JPH02214260A - Color image processing device and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

The present invention inputs an image including color information such as a color document,
This system has functions for storing and searching, and for outputting to a display, printer, etc., and can efficiently encode images that are a mixture of monochrome and color images.In addition to displaying color images when searching, the system can also display monochrome images at high speed. The present invention relates to an image processing system that also has a display function.

[Prior Art 1] Conventionally, when storing and communicating image information, data is generally encoded and used in order to suppress redundancy and reduce the amount of data. On the other hand, in devices that handle color images as digital data, the five images are treated as three types of multivalued data created by separating the five images into the three primary colors of red, green, and blue. (Hereinafter, they will be referred to as R, G, and B, respectively.) However, these three types of data have a high correlation between the three colors. Therefore, redundancy is high, and encoding efficiency is low if left as is. On the other hand, on a TV or VTR, etc., RGB color image data is transmitted with luminance information. (hereinafter referred to as Y) and 2
A method of converting into different types of color difference information (hereinafter referred to as ■ and Q) is widely used, and an example of using this method for documents is also shown. (For example, JP-A-63-9
However, in conventional devices that use luminance/chrominance conversion, information compression is performed using a multi-value data encoding method such as orthogonal transformation. This method is also used in the known example. However, when this encoding method for multivalued data is applied to document images, the following problems arise. (a) When handling line figures such as characters, encoding efficiency decreases significantly. (b) Documents cannot be directly output to devices that handle them as binary images, such as FAX or electronic file systems. On the other hand, in a digital copying machine or the like, the input image data of 33 colors of R, G, and B is used as it is and outputted without converting it to luminance/color difference. Furthermore, when binarization processing is required, such as when outputting to a printer, multivalued RGB data is binarized as is. A known example of a highly functional version of this system is, for example, Japanese Patent Laid-Open No. 174472/1983. This known example shows a method in which luminance information is calculated from R, G, and B, and the binarization power formula is switched according to the calculated value. However, the R, G, and B formats have high data redundancy and low encoding efficiency, so they are not suitable for devices that store and transmit data, such as copying machines. In particular, when there are monochrome parts in the five images, this method requires exactly the same R, G, and H data, even though color information is not required. Even in color documents, many areas of text are monochrome. Therefore, this method is not suitable for an electronic file system that stores a large amount of document image data, or for a fax machine that needs to send document images at a low data transfer rate. PROBLEM TO BE SOLVED BY THE INVENTION 1 Generally used color documents often include a large monochrome area, although some of the images include a color image. Furthermore, there are many regions of not only halftone images such as photographs but also line figures such as single characters. Therefore, systems that target documents. Even if the system is intended for color photographs, it is important to be able to efficiently handle monochrome images and text. However, as mentioned above, conventional systems for handling color images have been intended only for color halftone images. Therefore, there has not been much consideration to handling documents containing a mixture of color images, monochrome images, and even text. For example, a method using R, G, BayK color data is
It targets documents consisting only of color images. Therefore, all three types of information, R, G, and B, are required even for the monochrome portion. On the other hand, data encoding methods using conversion to luminance/color difference were originally devised for TV images and the like. Therefore, it has effective characteristics in cases where the concentration changes slowly. On the other hand, for characters, which make up a large proportion of a document, the density changes are extremely large, so encoding using orthogonal transformation is extremely inefficient. Further, many of the FAX machines and electronic file systems that have been widely used so far are equipped with input/output devices for processing monochrome binary images. Therefore, color document image systems can be used more widely if they are compatible with these systems. For this purpose, data consistency is required, but conventional examples do not take this point into consideration. Also, if the output device is a conventional monochrome device, RB
In the G method, data for only one of the three primary colors is output as a substitute. Therefore, information about specific colors is often missing. The first object of the present invention is to solve the above-mentioned problems, and to improve color images, especially images with mixed monochrome parts, which are often found in documents, etc.
