JPH01277230A - Copying method - Google Patents

Abstract

PURPOSE:To faithfully reproduce a color or a neutral color by determining a color image region in accordance with the read original density and classifying the original to a color image and a black-and-white image by features of this color image region and setting a color copy condition in accordance with this classification. CONSTITUTION:The original density of the original having a color image and/or a black-and-white image is read, and the color image region is determined in accordance with this read original density. The original is classified to at least the color image and the black-and-white image by features of this color image region. A copy condition is set in accordance with this image classification. Thus, a stable copy image of high quality is obtained, and even the black- and-white image is copied with a satisfactory color balance by a color copying machine.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a copying method for copying an original using a color copying machine.

<Prior Art> Normally, the originals to be copied by a copying machine include originals mainly consisting of color images with a small number of gradations, originals with multi-gradation color images,
Examples include originals that mainly consist of black and white images such as characters, originals that have multi-tone black and white images, and the like.

In addition, faithful reproduction or preferable reproduction is required for each manuscript.

As one of these methods, it is common practice to copy a color original using a black-and-white copying machine to obtain a black-and-white copy. In this case, the background of color documents tends to be dark, and therefore requires different exposure control from that of black and white documents.

Further, Japanese Patent Application Laid-Open No. 57-20749 discloses a method of obtaining a black and white copy by selecting the color of recording paper in accordance with the background color of a color original.

As described above, it is necessary to distinguish between a color original and a monochrome original, and Japanese Patent Laid-Open No. 177367/1983 discloses a method for obtaining a monochrome copy by using a sensor to determine whether the original is a color original or not.

In this method, color originals, especially originals with a colored background, are detected from black and white originals based on the percentage of the R, G, and B light amounts relative to the total light amount of the three colors. If it is determined that this is the case, the copy is automatically made lighter so that the density of the background does not become too dark. This discrimination method is prone to errors when the image area ratio is small or the image density is low.

<Problems to be Solved by the Invention> However, the copying method disclosed in the above publication is applied to detecting a color original when copying the color original into a black and white copy. Faithful reproduction of a color original by black-and-white copying is out of the question, and is completely different from the problem of copying a black-and-white original using a color copier to obtain a copy.

To copy multi-tone black and white originals (for example, B/W photos, B/W prints, printed originals, etc.), the black and white copying machine has a hard gradation.
It is insufficient in terms of faithful reproduction. Color copying machines aim to achieve faithful density and color reproduction for multi-tone color originals, and have been commonly used for copying multi-tone black and white originals.

However, color images are mainly formed from color materials of the three primary colors, and while appropriate exposure conditions are set for such images, black in black and white images such as text is formed by color materials and various color materials. In many cases, the mixture merely makes the material visually black, and there is a problem in that under the same copying conditions, the black reproduced in a copy is not necessarily black for the copying material. It also has a high ability to distinguish between visually neutral colors (achromatic colors). Therefore, color deviations from neutral colors are easily noticeable, and it is necessary to reproduce gray with accuracy equal to or higher than that of color originals.

It is difficult to copy color originals and black and white originals under the same copying conditions. Further, although it is easy to visually distinguish between color and black-and-white documents, there are cases where the distinction is forgotten, and black-and-white documents also have black-and-white images with different coloring materials that are difficult to visually distinguish, so they need to be further classified.

According to the present invention, when an original is copied using a color copying machine to obtain a copy, it is possible to automatically classify the image into a color image and a black and white image and select appropriate color copying conditions, thereby achieving faithful color reproduction or neutral color reproduction. The purpose of the present invention is to provide a copying method that allows high-quality, stable images to be obtained.

<Means for Solving the Problems> In order to achieve the above object, the copying method of the present invention copies a document having a color image and/or a monochrome image using a color copying machine, and the document density of the document is A color image area is determined based on the density of the read document, the color image area is classified into at least a color image and a monochrome image based on the characteristics of the image, and color copying conditions are set according to the image classification. .

<Operation> According to the present invention, the document density of a document having a color image and/or a monochrome image is read, and a color image area is determined from the read document density.

Depending on the characteristics of this color image area, it is classified into at least color images and monochrome images.

Copying conditions are set according to the classification of this image.

<Example> Examples will be described with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of a silver salt photographic color copying machine (hereinafter sometimes abbreviated as a copying machine) as an embodiment of an image recording apparatus to which the copying method of the present invention is applied.

As shown in FIG. 1, a transparent document ffi! Placement surface 10
A document 11 is placed on top of the document 11 with the document surface facing down.
The document is held down by a document holding plate 12 whose lower surface is white.

