JP2000065550A - Image processing method, image processing system, engraving method for photogravure plate and engraving system for photogravure plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable automatically measuring an area and a volume of a channel- generating cell of a cylinder for a photogravure printing. SOLUTION: A microscope 1 is used for obtaining an expanded image of a channel generating cell formed in a cylinder cell, and a cell image shot by the microscope 1 is captured into an image processing device 2 by a video capture board 6. A CPU 7 of the image processing device 2 automatically determines a threshold value based upon a captured image to digitize the image, and treatments such as removing a noise, extracting a profile, separating a cell, removing an incomplete cell are automatically done. Then, each cell is extracted from the channel generating cell and a volume of the extracted cell is calculated from a shape of the cell extracted and engraving condition data when forming the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a system for measuring the area and volume of a cell of a gravure printing cylinder, in particular, a cell called a channel generating cell, and to obtain a gravure plate using the same. Gravure engraving method and a gravure engraving system for the same.

[0002]

2. Description of the Related Art As a cell formed on a gravure plate surface of a gravure printing cylinder, there is a cell called a channel generation cell. FIG. 21 is a diagram showing an example of this. In FIG. 21, a portion painted black is an engraved portion, and ink is placed on this portion. The large diamond-shaped large area part painted in black is generally called a cell, and the cells arranged in the horizontal direction in the figure are called channels whose width in the vertical direction is narrowed. Connected by parts. In the figure, the portion indicated by A is a channel. Further, in the figure, the portions represented in white are portions that are not engraved, and are generally called banks.

[0003] Such a channel generation cell is generally formed by engraving with an engraving needle.
It is known that the area and volume of cells formed vary depending on the wear of the engraved portion of the engraving needle, the conditions of the gravure plate surface of the cylinder, and the like.

[0004] Variations in the area and volume of the cells formed on the gravure plate surface, especially variations in the cell volume, greatly affect the quality of printing. That is, in gravure printing, printing is performed by transferring the ink contained in the concave cells formed on the gravure plate surface to the printing paper, and the printing density changes depending on the amount of ink contained in the cells, The formation of cells of the correct volume on the gravure printing plate is critical for obtaining proper print quality.

Therefore, when engraving a cell on a gravure printing plate, usually, prior to actual engraving for engraving a picture, a cell having a predetermined volume is formed for predetermined input data. The engraving conditions are set. For this reason, it is common practice to perform test engraving at an appropriate location on the gravure plate to determine whether the engraving conditions are appropriate.

Conventionally, whether or not the engraving conditions are appropriate is determined by observing the cells formed on the gravure plate surface by test engraving with a microscope with a scale and measuring the dimensions of the cells. Have been done. That is, it is determined whether the engraving condition is appropriate based on whether the vertical dimension or the left-right dimension of the cell is a predetermined dimension with respect to predetermined input data.

[0007]

However, in the conventional measurement, since the cursor is manually adjusted to the width and length of the enlarged and displayed cell, there is an individual difference, and reproduction when the same individual is repeatedly measured is performed. Poor nature. In addition, it is normal to repeatedly perform measurement → adjustment → engraving → measurement to increase the adjustment accuracy, but it is not easy to perform the adjustment sufficiently due to limitations in workability and work time.

When the cell size and the cell volume are in a one-to-one relationship, an appropriate determination can be made by the above-described method. Therefore, this method cannot determine with sufficient accuracy. In particular, this method cannot be used when the demand for print quality is high. For example, in order to shorten the production time of the gravure plate, engraving may be performed on the gravure plate surface using a plurality of mechanical engraving heads, for example, 4 to 8 mechanical engraving heads simultaneously. In that case, a slight difference in the engraving characteristics of the mechanical engraving head appears as a difference in color tone between adjacent patterns on the printed matter. The difference in color tone is extremely conspicuous because they are adjacent to each other, and the demand for print quality is high. However, the above-described method cannot cope with such a case.

[0009] For this reason, in the prior art, poor color tone was found only after printing was actually performed in the printing process, and the gravure plate had to be corrected or reprinted (reproduced).
The waste of material, time, labor and downtime of the printing press is extremely high.

Therefore, according to the present invention, the area and volume of the cell engraved on the gravure plate surface on which the channel generating cells are formed can be automatically and accurately measured, and the gravure plate surface can be well managed. It is an object of the present invention to provide an image processing method and an image processing system capable of greatly reducing the burden on an operator when measuring the area and volume of a cell.

It is another object of the present invention to provide a gravure engraving method and a gravure engraving system capable of forming a cell having a good volume irrespective of the degree of wear of the engraving needle. Is what you do.

[0012]

In order to achieve the above-mentioned object, an image processing method according to the present invention takes an image of a channel generating cell and extracts a contour forming the channel generating cell from the image. The cell is divided at the channel portion of the contour, and at least the area and the volume of the divided cell are measured.

An image processing system according to the present invention comprises: an image acquiring means for acquiring an image of a channel generating cell engraved on a gravure plate of a cylinder; an image from the image acquiring means; The contour forming the cell is extracted, the cell is divided at the channel portion of the contour, and at least the area,
Image processing means for measuring the volume.

The gravure plate engraving system according to the present invention comprises:
An imaging unit that captures channel generation cells formed on the gravure plate and obtains image data; an engraving condition input unit that inputs engraving conditions when forming the channel generation cells and obtains engraving condition data; , The contour forming the channel generation cell is extracted from the image, the cell is divided at the channel portion of the contour, and the volume of the divided cell is calculated based on the cell shape and the engraving condition data. And a cell volume calculating means. Here, the engraving condition data is
The engraving needle angle, which is the angle of the engraving needle attached to the engraving head, and the engraving needle wear degree of the engraving needle are allowed.