An object of the present invention is to provide an apparatus for efficiently encoding and storing color images. Another second objective is to provide a color image processing device that is compatible with conventional image processing devices that are intended for monochrome images. Furthermore, another third object of the present invention is to provide an image processing device that can display each image in monochrome at high speed, for example, when searching the contents of a large amount of color image data stored on an optical disk or the like. It is in. On the other hand, the color image processing method proposed by the present invention aims to provide a method for effectively recording images such as color documents with a small amount of data. This is the fourth purpose. A fifth object of the present invention is to provide a color image processing method for storing color image data in a format that maintains compatibility with conventionally stored monochrome image information. [Means for Solving the Problems 1] In order to achieve the above-mentioned first object, the present invention provides multivalued R
means for obtaining a multi-value YIQ signal from a GB signal; a means for binarizing the obtained multi-value YIQ signal; a means for storing or transmitting the obtained binary signal; It has means for restoring a multi-value YIQ signal from a YIQ signal, and means for outputting a multi-value RGB signal from a multi-value YIQ signal. In addition, in order to achieve the second objective, as a means for binarizing the YIQ signal mentioned above, a means for binarizing the luminance data by W-like halftone image processing, and a means for binarizing the luminance data by W-like halftone image processing, and a conventional monochrome and means for accumulating each YIQ data in the same format as an image. In order to achieve the third object, the present invention provides a means for reading only a luminance signal out of luminance/color difference signals accumulated in the form of a pseudo halftone image, and a means for reading out only a luminance signal, and a means for reading out binary data of the read luminance signal. and means for displaying a monochrome pseudo-halftone image. In addition, in order to achieve the fourth object, the present invention converts image data inputted as RGB multi-value data such as a document into a luminance/color difference signal, and further performs encoding when the value of the color difference signal is 0. The color difference signal is binarized by pseudo halftone processing, encoded, and stored so that the amount of data is minimized. Furthermore, the present invention binarizes the luminance/chrominance signals of input image data using the same processing method as conventional image processing devices for binary monochrome images, and in the same format as conventional devices that want to maintain compatibility. The fifth objective is achieved by recording the image data after binarization. [Function] The function of each part in the above problem solving means will be explained. First, the problem that encoding efficiency decreases when dealing with monochrome images can be solved by converting the R, G, and B signals into luminance signals and color difference signals, and then encoding them. This is because the value of the color difference information in the monochrome portion of the image is almost 0, so the data can be minimized by encoding. Furthermore, human vision has a lower resolution for color difference signals than for luminance information. Therefore, even if the color difference signal is recorded at a lower resolution than the luminance information, deterioration in image quality can be suppressed, so that the encoding efficiency can be further improved. On the other hand, problems such as ``low encoding efficiency for character images'' and ``low compatibility with monochrome systems'' when using conversion to luminance and 7-color differences are caused by the fact that the converted multivalued data is This problem can be solved by converting it into binary image data through halftone processing. Binary data obtained by pseudo halftone processing etc. is processed using MH (Modi) similar to conventional monochrome binary image devices.
Huffman), MR (Mod.
It can be encoded using a method such as (ifedRead). Furthermore, when the luminance information is binarized, a monochrome binary image of the original image is obtained. Therefore, when outputting with a conventional monochrome system, consistency can be achieved by outputting only luminance information, and information on specific colors will not be lost.
Furthermore, these binary image encoding methods do not cause the problem that the encoding efficiency suddenly decreases in line graphic parts such as characters. Furthermore, in these binary image data encoding methods, 0
Alternatively, the amount of data in the portion where 1s are continuous can be minimized. In the case of monochrome images, the color difference information is almost O as mentioned above.
become. Therefore, in the monochrome portion, the data amount of color difference information can be minimized by encoding, so the data amount can be suppressed to approximately the same amount as that of conventional monochrome devices. On the other hand, when outputting a color image, a multivalued luminance signal and color difference signal are required. This multivalued data is calculated from a binary pseudo halftone image. The pseudo-halftone image expresses the density by the local distribution density of black pixels. Therefore, the density of a certain pixel can be estimated from the distribution state of neighboring black pixels. [Embodiments] Before describing embodiments of the present invention, the operating principle of the present invention will be described below. The image data is input as multivalued data of three colors, R, G, and B. For example, by applying the matrix transformation (1) shown below to these three types of multi-valued data, the luminance signal (hereinafter referred to as Y
