CN112258501A - Printing plate mesh point detection method, printing plate measuring instrument and readable storage medium - Google Patents
Printing plate mesh point detection method, printing plate measuring instrument and readable storage medium Download PDFInfo
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- 238000007639 printing Methods 0.000 title claims abstract description 316
- 238000001514 detection method Methods 0.000 title claims abstract description 88
- 238000003709 image segmentation Methods 0.000 claims abstract description 47
- 230000011218 segmentation Effects 0.000 claims description 67
- 238000000034 method Methods 0.000 abstract description 12
- 238000005259 measurement Methods 0.000 description 9
- 238000004891 communication Methods 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 238000001739 density measurement Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000691 measurement method Methods 0.000 description 4
- 238000005192 partition Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
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- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0004—Industrial image inspection
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/10—Segmentation; Edge detection
- G06T7/136—Segmentation; Edge detection involving thresholding
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- G—PHYSICS
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- G06T7/10—Segmentation; Edge detection
- G06T7/194—Segmentation; Edge detection involving foreground-background segmentation
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- G—PHYSICS
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- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/20—Special algorithmic details
- G06T2207/20076—Probabilistic image processing
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- G—PHYSICS
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- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/30—Subject of image; Context of image processing
- G06T2207/30108—Industrial image inspection
- G06T2207/30144—Printing quality
Abstract
The application discloses a printing plate mesh point detection method, a printing plate measuring instrument and a readable storage medium, wherein the printing plate mesh point detection method comprises the following steps: the method comprises the steps of obtaining a printing plate dot image of a printing plate to be detected, carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result, carrying out image binarization on the printing plate dot image based on the image segmentation result to obtain a binary image, and carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result. The method and the device solve the technical problem of low printing plate mesh point detection accuracy.
Description
Technical Field
The application relates to the technical field of printing, in particular to a printing plate mesh point detection method, a printing plate measuring instrument and a readable storage medium.
Background
With the continuous development of printing technology, the requirement of users on the printing quality is higher and higher, and one of the important factors influencing the printing quality is the size, shape and inking condition of printing plate dots, so that accurate dot detection on the printing plate dots is extremely important.
Disclosure of Invention
The application mainly aims to provide a printing plate dot detection method, a printing plate measuring instrument and a readable storage medium, and aims to solve the technical problem that in the prior art, the printing plate dot detection accuracy is low.
In order to achieve the above object, the present application provides a printing plate dot detection method, which is applied to a printing plate measuring instrument, and includes:
obtaining a printing plate dot image of a printing plate to be detected, and carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result;
carrying out image binarization on the printing plate dot image based on the image segmentation result to obtain a binary image;
and carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result.
The application still provides a printing plate site detection device, printing plate site detection device is virtual device, just printing plate site detection device is applied to the printing plate measuring apparatu, printing plate site detection device includes:
the image segmentation module is used for acquiring a printing plate dot image of a printing plate to be detected, and performing threshold-based image segmentation on the printing plate dot image to obtain an image segmentation result;
the image binarization module is used for carrying out image binarization on the printing plate mesh point image based on the image segmentation result to obtain a binary image;
and the mesh point detection module is used for carrying out mesh point detection on the printing plate to be detected based on the binary image to obtain a target mesh point detection result.
The present application further provides a printing plate measuring instrument, the printing plate measuring instrument is an entity device, the printing plate measuring instrument includes: a memory, a processor and a program of the printing plate dot detection method stored on the memory and executable on the processor, wherein the program of the printing plate dot detection method, when executed by the processor, may implement the steps of the printing plate dot detection method as described above.
The application also provides a readable storage medium, wherein a program for realizing the printing plate dot detection method is stored on the readable storage medium, and when the program for realizing the printing plate dot detection method is executed by a processor, the steps of the printing plate dot detection method are realized.
