CN109727232A - Method and equipment for detecting dot area ratio of printing plate - Google Patents
Method and equipment for detecting dot area ratio of printing plate Download PDFInfo
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Abstract
The invention discloses a kind of detection method of the dot area percentage of printing plate and equipment, wherein detection method includes the following steps: acquiring the halftone dot image of printing plate；Gray processing processing is carried out to halftone dot image, to generate gray level image；By Binary Sketch of Grey Scale Image, to generate binary image；Binary image is filtered, to generate filtered image；The ratio of the total quantity of the quantity for the pixel that site is characterized in filtered image and the pixel of filtered image is calculated, to obtain the dot area percentage of printing plate.Present invention reduces the complexities of the detection of the dot area percentage of printing plate, improve detection speed, save the time.Also, the present invention is conducive to the miniaturization and portability of the detection system of dot area percentage, is applied to flexographic printing system scene with can be convenient and draws a design and verify.
Description
Technical field
The invention belongs to the detection technique field of printing plate dot area percentage more particularly to a kind of dot area percentages of printing plate
Detection method and equipment.
Background technique
At present during calculating the dot area percentage of printing plate, printing plate halftone dot image is often acquired using camera, so
Afterwards, halftone dot image is transmitted to large-scale work station, is calculated.Since large-scale work station is bulky, inconvenient, operation is multiple
Miscellaneous, cost is very high, and scheme is difficult to apply to flexographic printing system scene and draws a design and verify in this, cannot provide the net of printing plate in real time
Point the area ratio.
Summary of the invention
Technical problems to be solved of the embodiment of the present invention are the calculating in order to overcome the printing plate dot area percentage of the prior art
At high cost, unhandy defect provides the detection method and equipment of a kind of dot area percentage of printing plate.
The embodiment of the present invention is to solve above-mentioned technical problem by following technical proposals:
The embodiment of the present invention provides a kind of detection method of the dot area percentage of printing plate, comprising the following steps:
S1, the halftone dot image for acquiring printing plate；
S2, gray processing processing is carried out to halftone dot image, to generate gray level image；
S3, by Binary Sketch of Grey Scale Image, to generate binary image；
S4, binary image is filtered, to generate filtered image；
The ratio of the total quantity of the pixel of S5, the quantity for calculating the pixel that site is characterized in filtered image and filtered image
Value, to obtain the dot area percentage of printing plate.
Preferably, halftone dot image is rgb color image, step S2 includes:
Gray processing processing is carried out to each pixel of halftone dot image according to the following formula,
F=[0.395 × R+0.641 × G+0.234 × B+0.5], wherein f is the gray value of pixel, and R is the red of pixel
The brightness value of chrominance channel, G are the brightness value of the green channel of pixel, and B is the brightness value of the blue channel of pixel.
Preferably, step S3 includes:
Using Da-Jin algorithm by Binary Sketch of Grey Scale Image.
Preferably, step S4 includes:
Successively each pixel of binary image is handled as follows with sequence from left to right, from top to bottom:
The value of pixel is replaced with into correction value, correction value is all pixels adjacent with pixel in binary image
It is worth the resulting value of phase exclusive or；The pixel adjacent with pixel is the pixel on the adjacent left side of pixel, right side, upside, downside.
Preferably, the pixel of characterization site is the pixel that value is 1.
Preferably, method is further comprising the steps of between step S4 and step S5:
Quantity Ni, the i ∈ [1, r] for the pixel that the every a line pixel median for calculating filtered image is 1, wherein r is filtering
The line number of the pixel of image afterwards；If the value of the first row of filtered image be 1 pixel quantity N1 be greater than 0 and be less than etc.
The first row is then deleted in Nj, j ∈ [2, r-1]；If the quantity Nr for the pixel that the value of the last line of filtered image is 1 is big
In 0 and being less than or equal to Nj, j ∈ [2, r-1] then deletes last line；
Quantity Mk, the k ∈ [1, c] for the pixel that each column pixel median for calculating filtered image is 1, wherein c is filtering
The l columns of the pixel of image afterwards；If the quantity M1 for the pixel that the value of the first row of filtered image is 1 is greater than 0 and is less than
First row is then deleted equal to Mn, n ∈ [2, c-1]；If the quantity Mc for the pixel that the value of last column of filtered image is 1
Greater than 0 and it is less than or equal to Mn, n ∈ [2, c-1] then deletes last column；
Image after output is cut；
Step S5 further include: calculate cut after image value be 1 pixel quantity account for cut after image pixel it is total
The percentage of quantity, using percentage as the dot area percentage of printing plate.
