CN103888690B - Device and method for detecting defect pixel - Google Patents
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Abstract
Disclose a kind of device and method for detecting defect pixel.The equipment includes：Calculator calculates the gradient of the pixel value for the neighborhood pixels group for including neighborhood pixels on surrounding target pixel and a direction being arranged in multiple predetermined directions；Recognition unit identifies the direction of the gradient minimum calculated by calculator among the multiple predetermined direction；Determiner, difference between pixel value and the pixel value for the neighborhood pixels being included in neighborhood pixels group based on object pixel, determine whether object pixel is defect pixel, the neighborhood pixels are identical and adjacent with object pixel as object pixel color on the direction identified by recognition unit.
Description
This application claims in the 2012-0277230 Japan Patents for being submitted to Japanese Patent Office on December 19th, 2012
Apply and on 08 28th, the 2013 10-2013-0102660 South Korea patent applications for being submitted to Korean Intellectual Property Office
Equity, it is open to be completely contained in this, for reference.
Technical field
One or more embodiments of the present invention are related to a kind of device and method for detecting defect pixel, can answer
The filter different for four is assigned to the imaging device of each 2 × 2 pel array.
Background technology
Imaging device, such as charge coupled device（CCD）Or cmos image sensor（CIS）,
Inevitably lead to defect pixel.
For the picture element flaw as caused by manufacturing process, when picture element flaw is forwarded to factory shipment, imaging device is remembered
The location information of defect, with the position information correction defect based on defect when executing shooting.In addition to this, when executing shooting
When, imaging device dynamically detects and corrects the picture element flaw being happened in Manufactured imaging device.
As determine the object pixel of image captured whether be defect pixel technology, compare the pixel of object pixel
The method of value and pixel value with the adjacent pixel with object pixel same color, to determine whether object pixel is isolated picture
Element.However, if defect pixel is present on or around three rows of the image captured, being difficult with has and target picture
The adjacent pixel of plain same color detects defect pixel.Therefore, as disclosed in patent document 1, bayer arrangement（Bayer
arrangement）Imaging device detected by using green (G) pixel being arranged in grid pattern around object pixel
Edge direction simultaneously determines object pixel based on the Pixel Information of green (G) pixel adjacent to object pixel in edge direction
Whether it is defect pixel, to improve detection performance.
【Prior art document 1】Japanese publication number is the patent document of 2008-154276
Invention content
However, for the imaging device of the four different filter wherein arranged with each 2 × 2 pixel period,
There is no suitable detections similar to the pixel of the edge direction of the G pixels of bayer arrangement.Likewise, it may be difficult to by using having and mesh
The adjacent pixel detection of mark pixel same color is present in the defect pixel on or around three rows of the image captured.
One or more embodiments of the present invention include the device and method for detecting defect pixel, are set by described
Standby and method, the imaging device that four different filter are assigned with each 2 × 2 pixel period are true based on multiple colour elements
Surely the defect pixel being present on or around three rows of the image captured.
Other aspects will partially elaborate in the description that follows, and partly will be apparent from description, or can
It is learnt by the practice of the embodiment of proposition.
According to one or more embodiments of the present invention, a kind of equipment for detecting defect pixel, including：It calculates
Device, calculate include neighborhood pixels on surrounding target pixel and a direction being arranged in multiple predetermined directions neighborhood pixels
The gradient of the pixel value of group；Recognition unit, the gradient minimum that identification is calculated by calculator among the multiple predetermined direction
Direction；Determiner, between pixel value and the pixel value for the neighborhood pixels being included in neighborhood pixels group based on object pixel
Difference determines whether object pixel is defect pixel, the neighborhood pixels on the direction identified by recognition unit with object pixel
Color is identical and adjacent with object pixel.
Neighborhood pixels group may include identical as object pixel color on the direction identified by recognition unit and and target picture
The adjacent neighborhood pixels of element.
Calculator can be based on the colour element for neighborhood pixels group adjacent with object pixel in a predetermined direction
The difference between the pixel value calculated separately is combined to calculate gradient.
If the pixel value of object pixel adjacent with object pixel on the direction identified by recognition unit two is identical
Relative size relationship between the pixel value of the adjacent pixel of color is identical, and the pixel value of object pixel and described two phases
It is all higher than threshold value with all differences between the pixel value of the adjacent pixel of color, it is determined that device can determine that object pixel is defect picture
Element.
The equipment may also include：Corrector corrects the pixel value of object pixel.If it is determined that device determines that object pixel is
Defect pixel, then corrector can be based on the pixel value of the pixel value of neighborhood pixels correction object pixel.
Corrector can based on it is identical as object pixel color on the direction identified by recognition unit and with object pixel phase
The pixel values of the neighborhood pixels of adjacent neighborhood pixels group corrects the pixel value of object pixel.
