JPH0416342B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to an apparatus for inspecting deprinting of a color mark provided for inspecting printed matter, and more specifically, the present invention relates to an apparatus for inspecting deprinting of a color mark provided for inspecting printed matter, and more specifically, it divides a color mark into meshes, sets a threshold,
This invention relates to a color mark deprinting inspection device using data processing. PRIOR ART Usually, printed matter is provided with four color marks, for example, in the case of four-color printing, four color marks: black, red, eye, and smear, on the edge of the printed matter in order to inspect color decolorization. By counting these color marks,
Tested for color bleaching. The reading of these color marks has mostly been checked visually, but not only is the inspection time-consuming, but there are many inspection errors due to fatigue. Therefore, in recent years, devices have been used that automatically read color marks and inspect for deprinting. However, since color marks are only for inspection purposes, they are usually small, and as a result, automatic reading inspections are often not carried out accurately due to dust, blurring, ink splatters, etc. is produced in a wide variety of products, and it is difficult to limit the dimensions of the color mark. Therefore, there is a need for a color mark deprinting inspection device that is not affected by such dust, smudges, ink splatters, etc., and that does not impose restrictions on the size of color marks. Purpose of the Invention The present invention has been made in view of the above-mentioned current situation, and it divides color mark data captured by a television camera into meshes, sets multiple thresholds, and eliminates dust, fading, ink splatter, etc. To provide a color mark deprinting inspection device that accurately reads color marks by removing misidentified data. Hereinafter, the present invention will be explained in detail by one embodiment with reference to the drawings. FIG. 1 is a block diagram showing the entire apparatus of the present invention. The main components include a detection unit 200 that captures data on the inspected object 2, a control unit 300 that analyzes data, and an output unit 40 that outputs and displays analysis results.
Consists of 0. First, the detection section 200 will be explained. When the inspected object 2 reaches the measurement position, the object detection sensor 22 senses the object and sends a timing signal to the DMA interrupt circuit 28. Next, the DMA interrupt circuit 28
Send a hold signal to CPU100 and temporarily
Stop the CPU100, and then print the image again.
Address data and a write signal are sent to store data in the RAM 130. An image of the object to be inspected 2 is captured by a television camera 18, digitally converted by a binarization circuit 14, and stored in an image RAM 130 based on address data and a write signal from the DMA interrupt circuit 28. At this time, the synchronization signal generation circuit 20 generates a constant synchronization pulse, and the timing of the television camera 18 and the DMA interrupt circuit 28 is determined. When the image capture is finished, the DMA interrupt circuit 28 sends an interrupt signal.
Send it to the CPU 100 and operate the CPU 100.
Any of the three images, the analog image from the television camera 18, the digital image passed through the binarization circuit 14, and the image from the memory, can be viewed on the monitor television 10 through the changeover switch 16 and the changeover circuit 12. . Next, the control section 300 will be explained. image
The RAM 130 stores image data from the detection section 200. The CPU 100 analyzes data in the image RAM 130 according to a program procedure from the ROM 110 in which a processing program is stored, and stores the results in the working RAM 120. The CPU 100 is connected to the main parts through an address bus, a data bus, and a control signal line, and addresses, data, and control signals are exchanged. Next, the output section 400 will be explained. I/
The O instruction decoding circuit 58 detects the address signal,
and control signals, starting from address 4 bits.
Generate 16 I/O addresses. The data display circuit 50 displays the calculation result data on the data bus and the I/O instruction decode circuit 58.
The machine stop signal circuit 60 and the alarm signal circuit 62 display the calculation results at the required position on the data display 52 using the I/O address obtained based on the address signal and control signal from
If there is an abnormality as a result of image processing by the CPU, a control signal from the I/O command decoding circuit 58 outputs a stop signal for the machines on the production line or causes a buzzer to sound. Further, a switch group 56 and a data input circuit 54 are provided for externally setting a threshold value that is a reference for data analysis in the control section 300, and are connected to a data bus. Here, a case in which a color mark is specifically read using the apparatus according to the present invention will be explained based on the flowchart shown in FIG. FIG. 2 is an explanatory diagram showing an example of a printed object to be inspected. Color mark 3 is small in the upper left corner and consists of three color marks indicating that it is three-color printing. When printing on an object to be inspected, ink printing is performed independently for each color. For example, when the first color is printed, the first color mark is simultaneously printed on the upper left corner. By the way, as shown in FIG. 3, the color mark 3 may actually be affected by dust adhesion, fading, ink splatter, etc. First, the television camera 18 captures the area including the color mark, and binarizes the density using a threshold value. Next, through the image RAM 130,
The CPU 100 creates dots divided into x parts in the horizontal direction and y parts in the vertical direction (in this example, divided into 10 parts), and binarizes the density using a threshold value. Let each dot after binarization be Mxy, and if the dot after binarization becomes a colored part, the value of Mxy is 1, and if it becomes a colorless part,
Set the value of Mxy to 0. Next, the value of Mxy is integrated in the vertical direction for each horizontally divided unit. ₁₀ 〓 ^y=1 Mxy As a result, as shown in FIG. 4A, the graph becomes distorted due to ink skipping, dust, blurring, etc. Next, the maximum value ymax is determined for the data shown in FIG. 4A. ymax indicates an almost completely colored part, and corresponds to 10 in this example. Here, as a reference, the color mark to dust length ratio m (3 in this example) is input through the data input circuit 54, and ymax/m=10/3=3.3=BTH is performed for the above ymax. Then, find the fighting value BTH. By setting BTH to the data shown in FIG. 4A and performing binarization, the data shown in FIG. 4B is obtained. this
Binarization using BTH removes small noise components, but large dust and blur components that exceed the threshold remain. Therefore, the colorless area is shown in the horizontal direction of the data in Figure B.

