JPH0487454A - Reading method for color correction sample - Google Patents

Abstract

PURPOSE:To enable accurate read without executing an alignment by providing a marker patch having arrangement position information of a color sample image on recording paper. CONSTITUTION:A color correction sample 2 is constituted by placing color patches 101 consisting of total 228 pieces of 19 lines X 12 rows vertically and horizontally, respectively by arranging them like a lattice on recording paper 100, and also, placing adjacently 20 pieces of marker patches 102 in one row of its left. The color correction sample 2 is read by an image scanner 4, existence of the marker patch 102 to a certain line and a position THi related to the main scanning direction are known, and a position against the sub- scanning direction is identified. In such a way, by the image scanner 4, position information in the main scanning direction and the sub-scanning direction of the maker patch 102 is read, and by this position information, arrangement positions Xj, Yi of a color patch to be read are determined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reading method for reading a color correction sample using an image league or the like for color correction processing in an image forming apparatus such as a color copying machine.

[Prior Art] Conventionally, in image forming apparatuses such as color copiers and color printers that output multi-tone color images, color correction has been used to correct nonlinear recording characteristics caused by the image forming means to linear characteristics. Corrections may be made. At that time, in order to understand the recording characteristics of the image forming device, a color sample image consisting of dozens to hundreds of colors is output on recording paper, and the color data of the sample is read by an image scanner or other image reading device. There is a need.

When performing this process, first, rectangular areas of a specific color (hereinafter referred to as color batches) are arranged vertically and horizontally on the recording paper. Next, when reading this color correction sample, the position and image f of each color sample on the recording paper must be
In order to set the reading areas of the jA reading device to correspond correctly, an operator manually adjusts the position of the color correction specimen recording paper on the image reading device before reading.

[Problem to be Solved by the Invention] However, in the above reading method, in order to arrange tens to hundreds of color batches on - sheets of color correction sample recording paper, the size of each color patch must be adjusted. is quite small and requires high alignment accuracy when placing the color correction specimen recording paper on the image reading device, so it is time-consuming and time-consuming to manually set the recording paper on the image reading device. It was time consuming. Moreover, the only way to know whether the sample data of each color patch of the color correction sample read in this way has been read correctly is to estimate the read color batch data from the color batch arrangement of the color correction sample. This was quite difficult and unreliable.

The present invention has been made to solve the above-mentioned problems, and when a color correction sample is read by an i#gA reading device, the position information of the color correction sample to be read is obtained by calculation, and the position information of the color correction sample to be read is obtained by calculation. By accurately reading the color correction sample recording paper, it is possible to simplify the alignment work of setting the color correction sample recording paper on the image reading device, and it is possible to read each color batch data on the recording paper without manually aligning the recording paper with such high precision. An object of the present invention is to provide a method for reading a color-corrected sample that can be read accurately.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses an image reading method that reads a two-dimensional image in a main scanning direction and a sub-scanning direction using a color correction sample printed on recording paper. In a method for reading a color correction JE specimen read by a device, a marker patch that is distinguishable from the color correction specimen and the background of the recording paper is placed close to the color correction specimen on the recording paper and along the sub-scanning direction of the image reading device. The position of the marker patch in the main scanning direction and the sub-scanning direction is read by an image reading device, and based on the position information of this marker patch,
The arrangement position of the color correction sample to be read is determined.

[Operation] According to the above method, by providing the marker patch having the arrangement position information of the color sample image on the recording paper, when the image reading device scans to read the color correction sample,
This marker patch is detected and absolute position information of the marker patch on the recording paper is obtained. The relative positional relationship between the marker patch and the color sample (color batch) of the color correction sample is
When recording a color sample on a recording paper, if a certain rule is determined, the relative position between the known marker patch and the color sample can be determined based on the absolute position information of the detected marker patch on the recording paper. It is possible to obtain absolute positional information of the color corrected sample image and, ultimately, the color batch on the recording paper, depending on the positional relationship.

Using this absolute position information, the image reading device can determine which color batch the read data corresponds to.

Further, since the marker patches are arranged linearly along the sub-scanning direction of the image reading device, the position distribution of the marker batches along the sub-scanning direction with respect to the main scanning direction can be obtained. As a result, the arrangement information of the color correction sample recording paper, such as the amount of inclination of the color sample image, is calculated.