The present invention also provides a kind of detection devices of portable dot area percentage, including a portable housing, Image Acquisition list
Member, gray processing processing unit, binarization unit, filter unit, dot area percentage computing unit；
Image acquisition units are set in portable housing, gray processing processing unit, binarization unit, filter unit, site
The area ratio computing unit is set to the inside of portable housing；
Image acquisition units are used to acquire the halftone dot image of printing plate；
Gray processing processing unit is used to carry out gray processing processing to halftone dot image, to generate gray level image；
Binarization unit is used for by Binary Sketch of Grey Scale Image, to generate binary image；
Filter unit is for being filtered binary image, to generate filtered image；
Dot area percentage computing unit is schemed after being used to calculate the quantity and filtering of the pixel for characterizing site in filtered image
The ratio of the total quantity of the pixel of picture, to obtain the dot area percentage of printing plate.
Preferably, detection device further includes display unit, display unit is set to the outer surface of portable housing, display unit
For showing the dot area percentage of printing plate.
Preferably, image acquisition units include CMOS (Complementary Metal Oxide Semiconductor,
Complementary metal oxide semiconductor) imaging sensor, the resolution of cmos image sensor is 5,000,000 pixels~25,000,000 pictures
Element.
Preferably, detection device further includes cutting unit, the inside that unit is set to portable housing is cut；
Gray processing processing unit is also used to carry out gray processing processing to each pixel of halftone dot image according to the following formula:
F=[0.395 × R+0.641 × G+0.234 × B+0.5], wherein f is the gray value of pixel, and R is the red of pixel
The brightness value of chrominance channel, G are the brightness value of the green channel of pixel, and B is the brightness value of the blue channel of pixel；
Binarization unit is also used to use Da-Jin algorithm by Binary Sketch of Grey Scale Image；
Filter unit be also used to sequence from left to right, from top to bottom successively to each pixel of binary image into
The following processing of row: the value of pixel is replaced with into correction value, correction value is all pictures adjacent with pixel in binary image
The resulting value of value phase exclusive or of element；The pixel adjacent with pixel is the pixel on the adjacent left side of pixel, right side, upside, downside；
Quantity Ni, the i ∈ [1, r] that unit is used to calculate the pixel that every a line pixel median of filtered image is 1 is cut,
Wherein r is the line number of the pixel of filtered image；If the quantity N1 for the pixel that the value of the first row of filtered image is 1 is greater than
0 and it is less than or equal to Nj, j ∈ [2, r-1] then deletes the first row；If the pixel that the value of the last line of filtered image is 1
Quantity Nr be greater than 0 and be less than or equal to Nj, j ∈ [2, r-1] then deletes last line；
Cut unit be also used to calculate filtered image each column pixel median be 1 pixel quantity Mk, k ∈ [1,
C], wherein c is the l columns of the pixel of filtered image；If the quantity M1 for the pixel that the value of the first row of filtered image is 1
Greater than 0 and it is less than or equal to Mn, n ∈ [2, c-1] then deletes first row；If the value of last column of filtered image is 1
The quantity Mc of pixel is greater than 0 and is less than or equal to Mn, and n ∈ [2, c-1] then deletes last column；
It cuts unit and is also used to export image after cutting；
Dot area percentage computing unit be also used to calculate cut after image value be 1 pixel quantity account for cutting after image
Pixel total quantity percentage, using percentage as the dot area percentage of printing plate.
The positive effect of the present invention is that: present invention reduces the complexity of the detection of the dot area percentage of printing plate,
Detection speed is improved, the time is saved.Also, the present invention is conducive to the miniaturization of the detection system of dot area percentage and portable
Property, it is applied to flexographic printing system scene with can be convenient and draws a design and verify.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the detection device of the portable dot area percentage of the embodiment of the present invention 1.