The gravure engraving method according to the present invention includes a test engraving step of performing test engraving on the basis of reference data to form test engraving channel generation cells on the gravure plate surface; Cell volume calculation for extracting a contour forming a channel generating cell from a captured image, dividing the cell at the channel portion of the contour, and calculating the volume of the divided cell based on the cell shape and engraving condition data. And comparing the measured volume data obtained in the cell volume measurement process with the reference volume data to determine the necessity of correcting the engraving condition. The engraving conditions are corrected based on the engraving conditions, and the engraving conditions are corrected based on the engraving conditions. Characterized in that consisting of the engraving process of completing a gravure plate to form a channel generation cell on a gravure printing plate subjected to the engraving are. Here, when the engraving condition correcting step is performed, the test engraving step, the cell volume measuring step, and the comparing / determining step may be repeated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments will be described with reference to the drawings. First, an image processing system according to the present invention, that is, an area and a volume of a channel generating cell formed on a gravure plate are automatically measured. An image processing system will be described, and then an embodiment of the gravure engraving system according to the present invention will be described.

FIG. 1 is a diagram showing an embodiment of an image processing system according to the present invention. In the figure, 1 is a microscope, 2 is an image processing device, 3 is an input unit, 4 is a monitor, 5 is a printer, 6
Is video capture board, 7 is CPU, 8 is RO
M and 9 are RAMs and 10 is a storage unit.

The microscope 1 is for picking up an enlarged image on the gravure plate surface on which the channel generating cells are formed, a light source for illuminating the surface of the gravure plate surface, and for obtaining an enlarged image of the gravure plate surface. The microscope is provided with a microscope and a CCD camera for capturing an enlarged image obtained by the microscope. The CCD camera may be a black and white camera. That is, the microscope 1 functions as an image acquisition unit.

As the image processing device 2, a personal computer or a workstation can be used. C
The PU 7 executes processing to be described later, and the ROM 8
Stores a program for executing processing to be described later, various data used when executing processing to be described later, and the like. The RAM 9 is used when the CPU 7 executes processing to be described later.

The storage unit 10 is a large-capacity storage device such as a hard disk. Although not shown, the storage unit 10 stores engraving condition data used when calculating the cell volume, and various tables described later.

The image processing apparatus 2 includes a microscope 1
The video capture board 6 for taking in the image picked up by the device is connected. The input unit 3 includes an input device such as a keyboard and a mouse.

Here, the engraving condition data will be described as follows. Obviously, when determining the volume of a cell, the depth of the cell must be known. By the way, when engraving a cell with an engraving needle, the three-dimensional shape of the cell to be engraved differs depending on the shape of the needle of the engraving needle. In this case, the angle of the engraving needle is particularly important. If the angle is different, the depth of the cell will be different even if the opening shape of the cell is the same. This indicates that it is necessary to know the angle of the engraving needle when obtaining the cell volume.

Further, the degree of wear of the engraving needle also becomes a problem. This is because the wear of the engraving needle progresses according to the use time, and the needle shape of the engraving needle gradually changes. As a result, even when the engraving conditions are the same except for the wear of the engraving needle, the cell obtained by engraving is obtained. This is because the shape of the opening differs from the depth of the cell. The progress of wear of the engraving needle is determined by the use time. However, strictly speaking,
The degree of wear depends not only on the usage time, but also on the quality of the engraving needle, the difference in the image data to be engraved, the difference in the physical properties of the gravure cylinder plate to be engraved, etc.
It can be approximated that the degree of progress of wear is determined by the use time. Therefore, at least an engraving needle angle and a use time corresponding to the degree of abrasion of the engraving needle are input from the input unit 3 as engraving conditions, and registered in the storage unit 10 as engraving condition data.

Next, the processing performed by the image processing system shown in FIG. 1 will be described with reference to FIG. 2 together with the image processing method according to the present invention.

First, the operator sets the microscope 1 so that an enlarged image of a channel generation cell at a desired portion of the gravure printing plate to be measured can be obtained. The input unit 3 sets the density to be achieved when printing and the magnification of the microscope 1 at this time. Then, execution of image capture is instructed from the input unit 3.

Thus, the image data from the microscope 1 is transmitted to the image processing device 2 via the video capture board 6.
It is taken in. The digitization of the image captured by the microscope 1 may be performed inside the microscope 1 and the digital image data may be transferred to the video capture board 6, or the microscope 1 may output an analog image signal. Alternatively, the video may be digitized by the video capture board 6.

Then, the CPU 7 develops the acquired image data in the RAM 9 and displays the image data on the monitor 4.
At this time, it goes without saying that the image data may be stored in the storage unit 10.

The above is the processing for capturing an image from the microscope 1 in step S1 in FIG. 2. After the processing in step S1, the operator instructs the input unit 3 to execute image processing.

When execution of image processing is instructed, the CPU 7
Performs the process of binarizing the captured image data,
Prior to this, first, a process of determining a threshold value T for binarization is performed. In the process of determining this threshold T, C
The PU 7 obtains the gradation value of each pixel of the image data expanded in the RAM 9, creates a histogram for each gradation value, and determines the threshold T based on the histogram.