Object pixel and neighborhood pixels can be the pixels to form the image exported by imaging device, wherein four are not
With filter with the matrix arrangement of each 2 × 2 pel array on the image.
According to one or more embodiments of the present invention, a method of detection defect pixel, including：Calculate includes enclosing
The pixel value of the neighborhood pixels group of neighborhood pixels on object pixel and a direction being arranged in multiple predetermined directions
Gradient；The direction of the gradient minimum of calculating is identified among the multiple predetermined direction；Pixel value based on object pixel and packet
The difference between the pixel value of the neighborhood pixels in neighborhood pixels group is included, determines whether object pixel is defect pixel, the neighbour
Nearly pixel is identical and adjacent with object pixel as object pixel color on the direction of identification.
Description of the drawings
Through a description of the embodiment given below with reference to the drawings, these and or other aspects of the invention will become
Understand and it is more readily appreciated that wherein：
Fig. 1 is to show the diagram according to an embodiment of the invention for detecting the equipment of defect pixel；
Fig. 2 is to show the block diagram according to an embodiment of the invention for detecting the structure of the equipment of defect pixel；
Fig. 3 is the pixel for showing the image according to an embodiment of the invention for being input to the equipment for detecting defect pixel
The diagram of structure；
Fig. 4 is to show the flow chart according to an embodiment of the invention for detecting the operation of the equipment of defect pixel；
Fig. 5 is to show that the image of the equipment processing according to an embodiment of the invention for being sensed by defect pixel shows
Figure；
Fig. 6 is to show the distribution index according to an embodiment of the invention for by calculator calculating on 0 ° of direction
The diagram of neighborhood pixels group；
Fig. 7 is to show the distribution index according to an embodiment of the invention for by calculator calculating on 90 ° of directions
Neighborhood pixels group diagram；
Fig. 8 is to show the distribution index according to an embodiment of the invention for by calculator calculating on 45 ° of directions
Neighborhood pixels group diagram；
Fig. 9 is to show the distribution index according to an embodiment of the invention for by calculator calculating on -45 ° of directions
Neighborhood pixels group diagram；
Figure 10 is to show the diagram with the combination of the adjacent pixel of object pixel same color；And
Figure 11 is the diagram for showing the method according to an embodiment of the invention that defect pixel is determined by using determiner.
Specific implementation mode
Embodiment is described in detail now, the example is illustrated in the accompanying drawings, wherein identical label is always shown
Same parts.In this respect, the present embodiment can have different form and should not be construed as limited to implementation set forth herein
Mode.Therefore, only embodiment is described below by way of with reference to attached drawing to explain many aspects of present embodiment.
With reference to Fig. 2, the equipment 1 for detecting defect pixel includes：Calculator 11, recognition unit 13 and determiner 15.Meter
The gradient that device 11 calculates the pixel value of neighborhood pixels group is calculated, neighborhood pixels group is by surrounding target pixel and in multiple predetermined directions
A direction on arrange multiple color neighborhood pixels composition.The identification of recognition unit 13 is minimum by the gradient that calculator calculates
Direction.Difference between the pixel value of pixel value and neighborhood pixels of the determiner 15 based on object pixel, determines that object pixel is
No is defect pixel, and the neighborhood pixels are among the upwardly-directed neighborhood pixels group in the side identified by recognition unit and mesh
Marking pixel has the pixel of same color.
Equipment 1 according to the ... of the embodiment of the present invention is described now with reference to Fig. 1.
Fig. 1 is the diagram for showing equipment 1 according to an embodiment of the invention.As shown in Figure 1, the detection of equipment 1 and correction chart
As 20 defect pixel 210.Here, image 21 refers to a part for the image 20 being extended, and each list in image 21
First lattice indicate a pixel.Image 21 include have in the center there is the band-like portions of the pixel of high value, and with
Its both ends has the band-like portions of the pixel of low value, wherein defect pixel 210 has low pixel value and is located at image 21
Center.The defect pixel 210 of 1 detection image 21 of equipment and the image 22 for exporting the correction with the pixel 220 corrected.Now
The operation of equipment 1 will be described.
Equipment 1 is directed to the object pixel that will be estimated according to whether object pixel is defect pixel, identifies for being arranged in
Minimum pixel value variation occurs for the adjacent pixel around object pixel（That is, minimal gradient）Direction.For example, in image 21,
Band-like part with big pixel value is directed to the picture that object pixel 210 continues on 90 ° of directions, therefore is arranged on 90 ° of directions
The gradient of the pixel value of element is smaller.Part with small pixel value and the part with big pixel value 0 ° of object pixel 210,
On 45 ° and -45 ° of directions alternately, and 0 °, 45 ° of object pixel 210 and the pixel value of the pixel on -45 ° of directions are arranged in
Gradient is very big.Therefore, equipment 1 identifies that 90 ° of directions are the directions of gradient minimum.