The application provides a printing plate mesh point detection method, a printing plate measuring instrument and a readable storage medium, compared with the technical means of carrying out printing plate mesh point detection by a density measurement method and a colorimetric measurement method adopted in the prior art, the method firstly carries out image segmentation based on a threshold value on a printing plate mesh point image after obtaining the printing plate mesh point image of a printing plate to be detected so as to achieve the purpose of segmenting a background part and a non-background part of the printing plate mesh point image, wherein the non-background part is an inking part of the printing plate mesh point, the background part is a blank part of the printing plate mesh point, an image segmentation result is further obtained, then image binarization is carried out on the printing plate mesh point image based on the image segmentation result so as to endow the background part and the non-background part of the printing plate mesh point image with a gray value with a larger brightness difference, and further achieve the purpose of accurately distinguishing the blank part and the inking part of the, wherein, it should be noted that, due to the limitation of the material of the printing plate, the blank part and the inking part of the printing plate usually have the defect of small image contrast, etc., which further causes the deviation of the measurement of the dot area rate of the printing plate, and further based on the background part and the non-background part with different brightness in the binary image, the dot detection is performed on the printing plate to be detected, and the target dot detection result is obtained, thus the purpose of measuring the dot area rate of the printing plate to be detected based on the blank part and the inking part of the printing plate which are accurately distinguished can be realized, the measurement precision of the dot area rate is improved, the technical defect that when the printing plate dot detection is performed by a density measurement method and a colorimetric measurement method in the prior art, due to the limitation of the material of the printing plate, the deviation exists when the measurement of the dot area rate of the printing plate, and further, the accuracy of printing plate mesh point detection is improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a schematic flow chart of a printing plate dot detection method according to a first embodiment of the present application;
FIG. 2 is a schematic diagram of a binary image in the printing plate dot detection method of the present application;
FIG. 3 is a schematic flow chart of a printing plate dot detection method according to a second embodiment of the present application;
fig. 4 is a schematic device structure diagram of a hardware operating environment according to an embodiment of the present application.
The objectives, features, and advantages of the present application will be further described with reference to the accompanying drawings.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In a first embodiment of the printing plate dot detection method of the present application, referring to fig. 1, the printing plate dot detection method includes:
step S10, obtaining a printing plate dot image of a printing plate to be detected, and carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result;
in this embodiment, it should be noted that the printing plate to be detected needs to be subjected to dot detection, and the dot image of the printing plate is a grayscale image of the printing plate to be detected.
Obtaining a printing plate dot image of a printing plate to be detected, performing threshold-based image segmentation on the printing plate dot image to obtain an image segmentation result, specifically, obtaining the printing plate dot image of the printing plate to be detected, and performing threshold-based image segmentation on the printing plate dot image to divide each pixel point in the printing plate dot image into each first type pixel point and each second type pixel point, where the first type pixel points are pixel points belonging to the printing plate dots in the printing plate dot image, the second type pixel points are pixel points not belonging to the printing plate dots in the printing plate dot image, and further taking the division result of each first type pixel point and each second type pixel point as the image segmentation result, for example, assuming that the value range of the gray value corresponding to the pixel point of the printing plate dot image is 0 to L, and if the threshold value is t, the first type pixel points are pixel points with the gray value ranging from 0 to t, and the second type pixel points are pixel points with the gray value ranging from t to L.
The step of acquiring the printing plate dot image of the printing plate to be detected comprises the following steps:
step S11, collecting the printing plate shooting image of the printing plate to be detected;
in this embodiment, a shot image of the printing plate to be detected is acquired, specifically, the printing plate to be detected is irradiated based on a preset illumination system, so that the printing plate to be detected is amplified by the preset illumination microscope system under the illumination irradiation condition, and a dot image of the printing plate to be detected is acquired by the preset photoelectric conversion system.
And step S12, graying the image shot by the printing plate to obtain the dot image of the printing plate.
In this embodiment, it should be noted that the image taken by the printing plate is a color image, and the dot shape feature of the dot is used for performing the dot detection, and the dot color of the dot is redundant information.
Graying the image shot by the printing plate to obtain the printing plate dot image, specifically, graying the image shot by the printing plate to remove redundant information in the image shot by the printing plate to obtain the printing plate dot image.