The details are as follows. When the histogram has two distinct peaks on the black side and the white side as shown in FIG. 3A, the grayscale value that is the minimum value between the two peaks may be determined as the threshold value T. However, actually, the peak on the white side in FIG. 3A does not clearly appear due to an image of a scratch or dirt on the gravure plate surface or dust attached on the gravure plate surface, and is schematically shown in FIG. 3B. It may be like this. However, even in the case of the histogram as shown in FIG. 3B through various experiments, when the tone value at the position where the frequency suddenly decreases after passing the black-side peak and becomes gentle again becomes the threshold value T, it is preferable that the threshold value be 2 It was confirmed that it could be priced. The method of determining such a threshold is shown in FIG.
Naturally, it is also effective in the case shown in FIG. In FIG. 3, the gradation value is 2 from all black to all white.
It has 56 gradations.

Then, based on the histogram, the CPU 7 determines that the frequency suddenly decreases after passing the peak on the black side,
A process of setting a tone value at a position where the tone becomes gentle again as a threshold value T is performed. As a result, in the case of FIG. 3B, the gradation value indicated by T in the figure is determined as the threshold value. In addition,
It has been confirmed that the threshold value T is a value between 80 and 120 in most cases when the gradation value is 256 gradations from all black to all white.

When the threshold T is determined as described above, C
The PU 7 binarizes the image data developed in the RAM 9 using the threshold T. Then, the CPU 7 displays the binarized image on the monitor 4. At this time, it is natural that the binarized image data may be stored in the storage unit 10. The above is the binarization processing in step S2 in FIG.

As described above, there are cases where the gravure plate surface of the cylinder has scratches and dirt, or dust is attached, and these scratches, dirt, or dust portions are the binary values of step S2. Although a black image is obtained by the conversion process, an image based on such scratches, dirt, dust, and the like is unnecessary when measuring the cell area and needs to be removed. For this purpose, the noise removal processing in step S3 in FIG. 2 is performed. When the binarization processing is completed, the CPU 7 performs noise removal on the obtained binary image by, for example, a morphological method. The resulting image is displayed on the monitor 4. At this time, it is natural that the binarized image data may be stored in the storage unit 10. This is the noise removal processing in step S3. Since the morphological processing is well known, a detailed description thereof will be omitted.

FIGS. 4 and 5 show examples of images obtained by the noise removal processing in step S3. FIG. 4 is a diagram showing an example of the image binarized in step S2. A white dot appears in a cell portion, and a black portion also appears in a dot or straight line on a bank. . This is a noise component based on scratches, dirt, or attached dust on the gravure plate surface.

When this image is subjected to noise removal processing by a morphological method in step S3,
The image shown in FIG. 5 is obtained, and a thin black line or a small black spot based on a scratch, dirt, or attached dust can be removed.

In the above description, morphology is used as a noise removing method. However, the method is not limited to the morphological method, and any method capable of removing noise components may be used.

When the CPU 7 completes the noise removal processing in step S3, the CPU 7 next performs contour extraction processing on the noise-removed image (step S4).
For this, a known method of sequentially following the boundary between a white pixel and a black pixel may be used. Then, the route that has been followed is generated as vector data.

By the contour extraction processing in step S4, a contour as shown in FIG. 6 is extracted from the binary image shown in FIG. When the CPU 7 completes the contour extraction processing in step S4, the CPU 7 displays the contour image as shown in FIG. At this time, it is natural that the image data of the contour may be stored in the storage unit 10. In this contour extraction processing, the CPU 7
When sequentially following the boundaries between white pixels and black pixels,
It recognizes whether the pixel above the boundary is black or white and adds that information as an attribute of the outline vector data. This attribute information is used in the process of removing incomplete contours later. Therefore, the vector data of the outline indicated by R ₁ in FIG. 6, black information is added as an attribute, information of white is added as attribute to the vector data of the contour shown by R _2.

Next, the incomplete contour is removed (step S).
5). In order to obtain the cell area and volume, step S
It is clear that the contour extracted by the contour extraction of No. 4 needs to be continuous at least from one end to the other end of the image, and should not be interrupted in the middle. For example, in the case of FIG. 6, one outline needs to be continuous at least from the left end to the right end of the figure.

Therefore, as a first stage of the incomplete contour removal, a contour that is not continuous from one end to the other end of the image is removed as an incomplete contour. In the process of the first stage, in the case of the image shown in FIG. 6, it is only necessary to remove the outline that is in contact with the upper end or the lower end of the image. Specifically, as shown in FIG. 7, if xy coordinates are taken and the size of the image in the y direction is y _max , CP
Since U7 recognizes the size y _max of the image, the vector data of each contour is examined, and y = 0 or y = y _max
Vector data containing the value of
A process of deleting the vector data of the contour may be performed.
The image shown in FIG. 7 is the same as the image shown in FIG.

By the above-described first-stage processing, the contour shown by B in FIG. 7 is removed, and the eight contours R shown in FIG.
Image composed of ₁ to R ₈ is obtained. These eight contours R
₁ to R ₈ can of course be continuous from the left end to the right end in the x direction of the image.

By the way, in the image shown in FIG. 5, since the channel generation cells are connected in the horizontal direction, the contours of the channel generation cells in a certain row are arranged two in the vertical direction.
In this way, two contours form a pair.