Further, a white reference plate 13 is attached to the lower surface of the left end of the document placement surface 10. This reference plate may be colored other than white, such as gray.

The light source unit 14 includes a light source 15, a reflector 16, and a mirror 17, and reciprocates in parallel with the document placement surface 10 to illuminate the document 11 with a slit. Mirror unit 1
8 is two mirrors 19.2 extending in a direction perpendicular to the plane of the paper.
0 and returns the light from the light source unit 14 in parallel. Further, this mirror unit 18 moves in the arrow direction at 1/2 speed in synchronization with the light source unit 14 in order to correct the focal shift caused by the movement of the light source unit 14.

The lens unit 22 moves back and forth along the optical axis during magnification conversion. In this lens unit 22, a yellow filter Y1, a magenta filter M, and a cyan filter C are arranged near the principal point of the lens between the front group 23 and the rear group 24.

These color filters Y%M and C are movable in the direction orthogonal to the optical axis, and the amount of insertion in the optical path adjusts the light quality with the slit light to correct the color balance.
Such a filter device is known, for example, from Japanese Patent Publication No. 44-254.
It is described in Publication No. 2. Also, behind the rear group 24, there are two aperture plates 25 and 26 that move in opposite directions.
is located.

In the illustrated example, the two aperture plates 25 and 26 are movable, but they may be fixed.

Further, in addition to the color filters Y, M, and C, an ND filter may be added.

Each color filter Y%M, C and aperture plate 25 if necessary
．． 26 includes a drive unit 131.1 as shown in FIG.
32.133.134 are provided.

These driving units 131 to 134 may normally be driven using pulse motors, solenoids, or the like.

The light passing through the lens unit 22 passes through the mirror 28.2.
After being turned back at 9, it reaches an optical path switching mirror 31 whose rotation center is an axis 30. When measuring reflected light, the condensing mirror 32 is inserted into the optical path as shown by the dotted line, the optical path switching mirror 31 is also withdrawn from the optical path as shown by the dotted line, and the reflected light from the original 11 is focused. Photometry means 3
Put it in 3.

The condensing mirror 32 includes a plurality of mirrors 32a, and as shown in FIG. 2, each mirror 32a is arranged at an angle corresponding to the distance from the optical axis, so that almost all of the slit light is Focus all or part of the light. The photometry means 33 includes a red sensor 3.3a, a green sensor 33b1, and a blue sensor 33c, and measures the three-color light components of the reflected light.

A control means 50 is connected to the photometry means 33 .

The control means 50 controls the color filter Y, color filter Y,
M and C are controlled through their driving units 131 to 133.

The control means 50 is composed of known control means, and includes a CPU
Copying conditions determined in advance according to the type of image are stored in a known storage means together with the I10 board and the I10 board, as will be described later.

The magazine 35 stores a photosensitive material 36, which is a copying material, in a rolled state. This photosensitive material 3
6 is drawn out by a pair of drawing rollers 37 and 38, and cut by a cutter 39 after being drawn out a certain length. The cut photosensitive material 36a stops at a position where its leading end is caught by a pair of rollers 40, 41.

Opposed to this roller pair 40.41 is a roller pair 42.43.
A slit exposure position is formed between two of these four rollers 40 to 43, and light from the optical path switching mirror 31 is incident thereon.

During copying, the rollers 40 to 43 rotate in synchronization with the light source unit 14, and a processing section (not shown) is installed that processes the exposed photosensitive material 36a. In this processing section, development, bleaching/fixing, and washing are performed.

A take-out tray (not shown) for sending out the dried photosensitive material 36a is provided downstream of the processing section.

Next, setting of copy conditions will be explained with reference to FIG.

When setting conditions, a mode designation key (not shown) is operated to enter the copying condition setting mode.

Next, after setting the original 11 on the original placing surface 10, a copy key (not shown) is operated. In this copying condition setting mode, the color filters Y%M, C and the aperture plate 25.
26 to the standard position. In addition, the condensing mirror 32
is inserted into the optical path as shown by the dotted line, and the optical path switching mirror 31 is retracted to the position shown by the dotted line.

Thereafter, the light source unit 14 and the lens unit 22 move synchronously six times to illuminate the reference plate 13 and the original 11 with slit light to perform scanning.

The reflected light from the reference plate 13 and the original 11 is reflected by a mirror 17.
．． 19-20, lens unit 22, mirror 28.29
The light is incident on the condensing mirror 32 after the edges of the light are sequentially edged. As shown in FIG. 2, the condensing mirror 32 condenses almost all or a portion of the slit light and guides it to the photometry means 33. This photometry means 33 is composed of a red sensor 33a, a green sensor 33b, and a blue sensor 33c, so that the three color components of the reflected light are each measured.

