JPS6019359A - Color picture processing device - Google Patents

Abstract

PURPOSE:To obtain a color picture processing device excellent in color reproducibility by forming a prescribed picture data based on a reading signal from a reader. CONSTITUTION:In a system where a reader 4 reads a picture printed out after a prescribed picture data is outputted from a pattern generator 1 and printed out, an LUT is constituted so that the picture is converted into the original picture data by using the read picture data as addresses. Thus, it is not so simply executed to write all data (e.g., 64<3>) in the LUT, because data quantity is too much practically. Then the picture data generated from the pattern generator 1 is thinned properly, and the LUT is written according to the thinned picture data and other addresses of the LUT not written are interpolated afterward, allowing to write data to all the addresses of the LUT.

Description

[Detailed Description of the Invention] I) Technical Field The present invention is directed to converting color image data and performing orthogonal processing to
The present invention relates to an image processing device.

n) Prior Art Conventional devices using a masking method are well known as color image processing devices for printing color images with good color reproducibility. In this masking method, many high-order masking equations (eg, Clapper's equation, etc.) are used to perform advanced color correction.

However, although such an equation is a high-order equation, it is at most a quadratic equation or a cubic equation, and it is not always possible to obtain sufficient color reproducibility. Moreover, it is extremely difficult to determine the coefficients of this equation, and only υ
That's what you get. In addition, the color temperature of the input optical system (lens system) and illumination system for reading the courtesy image has changed 1J,! This inconvenience arises in that this coefficient must be corrected even when the color of the transfer paper base changes.

(2) Purpose The present invention has been made in view of the above points, and it is an object of the present invention to provide a color image processing device with excellent color reproducibility.

Another object of the present invention is to provide a color image processing device capable of faithful color reproduction with an inexpensive configuration.

■ ■) Examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a color 1a (image processing device lf) according to an embodiment of the present invention. In the figure, a pattern generator 1 outputs image data of a predetermined color and density to a printer 2.

2 is a printer having a configuration as shown in FIG. 7, for example, which visualizes the image data sent from the pattern generator 1 and prints it onto a transfer paper 3. Form. Further, 4 is a reading device for reading the color image formed on the transfer paper 3 and forming a reading signal;
10ti is a memory for storing the image data output from the reading device 4; 6 is a look-up table (LUT) for converting the read image data stored in the memory 5;
This is an external signal α multiplexer). To explain the operation, the pattern generator 1 generates an image of a predetermined color and density. Next, the image 11 on this transfer paper is read 9 by the reading device 4 and stored in the memory 5. What is the image data 1) A2 in the memory 5 and the original image data 1) A1 output from the pattern generator 1? The value will normally be determined depending on the characteristics of the device, etc.

Therefore, a B jump is formed in the image data 1)A2 in the memory 5.

Then, look at the image data l) A2 in the memory 5 Φ
Image 1 can be reproduced by converting the 9-dimensional image data II) Ai into 9-original image data II) Ai and outputting this to the printer 2 by switching the switching device. In this embodiment, the image data It) A2 in the memory 5 is
is the original image data 1) Att/s to be converted to A1,
Image data 1) Table (memory) with A1 as the output value
It is.

By using L U 'f' in this way, n;f+
It becomes possible to faithfully reproduce the original image read by the scanning device.

FIG. 2 is a diagram for explaining FIG. 1 in more detail.
I and UT will be explained in more detail using the second movement.

Components having the same functions as those in FIG. 1 are given the same reference numerals, and their explanations will be omitted.

The image data from the pattern generator 1 corresponds to 05 degree data of a certain color, and this value is calculated as Di - (I).
ir, Dig, Dib).

Such data is subjected to yellowing by the complementary color conversion circuit 8 and printed out.

In the case of a normal printer, since it is possible to output 64 levels of density for each color, N-64-262144 combinations of image data generated by the pattern generator 1 and the printer 2 can be considered.

Assuming that printer 2 is able to print all of these data, and if the 11x circle of the printed image is represented by the set shown in Figure 6 (1), this set can be output by printer 2. It can be said to be the color reproduction area.

Next, this printed image is read by the anti-vomiting device 4, and a well-known log conversion circuit 7 performs log conversion to convert the degree of intoxication, resulting in 1)'i - (1)ir', J)ig', I)
The image data of ib') is stored in the memory 5.No.1. Ru.

Set 1 in Figure 3) I is cased to memory 5! l'! It represents the color reproduction area when the image data is printed out without going through the UT. Normally, when images are transferred through the reading device 4, the range of image data that can be output is reduced due to the characteristics of the reading device, and the color reproduction area (color reproducibility) is reduced. Therefore, in this embodiment, the image data stored in the memory 5 is converted by LUT, and the set of member)' is expanded to the falcon and case of 1). By using the JLUT to expand the range of image data that can be output, the nine-color reproduction area is expanded and a faithfully reproduced image can be obtained.