Fig. 2 is that the filter unit of the detection device of the portable dot area percentage of the embodiment of the present invention 1 handles the first row
The schematic diagram of the pixel of first row.
Fig. 3 is that the filter unit of the detection device of the portable dot area percentage of the embodiment of the present invention 1 handles the first row
The schematic diagram of the pixel of secondary series.
Fig. 4 is the flow chart of the detection method of the dot area percentage of the printing plate of the embodiment of the present invention 1.
Fig. 5 is the structural schematic diagram of the detection device of the portable dot area percentage of the embodiment of the present invention 2.
Fig. 6 is the flow chart of the detection method of the dot area percentage of the printing plate of the embodiment of the present invention 2.
Specific embodiment
The present invention is further illustrated below by the mode of embodiment, but does not therefore limit the present invention to the reality
It applies among a range.
Embodiment 1
The present embodiment provides a kind of detection devices of portable dot area percentage, referring to Fig.1, the detection device include once
Take shell (not shown), image acquisition units 101, gray processing processing unit 102, binarization unit 103, filter unit
104, dot area percentage computing unit 105.Image acquisition units 101 are set in portable housing, gray processing processing unit 102,
Binarization unit 103, filter unit 104, dot area percentage computing unit 105 are set to the inside of portable housing.
Image acquisition units 101 are used to acquire the halftone dot image of printing plate.Gray processing processing unit 102 is used for halftone dot image
Gray processing processing is carried out, to generate gray level image.Binarization unit 103 is used for by Binary Sketch of Grey Scale Image, to generate binaryzation
Image.Filter unit 104 is for being filtered binary image, to generate filtered image.Dot area percentage computing unit
The ratio of 105 total quantity for calculating the quantity for the pixel for characterizing site in filtered image and the pixel of filtered image,
To obtain the dot area percentage of printing plate.
Using the portable dot area percentage of the present embodiment detection device when, user can hold the detection device, right
Flexographic printing system carries out scene and draws a design, and the halftone dot image of printing plate is acquired by image acquisition units 101.In the present embodiment, scheme
Picture acquisition unit uses cmos image sensor, and the resolution of the cmos image sensor is 10,000,000 pixels.It is optional at other
Embodiment in, image acquisition units can use CCD (charge-coupled device) imaging sensor, the solution of image acquisition units
The preferred range of analysis degree is 5,000,000 pixels~25,000,000 pixels.
Then, gray processing processing unit 102 carries out gray processing processing to halftone dot image.In the present embodiment, at gray processing
It manages unit 102 and gray processing processing is carried out to each pixel of halftone dot image according to the following formula:
F=[0.395 × R+0.641 × G+0.234 × B+0.5], wherein f is the gray value of pixel, and R is the red of pixel
The brightness value of chrominance channel, G are the brightness value of the green channel of pixel, and B is the brightness value of the blue channel of pixel.At the gray processing
The precision of subsequent processing can be improved in reason method.After gray processing processing, gray level image is obtained.
Next, binarization unit 103 is by Binary Sketch of Grey Scale Image, to generate binary image.In the present embodiment, two
Value unit 103 uses Da-Jin algorithm by Binary Sketch of Grey Scale Image.Each of gray level image pixel have gray value f, i.e., its
Gray level is that a width figure (can be divided into foreground point pixel and background dot pixel according to f by f.Foreground point pixel refers to all gray levels
Lower than the pixel for being equal to t*, background dot pixel refers to that the pixel greater than t*, t* are the binarization segmentation threshold of prospect and background
Value).The ratio that foreground point pixel accounts for the total pixel of gray level image can be denoted as w0, and the mean value of the pixel value of foreground point pixel is denoted as u0,
The ratio that background dot pixel accounts for the total pixel of gray level image can be denoted as w1, and the mean value of the pixel value of background dot pixel is denoted as u1.It is then whole
The mean value of the pixel of a gray level image is denoted as u=w0*u0+w1*u1.Construct objective function g (t)=w0* (u0-u) ^2+w1*
(u1-u)^2.It calculates g (t), when g (t) is maximum, corresponding t can be identified as binarization segmentation threshold value t*.In gray level image
The value of pixel of the gray value greater than binarization segmentation threshold value t* is labeled as 1, and gray value is not more than binarization segmentation in gray level image
The value of the pixel of threshold value t* is labeled as 0, to obtain binary image.By binary conversion treatment, each pixel only needs one
Bit can characterize, and greatly reduce the operand of subsequent processing.