Therefore, as a second stage of the process of removing incomplete contours, a search is made as to whether there are any unpaired contours among the contours left in the first stage processing. , The contour is removed as an incomplete contour. When performing this processing, the CPU 7 refers to the attribute of the vector data of each contour, and recognizes the vector data of the contour whose attribute is white and the vector data of the attribute immediately below this contour as a pair. For example, at the position of x = 0, the vector data of the contour is searched from the smaller value of the y value to the larger value of the y value,
It is sufficient to perform a process of pairing the data immediately below the vector data with the black outline vector data. By treatment of the second stage, in the case shown in FIG. 8 is vector data of the outline indicated by the vector data and R ₈ contour shown by R ₁ are removed, as shown in FIG. 9, the contour of the R ₂ to R ₇ Is left as a complete contour. Then, the CPU 7 determines that R ₂ and R
The outline of ₃ is recognized as forming a pair, the outline of R ₄ and R ₅ is recognized as forming a pair, and the outline of R ₆ and R ₇ is recognized as forming a pair. As described above, the incomplete contour is removed by the two-stage processing.

When the processing in step S5 is completed, the CPU
7 performs the cell division processing in step S6. This process is a process of dividing cells connected by channels into individual cells. For gravure version management,
Since it is important to manage the area and volume of each cell, this cell division processing is performed.

Now, in order to divide the cells one by one,
What is necessary is just to divide at the position of a channel. For this purpose, in this processing, first, the number of pixels in the y direction between the two contours recognized as a pair in step S5 is determined at all pixel positions in the x direction, and the data sequence of the number of pixels between the two contours is obtained. A smoothing process is performed to recognize the position of the x coordinate that takes the minimum value as the position of the channel, a gap having a width of 1 pixel is provided at the position of the channel, and a straight line is formed between the contours forming a pair on both sides of the gap. To perform cell division.

Here, the reason why the smoothing process is performed on the data sequence of the number of pixels between the two contours is as follows.
That is, for example, when a data string in the vicinity of the channel of the number of pixels between the contours forming a pair is represented by a graph, a line graph shown in FIG. 10A is obtained, and the number of pixels may be minimized at a plurality of places. Therefore, a smoothing process is performed on these data strings, and an x position at which the number of pixels is minimized is obtained as shown by a smooth curve shown in FIG.

When the above-described cell division in step S6 is performed on the image shown in FIG. 9, an image as shown in FIG. 11 is obtained. In FIG. 11, cells arranged in the horizontal direction in the figure are divided at channel positions.

Next, the CPU 7 removes incomplete cells from each of the divided cells (step S7). This may be performed by a process of extracting a closed region surrounded by black pixels in white pixels, and can be performed by a known method. For example, in FIG. 12A, if a hatched rectangle is a black pixel and a non-hatched rectangle is a white pixel,
When there is a black pixel P adjacent to a white pixel, the black pixel P follows a black pixel adjacent to the white pixel as shown by an arrow from the black pixel P, and closes only when returning to the first black pixel. It is sufficient to use a method of generating the tracing route as vector data.

Therefore, in the area of the black pixel as shown in FIG. 12B, even if the black pixel adjacent to the white pixel is traced from the black pixel indicated by P in the figure as indicated by the solid arrow, Even if the tracing is performed as indicated by the arrow, the end reaches the end of the binary image data, and since there is no image data thereafter, it is not possible to return to the first black pixel P, so that it is not recognized as a closed area. . According to this, for example, as shown by D in FIG. 11, an image in which all of the closed region is not completely included in the image is recognized as an incomplete cell and removed. This is useful. This is because it is meaningless to measure the area and volume of the region shown by D in FIG. Accordingly, the image shown in FIG.
When subjected to the process, and only four closed area indicated by Q ₁ to Q ₄ in FIG. 11 is extracted as a complete cell.

Next, the CPU 7 measures the area and volume of the complete cell extracted in step S7, and displays the result (step S8). The area of each cell is
The number of pixels in the closed region recognized in the process of step S7 may be counted, and the number of pixels may be used as a pseudo cell area. It is also possible to obtain an average area value, a maximum area value, a minimum area value, a standard deviation, and the like of the extracted cells.

The volume of each cell is obtained as follows. For example, the channel generation cell shown in FIG. 11 is engraved in the x direction, but the engraving needle angle at the time of engraving is known in advance by the input engraving condition data. And the cell y
The relationship between the width in the direction and the cross-sectional shape in the depth direction of the cell at that time is also known. That is, for example, if the shape of one cell is as shown in FIG. 13A and the width in the y direction at the position _xn is δ, the cross-sectional shape in the depth direction of the cell at the position _xn Is known in advance as shown in FIG. 13B, and the area of the cross section is also known. Accordingly, at all the x-coordinate positions of the cell, the area of the cross section of the cell at the x-coordinate position is obtained from the width in the y direction, and the sum of the obtained cross-sectional areas is calculated.
The volume of the cell can be determined. Here, the number of pixels in the cross-sectional shape may be used for the area of the cross-section of the cell.

In order to obtain the cell volume by such an operation, a table in which the area of the cross section with respect to the width in the y direction of the extracted cell is previously prepared for each angle of the engraving needle is prepared. The table to be used is selected based on the engraving needle angle of the cell, and the area of the cross section of the cell at the x-coordinate position is determined from the width in the y-direction at all the x-coordinate positions of each cell using the table. What is necessary is just to calculate the sum of the areas of the obtained cell cross sections.

The CPU 7 measures the volume of the cell by performing the above processing. Here, as described above, the CPU 7
It is natural that a table in which the area of the cross section of the cell with respect to the width of the cell in the y direction is written for each engraving needle angle is registered. As for the volume, similarly to the area, an average volume value, a maximum area value, a minimum area value, a standard deviation, and the like of the volume value may be obtained.