Next, a method for creating the LUT will be explained.

As mentioned above, in the system in which the pattern generator 1 outputs the predetermined image data (j) AI and prints out the image, and then the reading device 4 reads the printed image, the LUT stores all of the data that has been read. To store data at an address, output all zero-matched image data from the pattern generator 1, and do not write it one by one.

Therefore, for example, if all 64 types of data are 1. Writing to the UT is not easy in reality as there is too much data to be opened.

Therefore, as a countermeasure to this problem, the image data generated from the pattern generator 1 is thinned out appropriately, and according to this thinned out image data, rJ T K jlf is added. If you interpolate], you can easily apply it to all addresses.
Data can be written to.

For example, if the density level of each color generated from the pattern generator is reduced to 8 levels as shown in Figure 4, N-
It is sufficient to perform 111 incorporation of data for 8''-512 ways.

1) 1' in FIG. 4 shows the image data I: which is obtained by printing out the image data shown in I) 1 in the same figure, and reading it by the reading device 4. Therefore, if you write the image data shown in Figure 4 D1' to the address and the image data shown in Figure 4 IDI to that address, the LUT will be created. .In addition, 1) +r・D
lr', Dtrr * Dtg', Dxh m D
zb'ha! 1 each red.

This shows each color density data of green and blue.

By the way, as shown in FIG. 4 j) 1, in this implementation fl+, image data from a one-move pattern generator whose thinning interval is as large as possible is sampled. By performing such sampling, it is possible to enlarge the PT current area in the yellow color.

FIG. 5 shows the color reproduction area when the image data shown in FIG. 4]Dt, I)t' is printed out.

Further, in FIG. 5, the cluster indicates the maximum range of color reproduction areas that can be output by the printer 2, similar to that shown in FIG.

As can be seen from the figure, in this embodiment, even though the image data generated from the pattern generator t/- is thinned out, the thinning interval is set large, so that the color reproduction area is not reduced.

Next, a method of thinning out image data generated by the pattern generator 1 will be explained. When using LUT,
The image data from the reading device, R II) □', is addressed to r, and the data stored at this address is output to the printer 2.
In tFI', one image data must be obtained for one address. For this purpose, the LUT
In the middle of the day. I) Conversion formula to □' % formula % (1) Tangled inverse conversion formula 111, -f-"(1),') -...-(2) is
It must be a one-valued number for p□′.

For this purpose, □' in equation (1) should be as shown in Figure 6,
It is necessary that t(i) be a 11%□11 increasing (or monotonically decreasing) function with pole 1/j.

That is, f J,, *O(0<1■31・”−,−) −−−−
−(?,) must be obtained.

However, if the thinning interval of the image data to be sampled is made too small, an error △ will occur in the image data l)1/ due to the influence of the characteristics of the reading device, so the condition of equation (3) may not be satisfied. be. That is, LLJ
When forming T, for one address 1), ′, 2
There is a possibility that more than one data D□ will be generated.

Therefore, we set equation (1) to be a simple s'i increasing function,
The relationship between the error △ due to device characteristics and the thinning interval (sampling [IJ) is determined.

From Figure 6, if D□′ has an error of p□′±△, then f
It will be from type 63.

,−,Il,)bI −1), '> 2 △””
(4) Here, lDa, Jl)b is pjii data sampled from pattern generator 1, J)
1. ．． 21M) b' is the image that was printed out at that time using a reading device for ¥1? Indicates the value taken.

That is, the sampling rlj needs to be taken roughly to a certain extent as shown in equation (4).

Also, interpolation of other addresses of LUT can be performed, for example, by B-5p
By using the line function etc., II'I(
Continuous writing of image data is possible.

FIG. 7 is an explanatory diagram of a color image recording device that is an example of the printer 2. As shown in FIG. The color plTi image recording device shown in FIG. 7 consists of an electronic copying device (laser beam printer) including a plurality of photosensitive drums arranged side by side, and images formed by this electronic copying device are sequentially printed onto transfer paper in overlapping colors. This is a device that records data over and over again.