Equipment 1 determines target picture based in neighborhood pixels present on the direction of gradient minimum corresponding with neighborhood pixels
Whether element is defect pixel.For example, in image 21, the pixel with big pixel value is prolonged on 90 ° of directions of object pixel 210
It is continuous.Therefore, the pixel value and the pixel value in neighborhood pixels present on 90 ° of directions that equipment 1 compares object pixel 210, with true
Whether whether the pixel that sets the goal 210 have minimum pixel value to be defect pixel.
As described above, the direction of the gradient minimum of the pixel value of neighborhood pixels of the identification of equipment 1 around object pixel is simultaneously
Defect pixel is determined using the neighborhood pixels being arranged on the direction of gradient minimum.Therefore, equipment 1 can be based on multiple colour elements
To determine the defect pixel being present on three rows of the image captured.
Here, it is however generally that, imaging device has the filter of bayer arrangement, and bayer arrangement includes with each 2 × 2 pixel
One red (R) filter, two green (G) filters and blue (B) filter in period.The figure obtained by this imaging device
As including the G pixels arranged with grid pattern, and the quantity of the quantity ratio R pixels of G pixels and the quantity of B pixels are big.At this
In kind imaging device, R pixels are repeated with each two pixel, and B pixels are repeated with each two pixel, and G pixels are with every a picture
Element repeats.Therefore, in patent document 1, identify that edge direction, a large amount of G pixels are adapted to detect for using a large amount of G pixels
Edge direction and arrange in a narrow space.
However, if the filter different from R, G and B filter is arranged instead of G filter in bayer arrangement, obtain
The quantity of R, G and B pixel of image become equal with the quantity of other colour elements.Also, each colour element is every two
A pixel is spaced from each other.Therefore, the image of acquisition does not have the pixel for being adapted to detect for edge direction, therefore is difficult by patent document
Introduction in 1 is applied to the detection of edge direction.
Equipment 1 is not limited only to G pixels.Conversely, direction of the equipment 1 using other colour elements identification gradient minimum, and base
In the angle detecting defect pixel of identification.Therefore, although the filter of image device has bayer arrangement, and four different filters
Look mirror is implemented with each 2 × 2 pixel period, but equipment 1 can stable detection defect pixel.
Equipment 1 has been described above.The structure of equipment 1 is described now with reference to Fig. 2 and Fig. 3.
Fig. 2 is to show the block diagram according to an embodiment of the invention for detecting the structure of the equipment 1 of defect pixel.Such as figure
Shown in 2, equipment 1 includes：Calculator 11, recognition unit 13, determiner 15 and corrector 17.Equipment 1 is exported from capture apparatus 2
Then the image of correction is output to camera signal processor 3 by image detection defect pixel, correct defective pixels.It now will be detailed
Element, capture apparatus 2 and the camera signal processor 3 of thin description equipment 1.
Capture apparatus 2 has imaging device, and the image of capture is output to equipment 1.The filter of capture apparatus 2 can have
There are various types of structures, bayer arrangement etc..In the present embodiment, the imaging device of capture apparatus 2 includes each 2 × 2
Pixel period is with four different filter of matrix arrangement.In detail, capture apparatus 2 includes being filtered instead of the G of bayer arrangement
Mirror and the filter of infrared (IR) filter added.Here, show that the capture apparatus 2 with filter is output to equipment in Fig. 3
Image.
Fig. 3 is the diagram for the dot structure for showing the image 23 according to an embodiment of the invention for being output to equipment 1.Such as figure
Shown in 3, the image 23 for being output to equipment 1 includes being arranged with each 2 × 2 pixel period and corresponding respectively to R, G, B of filter
With IR pixels.In addition, hereinafter, being included in the symbol shown in table 24 of the pixel in image 23 to identify.For example, picture
Plain A11 is R pixels, and the pixel B 12 adjacent with pixel A 11 is G pixels.In addition, having and 33 same color of pixel A and neighbour
It is bordering on the adjacent pixel A 11 of pixel A 33, A13, A15, A31, A35, A51, A53 and A55 are referred to as the same color of pixel A 33
Adjacent pixel.
The image exported from capture apparatus 2 is input into equipment 1, in detail, is input to calculator 11 and corrector
In 17.
Calculator 11 calculates the gradient of the variation of the pixel value of the pixel of expression neighborhood pixels group in a plurality of directions, institute
It states neighborhood pixels group and is directed to the object pixel that export from capture apparatus 2 and arrange in a plurality of directions, wherein neighborhood pixels group includes
Multiple neighborhood pixels.The method that description is calculated into gradient by using calculator 11 later.Calculator 11 is defeated by the gradient of calculating
Go out to recognition unit 13.
Recognition unit 13 identifies the direction of gradient minimum based on the gradient calculated by calculator 11.Recognition unit 13 will be known
Other direction is output to determiner 15.