It is possible to obtain two types of color difference signals (hereinafter referred to as "Q" and "Q"). This determinant is an example of a conversion formula from an RGB signal to a luminance/color difference signal, and is a determinant used in an NTSC television signal. (See, for example, New Edition Color Science Handbook, edited by the Color Society of Japan, published February 25, 1980) Next, these three types of signals are binarized. I and Q indicate approximately 0 for monochrome images. Therefore, in order to improve the coding efficiency of the data after binarization, it is sufficient that the values after binarization become O's or 1's continuously in the portion where the multi-valued data (2) and Q become O. However, among these three types of signals, I and Q can take negative values. Therefore, when this color difference signal is O,
In order to obtain a continuous output of O's or 1's, the binarization process is performed in the following manner. First, two pieces of image data Ip consisting only of O and positive values are obtained by setting ■ and Q according to the values of one image data. It is separated into In and Qpt Qn. Specifically, the value I of the coordinates (xx+yi) of the image data I
If (x engineering, y,) is positive, IP (Xll 3't) = I (Xx* y
Set Ip and In as z)"s(X engineering + yt) = 0, and if I(xz + V2) is negative,
I p (Xa + yz) ='OIn (X21
yz) = I Ohl Ya). In addition, here, I, and 1. represent data consisting only of positive and negative values of the I signal, respectively.Similarly, image data Q after separation is written as Q and QQ. As a result, the multi-valued image data I and Q, in which positive and negative values are mixed, are converted into two multi-valued image data each consisting of only 0 or positive values. As a result of positive/negative separation, the three types of data Y, I, and Q are:
Y, Ip. ■. There are five types of multivalued data: HQpt Qn. Next, this converted multivalued image data is subjected to binarization processing. Note that in this embodiment, Y, I, and Q will be used hereinafter. In the case of binary data for R, G, and B, "r'" is added to the variable. Therefore, the data after converting the ■ signal into a positive value is written as Ip, and the data after converting into a binary signal is written as I'p. As a result, multivalued color image data consists of five types of binary data Y' I I' P+ I' nl Q' P+
When storing 6 image data of Q' n, these 5
It encodes and stores different types of binary data. As a result, 1
The two color images can be recorded in the same way as the five monochrome binary images. Further, among these, only the luminance information Y' can handle the monochrome binary image of the original image. On the other hand, when the input image is a monochrome image, I'P#I'n+Q'PtQ'n representing the color difference are all O, and the encoding efficiency is extremely improved. Further, as described above, if the resolution of the color difference information is lowered, the amount of data can be further reduced. For example, if the resolution in both the main and sub-scanning directions is reduced to 1/2, the amount of data for each color difference signal will be 1/4, so a color image can be handled with twice the amount of data as a monochrome image. Next, a method for reproducing a color image from the accumulated information will be explained. First, the encoded data for five images is decoded to produce five types of binary data Y'*I' p, ■'. IQ'”Q
0th order Y ' HI ' p, I' nl to obtain 10
From Q'PHQ', multi-value data Y, jp, In, Q
Generate p, Qn. Then, ■ and Q can be calculated by adding Ip and In, and Qp and Qn, respectively. As a result, a luminance signal Y and two types of color difference signals ■ and Q are obtained. From this multi-value data YIQ, multi-value data RGB is obtained by performing inverse transformation of the above determinant (1). For example, the inverse transformation of equation (1) can be realized by the following equation (2). Here, the principle of processing for obtaining multivalued data from binary image data accumulated as a pseudo halftone image is as follows. Normally, when a human views a pseudo-halftone image, the density of a certain point on the pseudo-halftone image is perceived by the distribution state of black pixels in the vicinity thereof. Therefore, in the case of binary image data obtained by performing pseudo halftone processing on multivalued image data, by using the distribution state of the binary data, it is possible to obtain multivalued image data equivalent to the original image to the human eye. be able to. Specifically, the density of each pixel can be determined by scanning the original image with a scanning window of a specific size and detecting the distribution state of neighboring black pixels for each pixel. Using the same principle, color difference signals can also be binarized and stored through pseudo halftone processing. According to the above principle, color image data input in multi-value RGB three primary colors can be stored as binary luminance/color difference signals. In the case of displaying/outputting a color image, these multivalued R, G,
B data can be displayed on a full-color display, each data can be binarized, and color L B P (L
a5er Beam Printer) or a color display. Note that in this embodiment, a display that displays an image composed of multivalued RGB data will be referred to as a "full color CRT".
A display that displays images using binary RGB data is called a "color CRT." Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of the basic configuration of the present invention. First, we will show the overall data flow. The image data is inputted from the image input unit 10 into 8 pieces of RGB each.
It is manually generated as bit multi-value data. The signal line bundle 20 in the figure consists of 24 signal lines through which 8-bit multi-valued color image data of each of R, G, and B passes. Hereinafter, in this embodiment, the input R, G, and B data will be referred to as R-work, G, and B-work, respectively. For R, G, and B, the RGB/YIQ converter 100 converts the image luminance signal Y and two types of color difference signals 1 and Q.