In the figure, 11a to 11d are scanning optical systems, and the scanning optical system extracts required image information from an image memory, etc. (not shown) as a light beam l\(+/-zerby J<), and this light beam is cyan. (0), magenta (M
), yellow (Y), and black (Be), the photosensitive drums 12a to 12 (I Jl
It is configured to form an image. This photosensitive drum 12
Developing devices 13a to 13d are arranged near the a to 12C1, and charging devices are arranged opposite to the photosensitive drums 12a to 12d on the side of the conveyor belt 17 for conveying paper (not shown). 14a to 14d are arranged. Above 1
To explain the operation of the first precept, the scanning optical system 11a
The modulated light beam outputted from ~11d forms an optical image on each of the photosensitive drums 12a-12d, and then the formed image becomes an electrostatic latent image through an electrophotographic process, and is transferred to the developing devices 13a-13ct. The charger 14 was
Each color is sequentially transferred to the recording paper held on the conveyor belt 17 by a to 14d to form a color image. FIG. 8 shows one of the four scanning systems 11a to 11d shown in FIG.
FIG. 2 is a schematic perspective view showing two details, in which the light beam modulated by the half-3Q body laser 21 passes through the collimating lens 20.
The light is collimated by the rotating polygon mirror 22 and deflected by the rotating polygon mirror 22. The polarized light beam is focused on the photosensitive drum 12 by an imaging lens 2 called an fθ lens to perform beam scanning. During this beam scanning, the tip of one line of the light beam is reflected by a mirror 24 and guided to a detector 25. This didektor 25
The detection signal from is in the well-known scanning direction H (
It is used as a synchronization signal in the horizontal direction. This signal name will hereinafter be referred to as a BID signal or a horizontal synchronization signal.

Is Figure 9 a reading device? This shows one example of 74.

In the figure, a color original 30 is irradiated with light from a corner 7, and the reflected light passes through a mirror 36 and a lens 31 to a CC.
Because it is transmitted to the JD line sensor, the color original G
150 images are formed on a CCI line sensor 32 and read at high resolution.

CCI) line sensor 32 is, for example, 20 as shown in FIG.
Six rows of 3/18-bit light receiving sections are arranged, and blue (B), green (G), and red (J() filters 154B, 64G, and 34R are adhered in stripes to each row.

The national affairs data outputted from the reading device shown in FIG. 9 corresponds to the image information of the same point on the manuscript simultaneously separated into five colors.

FIG. 11 shows another reading device with which the present invention can be used. Immediately after the lens filter 1, a gicroic filter 35R, filter 5b for three-color separation is provided to separate the three colors, and the image of each color is sent to the CCII) line sensor 32a.

32b, leading to 32G. Even in an apparatus such as No. 171J, three-color separation image information at the same point on a document can be obtained as a time-series signal.

Red (R), green (G) obtained in this way,
Each blue (B) signal is input as a luminance signal (that is, a signal linear in reflectance) to the U-phantom conversion circuit 7 shown in FIG. 2 described above.

Note that lookup table (,T,UT)6 is RA
It is preferable to use M for planting. It is a reading device fη,
This is because when the color of the transfer paper changes, the stored data values can be rewritten. Further, the data value of the LUT 6 can be easily changed, for example, as shown in FIG.
6 was installed between the memory 5 and the complementary color conversion circuit 8, but
It may be installed at another location, for example, between the reading device 4 and the I/OG conversion circuit 7.

Further, although a printer is used in this embodiment, other recording devices such as CKv or the like may be used.

Further, instead of the pattern generator, a computer or the like may be used to send out predetermined image data.

(a) More than the effect BY, as stated above, according to the present invention, fl+i Jli
By taking such measures, faithful color reproduction can be achieved. Also, even if the Be/'ε removing device etc. has changed, Lpir can be rewritten (the reproduced image hidden in J can be reproduced).

[Brief explanation of the drawing]

A schematic horizontal diagram of the color image processing device of this embodiment, FIG. 6 is a diagram for explaining the color reproduction area, i'+', 4M is the image image generated from the pattern generator.
Fig. 5 is a diagram showing the color reproduction area when using the image data of No. 4 and No. 1, and No. 1 is LTJ'[' A diagram showing the change from 113 to 11, F (1 schematic diagram, Fig. 8 shows the scanning Perspective view of the optical system, Fig. 9 Schematic diagram of the Gi reader, Fig. 1°O is CC
I) line center σ) fll'l': Schematic diagram, FIG. 11 shows another reading device V1, f+! Figure 12 shows N showing L-1' connected to CPtJ. Here, 1 is a pattern generator, 2 is a printer, 4 is a print image, 4 is a reading device, 5 is a memory, 6-digit look/Y-tub table, 7 is L (XI 7A biconversion circuit,
8 is a complementary color conversion circuit.

Claims (1)

[Claims] A predetermined r! a pattern generator that outputs JJ image data; a recording device that records the predetermined image data; and a reading device that reads the image recorded by the recording device; A color image processing device characterized in that it forms image data of.