Determiner 15 determines whether object pixel is defect pixel using the direction identified by recognition unit 13.In detail
Say, determiner 15 based on it is adjacent with object pixel on the direction identified by recognition unit 13 and with object pixel have identical face
Two neighborhood pixels of color（That is, the adjacent pixel of same color）Pixel value, determine whether object pixel is defect pixel.Really
Determine device 15 and definitive result is also output to corrector 17.
Corrector 17 corrects the object pixel of the image exported from capture apparatus 2 based on the definitive result of determiner 15.
More particularly, the pixel of pixel of the corrector 17 based on the neighborhood pixels group being arranged on the direction identified by recognition unit 13
Value corrects the pixel value of object pixel.The image of correction is output to camera signal processor 3 by corrector 17.
Camera signal processor 3 executes compression, such as gamma correction, white balance tune to the image that defect pixel has been corrected
Whole or color interpolation.
The structure of equipment 1 has been described.
The operation of equipment 1 is described now with reference to Fig. 4 to Figure 11.Equipment 1 operation S104 to operation S124 in determine from
Whether the pixel for the image that capture apparatus 2 exports is defect pixel and is operating S128 lieutenant colonel's positive goal pixel.
Fig. 4 is the flow chart for the operation for showing equipment 1 according to an embodiment of the invention.As shown in Figure 4, it is operating
In S104, calculator 11 calculates the gradient of the pixel value of neighborhood pixels group in a plurality of directions, wherein neighborhood pixels group is by enclosing
The neighborhood pixels of the multiple colors arranged on a direction around object pixel and in multiple predetermined directions are constituted.More specifically
It says, calculator 11 calculates the pixel value for being included in all adjacent pixels in sets of adjacent pixels, and the sets of adjacent pixels is present in
On the distribution index direction calculated for indicating gradient.
Here, the processing of gradient is calculated by calculator 11 now with reference to Fig. 5 detailed descriptions.Fig. 5 is shown according to this
The diagram for the image of the embodiment of invention handled by equipment 1.The image 26 of Fig. 5 has showing for 12 bits shown in table 25
Example property pixel value.Each pixel of the image 26 of Fig. 5 corresponds to the table 24 in Fig. 3.Such as the image 21 of Fig. 1, image 26 wraps
Include the band-like portions of the pixel in the center there is high level, and the band-like portions in pixel of its both ends with low value.Here,
It will be detected as defect pixel by equipment 1 and corrected object pixel corresponds to pixel value 365 and in table 25
Image 26 center pixel A 33.
In operating S104, calculator 11 calculates the gradient of the pixel value of each neighborhood pixels group in a plurality of directions.
For example, calculator 11 calculates the ladder of the pixel value of the neighborhood pixels group of the neighborhood pixels for all colours for including neighborhood pixels group
The neighborhood pixels of degree, all colours of the neighborhood pixels group surround the object pixel A33 of Fig. 5 in 0 °, 90 °, 45 ° and -45 ° of sides
Arrangement upwards.Here, Fig. 6 to Fig. 9 show to be included in neighborhood pixels group and be arranged in 0 ° around object pixel A33,90 °,
Color neighborhood pixels on 45 ° and -45 ° of directions.
Fig. 6 is to show the distribution index according to an embodiment of the invention for by the calculating of calculator 11 on 0 ° of direction
Neighborhood pixels group diagram.Fig. 7 is to show according to an embodiment of the invention be used for through the calculating of calculator 11 in 90 ° of directions
On distribution index neighborhood pixels group diagram.Fig. 8 is to show according to an embodiment of the invention be used for through calculator 11
Calculate the diagram of the neighborhood pixels group of the distribution index on 45 ° of directions.Fig. 9 is to show according to an embodiment of the invention be used for
The diagram of the neighborhood pixels group of the distribution index on -45 ° of directions is calculated by calculator 11.
Using neighborhood pixels group shown in Fig. 6 to Fig. 9, calculator 11 is by using four be arranged in around object pixel
The pixel value of the adjacent pixel of color is planted to calculate distribution index.Here, calculator 11 is based on to including in neighborhood pixels group
The adjacent pixel of different colours combines the difference between the pixel value calculated to calculate distribution index, and the neighborhood pixels group is pre-
Determine to be directly adjacent to each other on direction or across object pixel and it is adjacent to each other.In detail, calculator 11 is based on following equation
1-4 calculates the distribution index d0 on 0 ° of direction, the distribution index d1 on 90 ° of directions, the distribution index on 45 ° of directions
The d2 and distribution index d3 on -45 ° of directions.