Converted to engineering. Next, convert ■Yo and Ql into positive values, and obtain four types of multivalued data I 2 F I I 1 n l Q 2 P I
Q i n is calculated, and five binarization processing units 3
00, 301, 302°, 303.304, respectively. The signal line bundle 30 in the figure includes five types of image data Y ij
I 2 P I I 2 fi l Q 2 P I
1-bit data obtained by binarizing Q Z n, Y'''I'3''I'3nlQ'3p
It consists of five signal lines through which tQ'3n passes. In addition, 40 also passes three types of 1-bit data, the contents of which will be described in detail later. When storing these five types of binary data, the code/decoder 5
For example, optical disk 560 is encoded one by one by 30.
Accumulate in. Here, data obtained by encoding the data on the signal line 30 passes through the signal line 50. Therefore, in this embodiment, three types of data are handled. Therefore, a circuit for converting data is provided between each signal line, and a memory for storing data is connected as necessary. Next, the conversion processing performed between each signal line will be explained. In the figure, each section above the signal line 20 handles three types of multivalued image data: R, G, and B. In the figure, reference numeral 10 optically reads a document, etc. using known means, and generates 8-bit multi-value digital data R processing; G1. The image input section 15 outputs the B image, and the image input section 15 outputs R, , G□,
A selector 21, 22, and 23 transfers the image data of the B process to an appropriate signal line bundle, and is a memory that stores the multi-value data of each of the R, G, and B1 lines. Now, from the image input unit 10, R1, G, and Bo are scanning line 1.
Assume that the duties are sent to the selector 15 one by one. At this time, the selector 20 selects the signal line bundle 2 according to each data.
Select the signal line in 0 and send data to the memories 21, 22, and 23. Here, the memories 21, 22, and 23 have R-work and G-work. B1 are respectively accumulated. In addition, in this example, R work,
Since G and B8 are each sequentially input for one scanning line, the memories 21 and 22 must have a capacity that can store at least one scanning line's worth of data. Therefore, the image input unit 10 scans the document three times, and -
In the case of an apparatus that outputs R, G, and B data one screen at a time, the memories 21 and 22 must have a capacity to store at least one screen's worth of data. Also, if R, G, and H data are repeatedly output for each pixel, the memory 2
1,22°23 can be made unnecessary. In addition, 1 image input section 1
According to o, when R, G, and B are input simultaneously using 24 signal lines, the selector 15 is unnecessary. Next, R, G, B on the signal line 20 and 2 on the signal line 3o.
Value data, Y' xv I'3"I' 1ntQ
The part related to the conversion between 'xP*Q'3n will be explained. Again, the flow of data and the functions of each part will be explained first, and the internal configuration of each part will be explained in detail later. The input multivalued R, G, B data is divided into R for each pixel.
The GB/Y IQ converter 100 inputs three types of multi-valued data Y0. Converted to I, , Q engineering. Therefore, as in this embodiment, from the image input section, RGB
When data for each scanning line is input, the R and G data are stored in the memory 21 and 22, and when the B data is input, they are output from the memory for one pixel at a time. RGB/YI by aligning RGB data for each pixel
The signal is input to the Q conversion section 100. Methods for implementing RGB/Y IQ conversion for digital data are already widely known, and the present invention uses these known means. YL of the output multivalued data, 11. Q and data are each binarized by pseudo halftone processing. However, the color difference signal and Q can take negative values. Pseudo/halftone processing does not target signals with a mixture of positive and negative values, so the I and Q signals are converted to positive values. As described above, the value of the color difference signal is 0 when the input image is monochrome. After binarization, high coding efficiency can be obtained in the part where [10Jl is continuous. Therefore, when the input value is a series of O's, the color difference signal is converted to a positive value so that the data after binarization is also a series of O's.
It is necessary that the conversion be such that when the input value is 0, the output value is also O. Therefore, in this embodiment, 0 separation is handled by separating ■ and Q into two images: an image consisting only of O and positive values, and an image consisting only of 0 and negative values. 200 and 201. Here, I, n, and Q2n can be converted into positive values by recording the absolute values of the input values. Positive multi-value data I 2 P * I 2 n * Y
z t Q z P + Q 2 n are 2
Valued binary image data I'3PHI' 3n
I Y'``Q'3''Q'``1'' passes through the signal line bundle 30 to the memories ``゜32, 33, 34, respectively.
It is accumulated in 35. With this series of configurations, multivalued RGB data can be
It can be treated as value image data. When images are stored on, for example, an optical disk or transferred using a line such as a FAX, data obtained by encoding these five binary images is used. Specifically, the signal line bundle 30
Selector 52 selects the five types of binary image data that exist above.
