JPH0535853A - Inspection device for printed matter - Google Patents

Abstract

PURPOSE:To enable easy and precise inspection by decomposing a complicate pattern print into simple patterns by using color information and inspecting the decomposed images. CONSTITUTION:An image converting circuit 103 converts the color image of the printed matter P to be inspected into the image data from which a 1st pattern is removed, a differentiator 104 finds the difference between the image data of a 2nd pattern and standard pattern data read out of a standard pattern memory 105, and an accumulator 106 inspect a print latch as to an input image by accumulation. Consequently, the simple images can easily and accurately be extracted from the complicate image and the defect of the print can accurately be inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting printed matter including a color image.

[0002]

2. Description of the Related Art As a method and apparatus for inspecting printed matter, for example, the method disclosed in the specification and drawings of Japanese Patent Publication No. 20477/1990 is known. This method is to inspect a printed matter by comparing a grayscale image of the printed matter with standard data.

[0003]

Conventionally, since the printed matter is inspected by comparing the light and shade information of the printed matter with standard data, the inspection of the printed matter having a plurality of color patterns has a simple black and white pattern. There was a problem that the error was large compared to the inspection of printed matter.

It is therefore an object of the present invention to provide a printed matter inspection apparatus capable of easily and accurately inspecting a printed portion of a printed matter having a plurality of color patterns.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention decomposes a complicated printed matter into regions by color information and decomposes it into a simple pattern, and uses standard data for each decomposed pattern. It is intended to provide an inspection device for printed matter that performs an inspection by comparison.

[0006]

The printed image is inspected as a simple pattern by collecting the color image of the printed matter to be inspected, extracting the converted color image data of only the specific color from the color image, and comparing it with the standard pattern.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction and operation of a printed matter inspection apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In FIG. 1, the print P to be inspected is scanned by the line sensor 101 in the direction of arrow a, and R, G, and B
The color image input circuit 102 performs A / D conversion and standardization as digital color image data having color components. The color image is digital image data of three components of R, G and B, and the image conversion circuit 10 is provided for each pixel.
3 is supplied.

Here, as shown in FIG. 2, the printed matter P to be inspected has a plurality of strip-shaped patterns 202 of green as a first color and a mark in a red circle as a second color on the paper 201. It has a circular pattern 203 that is written. In this embodiment, the image conversion circuit 103 in FIG. 1 removes the first pattern 202 in the printed matter P in FIG. 2 and converts it so that only the second pattern 203 remains on the paper 201 as shown in FIG. To do. The image conversion circuit 103 is a circuit that sets parameters l, m, and n for R, G, and B values of input image data and calculates y such that y = lR + mG + nB (1) pixel by pixel. . here,
The parameters l, m, and n of the equation (1) are the first pattern 202.
To be removed.

As shown in FIG. 4, the color P (Rp, Gp, Bp) of the paper 201 is set in the three-dimensional space having the three colors of red (R), green (G), and blue (B) as coordinate axes. Color F (Rf, Gf, Bf) of the first pattern 202, second pattern 2
The coordinates of the color C (Rc, Gc, Bc,) of 03 are shown in FIG. In FIG. 4, the vector CV1 → when the color coordinates P (Rp, Gp, Bp) of the paper 201 are mapped onto the color coordinates C (Rc, Gc, Bc) of the second pattern 203 is CV1 → = ( Rc-Rp, Gc-Gp, Bc-Bp) (2). Similarly, set the coordinates P (Rp, Gp, Bp) to the coordinates F.
Vector CV when mapped onto (Rf, Gf, Bf)
2 → is CV2 → = (Rf-Rp, Gf-Gp, Bf-Bp) (3) Therefore, the vector S → is S → = {(CV1 →, CV2 →) / (| CV2 → | 2) } CV2 → −CV1 → (4) The parameters l, m and n are calculated as (l, m, n) = (255 / | S → |) S → ... (5).

This means that, on the coordinates of FIG. 4, the point F (Rf, Gf, Bf) is erased by superimposing the coordinate point F and the coordinate point C (performing coordinate conversion) when viewed from the coordinate point P. It means to do.

That is, the input color image is converted into the conversion circuit 1 according to the equation (1) in which l, m and n defined as above are substituted.
By performing conversion at 03, the output A of the image conversion circuit 103 becomes image data in which only the red pattern 203 in which the green pattern 202 is erased is extracted as a color component, as shown in FIG. The details of this image conversion circuit 103 are in the application by the same applicant, Japanese Patent Publication No. 254308/1990, and therefore will not be described here any further.

The data A of the image 203 shown in FIG. 3 is supplied to one input of the differentiator 104, and the difference data for each pixel from the standard pattern supplied from the standard pattern memory 105 to the other input is calculated. . Here, the subtractor 104
Is the absolute value of the difference between the input image data A and the standard data B |
A-B | is output. The standard pattern memory 105 is read and controlled by the output of the memory control circuit 108 which is controlled by the timing signal *) output from the color image input circuit 102.

The difference data output from the difference unit 104 is added by the accumulator 106 for all the pixels of the image 201 in FIG. 3 and sent to the decision circuit 107. This accumulated difference data has a large value when there is a defect in the printing of the image 203 of FIG. 3, and by comparing it with the standard value, the printing defect such as stains and omissions can be easily and accurately detected. The determination result of whether the printing of the printed matter P is normal is the determination circuit 107.
Is output from.

[0015]

As described above, according to the present invention,
It is possible to provide a printed matter inspection apparatus that can easily and accurately inspect a complicated pattern print by separating the complicated pattern print by color information, decomposing it into a plurality of combinations of simple patterns, and inspecting each pattern.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an inspected print part of FIG.

FIG. 3 is a diagram showing an example of an output image of an image conversion circuit in FIG.

4 is a diagram showing a procedure for obtaining a parameter given to the image conversion circuit of FIG.

[Explanation of symbols]

P ... Printed material to be inspected, 101 ... Line sensor, 102 ... Color image input circuit, 103 ... Image conversion circuit, 104 ... Difference device, 105 ... Standard pattern memory, 106 ... Accumulator,
107 ... Judgment circuit, 108 ... Memory control device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshikazu Tagami             70 Yanagicho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture             Toshiba Yanagimachi Factory (72) Inventor Yuki Makino             70 Yanagicho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture             Toshiba Yanagimachi Factory

Claims (3)

[Claims] 1. A means for collecting color image data of an inspected printed matter, a means for obtaining converted color image data having a predetermined color component from the collected color image data, the converted color image data and standard pattern data. And a means for obtaining difference data between the printed matter and the inspection result of the printed matter to be inspected based on the difference data. 2. The printed matter according to claim 1, wherein the means for obtaining the converted color image data includes data conversion means for extracting data of a desired color component from the color image data of three colors of R, G and B. Inspection device. 3. The printed matter inspection apparatus according to claim 1, wherein the means for obtaining the difference data includes means for accumulating a difference of each pixel of the color image data.