d0=|A31-A35|+|B32-B34|+|C21-C23|
+|C23-C25|+|C41-C43|+|C43-C45|
+|D22-D24|+|D42-D44| …(1)
Wherein, the right of equation 1 indicates to combine for each of the adjacent pixel of same color on 0 ° of direction and calculate
Pixel value absolute value of the difference summation, the adjacent pixel of the same color on 0 ° of direction is included in shown in Fig. 6
In neighborhood pixels group on 0 ° of direction.
d1=|A13-A53|+|B12-B32|+|B32-B52|
+|B14-B34|+|B34-B54|+|C23-C43|
+|D22-D42|+|D24-D44| …(2)
Wherein, the right of equation 2 indicates to combine for each of the adjacent pixel of same color on 90 ° of directions and calculate
Pixel value absolute value of the difference summation, the adjacent pixel of the same color on 90 ° of directions is included in shown in fig. 7
In neighborhood pixels group on 90 ° of directions.
d2=|A13-A31|/2+|A15-A51|+|A35-A53|/2
+|B14-B32|+|B34-B52|+|C23-C41|
+|C25-C43|+|D22-D40|/2+|D24-D42|
+|D26-D44|/2 …(3)
Wherein, the right of equation 3 indicates to combine for each of the adjacent pixel of same color on 45 ° of directions and calculate
Pixel value absolute value of the difference summation, the adjacent pixel of the same color on 45 ° of directions includes as shown in fig. 8
In neighborhood pixels group on 45 ° of directions.In addition, being the adjacent pixel of the same color of equation 1 and equation 2 in equation 3
Combination quantity, indicate that the Section 4 of the combination of the position farthest from object pixel A33 is multiplied by 1/2.
d3=|A11-A55|+|A13-A35|/2+|A31-A53|/2
+|B12-B34|+|B32-B54|+|C21-C43|
+|C23-C45|+|D20-D42|/2+|D22-D44|
+|D24-D46|/2 …(4)
Wherein, the right of equation 4 indicates to combine each of the adjacent pixel of same color on -45 ° of directions and calculate
Pixel value absolute value of the difference summation, the adjacent pixel of the same color on -45 ° of directions is included in shown in Fig. 9
- 45 ° of directions on neighborhood pixels group in.In equation 4, the 4th of the combination of the position farthest from object pixel A33 is indicated
It is equally multiplied by 1/2 in item and equation 3.
If calculated distribution index is all very big in equation 1 to equation 4, distribution index indicates the pixel of neighborhood pixels
The gradient of value is very big.If distribution index all very littles, distribution index indicates gradient very little.In addition, for the small of some direction
Gradient means that the variation for arranging the pixel value of pixel in this direction is small, and arranges the pixel of pixel in this direction
Correlation between value is high.Here, in equation 1 to equation 4, calculator 11 is counted without using the pixel value of object pixel A33
Calculate distribution index.Therefore, although object pixel A33 is the defect pixel for having outlier pixel values, calculator 11 can not be by different
The influence of normal pixel value and calculate distribution index.
If calculating the distribution index of multiple directions in operating S104, the identification of recognition unit 13 is counted by calculator 11
The direction of the distribution index minimum of calculation.For example, as shown in Figure 4, recognition unit 13 identifies that the distribution calculated by following equation 5 refers to
Mark minimum direction：
dmin=MIN(d0,d1,d2,d3) …(5)
Wherein, dminIndicate the minimum value among distribution index d0, d1, d2 and d3.Shown in table 25 according to Fig. 5
Pixel value and equation 1 are to equation 5, dmin=d1.Therefore, recognition unit 13 identifies that 90 ° of directions are the distribution index of object pixel A33
Minimum direction.
In operating S112, determiner 15 determines minimum value dminWhether threshold value th1 is less than or equal to.
If the minimum value d in operating S112minMore than threshold value th1, it is determined that device 15 determines that object pixel is not defect picture
Element.In this case, processing shown in Fig. 4 terminates.If the minimum value d in operating S112minLess than or equal to threshold value
Th1, it is determined that device 15 calculates the pixel value of object pixel in operating S116 and on the direction identified by recognition unit 13
Difference between the pixel value of the adjacent pixel of two same colors adjacent with object pixel.
In operation s 120, calculator 11 determine object pixel pixel value whether the adjacent pixel with two same colors
Pixel value between relative size relationship it is identical and it is being calculated in step S116 it is all difference whether be greater than or equal to threshold value
th2.In other words, calculator 11 determines the condition of following equation 6 whether it is satisfied：
(((Target Pixel-P0≥th2)AND(Target Pixel-P1≥th2))
OR
((P0-Target Pixel≥th2)AND(P1-Target Pixel≥th2))) …(6)
Wherein, " Target Pixel " indicates the pixel value of object pixel, and P0 and P1 indicate adjacent with object pixel respectively
Same color adjacent pixel pixel value.