The light quantity signals output from each of the sensors 33a to 33c are logarithmically converted, and converted into a density signal from this value and the logarithmically converted value of the photometric value of the reference plate 13, and the original density of the original 11 is determined.

Then, this document density is stored.

Note that as the value corresponding to the photometric value, for example, a logarithmically converted value of the photometric value, a functional formula corresponding to brightness, or a conversion value based on a conversion table may be used.

A color image area is determined from the document density read as described above.

Specifically, the color image area may be determined based on whether the color deviation from a neutral color (achromatic color) is equal to or greater than a certain value. At this time, depending on the case, the color density may be determined after calculating the color density based on the density of the read document.

As an index indicating this color bias, for example, (R-CR
m r n ) + (G − Cam In ) +
(B −CB+m1n) (Here, CR1jIn%Calns C8+*In is R,G.

B represents the logarithmic value of the photometric value of each color, R, 0%
represents the minimum value among each of B. ] etc. may be used.

Not limited to the above example, a value corresponding to a difference from a constant color (for example, a neutral color) can be used as the color bias.

Specifically, saturation, hue, etc. may be used.

The saturation is l (R-W) + (G-W) + (B
-W)l (However, W= (kl B+2 G+
ks B)/(kl + kz + ks), where kl, kz, and ki each represent a constant. ), 1 (R-G)I+I (B-G)l,l R-G B
+ l G-B l, (R-G)" + (B-G)", (R/G ten B/G)
, (in the above, R, G, and B have the same meanings as described above), chroma values in the C, 1, and E color system, values determined from the color coordinate table, etc. are used. be able to.

In addition, hue can be the value of (R-G)/(G-B), the angle in color coordinates, the angle of coordinate points in a chromaticity diagram,
A value determined from color changes in a color coordinate table or the like may be used as a reference.

As described above, after determining the color image area, based on this color image area, the original 11 to be copied is composed at least mainly of color images (hereinafter referred to as a color original).
The original is classified based on whether it is a black-and-white image (hereinafter referred to as a black-and-white original).

Such classification is performed by determining the color image area (indicated by - in the figure) based on the relationship between saturation and document position, as shown in FIG. This is performed by determining the portion that is determined to be a color image area using the degree threshold (ke) as a reference.

This determination may be made by comparing the ratio of the color image area to the total area or the color image area itself, area, number, distance, etc., ratio, distribution, etc. using the threshold value as a reference. Furthermore, as a matter of course, if a color image area does not exist, the document is classified as a black and white document.

Based on this determination, the document shown in FIG. 5a is classified as a color original, and the document shown in FIG. 5b is classified as a black-and-white document.

As shown in FIG. 5b, even a black and white original may appear highly saturated. The reason for this is that when the image density is high, the color of the original is not necessarily neutral, the accuracy of the photometric system, and the difference in spectral sensitivity distribution between the naked eye and the photometric system. In some cases, the color may not be neutral.

Conversely, even if the document is a color document, it may not be determined as a color image area. The reason for this is that when two or more different colors coincidentally have a color close to a neutral color, when the image does not have high saturation due to low density or high density, or when the background of neutral colors including white background This is the case when the image occupies a large area and the color image part is small, or when it includes a background part, a character part, or a part of the black and white image. Therefore, it will be erroneous to judge the monochrome image power of a color image based on the average value of photometric values, the color of partial side light values, or the color balance of the three primary color values.

The present invention eliminates these drawbacks.

In the above, documents are only classified as color documents or black and white documents, but the document may be further classified according to the type of color image in a color document or the type of black and white image in a black and white document.

That is, color images may be further classified into photographs, prints, illustrations, etc., or may be classified according to color materials, gradation, etc. Such classification may be performed by analyzing the image area of the document, or conversely by analyzing the non-image area.

Similarly, black and white images may be further classified into text images, multi-tone images, and the like.

For this reason, it is possible to classify documents having both color images and black and white images based on their characteristics.

In addition to the above-mentioned characteristics of both, if the photometry means 33 is capable of photometry of three or more colors, it is possible to accurately separate the colors from more detailed characteristics.

For example, by using a 700nm photometric sensor for the three colors of 450nm, 550nm, and 650nm, approximately 700nm can be seen in black and white images made of silver or black plates, and in paints.
It is possible to separate a black-and-white image created from a coloring material having no absorption at m or more. In this case, even if the images are visually black and white, the copying conditions for the two images are different.