0 is selected one by one and input to the code/decoder 530. The encoder/decoder 530 encodes the input binary image data one by one using a known method such as MH, MR, or MMR, and outputs it to the signal line 50 . As a result, the code data recorded on the optical disc has the same format as monochrome binary image data. With the above method, color image data expressed by three RGB multi-value image data can be It can be encoded and handled in the same format as the monochrome binary image data of a disc. On the other hand, if you want to read the encoded data stored on an optical disc or the like and output a color image, take the following procedure. On the disk, codes of five pieces of binary image data encoded using the above-mentioned method are recorded.Therefore, these data are read out one by one and decoded by the code decoding section 530 to produce five types of data. Binary image data I ' 3Pj I' 3njY ' ” Q' 3p
+ Q' 3n is obtained, and memory "゜32.33,3
Accumulates at 4.35. A multi-value RGB signal is generated from this binary YIQ signal. First, five types of binary data I'3"I' 3n are stored in the memories ", 32, 33, 34, and 35. Y' 39 Q'3"Q' sn are transferred to five halftone converters 400, 401° 402, 403, 404 through the signal line bundle 30, respectively, and five types of multi-value data I4P# I4°# Y4t Q4” Convert to Q4n. This conversion means will be described in detail later. Next, the adders 610 and 620 convert the converted five-sided positive multi-valued data into three-sided multi-valued data I in which positive and negative are mixed.
Calculate s, Ys, and Qs. The YIQ/RGB converter 700 converts the multivalued data Ii, Ys, and Qs by known means, and converts the multivalued image data R.
,,G,,B, are output. With the method described above, multivalued image data RGB can be obtained from the accumulated code data. Next, a means for displaying and outputting this image data will be described. First, when displaying on the full-color display device 70, the three types of multivalued data RGB on the signal line bundle 20 are displayed as they are. On the other hand, if the output device supports binary color images, RGB are converted into binary images by the binarization processing units 800 and 80, respectively.
1,802, the image is binarized by pseudo halftone processing. 2
The three types of digitized image data are sent to the color printer 80.
The data is transferred to a color CRT 75, etc., and output. On the other hand, when searching for a large number of images, it is necessary to display the contents of each image at high speed.In the present invention, the image data Y', which has already been binarized from the luminance information Y, is stored in the optical disk. ing. This image data Y' is an image representing the original image as a monochrome pseudo halftone image. Therefore, when displaying the image on the optical disk 560 at high speed, first of all the five types of code data, only the luminance information Y is read out, decoded by the code decoding section 530, and then transmitted from the signal line 30. Input to selector 90. selector 90
The following two types of operations (a
), (b) and execute it. (a) Data obtained by binarizing the multivalued data R input from the binarization processing unit 800 through pseudo halftone processing are sent to the signal line 4.
Transfer to the R signal line in 0. (b) The image data input from the Y signal line in the signal line 30 is transferred to the R and G signal lines in the signal line 40. Transfer each for B. Here, when the selector 90 performs the operation (b) described above, at the time when one of the five signals necessary to construct a color image is input. Monochrome images can be displayed on the color CRT 75. In addition, in systems for monochrome images, the above-mentioned (
Since the process b) is performed unconditionally, the luminance data Y'3
can be displayed/output as a monochrome image. Next, an example of the internal configuration of each part that has been described so far will be described in detail. First, the RGB/Y IQ converter 10
0 will be explained. The function of this part is for each pixel.
It inputs 8 bits of data for each of R, G□, and B, performs matrix transformation, and outputs three types of multivalued data of the pixel: Y, Ill, and Qt. There are already various known examples of RGB/YIQ conversion for digital data, and these are also applied in this embodiment. Next, 11. with a mixture of positive and negative values. The internal configuration of the positive/negative separation units 200 and 201 that convert Qi data into positive values will be explained. Note that these two determination units are completely the same. FIG. 2 is a diagram showing the internal configuration of the positive/negative separator 200. In the figure, 211 is a signal line that inputs the color difference signal I from the RGB/YIQ conversion unit 100, 212 is a signal line that inputs the value O that is the criterion for judgment, and 220 is the absolute value when the input value is a negative number. 230 is a comparator that determines the sign of the input value, and 240 and 250 are selectors that select and output one of the two input values based on the output of the comparator. Further, a signal line 241 is an output line of the selector 240 and outputs multi-value data I and P, and a signal line 251 is an output line of the selector 250 and outputs multi-value data Izn. First, when the input value I is positive, the comparator 230 outputs "1".