Then, filter unit 104 is filtered binary image, to generate filtered image.In the present embodiment, it filters
Wave unit 104 is successively handled as follows each pixel of binary image with sequence from left to right, from top to bottom: will
The value of pixel replaces with correction value, correction value for the adjacent pixel of all and pixel in binary image value phase exclusive or institute
The value obtained；The pixel adjacent with pixel is the pixel on the adjacent left side of pixel, right side, upside, downside.Fig. 2 shows two-values
Change the partial pixel in the upper left corner of image.When filtering, first to the first pixel P1 of the first row first row of binary image into
Row processing, the left side and upside of the first pixel P1 do not have pixel, and the adjacent pixel of the first pixel P1 is the second picture on the right side of it
The plain P2 and third pixel P3 on the downside of it.The pixel value 0 of second pixel P2 and the pixel value 1 of third pixel P3 are different or, obtaining
1, then as shown in figure 3, the value of the first pixel P1 is replaced by 1.Then, next the second pixel of pixel P2 is handled.The
The adjacent pixel of two pixel P2 is the first pixel P1, the 4th pixel P4 on the right side of it, the 5th pixel on the downside of it on the left of it
P5, three's exclusive or obtain 0, and then it is constant to remain 0 for the value of the second pixel P2.Then, the 4th pixel P4 is handled.Work as place
The last one pixel of the first row has been managed, first pixel (third pixel P3) of the second row is handled.And so on, until by two
The all pixels of value image are disposed, and obtain filtered image.By filtering, making an uproar in binary image is eliminated
The detection accuracy of dot area percentage can be improved in sound.
Next, characterizing the pixel of site after 105 statistical filtering of dot area percentage computing unit in image, (i.e. value is 1
Pixel) quantity and filtered image in pixel total quantity, and calculate the former and account for the percentage of the latter, which is to print
The dot area percentage of version.
The detection device of the portable dot area percentage of the present embodiment reduces answering for the detection of the dot area percentage of printing plate
Miscellaneous degree improves detection speed, saves the time.Also, due to reducing computation complexity, the gray processing processing of the present embodiment
Unit, binarization unit, filter unit, dot area percentage computing unit can integrate in a CPU (central processing unit), from
And realize miniaturization, portable design, it is applied to flexographic printing system scene with can be convenient and draws a design and verify.
The present embodiment also provides a kind of detection method of the dot area percentage of printing plate, and the detection method is using the present embodiment
The detection device of portable dot area percentage realizes that, referring to Fig. 4, detection method includes the following steps for this:
Step S201, the halftone dot image of printing plate is acquired；
Step S202, gray processing processing is carried out to halftone dot image, to generate gray level image；
Step S203, by Binary Sketch of Grey Scale Image, to generate binary image；
Step S204, binary image is filtered, to generate filtered image；
Step S205, the sum of the quantity for the pixel that site is characterized in filtered image and the pixel of filtered image is calculated
The ratio of amount, to obtain the dot area percentage of printing plate.
In step s 201, the halftone dot image of printing plate is acquired by image acquisition units 101.
In step S202, gray processing processing unit 102 according to the following formula carries out each pixel of halftone dot image
Gray processing processing:
F=[0.395 × R+0.641 × G+0.234 × B+0.5], wherein f is the gray value of pixel, and R is the red of pixel
The brightness value of chrominance channel, G are the brightness value of the green channel of pixel, and B is the brightness value of the blue channel of pixel.At the gray processing
The precision of subsequent processing can be improved in reason method.After gray processing processing, gray level image is obtained.
In step S203, binarization unit 103 uses Da-Jin algorithm by Binary Sketch of Grey Scale Image.It is each in gray level image
A pixel has gray value f, i.e. its gray level is that a width figure (can be divided into foreground point pixel and background dot pixel according to f by f.
