel of NxM size on image using current pixel point as center pixel Block；

The pixel acquisition unit is used to obtain the pixel value of all pixels point in the block of pixels of NxM size, and the sequence is single Member, by acquired all pixels point carry out sequence arrangement, obtains a sequence of pixel values for the size according to pixel value, each The corresponding arrangement number of pixel after arrangement；

The specified pixel determination unit is used to determine a specified small pixel from sequence of pixel values according to preset boundary threshold value Value and one specify big pixel value, and the specified small pixel value is that arrangement number is that number specifies the corresponding picture of the pixel of small value Plain value, it is absolute with the difference of preset boundary threshold value that the number specifies small value to number for the arrangement of the smallest pixel of pixel value Value；Described to specify big pixel value be arrangement number is the specified corresponding pixel value of pixel being worth greatly of number, and the number is specified Big value is the absolute value of the difference of the arrangement number and preset boundary threshold value of the maximum pixel of pixel value；

First difference computational unit determines the first difference for calculating the difference for specifying big pixel value and specified small pixel value；

Second difference computational unit is used for the size relation according to current pixel point and pixel median, determines current pixel point Type of pixel, and the second difference is determined according to the type of pixel of current pixel point；

First judging unit is used to carry out the first judgement to the first difference and the second difference, and the recording unit is for recording First judging result, first judgement includes: to judge whether the second difference and the quotient of the first difference are greater than the first default error, If then determining that current pixel point is doubtful bad point, otherwise determine that current pixel point is non-doubtful bad point.

17. dead pixel points of images detection device as claimed in claim 16, which is characterized in that the judging unit further includes second sentencing Disconnected unit；

The second judgment unit is used to carry out all pixels point in sequence of pixel values the second judgement, and the recording unit is used for Record the second judging result, second judgement includes: to determine in sequence of pixel values, arrangement number be located at the specified big value of number with Between number maximum value or specifying the pixel between small value positioned at number minimum value and number is doubtful bad point, and is determined It is non-doubtful bad point that arrangement number, which is located at the pixel within the scope of other,；The number maximum value is the maximum pixel of pixel value Corresponding arrangement number, the number minimum value are the corresponding arrangement number of the smallest pixel of pixel value.

18. dead pixel points of images detection device as claimed in claim 17, which is characterized in that described device further includes logical operation list Member；

The logical unit is used to carry out the first logical operation to the first judging result, the second judging result, if first patrols Operation result is collected if true, determining that current pixel point is bad point, if the first logic operation result is if false, determine that current pixel is not Bad point.

19. the dead pixel points of images detection device as described in claim 16 or 17, which is characterized in that the computing unit includes second order Gradient mean value computing unit, minimum second order gradient mean value computing unit, texture value computing unit, the judging unit includes third Judging unit；

The second order gradient mean value computing unit is for calculating all pixels in presetted pixel block centered on current pixel point Second order gradient mean value of the point on different preset directions, the corresponding second order gradient mean value of each preset direction；

The minimum second order gradient mean value computing unit is obtained for being minimized to all second order gradient mean values being calculated Minimum second order gradient mean value simultaneously records；

The texture value computing unit obtains texture value for calculating the corresponding texture value of pixel in presetted pixel block；

The third judging unit is used to carry out third judgement to minimum second order gradient mean value and texture value, and the recording unit is used In record third judging result, the third judgement includes: to judge whether the difference of minimum second order gradient mean value and texture value is greater than Otherwise second default error determines that current pixel point is non-doubtful bad point if then determining that current pixel point is doubtful bad point.

20. dead pixel points of images detection device as claimed in claim 19, which is characterized in that described device further includes logical operation list Member；

The logical unit is used to carry out the second logical operation to the first judging result and third judging result, if second patrols Operation result is collected if true, determining that current pixel point is bad point, if the second logic operation result is if false, determine that current pixel is not Bad point.

21. dead pixel points of images detection device as claimed in claim 19, which is characterized in that described device further includes logical operation list Member；

The logical unit is used to carry out third logic to the first judging result, the second judging result and third judging result Operation, if third logic operation result is if true, determine that current pixel point is bad point, if third logic operation result is if false, sentence Settled preceding pixel is not bad point.

22. the dead pixel points of images detection device as described in claim 18 or 20 or 21, which is characterized in that described device further includes bad Point replacement unit, the bad point replacement unit are used for being determined as that the pixel of bad point replaces its original picture using pixel median Element value.

23. the dead pixel points of images detection device as described in claim 18 or 20 or 21, which is characterized in that described device further includes bad Point replacement unit, the bad point replacement unit is used for the type of pixel according to current pixel point, to the pixel for being determined as bad point Using specified small pixel value or big pixel value is specified to replace its original pixel value.

24. dead pixel points of images detection device as claimed in claim 23, which is characterized in that the type of pixel include max type and Min type, " bad point replacement unit is used for the type of pixel according to current pixel point, uses and specifies to the pixel for being determined as bad point Small pixel value specifies big pixel value to replace its original pixel value " it specifically includes:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, and bad point replacement is single Member is for being determined as the pixel of bad point using specifying big pixel value to replace its original pixel value；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, and bad point replacement is single Member is for being determined as that the pixel of bad point replaces its original pixel value using specified small pixel value.

25. dead pixel points of images detection device as claimed in claim 16, which is characterized in that described " the first difference computational unit is used The difference of big pixel value and specified small pixel value is specified in calculating, determines the first difference " include:

First difference computational unit is used to calculate the difference for specifying big pixel value and specified small pixel value, obtains the first intermediate difference, And judge whether the first intermediate difference is greater than default first difference, if then determining that the first intermediate difference is the first difference, otherwise Determine that default first difference is the first difference.

26. dead pixel points of images detection device as claimed in claim 16, which is characterized in that the type of pixel include max type and Min type, " the second difference computational unit is used for the size relation according to current pixel point and pixel median, determines current pixel point Type of pixel, and the second difference is determined according to the type of pixel of current pixel point " include:

When the value of current pixel point is greater than pixel median, it is determined that the type of pixel of current pixel point is max type, the second difference meter It calculates unit and is used to calculate the pixel value of current pixel point and the difference of specified small pixel value, obtain the second difference；

When the value of current pixel point is less than pixel median, it is determined that the type of pixel of current pixel point is min type, the second difference meter The difference that unit is used to calculate the pixel value for specifying big pixel value and current pixel point is calculated, the second difference is obtained.

27. dead pixel points of images detection device as claimed in claim 16, which is characterized in that described " block of pixels acquiring unit is used In acquisition using current pixel point as the block of pixels of NxM size on center pixel, image " include:

Block of pixels acquiring unit is used to obtain using current pixel point as the sub-block of TxS size on center pixel, image, then from NxM block of pixels is obtained in the TxS sub-block.

28. dead pixel points of images detection device as claimed in claim 27, which is characterized in that the TxS sub-block is 5x5 sub-block, then The block of pixels of the NxM size is 3x3 sub-block.

29. dead pixel points of images detection device as claimed in claim 16, which is characterized in that described image is bayer format-pattern, The pixel access of pixel includes the channel Gr, the channel Gb, channel B and the channel R, then the corresponding pixel value of each pixel is logical for Gr One of road component value, Gb channel components value, R channel components value, channel B component value.

30. the dead pixel points of images detection device as described in claim 16 or 29, which is characterized in that described device further includes that traversal is single Member；

The Traversal Unit is used for using next pixel of current pixel point as center pixel, and whether judges next pixel For doubtful bad point, and record judging result；It repeats the above steps, until all pixels point equal time in the block of pixels of NxM size Go through completion.