Step S20, carrying out image binarization on the printing plate dot image based on the image segmentation result to obtain a binary image;
in this embodiment, based on the image segmentation result, performing image binarization on the printing plate dot image to obtain a binary image, specifically, based on the image segmentation result, determining each first type pixel point and each second type pixel point in the printing plate dot image, and further giving a fixed preset gray value to each first type pixel point and each second type pixel point to obtain a binary image corresponding to the printing plate dot image, where in an implementable manner, a mathematical process of the image binarization is as follows:
in the formula (3.9), t is the threshold, f (x, y) is the grayscale value of the binary image, and f (i, j) is the grayscale value of the printing plate dot image.
The step of carrying out image binarization on the printing plate dot image based on the image segmentation result to obtain a binary image comprises the following steps of:
step S21, determining an image background part corresponding to the printing plate dot image and a corresponding printing plate dot part based on the image segmentation result;
in this embodiment, based on the image segmentation result, an image background portion corresponding to the printing plate dot image and a corresponding printing plate dot portion are determined, and specifically, an area occupied by each first type pixel point in the printing plate dot image is taken as the image background portion, and an area occupied by each second type pixel point in the printing plate dot image is taken as the printing plate dot portion.
And step S22, binarizing the image background part and the printing plate dot part to obtain the binary image.
In this embodiment, the image background portion and the printing plate dot portion are binarized to obtain the binary image, and specifically, a preset first gray value is assigned to each pixel point in the image background portion in the printing plate dot image, and a preset second gray value is assigned to each pixel point in the printing plate dot portion in the printing plate dot image to obtain the binary image.
Wherein the binary image comprises a first image portion and a second image portion,
the step of binarizing the image background part and the printing plate dot part to obtain the binary image comprises the following steps:
step S221, replacing the gray value of each pixel point in the image background part with a preset first gray value to obtain the first image part;
in this embodiment, the gray value of each pixel in the image background portion is replaced with a preset first gray value to obtain the first image portion, specifically, the gray value of each pixel in the image background portion is deleted and is completely replaced with the preset first gray value to obtain the image background portion after the preset first gray value is replaced, and the image background portion after the preset first gray value is replaced is used as the first image portion.
Step S222, replacing the gray value of each pixel point in the printing plate mesh point part with a preset second gray value to obtain a second image part;
in this embodiment, the gray value of each pixel in the printing plate dot part is replaced with a preset second gray value to obtain the second image part, specifically, the gray value of each pixel in the printing plate dot part is deleted and is completely replaced with the preset second gray value to obtain the printing plate dot part after replacing the preset second gray value, and the printing plate dot part after replacing the preset second gray value is used as the second image part.
And step S30, carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result.
Wherein the target dot detection result comprises a dot area rate,
the step of carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result comprises the following steps:
step S31, acquiring the total image area of the binary image, and measuring the target image area of the printing plate mesh point area in the binary image;
in this embodiment, it should be noted that the dot area of the printing plate is an area image of an inked portion of the printing plate to be detected, and it should be noted that, because the distance between the preset first gray value and the preset second gray value is very large when the image binarization is carried out, and the brightness difference between the image background area and the printing plate dot area is very large, and the boundary between the image background area and the printing plate dot area is obvious, for example, as shown in fig. 2, it is a schematic diagram of a binary image, wherein the white area is the printing plate mesh point area, the black area is the image background area, the white area has higher brightness than the black area, that is, the gray value of the white area is much greater than that of the black area, and the dot area ratios are 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90%.
The method comprises the steps of obtaining the total image area of a binary image, measuring the target image area of a printing plate dot area in the binary image, specifically obtaining the size information of the binary image, calculating the total image area based on the size information of the binary image, and measuring the target image area of the printing plate dot area in the binary image, wherein it needs to be stated that the accuracy of measuring the target image area of the printing plate dot area in the binary image is extremely high due to the fact that the brightness difference between the printing plate dot area and the image background area is extremely large, and then the boundary between the printing plate dot area and the image background area is clear, and further the calculation accuracy of the dot area rate can be improved.
Step S32, calculating the dot area ratio based on the total image area and the target image area.
In this embodiment, the dot area ratio is calculated based on the total image area and the target image area, and specifically, the dot area ratio is obtained by dividing the target image area by the total image area.