Foreground point pixel refers to that all gray levels are lower than the pixel equal to t*, and background dot pixel refers to that the pixel greater than t*, t* are prospect
With the binarization segmentation threshold value of background).The ratio that foreground point pixel accounts for the total pixel of gray level image can be denoted as w0, foreground point pixel
The mean value of pixel value is denoted as u0, and the ratio that background dot pixel accounts for the total pixel of gray level image can be denoted as w1, the pixel of background dot pixel
The mean value of value is denoted as u1.Then the mean value of the pixel of entire gray level image is denoted as u=w0*u0+w1*u1.It constructs objective function g (t)
=w0* (u0-u) ^2+w1* (u1-u) ^2.It calculates g (t), when g (t) is maximum, corresponding t can be identified as binarization segmentation
Threshold value t*.The value of pixel of the gray value greater than binarization segmentation threshold value t* is labeled as 1 in gray level image, gray value in gray level image
The value of pixel no more than binarization segmentation threshold value t* is labeled as 0, to obtain binary image.By binary conversion treatment, often
One pixel only needs a bit that can characterize, and greatly reduces the operand of subsequent processing.
In step S204, filter unit 104 is with sequence from left to right, from top to bottom successively to the every of binary image
One pixel is handled as follows: the value of pixel being replaced with correction value, correction value is all and picture in binary image
The resulting value of value phase exclusive or of the adjacent pixel of element；The pixel adjacent with pixel be the adjacent left side of pixel, right side, upside,
The pixel of downside.Fig. 2 shows the partial pixels in the upper left corner of binary image.When filtering, first to binary image
First pixel P1 of a line first row is handled, and the left side and upside of the first pixel P1 does not have pixel, the phase of the first pixel P1
Adjacent pixel is the second pixel P2 on the right side of it and the third pixel P3 on the downside of it.The pixel value 0 and third picture of second pixel P2
The pixel value 1 of plain P3 is different or, obtaining 1, then as shown in figure 3, the value of the first pixel P1 is replaced by 1.Then, to next picture
The second pixel P2 of element is handled.The adjacent pixel of second pixel P2 be its on the left of the first pixel P1, the on the right side of it the 4th
Pixel P4, the 5th pixel P5 on the downside of it, three's exclusive or obtain 0, and then it is constant to remain 0 for the value of the second pixel P2.Then, right
4th pixel P4 is handled.When the last one pixel for having handled the first row, first pixel (third picture of the second row is handled
Plain P3).And so on, until all pixels of binary image are disposed, obtain filtered image.By filtering,
The noise in binary image is eliminated, the detection accuracy of dot area percentage can be improved.
In step S205, the pixel for characterizing site after 105 statistical filtering of dot area percentage computing unit in image (is worth
Pixel for 1) quantity and filtered image in pixel total quantity, and calculate the former and account for the percentage of the latter, the percentage
The as dot area percentage of printing plate.
Embodiment 2
On the basis of the detection device of the portable dot area percentage of embodiment 1, the present embodiment provides a kind of portable
The detection device of dot area percentage, referring to Fig. 2, which further includes cutting unit 106, display unit 107.Cut unit
106 are set to the inside of portable housing, and display unit 107 is set to the outer surface of portable housing.Display unit 107 is for showing
The dot area percentage of printing plate.