As described above, the volume of each cell can be determined, but the cell volume obtained above does not take into account the degree of wear of the engraving needle. Therefore, a method that takes into account the degree of wear of the engraving needle will be described below. When calculating the cell volume, there are a simple method and a more accurate method in which the degree of wear of the engraving needle is taken into consideration.

First, a simple method will be described. In this method, a table of correction coefficients relating to the degree of wear of the engraving needle is obtained in advance by experiments or the like according to the engraving time or cell shape. Then, based on the engraving needle abrasion degree of the engraving condition data, an engraving needle abrasion degree correction coefficient is obtained by referring to a correction coefficient table relating to the engraving needle abrasion degree. Further, the cell volume obtained above is multiplied by the engraving needle wear degree correction coefficient obtained from the table. This makes it possible to calculate the cell volume in consideration of the engraving needle angle and the engraving needle wear degree of the engraving condition data.

Next, a more accurate method is as follows. In this method, a three-dimensional table in which three numerical values of the degree of wear of the engraving needle, the width of the cell in the y direction, and the area of the cross section of the cell are prepared in advance for each of various engraving needle angles. deep. In this three-dimensional table, the numerical value of the area of the cross section of the cell is present at two-dimensional coordinates (lattice points) determined by two numerical values of the numerical value of the degree of wear of the engraving needle and the numerical value of the width in the y direction. Such a three-dimensional table can be created, for example, by actually measuring channel engraved cells engraved at various engraving needle angles and at various engraving needle abrasion degrees.

Then, based on the engraving needle angle obtained from the engraving condition data, a corresponding three-dimensional table is selected from a plurality of tables, and a numerical value of the engraving needle wear degree obtained from the engraving condition data and the y-direction From the numerical value of the cell width, the numerical value of the cross-sectional area of the cell is obtained with reference to the selected three-dimensional table. The numerical value of the area of the cross section of the cell naturally takes into account the engraving condition data. Then, using the numerical value of the area of the cross section of the cell, the cell volume is calculated as described above.

As described above, when the number of dimensions increases, the number of data to be recorded in the table increases, which may cause a problem in data creation and storage in the table. There is a method of reducing the data amount by making each numerical value of the cell width in the y direction and the area of the cross section of the cell a discrete numerical value. The engraving needle angle is a geometric shape and is usually a discrete number. When obtaining the area of the cross section of the cell corresponding to the numerical value not recorded in the table, the area can be obtained by applying a known interpolation method.

When the area and volume of each extracted cell are measured as described above, the CPU 7 displays the measurement result on the monitor 4. At this time, the CPU 7 displays not only the area value and the volume value of the measurement result or their average value, the maximum value, the minimum value, and the standard deviation, but also the cell whose area and volume are measured. When displaying this cell, the CPU 7
Assigns a serial number to each cell. This serial number may be assigned based on the position of the center of gravity of the cell. Here, the lower the display position on the monitor 4 is, the higher the rank is. If the positions in the vertical direction are the same, the higher the display position is on the left, the higher the rank is. 14, serial numbers are assigned as shown in FIG.

Although not shown in FIG. 14, the CPU 7
Also displays the area value, volume value, and the like obtained by measurement on the screen displaying the cell shown in FIG. FIG. 15 shows an example of the display. In FIG. 15, "cell 1" indicates a cell to which "1" is added in FIG. The same applies to other cases. Actually, "xxx" in FIG.
Needless to say, the measured value is displayed in the part. In FIG. 15, the area value, the volume value, and the like are displayed as numerical values, but may be displayed as an appropriate graph such as a bar graph.

With such a display, the operator can easily grasp the degree of variation of the cell area and volume, and can judge the quality of the gravure printing plate.

The CPU 7 stores these measurement results in the storage unit 10. In the process of step S8, the measurement result may be automatically printed out by the printer 5.

As described above, according to this image processing system, after taking in the image picked up by the microscope 1, all the processes are performed automatically, so that the burden on the operator is very light. is there. Also, as mentioned above,
Since this image processing system can be configured with the microscope 1 and a personal computer or a workstation, it can be configured in a small size, and can easily measure cells formed on the gravure plate surface at a printing site.

In the above embodiment, the area of each cell is represented by the number of pixels in the cell.
If the actual size value of the display area of one pixel on the monitor 4 can be known from the magnification or the like, the measured area value or the like may be displayed as the actual size value.

The embodiments of the image processing method and the image processing system according to the present invention have been described above.
A usage form of such an image processing system will be described. FIG. 16 is a diagram showing an embodiment of a gravure plate engraving system to which the above-described image processing system is applied. In FIG.
3a, 23b, 23c, 23d, 23e and 23f are engraving heads of the gravure plate engraving device 21, 24 is a cell volume measuring device, 25 is an imaging means, 26 is an input unit including a keyboard and a mouse, and 27 is a display and a printer. An output unit 28 is a processing unit of the cell volume measuring device 24. The processing unit 28 is provided with an image input unit 30, an engraving condition input unit 31, and a cell volume calculation unit 32. 2
Reference numeral 9 denotes a storage unit of the cell volume measuring device 24, in which image data 33 and engraving condition data 34 are stored.

The gravure plate engraving device 21 is a gravure plate 22
And has a structure that rotates around its axis. In the example shown in FIG. 14, the engraving head 23 of the gravure plate engraving device 21 is composed of six pieces, and has a structure that moves while engraving in the direction parallel to the axial direction of the gravure plate 22. That is, the gravure plate 22 is rotated around its axis, and the engraving heads 23a to 23f are moved in the axial direction of the gravure plate 22, thereby engraving the entire surface of the gravure plate 22.