The embodiment provides a printing plate dot detection method, compared with a technical means of performing printing plate dot detection through a density measurement method and a colorimetric measurement method in the prior art, after a printing plate dot image of a printing plate to be detected is obtained, image segmentation based on a threshold value is performed on the printing plate dot image to achieve the purpose of segmenting a background part and a non-background part of the printing plate dot image, wherein the non-background part is an inking part of the printing plate dot, the background part is a blank part of the printing plate dot, an image segmentation result is further obtained, image binarization is performed on the printing plate dot image based on the image segmentation result to endow a gray value with a larger brightness difference on the background part and the non-background part of the printing plate dot image, and the purpose of accurately distinguishing the printing plate part and the inking part to be detected is further achieved, wherein, it should be noted that, due to the limitation of the material of the printing plate, the blank part and the inking part of the printing plate usually have the defect of small image contrast, etc., which further causes the deviation of the measurement of the dot area rate of the printing plate, and further based on the background part and the non-background part with different brightness in the binary image, the dot detection is performed on the printing plate to be detected, and the target dot detection result is obtained, thus the purpose of measuring the dot area rate of the printing plate to be detected based on the blank part and the inking part of the printing plate which are accurately distinguished can be realized, the measurement precision of the dot area rate is improved, the technical defect that when the printing plate dot detection is performed by a density measurement method and a colorimetric measurement method in the prior art, due to the limitation of the material of the printing plate, the deviation exists when the measurement of the dot area rate of the printing plate, and further, the accuracy of printing plate mesh point detection is improved.
Further, referring to fig. 3, based on the first embodiment in the present application, in another embodiment of the present application, the image segmentation result includes an image background portion corresponding to the printing plate dot image and a corresponding printing plate dot portion,
the step of carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result comprises the following steps:
step A10, determining a target segmentation threshold value based on image size information corresponding to the printing plate dot image and corresponding gray scale information;
in this embodiment, it should be noted that the grayscale information is image grayscale information of a printing plate dot image, where the image grayscale information is grayscale value range information of the printing plate dot image, for example, assuming that the image grayscale of the printing plate dot image is 256, the grayscale value range is 0 to 255.
Determining a target segmentation threshold based on image dimension information corresponding to the printing plate dot image and corresponding gray scale information, specifically, calculating gray scale value occurrence probabilities of gray scale values in the printing plate dot image within gray scale value ranges corresponding to the gray scale information based on the gray scale information and the image dimension information corresponding to the printing plate dot image to obtain the gray scale value occurrence probabilities of the gray scale values, further determining each to-be-selected segmentation threshold in the gray scale value range corresponding to the printing plate dot image, further based on each to-be-selected segmentation threshold, dividing the gray scale value range in the printing plate dot image into a first value range and a second value range, further based on each gray scale value occurrence probability corresponding to each to-be-selected segmentation threshold, each gray scale value in the first value range corresponding to each to-be-selected segmentation threshold, and each gray scale value in the second value range corresponding to each to-be-selected segmentation threshold, and calculating an evaluation index value corresponding to each to-be-selected segmentation threshold, wherein the evaluation index value comprises the inter-class variance of each gray value in a first value range and each gray value in a second value range, and further taking the to-be-selected segmentation threshold corresponding to the maximum evaluation index value as the target segmentation threshold.
Wherein, the step of determining the target segmentation threshold value based on the image size information corresponding to the printing plate dot image and the corresponding gray scale information comprises the following steps:
step A11, calculating the gray value occurrence probability of each gray value corresponding to the printing plate mesh point image based on the image size information and the gray information;
in this embodiment, it should be noted that the grayscale information is the number of occurrences of grayscale values in all grayscale values in the printing plate dot image.
Calculating the occurrence probability of the gray value of each gray value corresponding to the printing plate dot image based on the image size information and the gray information, specifically, inputting the image size information and the occurrence frequency of each gray value in the printing plate dot image into a preset gray value occurrence probability calculation formula, and calculating the occurrence probability of each gray value corresponding to the printing plate dot image, wherein the preset gray value occurrence probability calculation formula is as follows:
Pi＝ni/M*N
wherein n isiThe number of times of occurrence of the gray value in the printing plate dot image is represented by Pi, the occurrence probability of the gray value corresponding to a gray value in the printing plate dot image is represented by M, the length of the printing plate dot image is represented by N, and the width of the printing plate dot image is represented by N.