Cut unit 106 be used for calculate filtered image every a line pixel median be 1 pixel quantity Ni, i ∈ [1,
R], wherein r is the line number of the pixel of filtered image；If the quantity N1 for the pixel that the value of the first row of filtered image is 1
Greater than 0 and it is less than or equal to Nj, j ∈ [2, r-1] then deletes the first row；If the value of the last line of filtered image is 1
The quantity Nr of pixel is greater than 0 and is less than or equal to Nj, and j ∈ [2, r-1] then deletes last line；Unit is cut to be also used to calculate
Quantity Mk, the k ∈ [1, c] for the pixel that each column pixel median of filtered image is 1, wherein c is the pixel of filtered image
L columns；If the quantity M1 for the pixel that the value of the first row (column of the leftmost side one) of filtered image is 1 is greater than 0 and is less than
First row is then deleted equal to Mn, n ∈ [2, c-1]；If the value of last column (column of the rightmost side one) of filtered image is 1
The quantity Mc of pixel is greater than 0 and is less than or equal to Mn, and n ∈ [2, c-1] then deletes last column；Unit is cut to be also used to export
Image after cutting.The filtered image of the output of unit 104 that is, cutting unit 106 accepts filter, calculates the every of filtered image
The quantity for the pixel that one-row pixels intermediate value is 1.The quantity N1 for the pixel that the value of the first row of filtered image is 1 is not equal to 0, then
By the value of the first row of filtered image be 1 pixel quantity N1 one by one in addition to the first row and last line other are each
The quantity Nj (j ∈ [2, r-1]) for the pixel that capable value is 1 compares, if N1 is the smallest by one no more than in Nj (j ∈ [2, r-1])
It is a, then determine that the grid at filtered image top edges is imperfect, it is lower for the reference value of the detection of dot area percentage,
Then the first row of filtered image is deleted.While judging the first row, unit 106 is cut according further to similar
Method judges whether last line needs to delete, and cuts the leftmost side that unit 106 judges filtered image according further to preceding method
Whether one column and the column of the rightmost side one need to delete.After the completion of judgement, unit 106 is cut to meeting deletion condition in filtered image
Row or column deleted, that is, complete to the trimming operation of filtered image, image after output is cut.In other optional implementations
In mode, can first the first row of filtered image and last line be judged by cutting unit, then be deleted accordingly
Except operation, an intermediate image is obtained；Then the column of the leftmost side one of image and the column of the rightmost side one are sentenced between cutting cell pairs
It is disconnected, carry out corresponding delete operation, image after final output is cut.Alternatively, cut unit can first to filtered image most
The column of left side one and the column of the rightmost side one are judged, are then carried out corresponding delete operation, are obtained an intermediate image；Then it cuts
The first row and last line of image are judged between cell pairs, carry out corresponding delete operation, and final output is schemed after cutting
Picture.
Then, scheme after the quantity and cutting of the pixel that the value of image is 1 after the statistics of dot area percentage computing unit 105 is cut
The total quantity of the pixel of picture, and calculate cut after image value be 1 pixel quantity account for cut after image pixel sum
The percentage of amount, using the percentage as the dot area percentage of printing plate.By trimming operation, the dry of incomplete grid is eliminated
It disturbs, the dot area percentage of finally obtained printing plate is more accurate.
Display unit 107 shows the dot area percentage of printing plate, also shows that the halftone dot image of printing plate is for reference.
On the basis of the detection method of the dot area percentage of the printing plate of embodiment 1, the present embodiment also provides a kind of printing plate
Dot area percentage detection method, the detection method is real using the detection device of the portable dot area percentage of the present embodiment
Show, referring to Fig. 6, detection method includes the following steps for this:
Step S201, the halftone dot image of printing plate is acquired.
Step S202, gray processing processing is carried out to halftone dot image, to generate gray level image.
Step S203, by Binary Sketch of Grey Scale Image, to generate binary image.
Step S204, binary image is filtered, to generate filtered image.
Step S2041, judge whether the edge of filtered image meets deletion condition, if so, being deleted, output is cut out
Cut rear image.
Step S205 include step S2051, calculate cut after image value be 1 pixel quantity account for cutting after image
The percentage of the total quantity of pixel, using percentage as the dot area percentage of printing plate.
Step S206, the dot area percentage of printing plate is shown.