The number of [0] components is counted for each continuous part, and the maximum value xmax of the continuous part, which is the value of the colorless part, is determined. Then, as above, input the perceived size ratio n (3 in this example) between the colorless area and the dust area from the outside to find xmax/n=10/3=3.3=CTH. Set the fighting value CTH. Associating CTH with each colorless part in figure B, CTH
Cx
is obtained, and the graph shown in Figure C is obtained. The colorless area due to fading shown in Figure B becomes a colored area because it does not exceed CTH. Even in this case, components due to dust are still included. Therefore, in the horizontal direction of the data in C in the same figure, the data [I] indicating the colored part is counted for each continuous part, and the maximum value zmax of the continuous part that becomes the value of the colored part (in this example Now find 10).
Here, as before, the recognition l (3 in this example) is input from the outside, zmax/l=10/3≈3.3=ATH, and the colored part is binarized by ATH. As a result, Dx is obtained, and the data of the graph shown in D of the figure is obtained. The dust component in C in the same figure becomes a colorless part because it does not exceed ATH. The data obtained in this way has almost all noise components removed, and by counting the colored parts in the horizontal direction and comparing them with the number of color marks input from the outside, it is possible to detect the deprinting of printed matter. The presence or absence is determined. If unprinting is detected here, the machine stop signal circuit 6
An unprinting signal is sent to the 0 alarm signal circuit 62 through the I/O command decode 58, and the machine is stopped and an alarm is issued. Effects of the Invention The color mark deprinting inspection device according to the present invention makes it possible to remove misreading images such as dust, ink splatters, blurring, and density unevenness, and to perform accurate reading, and also to fix the size of the mark. There is no need to input dimension data for each type.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the entire inspection apparatus according to the present invention, FIG. 2 is an explanatory diagram showing an object to be inspected, and FIG.
FIG. 4 is a detailed explanatory diagram showing color marks, FIG. 4 is a graph showing each stage of processing color mark data, and FIG. 5 is a flowchart for reading color marks. 2...Object to be inspected, 3...Color mark, 10...Monitor television, 11...Light source, 12...Switching circuit, 14...
Binarization circuit, 16... Selector switch, 18... Television camera, 20... Synchronization signal generation circuit, 22... Object detection sensor, 28... DMA interrupt circuit, 50... Data display circuit, 52... Data display, 54... Data Input circuit, 56... Switch group, 58... I/O command decoding circuit, 60... Machine stop signal circuit, 62...
Alarm signal circuit, 100...CPU, 110...ROM,
120... Working RAM, 130... Image RAM,
200...Detection section, 300...Control section, 400...Output section.

Claims (1)

[Claims] 1 In the color mark deprinting inspection device, the area containing the color mark is captured by a television camera,
A means for creating dots by dividing them into x-divided horizontally and y-divided vertically, and then binarizing each dot into a colorless part or a colored part in terms of density using a threshold value, and For the unit, find the maximum value of the integral value obtained by the vertical direction, divide it by a certain value as a threshold value, and divide the integral value into a colorless part or a colored part with a binary value. Among the binarized integral values, find the maximum value of the continuous part that is the value of the colorless part when viewed in the horizontal direction, divide the value by a certain value as the threshold value, and calculate the value below the threshold value. A means of converting the value of the continuous colorless part to a value of the colored part, find the maximum value of the continuous part that becomes the value of the colored part when viewed horizontally, divide it by a certain value as the threshold value, and set it as the threshold value or less. means for converting values of continuous colored parts into values of colorless parts, means for counting colored parts when viewed in the horizontal direction, means for comparing the number of color marks inputted from the outside with the counted value, and said comparison. A color mark deprinting inspection device comprising: means for displaying a result; and means for outputting a signal based on the comparison result.