Step A12, acquiring an image gray level corresponding to the printing plate dot image, and generating a segmentation threshold value set based on the image gray level;
in this embodiment, it should be noted that the image gray level is the number of different gray values in the printing plate dot image, for example, it is assumed that the gray value of the gray value in the printing plate dot image ranges from 0 to 255, where the gray value is an integer, and the image gray level is 256.
And specifically, obtaining the image gray level corresponding to the printing plate dot image, taking each integer in the gray value range corresponding to the image gray level as each to-be-selected segmentation threshold value, and further taking a set formed by each to-be-selected segmentation threshold value as the segmentation threshold value set.
Step A13, based on the occurrence probability of each gray value, calculating the variance between segmentation classes corresponding to each to-be-selected segmentation threshold in the segmentation threshold set respectively;
in this embodiment, based on the occurrence probability of each gray value, the inter-partition variance corresponding to each to-be-selected partition threshold in the partition threshold set is respectively calculated, and specifically, the following steps are performed for each to-be-selected partition threshold:
dividing each gray value in the printing plate mesh point image based on the segmentation threshold to be selected so as to take each gray value smaller than the segmentation threshold to be selected as a first gray value part, take each gray value not smaller than the segmentation threshold to be selected as a second gray value part, further calculate the cumulative sum of the gray value occurrence probabilities corresponding to each gray value in the first gray value part to obtain the first part gray value occurrence probability, calculate the cumulative sum of the gray value occurrence probabilities corresponding to each gray value in the second gray value part to obtain the second part gray value occurrence probability, further calculate a first occurring average gray value based on the average value of each gray value occurring in the first gray value part and the first part gray value occurrence probability, and calculate a first occurring average gray value based on the average value of each gray value occurring in the second gray value part and the first part gray value occurrence probability, calculating a second occurrence average gray value, and substituting the first part of gray values, the first occurrence average gray value, the first part of gray values and the second occurrence average gray value into a preset inter-segmentation-class variance formula to calculate an inter-segmentation-class variance corresponding to the to-be-selected segmentation threshold, wherein the preset inter-segmentation-class variance formula is as follows:
D＝ω0*ω1(μ1-μ0)2
wherein, w0Is the probability of occurrence of the first part of gray values, w1Is the probability of occurrence of the first part of gray values, u1And u0 is the first occurrence mean gray value, wherein the first occurrence mean gray value and the second occurrence mean gray value are calculated as follows:
wherein t is the segmentation threshold to be selected, and i is a gray value.
Step A14, selecting a target inter-class variance from each of the inter-class variances, and using a to-be-selected segmentation threshold corresponding to the target inter-class variance as the target segmentation threshold.
In this embodiment, a target inter-class variance is selected from each of the inter-class variances, and a to-be-selected segmentation threshold corresponding to the target inter-class variance is used as the target segmentation threshold, specifically, a maximum value of each of the inter-class variances is used as the target inter-class variance, and the to-be-selected segmentation threshold corresponding to the target inter-class variance is used as the target segmentation threshold.
Step A20, segmenting the printing plate dot image into the image background portion and the printing plate dot portion based on the target segmentation threshold.
In this embodiment, the printing plate dot image is divided into the image background portion and the printing plate dot portion based on the target division threshold, specifically, based on the target division threshold, each gray value in the printing plate dot image is divided into a first type gray value and a second type gray value, an area occupied by the first type gray value in the printing plate dot image is used as the image background portion, and an area occupied by the second type gray value in the printing plate dot image is used as the printing plate dot portion.
The image background part at least comprises a first type pixel point, the printing plate mesh point part at least comprises a second type pixel point,
the step of segmenting the printing plate dot image into an image background portion and a printing plate dot portion based on the target segmentation threshold comprises:
step A21, acquiring each gray value in the printing plate dot image, and comparing each gray value with the target segmentation threshold value respectively;
step A22, taking the pixel point corresponding to the gray value not greater than the target segmentation threshold value as the first type pixel point;
and step A23, taking the pixel points corresponding to the gray values larger than the target segmentation threshold as the second type pixel points.