[Embodiment] Hereinafter, a method for reading a color correction sample according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a block configuration of a color copying machine equipped with a reading device for reading a color correction sample, and FIG. 2 is a diagram showing an example of the same correction sample.

The color copying machine 1 includes an image forming section 3 consisting of an engine section of a color laser printer that prints a color correction sample 2 on recording paper, etc., and a color correction sample 2 that is divided into a main scanning direction and a sub-scanning direction to form a two-dimensional image. An image scanner 4 (reading device) for reading, a CPU 5 for calculating placement position information of the color correction sample to be read at the time of reading, and a memory 6 for storing placement position information of the color correction sample 2, etc. for this calculation.
It is composed of.

The color correction sample 2 is printed on a recording paper 10 as shown in FIG.
0, a total of 228 color batches 101 of 19 rows and 12 columns each are arranged in a grid pattern, and further left -
2Of marker patches 102 in the row! A: They are placed next to each other. The size of the color patch 101 and the marker patch 102 is 255×2 at a resolution of 400 dpi.
It is 55 dots. The image scanner 4 (image reading device) placed the marker patch 102 on the left side of the color sample image of the color correction sample 2 (hereinafter, the combined area of the marker patch 102 and color batch 101 is referred to as the color sample image).
When reading this color sample image, the main scanning direction is from left to right.

Note that this restriction was determined in consideration of the ease with which the image reading device can process the read data.
It is not an essential part of the invention.

The marker patch 102 is colored in a color that can be discriminated by the image scanner 4 from a portion 103 (hereinafter referred to as a border) of the recording paper where no color sample image is recorded and by threshold processing of read data or the like. In this embodiment, the marker patch 102 is shown in black with halftone dots in the figure),
White is set as the border 103. Also color batch 10
1, each arrangement sets the color of the i-th row and j-th color patch to CI
J (+ = 1..19. J Eng 1
．． ．． 12).

FIG. 3 is a diagram showing the direction in which the image scanner 4 scans the color correction specimen 2, and FIG.
It is a figure which shows the synchronization signal output by.

As shown in FIG. 3, the image scanner 4 scans the color correction sample 2 from left to right in the main scanning direction and from top to bottom in the sub-scanning direction, and scans the color correction sample 2 sufficiently for the size of the color batch 101. Precise resolution (400dpi in this example)
The image is read and the dot data values are sequentially output to the CPU 5 line by line. In addition, the same scanner 4 has a fourth
As shown in the figure, a vertical synchronization signal Sv and a horizontal synchronization signal sh are output as signals indicating the reference position chamber at the start of data in the main scanning direction and sub-scanning direction, respectively, and in synchronization with this synchronization signal sh, the image Data is read.

Next, we will explain how to read the color correction specimen 2 output by the image forming section 3 with the above settings using the image scanner 4, as shown in FIGS.
This will be explained using b).

FIGS. 5(a) and 5(b) are a diagram showing a signal output when the image scanner 4 reads the color correction specimen 2, and a diagram showing the arrangement positions of the border 103 and marker patch 102 corresponding to this signal, respectively. It is. Figure 6(a) (
b) is a diagram illustrating regions in which color patch data is sampled.

Arranged in the i-th row and j-th column of the color sample! Color C of color batch lO1
1j (i=1°, 19.j=1..12), read data for each of the color patches 101, Dij (i=1..19.j=1..1)
2) It is necessary to find.

Now, when the image scanner 4 reads the color correction sample 2 shown in FIG. 1, the output is as shown in FIG. 5(a). That is, after detecting the vertical synchronization signal sh, if the scanning line for reading is in the area 401 on the recording paper 100 shown in FIG. is obtained. Next, when the reading scanning line reaches the area 402, data 412 corresponding to the marker patch 102 appears in the output. This is then processed by value processing to create a marker detection signal 422. Note that 421 shows a marker detection signal when the scanning line for reading is in the area 401.

The pulse width of the marker detection signal 422 clearly corresponds to the size of the marker patch 102 in the main scanning direction.
It is known. Therefore, if the number of dots is 127 or more consecutively, it is determined that the marker patch 102 exists in that reading line, and the horizontal synchronizing signal corresponding to the position in the main scanning direction is detected. The number of dots THi is stored in the memory 6.

Here, the value of 127 dots means 1/2 of the size of the marker patch 102 in the main scanning direction.