In addition to the three color photometric sensors mentioned above, we also have 500nm and 60nm sensors.
By using photometric sensors with different wavelengths such as 0 nm and 700 nm, it is possible to accurately determine whether an image is a color image composed of three dyes, a black and white image, or a silver or black plate.

After the documents are classified as described above, a predetermined optimal copying condition is selected according to the classification, and the color copying condition is set.

Such color copying conditions may be determined as exposure amounts depending on the type of color image or the type of monochrome image, and may be set as copying conditions 1.2.3, for example, as shown in FIG. .

The above exposure amount may be determined and stored in advance using a reference plate or a test chart (see Japanese Patent Application No. 62-37249, No. 62-37250, etc.). Alternatively, the copying conditions may be determined as a corrected exposure amount for copying conditions such as a color photo original or a color print original. Furthermore, the copying conditions based on the black and white image type classification for a black and white original may be modified according to predetermined conditions depending on the tint of the photometric value.

For example, if the photometric value at 700 nm has a density smaller than 650 nm, the copy tends to turn red, so it is better to set copy conditions that reduce the amount of haze compared to the copy conditions for black and white originals.

In addition to the amount of filter movement mentioned above, the exposure amount is determined by
It can be controlled by light emission amount, scanning speed, aperture aperture amount, etc.

After setting the copy conditions, a mode designation key (not shown) is set to copy mode. In this copy mode, the condensing mirror 32 is retracted from the optical path, and the optical path switching mirror 31 is retracted from the optical path.
is inserted into the optical path. Next, by turning on a copy key (not shown), a color copy is created. In this case, the light-sensitive material 3 is
Exposure 6a is performed.

In the above, a silver halide photographic color copying machine is mentioned as an image recording device, but it is not limited to this, and includes an electrophotographic color copying machine, a thermal transfer color copying machine,
Inkjet color copying machine, laser color copying machine,
It may also be a video color copier.

<Effects of the Invention> According to the present invention, since the original density of the original is read and the color image area is determined from the color original density, it is possible to accurately classify the original according to the type of image. Then, color copying conditions can be selected based on this accurate classification, and high quality and stable copied images can be obtained.

When copying a color image, copying conditions can be set using color materials, etc., and black and white images can also be copied with good color balance using a color copying machine.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of a silver salt photographic color copying machine to which the present invention is applied. FIG. 2 is a sectional view showing the function of the condensing mirror. FIG. 3 is a block diagram for explaining a method of setting copy conditions. FIG. 4 is a flowchart for explaining the flow of setting copy conditions. FIG. 5a and FIG. 5b are graphs for explaining the classification of images, respectively. Explanation of symbols 10... Original placement surface, 11... Original, 12...
- Original holding plate, 13... Reference plate, 14... Light source unit, 22... Lens unit, Y... Yellow filter, M... Magenta filter, C... Cyan filter, 31... - Optical path switching mirror, 32... Concentrating mirror, 33... Photometry means, 36
．． 36a...Photosensitive material, 50...Control means FIG, 2 32a FIG, 4 FIG, 5a Procedure Neho Seisho (self-motivated) June 14, 1985 1, Indication of the case 1988 Patent Application No. 107015 No. 2, Method of copying the title of the invention 3, Name of the person making the amendment Name (520) Fuji Photo Film Co., Ltd. 4, Agent 101 2!864-4498 Address 3-2-2 Iwamoto-cho, Chiyoda-ku, Tokyo Chiyoda Iwamoto Building 4th Floor Name (8015) Patent Attorney Nozomi Watanabe 6 Contents of Amendment (1) Page 15 of the Specification, Lines 16-18 ``Also, of course, the color image area...'' Of course, the present invention also includes changing ``to be classified as a monochrome original'' to ``If a color image area does not exist, the original is classified as a monochrome original due to the feature that there is no color image area.'' Instead of determining the color image area from the density, it is also possible to first determine the image area and then determine whether it is a color image area.Conversely, instead of determining the color image area (or determining the monochrome image area) After determining the black and white image area without
The present invention also includes these methods that may classify whether an image is a color image or not. ” he corrected. (2) Correct the color-image black-and-white image power J on the 16th page, line 18, as ``Is it a color image or a black-and-white image?'' (3) "Read the original density of the original and use the color original density" on page 20, lines 14-15 Itl g? rN
JL-) 141mffM1m1m#-SoJ u 1
m&j-.

Claims (1)

[Claims] (1) In a copying method in which a document having a color image and/or a black and white image is copied using a color copying machine, the document density of the document is read, a color image area is determined from the read document density, and the color image area is A copying method characterized by classifying at least color images or monochrome images based on characteristics, and setting color copying conditions based on the classification of the images.