In this embodiment, specifically, each gray value in the printing plate dot image is obtained, and each gray value is compared with the target segmentation threshold, if the gray value in the printing plate dot image is not greater than the target segmentation threshold, it is verified that the pixel value corresponding to the gray value in the printing plate dot image belongs to the background region of the printing plate dot image, and then the pixel point corresponding to the gray value not greater than the target segmentation threshold is used as the first type pixel point, and if the gray value in the printing plate dot image is greater than the target segmentation threshold, it is verified that the pixel value corresponding to the gray value in the printing plate dot image belongs to the printing plate dot region of the printing plate dot image, and then the pixel point corresponding to the gray value greater than the target segmentation threshold is used as the second type pixel point.
The embodiment provides a method for performing threshold-based image segmentation on a printing plate dot image, that is, determining a target segmentation threshold based on image size information and corresponding gray scale information corresponding to the printing plate dot image, and further segmenting the printing plate dot image into an image background portion and a printing plate dot portion based on the target segmentation threshold, wherein the printing plate dot portion is an inking portion of a printing plate dot, the background portion is a blank portion of the printing plate dot, and further performing image binarization on the printing plate dot image based on the image segmentation result to assign gray scale values with a large brightness difference to the background portion and a non-background portion of the printing plate dot image, so as to achieve the purpose of accurately distinguishing the blank portion and the inking portion of a printing plate to be detected, wherein it needs to be explained that, due to the limitation of the material of the printing plate, the printing plate usually has the defects of small image contrast and the like of a blank part and an inking part, so that deviation exists during the measurement of the dot area rate of the printing plate, and then the dot detection is carried out on the printing plate to be detected based on the background part and the non-background part with different brightness in the binary image to obtain the target dot detection result, so that the purpose of measuring the dot area rate of the printing plate to be detected based on the blank part and the inking part of the printing plate which are accurately distinguished can be realized, the measurement precision of the dot area rate is improved, and the method lays a foundation for overcoming the technical defect that the deviation exists during the measurement of the dot area rate of the printing plate due to the limitation of the material of the printing plate and the detection accuracy of the dot of the printing plate is low during the dot detection of the printing plate by.
Referring to fig. 4, fig. 4 is a schematic device structure diagram of a hardware operating environment according to an embodiment of the present application.
As shown in fig. 4, the plate gauge may include: a processor 1001, such as a CPU, a memory 1005, and a communication bus 1002. The communication bus 1002 is used for realizing connection communication between the processor 1001 and the memory 1005. The memory 1005 may be a high-speed RAM memory or a non-volatile memory (e.g., a magnetic disk memory). The memory 1005 may alternatively be a memory device separate from the processor 1001 described above.
Optionally, the plate gauge may further comprise a rectangular user interface, a network interface, a camera, RF (Radio Frequency) circuitry, sensors, audio circuitry, a WiFi module, and the like. The rectangular user interface may comprise a Display screen (Display), an input sub-module such as a Keyboard (Keyboard), and the optional rectangular user interface may also comprise a standard wired interface, a wireless interface. The network interface may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface).
Those skilled in the art will appreciate that the plate gauge configuration shown in fig. 4 does not constitute a limitation of the plate gauge and may include more or fewer components than shown, or some components in combination, or a different arrangement of components.
As shown in fig. 4, a memory 1005, which is a kind of computer storage medium, may include an operating system, a network communication module, and a printing plate dot detection program therein. The operating system is a program that manages and controls the hardware and software resources of the plate gauge, supporting the execution of the plate dot detection program, as well as other software and/or programs. The network communication module is used for realizing communication among components in the memory 1005 and communication with other hardware and software in the printing plate network point detection system.
In the printing plate measuring apparatus shown in fig. 4, the processor 1001 is configured to execute a printing plate dot detection program stored in the memory 1005, so as to implement the steps of any one of the above-described printing plate dot detection methods.
The specific implementation of the printing plate measuring instrument of the present application is substantially the same as that of each embodiment of the printing plate mesh point detection method, and is not described herein again.