With this method, it is possible to know the existence of the marker patch 102 for a certain line and the position THi in the main scanning direction.
The position in the sub-scanning direction is identified. This means that after the marker patch 102 appears for the first time as reading is performed in the sub-scanning direction, 12 such lines continue.
Judgment is made by the number of consecutive 7 lines. Here, the value of 127 lines means 1/2 of the size of the marker patch 102 in the sub-scanning direction. Then, the 127th line is set as the reference point TV in the sub-scanning direction.

After the reference point TV in the sub-scanning direction is obtained, Fig. 6(a)
As shown in FIG. 2, the position information of the color batch 101 to be read in the color correction sample 2 is represented by Xj.

Yi, and as shown in FIG. 6(b), the sizes of the sampled color batch 101 with respect to the main and sub-scanning are PX and P.
Y, the size of the sample area of the color patch 101 is sx,
sy, the position Xj is in the range shown by the following formula,
Yi refers to certain read data.

■In the main scanning direction, THi +PX-j-3X/2 ≦ XJ<THi
+px-j+sX/2 (j=1-.12)■For the sub-scanning direction, TV+PY-i-3Y/2 ≦ Yi<TV+PY-
i+sY/2 (i=f,,19) where, PX=255 (size of color patch and marker patch in main scanning direction) PY=255 (size of color patch and marker patch in sub-scanning direction) SX= 64 (Size of the sample area of the color patch in the main scanning direction) SY=64 (Size of the sample area of the color patch in the sub-scanning direction) Then, the read values are added for each color patch 101, and then the By calculating the average value, the reading value Di corresponding to each color C of the color batch 101 is obtained.
Find j.

Thus, marker batch 1 is created by image scanner 4.
02 in the main scanning direction and the sub-scanning direction, and based on this position information, the arrangement positions Xj and Yi of the color patches to be read can be determined.

In addition, in the method of reading the color correction sample 2 as described above, the movement of the color sample in the vertical and horizontal directions is corrected, but if the color sample is placed on the image scanner 4 at an angle, the data of the color batch 101 may not be correctly read. It cannot be read.

However, regarding this, it is easy to determine whether or not correct reading has been performed by referring to the value of the number of dots THi from the horizontal synchronization signal corresponding to the position of the marker patch 102 for each line in the main scanning direction. I can judge. In addition, since THi is obtained for each line of main scanning, by examining their distribution, it is easy to know in which direction and how much the color sample image is tilted.
An extremely effective index can be obtained when adjusting the set position of the color correction sample 2.

[Effects of the Invention] As explained above, according to the color correction sample reading method of the present invention, when a color correction sample is read by an image reading device, the precise precision of the color correction sample recording paper is not required as in the conventional method. Since each color batch data on the color correction sample recording paper can be read accurately without the need for alignment, it is possible to simplify the alignment work of setting this recording paper, and also to easily check the degree to which the color sample image is tilted. Therefore, it is possible to obtain an effective index for adjusting the set position, and therefore, it is possible to improve the reliability of color correction sample reading.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a color copying machine equipped with an image scanner for reading a color-corrected specimen in which the method of the present invention is carried out, FIG. 2 is a diagram showing an example of the same color-corrected specimen, and FIG. 3 is a scanning image of the image scanner. Figure 4 shows the direction, Figure 4 shows the synchronization signal output by the image scanner, Figure 5 <a) (
b) is a diagram showing the signal output by the image scanner when reading, and a diagram showing the area of the color correction sample corresponding to the signal, and Figure 6 (a>(b) is the area where the color batch data is sampled, respectively. 2... Color correction sample, 3... Image forming unit, 4... Image scanner (reading device), 5... CPU, 6
...Memory, 100...Recording paper, 101...Color number (・y, 102...Marker patch, 103...
Boy - Applicant Brother Industries, Ltd. Agent Patent Attorney Yasuo Itaya Figure (b) Figure (b)

Claims (1)

[Claims] (1) In a method of reading a color correction sample printed on a recording paper using an image reading device that reads a two-dimensional image in the main scanning direction and sub-scanning direction, the color correction sample on the recording paper is A marker patch that can be distinguished from the color correction sample and the background of the recording paper is placed close to the image reading device along the sub-scanning direction of the image reading device, and the image reading device detects the marker patch in the main scanning direction and the sub-scanning direction. A method for reading a color correction specimen, characterized in that the position of the color correction specimen to be read is determined by reading the position of the marker patch and determining the position of the color correction specimen to be read.