If being unsatisfactory for conditions above in operation s 120, it is determined that device 15 determines that object pixel is not defect pixel and ties
Beam processing.If meeting conditions above in operation s 120, it is determined that device 15 in operating S124 determine object pixel whether be
Defect pixel.More particularly, if the pixel value of object pixel and two phases on the direction identified by recognition unit 13
It is identical with the relative size relationship between the pixel value of the adjacent pixel of color, and the difference between pixel value is greater than or equal to threshold
Value th2, it is determined that device 15 determines that object pixel is the pixel of defect., if it is not, then determiner 15 determines object pixel
It is not the pixel of defect.
Here, will description about object pixel A33 in operate S116 and S120 by determiner 15 execute difference calculating and
With the comparison of threshold value th2.
The pixel value and the neighborhood pixels group on the direction of distribution index minimum that determiner 15 calculates object pixel A33
The difference of the adjacent pixel of same color.Determiner 15 compares the pixel of the adjacent pixel of object pixel A33 and two same colors
The size of value, and compare the difference and threshold value th2 of calculating, to determine whether object pixel A33 is defect pixel.Here, if divided
Cloth index is the minimum value on 0 °, 90 °, 45 ° and -45 ° of four directions, then by by determiner 15 calculate will be with threshold value th2
The combination P0 and P1 of the adjacent pixel of the same color for its difference that compares are as shown in Figure 10.
Figure 10 is the diagram of the combination of the adjacent pixel for the same color for showing object pixel A33.As shown in Figure 10, exist
The adjacent pixel of same color on 0 ° of direction of object pixel A33 is A31 and A35, and the same color on 90 ° of directions
Adjacent pixel be A13 and A53.The adjacent pixel of same color on 45 ° of directions of object pixel A33 is A15 and A51,
And the adjacent pixel of the same color on -45 ° of directions is A11 and A55.
The pixel value and the same color on the 90 ° of directions identified by recognition unit 13 that determiner 15 calculates object pixel
Adjacent pixel P0 (A13) and the pixel value of P1 (A53) between difference.If the pixel value of object pixel and two same colors
Adjacent pixel pixel value between relative size relationship it is identical, and the pixel value of object pixel and two same colors
All differences between the pixel value of adjacent pixel are more than threshold value th2, it is determined that device 15 determines that object pixel A33 is the picture of defect
Element.Otherwise, it determines device 15 determines that object pixel A33 is not the pixel of defect.
The object pixel A33 for being determined as defect pixel by determiner 15 can be with the adjacent pixel P0 and P1 than same color
The pixel value of bigger（Pattern 1：The top half of above equation 6）, and can have the adjacent pixel P0 and P1 than same color
Smaller pixel value（Pattern 2：The lower half portion of above equation 6）.It describes to be determined as lacking by determiner 15 now with reference to Figure 11
Fall into the pattern 1 and pattern 2 of pixel.
Figure 11 is to show that determiner 15 according to an embodiment of the invention determines the diagram of the method for defect pixel.Such as Figure 11
Shown in, for pattern 1, the pixel value that the pixel value of object pixel A33 is more than the adjacent pixel P0 of same color reaches threshold
Value th2 or more, and the pixel value more than the adjacent pixel P1 of same color reaches threshold value th2 or more.In such case
Under, determiner 15 determines that object pixel A33 is defect pixel.In other words, if meeting the following top half for representing equation 6
Equation 7, it is determined that device 15 determine as pattern 1 object pixel A33 be defect pixel.
A33-P0≥th2,A33-P1≥th2 …(7)
As shown in Figure 11, for pattern 2, the pixel value of object pixel A33 is less than the adjacent pixel P0 of same color
Pixel value reach threshold value th2 or more, and the pixel value less than the adjacent pixel P1 of same color reaches threshold value th2 or more
It is more.In this case, determiner 15 determines that object pixel A33 is defect pixel.In other words, if meeting following representative etc.
The equation 8 of the lower half portion of formula 6, it is determined that device 15 determines that the object pixel A33 such as pattern 2 is defect pixel.
P0-A33≥th2,P1-A33≥th2 …(8)
Since distribution index is minimum on 90 ° of directions, it is thus determined that device 15 calculate object pixel A33 pixel value and
Difference between the pixel value of the adjacent pixel A13 and A53 of same color on 90 ° of directions.If calculate difference meet equation 7 or
Equation 8, it is determined that device 15 determines that object pixel A33 is defect pixel.
Referring again to Fig. 4, if determiner 15 determines that object pixel is defect pixel, corrector 17 in operating S124
The pixel value of operation S128 lieutenant colonel's positive goal pixel after operating S124.In more detail, corrector 17 is based on by knowing
Have on the direction that other unit 13 identifies with object pixel same color and the pixel value of the adjacent pixels adjacent with object pixel
（That is, the pixel value of the adjacent pixel P0 and P1 of same color）To correct the pixel value of object pixel.Therefore, corrector 17 can incite somebody to action
The pixel value of defect pixel is set as similar to the pixel value of the adjacent pixel of same color.