The embodiment of the present application further provides a printing plate dot detection device, where the printing plate dot detection device is applied to a printing plate measuring instrument, and the printing plate dot detection device includes:
the image segmentation module is used for acquiring a printing plate dot image of a printing plate to be detected, and performing threshold-based image segmentation on the printing plate dot image to obtain an image segmentation result;
the image binarization module is used for carrying out image binarization on the printing plate mesh point image based on the image segmentation result to obtain a binary image;
and the mesh point detection module is used for carrying out mesh point detection on the printing plate to be detected based on the binary image to obtain a target mesh point detection result.
Optionally, the image segmentation module comprises:
the first determining unit is used for determining a target segmentation threshold value based on the image size information corresponding to the printing plate dot image and the corresponding gray information;
and the segmenting unit is used for segmenting the printing plate dot image into the image background part and the printing plate dot part based on the target segmenting threshold.
Optionally, the determining unit includes:
the generating subunit is used for acquiring an image gray level corresponding to the printing plate dot image and generating a segmentation threshold value set based on the image gray level;
the calculation subunit is configured to calculate, based on the occurrence probability of each gray value, a variance between segmentation classes corresponding to each to-be-selected segmentation threshold in the segmentation threshold set respectively;
and the selecting subunit is used for selecting a target inter-class variance from each of the segmentation inter-class variances and taking a segmentation threshold to be selected corresponding to the target inter-class variance as the target segmentation threshold.
Optionally, the segmentation unit includes:
the obtaining subunit is used for obtaining each gray value in the printing plate mesh point image, and each gray value is respectively compared with the target segmentation threshold;
the first comparison subunit is used for taking the pixel points corresponding to the gray values which are not greater than the target segmentation threshold value as the first type pixel points;
and the second comparison subunit is used for taking the pixel points corresponding to the gray values larger than the target segmentation threshold value as the second type pixel points.
Optionally, the image binarization module includes:
a second determining unit, configured to determine, based on the image segmentation result, an image background portion corresponding to the printing plate dot image and a corresponding printing plate dot portion;
and the binarization unit is used for binarizing the image background part and the printing plate dot part to obtain the binary image.
Optionally, the binarization unit includes:
the first replacement subunit is used for replacing the gray value of each pixel point in the image background part with a preset first gray value to obtain the first image part;
and the second replacing subunit is used for replacing the gray value of each pixel point in the printing plate mesh point part with a preset second gray value to obtain the second image part.
Optionally, the mesh point detecting module includes:
the measuring unit is used for acquiring the total image area of the binary image and measuring the target image area of the printing plate mesh point area in the binary image;
and the calculating unit is used for calculating the area rate of the mesh points based on the total area of the image and the area of the target image area.
Optionally, the printing plate dot detection device further comprises:
the acquisition module is used for acquiring a printing plate shot image of the printing plate to be detected;
and the graying unit is used for graying the image shot by the printing plate to obtain the printing plate mesh point image.
The specific implementation of the printing plate dot detection device of the present application is substantially the same as that of each embodiment of the printing plate dot detection method, and is not described herein again.
The embodiment of the application provides a readable storage medium, and the readable storage medium stores one or more programs, which can be executed by one or more processors for implementing the steps of the printing plate mesh point detection method described in any one of the above.
The specific implementation of the readable storage medium of the present application is substantially the same as that of each embodiment of the printing plate dot detection method, and is not described herein again.
The above description is only a preferred embodiment of the present application, and not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are included in the scope of the present application.
Claims (10)
1. A printing plate dot detection method is characterized by comprising the following steps:
obtaining a printing plate dot image of a printing plate to be detected, and carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result;
carrying out image binarization on the printing plate dot image based on the image segmentation result to obtain a binary image;
and carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result.
2. The printing plate dot detection method according to claim 1, wherein the image segmentation result comprises an image background portion corresponding to the printing plate dot image and a corresponding printing plate dot portion,
the step of carrying out image segmentation based on a threshold value on the printing plate dot image to obtain an image segmentation result comprises the following steps:
determining a target segmentation threshold value based on the image size information corresponding to the printing plate dot image and the corresponding gray information;
segmenting the printing plate dot image into the image background portion and the printing plate dot portion based on the target segmentation threshold.