When ■ is negative, the output of the two selectors Ip, I
. is determined by the following formula. As a result, both the multivalued data I2F and the data 2n. Takes 0 or a positive value. The other positive/negative separator 201 in FIG. 1 also has exactly the same configuration. Therefore, the output value of the positive/negative separator 201,
Q z p and Qo are also 0 or only positive values. Next, the five binarization processing units 300 to 3 shown in FIG.
The configuration and operation of 04 will be described below. In this embodiment, all five have the same configuration. Next, the operation of the binarization processing section 300 will be explained in detail. Various conventional binarization processing methods can be applied to binarization6.Therefore, by having multiple processing methods built-in and selecting the appropriate method based on instructions from the outside, it is possible to It is possible to output images or images according to the user's preferences. Figure 3 shows the 2
In this example, which is a diagram showing an example of the configuration of the value conversion processing section 300. An example of a configuration is shown in which one of pseudo halftone processing using systematic dither method, pseudo halftone processing using minimum average error method, and binarization processing using fixed threshold is selected as the binarization power formula. . In the figure, signal lines 241 and 341 indicate multilevel data Y3'' and 341, respectively, signals instructing the pseudo halftone processing method, and lines 442 and 443 indicate the lower addresses of the output image in the main and sub-scanning directions. Each bit is input. Multivalued image data Yz ("t Y) is input from the RGB/YIQ converter 100 to the adder 330 through the signal line 241. The adder 330 calculates yt (xt y) and the error data E (X+ y) input from the selector 335.
) and outputs multivalued data F (X+y). Here, the error data E (XI y) is usually 0,
The value input from the signal line 399 is used only when the minimum average error method is used as the binarization force formula. Therefore, the selector 335 outputs 0 unless the minimum average error method is specified as the processing method from the signal line 3''.
and is compared with the threshold T. Based on the result of this comparison, two image data Y' 3 (x+y) is determined. Here, the threshold value T is also determined by the selector 3 by the binarization method.
The 0 selection selected at 45 is executed according to an instruction input from the outside through signal line 341. In the case of the systematic dither method, the threshold value is periodically varied depending on the position of the output pixel. In this case, for example, the lower bits of the addresses in the main scanning direction and the sub-scanning direction of the output image are sent from the signal lines 342 and 343 to the ROM (Read 0
nly Memory) 347, and its output is used as a threshold. A matrix of threshold values is written in the ROM 347. In addition, in the case of a fixed threshold, the register 344
A fixed value to be output is selected from . In the case of the minimum average error method, it is necessary to calculate error data E (xt y) for binarization processing. This error data E (xt y) has been binarized (x
, y) 0 weighting coefficient δ(,, n ) - Example 4
0 in the figure is a pixel to be binarized at that time, and corresponds to the pixel at the coordinates (xt y) described here. Next, if the 1 weighting coefficient that explains the operation of each part is shown in Fig. 4,
E (xt y) is obtained by the following formula. At some point, the comparator 340 is set! When the multivalued data F(Xi-Ly2) of (S2-1°yz) is binarized, F(xt-ttya) is
The signal is input to a differentiator 355 and a selector 350. The subtractor 355 outputs the difference between the maximum possible value F wrax of the converted image data FCxs y) and F (xl-L ya). For example, when S2 (XI y) takes a value from 0 to 255, Ftaax = 2 5 5, and the differentiator 435 calculates E (xpy) = 178 (i (x 1 + y
1) + E (X + 1 ty 1) + s
(x 2t y)+εCxe y 2)+2 (
t(x, y-1) +iCxL y)) )2
Outputs s 5-52(x, -Lyz). Also, here: On the other hand, the error E of each pixel is either the difference between the multi-value data F and O, or the difference between F and the maximum value F-ax that F can take. This value can be obtained as follows: F (x, −1
#yz)>Fmax, the differentiator 355 outputs O. The selector 350 selects F (x, -1°ys) or Fmax-F according to the following conditions.
(x, -L Y*) with an error i (x□-1
, y engineering). The output ε (x, -1t V2) is connected to the signal line 359
is sent to the line buffer 370 or the like. error ε
Therefore, the process to obtain E (xt y) is performed using the latch 361
．． 375,378 and shift register 360.377
The operation of each part will be explained by taking as an example the case where the zero-order Q (xt y) is determined by When binary data Q (x-1, y) is determined by the binarization processing section, errors i (x-
1, y), i (x-2, y), i (xt
y-1), i (x-L y-1) -t (xt
l, y-1) -t (XI y-2) is output. Here, the selector 350 and the latch 378 output data ε (x-1, y), ε (xt y-1) is input to the shift register 360.377, and 2 * i
(x-1, y), and two lines ε(xt y-1) are output. The adder 390 adds the input six types of multi-value data to calculate 8*E (x, y), and sends it to the shift register 395. The shift register 395 shifts the input multilevel data to E(xyy
). The obtained E (X+y) is input to the selector 335 via a signal line 399. Here, selector 3
35 is an adder 330 which adds E (xt y) or 0 according to the data E flag sent from the external signal line 3''.