The imaging means 25 is the same as the microscope 1 in FIG. The cell volume measuring device 24 includes a processing unit 28 and a storage unit 2
9 is provided. The processing unit 28 includes an image input unit 3 for inputting an image of a cell engraved on the gravure plate 22 captured by the image capturing unit 25 by the image input unit 30.
0, engraving condition input means 31 for inputting engraving conditions,
And a cell volume calculation unit 32 that performs the above-described image processing on the image fetched from the image input unit 30 and obtains the volume of the cell extracted from the image.
Therefore, the image input means 30 corresponds to the video capture board 6 shown in FIG. Further, the cell volume calculation means 32 calculates the volume of the cell extracted from the image. As a method of calculating the volume of the cell, the simple method described above may be used, or a more accurate method may be used. May be used. As the engraving conditions input from the engraving condition input unit 31, the use time corresponding to the engraving needle angle and the engraving needle wear degree is input in the same manner as described above. The engraving conditions are input for each of the engraving heads 23a to 23f.

The storage section 29 has image data 33 for storing an image captured by the image input means 30 and engraving condition data 34 for storing engraving conditions inputted from the engraving condition input means 31.

FIG. 17 is a graph showing engraving characteristics when engraving a gravure plate. In FIG. 17, the output value on the horizontal axis is the value of data output to the gravure plate engraving device 21, and the cell volume on the vertical axis is the volume of cells formed on the plate surface of the gravure plate 22. Also,
The arrow shown in FIG. 17 indicates that the engraving characteristic A of the test cut value obtained by the test engraving is corrected to the engraving characteristic B of an appropriate reference value. That is, as described later, first, a test cut is performed, and the volume of the cell formed by the test cut is obtained by the above-described method, and the engraving characteristic obtained from the relationship between the output value at the test cut and the cell volume is obtained. In the case where it is as shown in a, the engraving conditions for correcting the engraving characteristics to the engraving characteristics of the reference value shown in b in the figure are obtained, and the engraving conditions for obtaining the appropriate engraving characteristics are changed for all the engraving heads 23a. 23b, 23c, 23d, 23e, 23f
The main engraving is performed by the gravure plate engraving device 21.

FIG. 18A shows the gravure plate 22 on which the test engraving and the main engraving have been performed, and FIG. 18B is a development view of the peripheral surface of the gravure plate 22. As shown in FIG. 18, the test engraving is performed for each engraving head 23a, 23b, 23c, 23d, 23e,
23f. In addition, the main sculpture of the pattern is also performed by each of the engraving heads 23a, 23b, 23c, 23d, 23e,
f. FIG. 18 shows each engraving head 23.
Each engraving area performed by a, 23b, 23c, 23d, 23e, and 23f is shown.

As shown in FIG. 16, the fact that the gravure engraving device 21 has six engraving heads 23a to 23f means that the engraving head 23a to 23f is composed of six engraving heads as compared with the case of having one engraving head. This means that the engraving of the entire plate can be completed six times faster. On the other hand, compared to the case of one engraving head, 6 engraving heads are used.
It is necessary to appropriately set engraving conditions for the double number of engraving heads 23a to 23f. This is because when engraving is performed using different engraving heads, a slight difference in engraving characteristics of the engraving head results in a difference in color tone between the patterns of the printed matter, and is conspicuous because the patterns are adjacent to each other. Therefore, it is necessary to set all appropriate engraving conditions for the engraving heads 23a to 23f in order to ensure print quality.

The differences in the engraving characteristics of the engraving heads 23a to 23f include the differences in the characteristics of the electric and mechanical systems for driving the engraving needles of the engraving heads 23a to 23f, as well as the differences in the sharpness and shape of the engraving needles. This is caused by the progress of wear of the engraving needle. Engraving characteristics as shown in A
Ideally, it is extremely difficult to equalize all the items caused by the difference in the characteristics in order to match the proper engraving characteristics B, but it is extremely difficult.

Therefore, normally, an appropriate conversion table for determining the input / output characteristics of image data is created, image data for gravure plate making is input to the conversion table, and the output image data converted by the conversion table is converted. The main image engraving is performed based on the corrected image data. This conversion table is shown in FIG.
Naturally, it is possible to obtain corrected image data that achieves appropriate engraving characteristics as shown in FIG. However, differences in sculpture characteristics are caused by various factors,
In some cases, it is not possible to set proper engraving conditions only by setting the conversion table. For example, there are cases where the wear of the engraving needle is remarkably progressing, and the characteristics of the electric system and the mechanical system for driving the engraving needle have changed greatly. In that case, if you set the engraving conditions, including re-grinding or replacing the engraving needle, re-adjusting the electric system and mechanical system, replacing the entire engraving head itself with a good engraving head, etc. Good.

Hereinafter, the process from the test engraving to the main engraving in the gravure engraving system shown in FIG. 16 will be described together with the gravure engraving method. FIG.
5 is a flowchart showing a process of the processing.

First, test engraving is performed (step S1).
0). This test engraving is based on the reference data,
8 is performed. Thus, a test cell is formed on the gravure plate surface 22. Here, the reference data for performing the test engraving includes not only data of a specific print density but also data of various print densities. For example, scale data of a predetermined density of several steps (about 2 to 10 steps) including a maximum print density to a minimum print density may be used. This scale data may be a patch having a small area at each density, or at least one cell at each density. In the latter case, the rate at which the effective printing area of the gravure plate 22 is limited by the test engraving may be small.