For example, referring to Fig. 3 and equation below 9, in order to correct the object pixel A33 as defect pixel, corrector 17
Target is replaced with the average value of the pixel A 13 of the adjacent pixel P0 and P1 of the same color on 90 ° of directions and the pixel value of A53
The pixel value of pixel A 33.
A33=(P0+P1)/2
=(A13+A53)/2 …(9)
A pixel among the pixel for detecting and correcting image 26 has been described（That is, defect pixel）Equipment 1
Operation.Equipment 1 executes operations described above for all pixels of image 26, to correct whole image 26.
The image corrected by equipment 1 is output to camera signal processor 3.
As described above, equipment 1 identifies the side of the gradient minimum of the pixel value for the adjacent pixels being arranged in around object pixel
To, and utilize the angle detecting defect pixel of identification.Therefore, equipment 1 is detectable is present in by four different filter with every
The defect pixel on or around three rows in the image of the assigned imaging device capture of a 2 × 2 pixel period.Equipment 1 can
The defect pixel of detection is corrected to improve the quality of the image captured.
All colour elements of the determiner 15 based on adjacent pixels group determine whether object pixel is defect pixel.For this purpose,
It is contemplated that being based only upon with the comparative example for determining defect pixel with the pixel of object pixel same color.However, comparing below
Compared in example, it is difficult the defect pixel detected that equipment 1, which can also detect,.
For example, the pixel A 33 of the image in Fig. 5 is the isolated point having in the band-like portions of big pixel value.However, than
Compared in example, the pixel value of the adjacent pixel of same color is only known as defect pixel, without pixel A 33 is determined as defect
Pixel.The reason is as follows that.Since there is pixel A 33 pixel value numerically with pixel A 11, A15, A31, A35, A51 and A55 to connect
Close pixel value, so pixel A 33 is not determined to defect pixel in comparative example, this is because pixel A 11, A15,
The pixel value of the adjacent pixel A13 and A53 of A31, A35, A51 and A55 and same color are different greatly.However, equipment 1 is using such as
The direction of upper all colour elements identification gradient minimum, and determine whether object pixel is defect picture using the direction
Element.Therefore, equipment 1 can determine that pixel A 33 is defect pixel and correction pixels A33.
The direction of all colour elements identification gradient minimum of the equipment 1 based on adjacent pixels group, and in the side of identification
The adjacent pixel of upward same color detects defect pixel.In another comparative example, be based only upon adjacent pixels group with
Object pixel has the potential defect pixel of pixel extraction of same color, and reduces defect pixel with reference to other colour elements
Range.However, in comparative example, detectable equipment 1 is difficult the defect pixel detected.
For example, in comparative example, it is difficult to which the pixel value with reference to the adjacent pixel of same color as described above will be in Fig. 5
The pixel A 33 of image be extracted as potential defect pixel.Therefore, it is difficult to determine whether pixel A 33 is defect pixel.For example,
In comparative example, as described above, pixel A 33 is with close with the pixel value of pixel A 11, A15, A31, A35, A51 and A55
Pixel value.Therefore, it is difficult whether determining pixel A 33 is potential defect pixel with reference to these pixel values.However, equipment 1 is based on
The direction of all colour elements identification gradient minimum of adjacent pixels group as described above, so that it is determined that pixel A 33 is defect picture
Element.
In the above-described embodiments, the image handled by equipment, four differences are exported by the imaging device with filter
Filter the imaging device is distributed to each 2 × 2 array, but not limited to this.For example, equipment 1 can be visitd from by having
The image detection defect pixel of the imaging device output of the filter of ear arrangement, and the pixel value of correct defective pixels.
As described above, above one or more embodiments according to the present invention, can be based on multiple pixel detection defect pictures
Element.Defect pixel is present in the image captured with the imaging device that each 2 × 2 array distributes by four different filter
On or around three rows.
The computer program for executing function identical with the element of equipment 1 can be written as by such as central processing unit
(CPU), the instruction that the hardware such as read-only memory (ROM), random access memory (RAM) execute.It is furthermore possible to also provide storage journey
The storage medium of sequence.
Although describing one or more embodiments of the present invention with reference to attached drawing, those of ordinary skill in the art answer
The understanding, in the case where not departing from the spirit and scope of the present invention being defined by the claims, it can be carried out in form and
Various variations in details.