3. The printing plate dot detection method according to claim 2, wherein the step of determining the target segmentation threshold based on the image size information and the corresponding gray scale information corresponding to the printing plate dot image comprises:
calculating the gray value occurrence probability of each gray value corresponding to the printing plate net point image based on the image size information and the gray information;
acquiring an image gray level corresponding to the printing plate dot image, and generating a segmentation threshold value set based on the image gray level;
based on the occurrence probability of each gray value, calculating the variance between the segmentation classes corresponding to each segmentation threshold to be selected in the segmentation threshold set respectively;
and selecting a target inter-class variance from the segmentation inter-class variances, and taking a segmentation threshold to be selected corresponding to the target inter-class variance as the target segmentation threshold.
4. The printing plate dot detection method of claim 2, wherein said image background portion includes at least a first type of pixel points, said printing plate dot portion includes at least a second type of pixel points,
the step of segmenting the printing plate dot image into an image background portion and a printing plate dot portion based on the target segmentation threshold comprises:
acquiring each gray value in the printing plate mesh point image, and comparing each gray value with the target segmentation threshold respectively;
taking pixel points corresponding to gray values not greater than the target segmentation threshold as the first type pixel points;
and taking the pixel points corresponding to the gray values larger than the target segmentation threshold as the second type pixel points.
5. The printing plate dot detection method according to claim 1, wherein the step of binarizing the printing plate dot image based on the image segmentation result to obtain a binary image comprises:
determining an image background part corresponding to the printing plate dot image and a corresponding printing plate dot part based on the image segmentation result;
and carrying out binarization on the image background part and the printing plate dot part to obtain the binary image.
6. The printing plate screen point detection method of claim 4, wherein the binary image includes a first image portion and a second image portion,
the step of binarizing the image background part and the printing plate dot part to obtain the binary image comprises the following steps:
replacing the gray value of each pixel point in the image background part with a preset first gray value to obtain the first image part;
and replacing the gray value of each pixel point in the printing plate mesh point part with a preset second gray value to obtain the second image part.
7. The printing plate screen dot detection method of claim 1, wherein the target screen dot detection result comprises a screen dot area rate,
the step of carrying out dot detection on the printing plate to be detected based on the binary image to obtain a target dot detection result comprises the following steps:
acquiring the total image area of the binary image, and measuring the target image area of the printing plate mesh point area in the binary image;
and calculating the dot area rate based on the total image area and the target image area.
8. The printing plate dot detection method according to claim 1, wherein the step of acquiring the printing plate dot image of the printing plate to be detected comprises:
collecting a printing plate shooting image of the printing plate to be detected;
and graying the image shot by the printing plate to obtain the dot image of the printing plate.
9. A plate measuring instrument, comprising: a memory, a processor and a program stored on the memory for implementing the printing plate dot detection method,
the memory is used for storing a program for realizing the printing plate mesh point detection method;
the processor is used for executing a program for realizing the printing plate dot detection method so as to realize the steps of the printing plate dot detection method according to any one of claims 1 to 8.
10. A readable storage medium, characterized in that the readable storage medium has stored thereon a program for implementing a printing plate dot detection method, which is executed by a processor to implement the steps of the printing plate dot detection method according to any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011249900.1A CN112258501A (en) | 2020-11-10 | 2020-11-10 | Printing plate mesh point detection method, printing plate measuring instrument and readable storage medium |
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| CN202011249900.1A CN112258501A (en) | 2020-11-10 | 2020-11-10 | Printing plate mesh point detection method, printing plate measuring instrument and readable storage medium |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113592831A (en) * | 2021-08-05 | 2021-11-02 | 北京方正印捷数码技术有限公司 | Method and device for detecting printing error and 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 |
-
2020
- 2020-11-10 CN CN202011249900.1A patent/CN112258501A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113592831A (en) * | 2021-08-05 | 2021-11-02 | 北京方正印捷数码技术有限公司 | Method and device for detecting printing error and storage medium |
| CN113592831B (en) * | 2021-08-05 | 2024-03-19 | 北京方正印捷数码技术有限公司 | Printing error detection method, device and 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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