Next, the cell volume of the test cell engraved for test is measured (step S11). The cell volume is measured for test cells corresponding to all density scale data engraved by the engraving heads 23a to 23f. This means that the test cell is imaged by the imaging means 25,
The data may be captured by the image input means 30 and an instruction to start volume measurement may be given to the cell volume calculation means 32.

As a result, the cell volume calculating means 32
By the above-described processing, a test cell is extracted from the captured image, and the volume of the extracted cell is calculated. As described above, the cell volume may be calculated by the simple method described above or by a more accurate method.

When the cell volume calculating means 32 calculates the volume of the cell extracted from the image, the result is output to a display and / or a printer as the output unit 27.

When the volume of the test cell is measured as described above, the measured volume data is compared with the reference volume data (step S12) to determine whether it is necessary to correct the engraving conditions. A determination is made (step S13). Here, the reference volume data is prepared in advance by collecting input data and measured volume data of cells for a good printed matter, that is, collecting engraving characteristics, and each reference data of the reference data is prepared. A predetermined allowable range is set for each value. Therefore, in the determination of step S13, it is determined that correction of the engraving condition is unnecessary if the measured volume data is within the allowable range, and that the engraving condition is required if the measured volume data is out of the allowable range. .

If it is determined in step S13 that correction is necessary, the engraving condition is corrected in step S14.

The engraving conditions are corrected by correcting the conversion table and setting appropriate data so that the measured volume data matches the reference volume data.
For example, the measurement volume data is a discrete measurement value given to each reference value of the discrete reference data used for performing the test engraving. Based on this measurement value, first, a curve is obtained. An approximation is performed to obtain continuous measured volume data. That is, data output to the gravure plate engraving device 21 (this is reference data input for engraving the test cell described above when viewed from the gravure plate engraving device 21 side). ) And the volume of the cells formed on the plate surface of the gravure plate 22 (this corresponds to the value on the vertical axis in FIG. 17), that is, the engraving characteristic is obtained as a continuous function. Then, in this engraving characteristic, input data for obtaining reference volume data for each input data is obtained.

The method is roughly as follows. For example,
Now, as data supplied to the gravure plate engraving device 21 for engraving a test cell, _three data I ₁ , I ₂ , and I ₃ are provided.
When there are two reference data, the test cells are engraved based on the reference data, and the volumes of the test cells are measured. It is assumed that they are V ₁ , V ₂ , and V ₃ respectively. It is assumed that the engraving characteristics as shown by C in FIG. The reference engraving characteristics are as shown by d in FIG. 20A, and I ₁ , I ₂ , I ₃
Proper cell volume in the case of three reference data is assumed to be V _R1, V _R2, V _R3, respectively.

At this time, based on the engraving characteristics of the actual engraving head indicated by C in FIG. 20A and the standard engraving characteristics indicated by B, when the data I ₁ is given, the cell having the volume V _R1 is obtained. To sculpt, I ₁ is _first converted to I ₁ ′
It can be seen that the cell may be engraved based on the value of I ₁ ′. Similarly, the volume when given the data that I ₂ is engraving a cell of V _R2 is "converted into its I ₂ 'once I ₂ to I ₂ may be engraved cells by the value of , in the volume when given the data that I ₃ is engraving a cell of V _R3 is "converted into its I ₃ 'once I ₃ a I ₃ that may be engraved cells by the value of I understand.

[0084] Therefore, on a graph showing the output characteristic of the data values, the value of I ₁ 'to the value of I ₂ I _2' I _1, the
The value of I ₃ plotted points to be converted respectively into I ₃ ',
By connecting these points smoothly, a conversion table having input / output characteristics as shown by E in FIG. 20B is created.

Using such a conversion table, the value of the image data having the picture to be fully engraved is corrected and supplied to the gravure engraving apparatus 21 to engrave the cell. _The data having a value of ₁ is corrected to I ₁ ′ by the conversion table and supplied to the gravure engraving apparatus 21, so that a cell having a volume _VR1 is engraved. The same applies to data of other values, and as a result, a reference engraving characteristic as indicated by d in FIG. 20A can be obtained.

After correcting the engraving conditions in step S14 in this way, it is determined whether there is a need for re-measurement (step S15). When the correction amount of the engraving condition in Step S14 is small, it is generally not necessary to perform re-measurement. Therefore, the main engraving in Step S16 may be performed immediately after correcting the engraving condition. However, when the correction amount of the engraving condition is not small, it is necessary to perform the re-measurement, so that the process returns to step S10 and the above-described process is repeated. When performing test engraving by returning from step S15 to step S10, test engraving is performed by correcting the reference data using the conversion table created in the engraving condition correction process of step S14.

If it is determined in step S13 that no correction is necessary, or if it is determined in step S15 that re-measurement is not necessary, engraving is performed (step S16). If it is determined in step S13 that the correction is not necessary, the image data of the picture to be subjected to the gravure printing may be directly supplied to the gravure plate engraving device 21 to perform the engraving. If it is determined in step S15 that re-measurement is not necessary, the value of the image data of the picture to be subjected to gravure printing is corrected by the conversion table created in step S14 and supplied to the gravure plate engraving apparatus 21. And then do the sculpture. Then, by this main engraving, engraving is performed based on appropriate engraving conditions, and cells are formed on the plate surface of the gravure plate 22 to complete the gravure plate.

The above-described processing for engraving condition correction and comparison determination can be realized by an information processing device such as a personal computer having software for that purpose. Description is omitted.