Claims (7)
1. a kind of equipment for detecting defect pixel, the equipment include：
Calculator, it includes neighborhood pixels on surrounding target pixel and a direction being arranged in multiple predetermined directions to calculate
The gradient of the pixel value of neighborhood pixels group；
Recognition unit identifies the direction of the gradient minimum calculated by calculator among the multiple predetermined direction；And
Determiner, pixel value based on object pixel and include in neighborhood pixels group on the direction identified by recognition unit
Difference between the pixel value of first neighborhood pixels adjacent with object pixel and identical with object pixel color, determines object pixel
Whether it is defect pixel,
Wherein, group of the calculator based on the colour element for neighborhood pixels group adjacent with object pixel in a predetermined direction
The difference between the pixel value calculated separately is closed to calculate gradient.
2. equipment according to claim 1, wherein if the pixel value of object pixel and in the side identified by recognition unit
Relative size between adjacent with object pixel upwards and identical with object pixel color two adjacent pixels pixel value is closed
It is identical, and all differences between the pixel value of object pixel and the pixel value of described two adjacent pixels are all higher than threshold value,
Then determiner determines that object pixel is defect pixel.
3. equipment according to claim 1, the equipment further include：
Corrector corrects the pixel value of object pixel,
Wherein, if it is determined that device determines that object pixel is defect pixel, then pixel value of the corrector based on neighborhood pixels corrects mesh
Mark the pixel value of pixel.
4. equipment according to claim 3, wherein corrector by recognition unit based on being identified in neighborhood pixels group
Pixel value adjacent with object pixel and identical with object pixel color the first neighborhood pixels on direction, to correct object pixel
Pixel value.
5. equipment according to claim 1, wherein object pixel and neighborhood pixels are formed and exported by imaging device
The pixel of image, wherein four different filter with the matrix arrangement of each 2 × 2 pel array on the image.
6. a kind of method of detection defect pixel, the method includes：
Calculate include neighborhood pixels on surrounding target pixel and a direction being arranged in multiple predetermined directions neighbouring picture
The gradient of the pixel value of element group；
The direction of the gradient minimum of calculating is identified among the multiple predetermined direction；And
Pixel value based on object pixel and include adjacent with object pixel on the direction of identification in neighborhood pixels group and
Difference between the pixel value of the first neighborhood pixels identical with object pixel color determines whether object pixel is defect pixel,
Wherein, the combination based on the colour element for neighborhood pixels group adjacent with object pixel in a predetermined direction is counted respectively
Difference between the pixel value of calculation, to calculate the gradient.
7. according to the method described in claim 6, wherein, if the pixel value of object pixel and on the direction of identification with target
Relative size relationship between pixel is adjacent and the pixel value of identical with object pixel color two adjacent pixels is identical, and
All differences between the pixel value of the adjacent pixel of the pixel value of object pixel and two same colors are all higher than threshold value, then by mesh
Mark pixel is determined as defect pixel.
Applications Claiming Priority (4)
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|---|---|---|---|
| JP2012-277230 | 2012-12-19 | ||
| JP2012277230A JP6063728B2 (en) | 2012-12-19 | 2012-12-19 | Defective pixel detection device, defective pixel detection method, and program |
| KR1020130102660A KR102015587B1 (en) | 2012-12-19 | 2013-08-28 | Device and Method for detecting defect pixel and computer-implemented program thereof |
| KR10-2013-0102660 | 2013-08-28 |
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| CN103888690A CN103888690A (en) | 2014-06-25 |
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| FR3038195B1 (en) * | 2015-06-26 | 2018-08-31 | Ulis | DETECTION OF PIXEL PARASITES IN AN INFRARED IMAGE SENSOR |
| JP2017158018A (en) * | 2016-03-01 | 2017-09-07 | キヤノン株式会社 | Image processing apparatus, control method of the same, and imaging apparatus |
| WO2020181522A1 (en) * | 2019-03-13 | 2020-09-17 | 深圳市汇顶科技股份有限公司 | Defective pixel detection method, image processing chip, and electronic device |
| CN110827245A (en) * | 2019-10-28 | 2020-02-21 | 上海悦易网络信息技术有限公司 | Method and equipment for detecting screen display disconnection |
| KR20210156553A (en) * | 2020-06-18 | 2021-12-27 | 에스케이하이닉스 주식회사 | Image sensing device and operating method of the image sensing device |
| CN113962974A (en) * | 2021-10-27 | 2022-01-21 | 阿波罗智联(北京)科技有限公司 | Image processing method, image processing apparatus, electronic device, and medium |
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| EP1594308A1 (en) * | 2004-05-07 | 2005-11-09 | Dialog Semiconductor GmbH | Single line Bayer filter RGB bad pixel correction |
| JP5311916B2 (en) * | 2008-07-31 | 2013-10-09 | 株式会社エルモ社 | Imaging device |
| JP5655355B2 (en) * | 2009-11-02 | 2015-01-21 | ソニー株式会社 | Pixel defect correction device, imaging device, pixel defect correction method, and program |
| JP2012217139A (en) * | 2011-03-30 | 2012-11-08 | Sony Corp | Image processing device and method, and program |
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