Output to. The output of the selector 335 is E (xt y)
Then, the final output Q becomes a pseudo halftone image. On the other hand, if the output of the selector 335 is O, the final output Q will be a simple binarized image using a fixed threshold. In addition, in the case of x=1 or y=1, E (xt y)
It happens that a part of ε necessary to obtain ε does not exist. In this case, for example, the line buffer 350
and 355 using the values recorded in E (XI
y). As mentioned above, in this system, the binarization method can be selected depending on the image and system configuration. For example, in the case of a monochromatic halftone image, the use of systematic dithering degrades the image quality. This is because the period of the halftone dots of the original image and the period of the dither matrix for the binarization process interfere, resulting in moiré. This problem can be solved if the original image is a halftone image by performing binarization processing using a method that does not have periodicity, such as the minimum average error method. Therefore, by including at least one type of pseudo-halftone processing method that does not have periodicity, such as the minimum average error method, as the binarization method for the image input device connected to the system, it is possible to further expand the selection of processing methods. Can be done. With the above configuration, multivalued color image data can be processed. Five types of binary image data I'3py1 from G,,B,
'3''Y' 39 Q'3''Q' 3M is calculated and output to the signal line bundle 30. The output image data is stored in a memory "゜3" connected to the signal line bundle 30, respectively.
It is accumulated at 2.33 and 34.35. If you want to store this image data on an optical disc, etc.,
It can be handled in the same way as storing two monochrome binary images. The selector 510 sequentially selects one of the signal line bundles 30 and transfers the five types of binary image data one by one to the code/decoder 530. The code/decoder 530 encodes the binary image data by known means such as MH encoding or MMR encoding, and writes the encoded data onto the optical disc 560 via the signal jIA50. In addition, a communication terminal 570 is connected to the signal line 50.
By connecting, code data can also be transferred to the outside. This communication terminal can be used as long as it can handle binary image code data, so it can also be connected to, for example, a FAX. In general devices that use MH codes or MMR codes, when O's continue on a scanning line, the amount of encoded data can be minimized. Therefore, in the monochrome portion of the input image, the color difference signal is O, so that the amount of data after encoding can be minimized. Therefore, when handling an image in which a color image and a monochrome image are mixed, the data amount of the color difference signal in the monochrome portion is almost O, so that high encoding efficiency can be obtained. Next, the binary image data I'PgI'n1Yl recorded in the five memories ", 32, 33, 34゜35
, Q/ , , QJ A, the configuration of each part for calculating multivalued RGB data will be explained. First, binary image data I'3''I' 3n*Y
' From 39Q'3PjQ'3n, multivalued data I 4''
l4nlY 41 Q4" The configuration of five 400° 401, 402, 403, and 404 for calculating Q4n will be explained. Since these five can be realized by the same configuration, here, the halftone conversion unit 400 First, we will explain the principle of the process of restoring multi-valued image data from binary image data.When a human views a pseudo-halftone image, the density of a certain point on the pseudo-halftone image is It is felt by the distribution state of black pixels in the vicinity.Therefore, in the case of binary image data obtained by performing pseudo halftone processing on multivalued image data, by using the distribution state of binary data,
To the human eye, multivalued image data equivalent to the original image can be obtained. Specifically, the density of each pixel is determined by scanning the original image with a scanning window of a specific size and detecting the distribution state of neighboring black pixels for each pixel. -For example,
The case where a 5×5 pixel scanning window is used will be explained using FIG. 5. Each rectangle in the figure represents a pixel. Here, the multivalue data knee of the center pixel (x, y) of the scanning window is the binary data I' 3P (x-2°y2
) ~I', P (X+2.y+2) are weighted according to their respective positions, and the sum is obtained. Note that, here, the binary data E' (xs y) indicates the value on the coordinates (x, y) in one image. The weighting coefficient is determined by the distance between the sampling point A and each pixel. FIG. 6 shows an example of weighting coefficients. Therefore, the halftone conversion unit 300 inputs the image data for 25 pixels in FIG. 5, and calculates the sum of products of this and the weighting coefficients shown in FIG. get. Therefore, the calculation in halftone conversion section 300 follows the following equation. % formula %) Here, G (x, y) is the coordinate (x-2+y) ~ (x
"2+y)" is the product-sum result for 5 pixels of data,
The product-sum result of G (x, y-2) to a (xt y+2) becomes the product-sum result for 25 pixels. Next, a specific configuration will be explained. FIG. 7 is a block diagram showing an example of the internal configuration of the halftone conversion section 400. 36 in the figure is one of the signal line bundles 30, and is a binary data data line.