As described above, according to the gravure engraving system, test engraving is performed prior to main engraving, and the volume of the test cell formed by the test engraving is measured. It is possible to determine whether the conditions are appropriate or not, and to correct the engraving conditions if not, so that a cell having a good volume can be formed regardless of the degree of wear of the engraving needle. Thus, gravure printing with good quality can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an image processing system according to the present invention.

FIG. 2 is a diagram showing a flow of processing in the image processing system shown in FIG.

FIG. 3 is a diagram for explaining a method of determining a threshold value in a binarization process in step S2 of FIG. 2;

FIG. 4 is a diagram showing an example of an image obtained by binarizing an image taken from a microscope 1;

FIG. 5 is a diagram illustrating an example of an image when noise removal is performed on the image illustrated in FIG. 4;

FIG. 6 is a diagram illustrating an example of an image in a case where an outline extraction process is performed on the image illustrated in FIG. 5;

FIG. 7 is a diagram for explaining the process of removing incomplete contours in step S5 of FIG. 2;

FIG. 8 is a diagram for explaining the process of removing incomplete contours in step S5 of FIG. 2;

9 is a diagram illustrating an example of an image obtained as a result of removing an incomplete contour from the image illustrated in FIG. 7;

FIG. 10 is a diagram for explaining the cell division processing in step S6 of FIG. 2;

FIG. 11 is a diagram for explaining the cell division processing in step S6 of FIG. 2;

FIG. 12 is a diagram for explaining a process of removing incomplete cells in step S7 of FIG. 2;

FIG. 13 is a diagram for explaining volume measurement of a cell.

FIG. 14 is a diagram showing an example of a display mode of a cell in step S8 of FIG. 2;

FIG. 15 is a diagram illustrating an example of display of measured area and volume.

FIG. 16 is a view showing one embodiment of a gravure plate engraving system according to the present invention.

FIG. 17 is a graph showing engraving characteristics when engraving a gravure plate.

FIG. 18 is a diagram showing a gravure plate on which test engraving and main engraving have been performed, and a development view of a peripheral surface of the gravure plate.

FIG. 19 is a flowchart showing processing from test engraving to main engraving in the gravure plate engraving system.

20 is a diagram for explaining a process of correcting an engraving condition in step S14 of FIG. 19;

FIG. 21 is a diagram illustrating an example of a channel generation cell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Microscope 2 ... Image processing apparatus 3 ... Input part 4 ... Monitor 5 ... Printer 6 ... Video capture board 7 ... CPU 8 ... ROM 9 ... RAM 10 ... Storage part 21 ... Gravure plate engraving device 22 ... Gravure plate 23a, 23b, 23c, 23d, 23e, 23f: engraving head, 24: cell volume measuring device, 25: imaging unit 26, input unit 27, output unit 28, processing unit 29, storage unit 30, image input unit 31, engraving condition input unit 32 ... Cell volume calculation means 33 ... Image data 34 ... Engraving condition data

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA58 AA59 BB01 BB24 BB27 CC00 DD03 DD06 FF04 JJ03 JJ16 JJ26 PP24 QQ04 QQ08 QQ23 QQ24 QQ25 QQ29 QQ32 QQ43 SS02 SS06 SS13 2H084 AA03 AE05 FA06 BA03 BA03 5

Claims (6)

[Claims] An image obtained by capturing a channel generation cell is taken in, an outline forming a channel generation cell is extracted from the image, a cell is divided at a channel portion of the outline, and the divided cell has at least an area and a volume. An image processing method characterized by measuring the following. 2. An image obtaining means for obtaining an image of a channel generating cell engraved on a gravure plate surface of a cylinder, and an image from the image obtaining means is taken in, and a contour forming a channel generating cell is extracted from the image. Then, the cell is divided at the channel portion of the outline, and the divided cell is
An image processing system comprising: an image processing unit that measures at least an area and a volume. 3. An image pickup means for picking up an image of a channel generating cell formed on a gravure printing plate to obtain image data, and an engraving condition inputting means for inputting engraving conditions when forming the channel generating cell and obtaining engraving condition data. Capturing an image from the imaging means, extracting a contour forming a channel generation cell from the image, dividing a cell at a channel portion of the contour, and regarding the divided cell,
A gravure plate engraving system comprising: a cell volume calculating means for calculating a volume based on a cell shape and engraving condition data. 4. The gravure plate according to claim 3, wherein said engraving condition data is an engraving needle angle which is an angle of an engraving needle attached to an engraving head, and an engraving needle wear degree of said engraving needle. Engraving system. 5. A test engraving process for forming a test engraving channel generating cell on a gravure plate by performing test engraving based on reference data; and generating a channel generating cell from an image of the test engraving channel generating cell. Extracting a contour to be formed, dividing a cell at a channel portion of the contour, and calculating a volume of the divided cell based on a cell shape and engraving condition data; and a cell volume measuring step. The measurement volume data obtained in the above, the comparison determination step to determine the necessity of correcting the engraving conditions by comparing the reference volume data, engraving conditions if the correction necessity is determined by the comparison determination step Engraving condition correction process to be corrected, and when the necessity of correction is determined by the comparison determination process, main engraving is performed based on the engraving condition and the gravure plate A gravure plate engraving method, comprising: forming a channel generating cell on the substrate and completing a gravure plate. 6. The gravure engraving method according to claim 5, wherein when the engraving condition correcting step is performed, the test engraving step, the cell volume measuring step, and the comparison determining step are repeated.