When it is implemented, cutting unit 106 and calculating every a line pixel median of filtered image is 1 in step S2041
Pixel quantity Ni, i ∈ [1, r], wherein r be filtered image pixel line number；If the first row of filtered image
Value be 1 the quantity N1 of pixel be greater than 0 and be less than or equal to Nj, j ∈ [2, r-1] then deletes the first row；If schemed after filtering
The quantity Nr for the pixel that the value of the last line of picture is 1 is greater than 0 and is less than or equal to Nj, and j ∈ [2, r-1] then deletes last
Row；Quantity Mk, the k ∈ [1, c] that unit is also used to calculate the pixel that each column pixel median of filtered image is 1 is cut,
Middle c is the l columns of the pixel of filtered image；If the quantity M1 for the pixel that the value of the first row of filtered image is 1 is greater than 0
And it is less than or equal to Mn, n ∈ [2, c-1] then deletes first row；If the pixel that the value of last column of filtered image is 1
Quantity Mc be greater than 0 and be less than or equal to Mn, n ∈ [2, c-1] then deletes last column；It cuts unit and is also used to export cutting
Image afterwards.The filtered image of the output of unit 104 that is, cutting unit 106 accepts filter, calculates every a line of filtered image
The quantity for the pixel that pixel median is 1.The quantity N1 for the pixel that the value of the first row of filtered image is 1 is not equal to 0, then will filter
After wave the value of the first row of image be 1 pixel quantity N1 one by one with other each rows in addition to the first row and last line
Value compares for the quantity Nj (j ∈ [2, r-1]) of 1 pixel, if N1 is one the smallest no more than in Nj (j ∈ [2, r-1]), then
Determine that the grid at filtered image top edges is imperfect, it is lower for the reference value of the detection of dot area percentage, then
The first row of filtered image is deleted.While judging the first row, unit 106 is cut according further to similar method
Judge whether last line needs to delete, cuts unit 106 according further to preceding method and judge that the leftmost side one of filtered image arranges
Whether need to delete with the column of the rightmost side one.After the completion of judgement, unit 106 is cut to the row for meeting deletion condition in filtered image
Or column are deleted, that is, complete the trimming operation to filtered image, image after output is cut.In other optional embodiments
In, can first the first row of filtered image and last line be judged by cutting unit, then carried out corresponding delete and grasped
Make, obtains an intermediate image；Then the column of the leftmost side one of image and the column of the rightmost side one are judged between cutting cell pairs, into
The corresponding delete operation of row, image after final output is cut.It can be first to the leftmost side of filtered image one alternatively, cutting unit
Column and the column of the rightmost side one are judged, are then carried out corresponding delete operation, are obtained an intermediate image；Then unit pair is cut
The first row and last line of intermediate image are judged, corresponding delete operation, image after final output is cut are carried out.
Then, in step S2051, the value of image is 1 after the statistics of dot area percentage computing unit 105 is cut pixel
Quantity and cut after image pixel total quantity, and calculate cut after image value be 1 pixel quantity account for cutting after scheme
The percentage of the total quantity of the pixel of picture, using the percentage as the dot area percentage of printing plate.By trimming operation, eliminate not
The interference of complete grid, the dot area percentage of finally obtained printing plate are more accurate.
Finally, display unit 107 shows the dot area percentage of printing plate in step S206, the half-tone of printing plate is also shown
As for reference.
Although specific embodiments of the present invention have been described above, it will be appreciated by those of skill in the art that these
It is merely illustrative of, protection scope of the present invention is defined by the appended claims.Those skilled in the art is not carrying on the back
Under the premise of from the principle and substance of the present invention, many changes and modifications may be made, but these are changed
Protection scope of the present invention is each fallen with modification.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811554335.2A CN109727232B (en) | 2018-12-18 | 2018-12-18 | Method and apparatus for detecting dot area ratio of printing plate |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811554335.2A CN109727232B (en) | 2018-12-18 | 2018-12-18 | Method and apparatus for detecting dot area ratio of printing plate |
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| Publication Number | Publication Date |
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| CN109727232A true CN109727232A (en) | 2019-05-07 |
| CN109727232B CN109727232B (en) | 2023-03-31 |
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| CN112258501A (en) * | 2020-11-10 | 2021-01-22 | 深圳拓匠印前科技有限公司 | Printing plate mesh point detection method, printing plate measuring instrument and readable storage medium |
| CN115861297A (en) * | 2023-02-14 | 2023-03-28 | 联禾印享文化科技(南京)有限公司 | Printing plate dot image detection and segmentation method and device based on deep learning |
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| CN115861297A (en) * | 2023-02-14 | 2023-03-28 | 联禾印享文化科技(南京)有限公司 | Printing plate dot image detection and segmentation method and device based on deep learning |
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