This is a signal line that inputs 3F. Input binary data I
'lp is the -order adder 421 and the line memory 41
Sent to 1. Now, from the signal line 36, the coordinates in the image (X÷3°y+2
) is input as binary data I' 3F (xt3.y+2). The four line memories shown here each function as a delay device that stores binary data for one scanning line. Therefore, binary data I
'3 When P (x + 3, Y + 2) is input, the line memory 411 outputs I.
' 3p (x + 3, Y + 1) are output from the line memories 412 to 414, respectively. I' 3p (xt3.Y) ~I' 3P (xt3
．． Y-2) is output. On the other hand, the -order adder 421 is an arithmetic unit that obtains a one-dimensional product-sum result G. When the weighting coefficients are as shown in FIG. 6, the following values are used for the weighting coefficients α and β, respectively. α=1.2,4,2. 1 β=1.2, 4, 2.1 Therefore, in this case, the output G of the primary adder 421
Xe y”2) is as follows: G(x, y+2)=I' 1p(x÷2.y+2)+
I'3p(x-2,y+2)+2X(I'
3F (x” 1 y Y+ 2) + I' 3J
X-1+ Y” 2))”4 x(I’ 3F(X, y
+2)) − order addition unit 421 for executing this process
An example is shown in FIG. 4” in the diagram, 432°433.4
34,435 are latches, 451.452,4 respectively
53 are shift registers, 460 are adders, 46
1 is a signal line that outputs the calculation result G()C+y"2). The input value I'3P(xt3.y+2) is sequentially held in latches 4" to 435 connected in series in five stages. At this time, the data held by each latch is transmitted from the signal lines 441 to 445! '3P(xt2.y+2) ~I' 3F(x
-2, y+2) is output. Outputs from signal lines 441 and 445 are sent to adder 460, and outputs from signal lines 442 and 445 are sent to adder 460.
Outputs from 443 and 444 are sent to shift registers 451 and 4
Sent to 52,453. Here, among the three shift registers, 451°453
performs a 1-bit shift, and 452 performs a 2-bit shift. As a result, the adder 460 has I' 3 P (X + 2, Y + 2)
HI' 3P (X-2, y+2). 2XI' 3P (xt1.y+2). 2XI' 2P (x-1,y+2)14XI' 3
P (x, y+2) is input and I4P (xty) is output. Further, this processing can also be realized using a ROM. In this case, outputs from five latches are input as addresses, and multivalued data I4p (xt y) is output. Other primary adders in FIG. 7, 422, 423, 424.
425 can also be realized using the same configuration. As a result, G(xty+2) is output from the signal lines 461, 462, 463, 464° and 465, respectively. G (xty+1> , G (x, y) , G (xt
y-1) and G (X+y-2) are output. Similar to the above-mentioned primary addition section which performs a product-sum operation using β on this G, signal lines 461 and 465 are connected to an adder 490, and 462 and 464 are connected to a shift register 4 which performs a 1-bit shift. "゜Connect to 473, 463 is 2 b
Data is input to a shift register 472 that shifts it. As a result, the adder 490 receives G (x, Y+2), G (x, Y-2), 2XG (x, Y+1), 2XG (x, Y-1), and 4XG (x, Y). , I4P (x, y) are output. Five halftone converters 421, 432, 433°444.
In 545, this process is applied to five types of binary image data, and five types of multivalued data ■4. . 14 n * Y 4 s Q 4 p p Q 4
Output n. Among this multivalued data, I4p, I411, and Q
4 P and Qo are each obtained by separating what was originally a single mixed positive and negative image and inverting the sign of one of them. Therefore, I4p and I4n are connected to Q4 by the positive/negative combining unit 610.
p and Q10 are added by 611, ■, and Q. Calculate. Here, the positive/negative combining units 610 and 611 perform calculations according to the following equations. I,"1.p I..Q,=Q4p-Q-rl These two positive/negative combining sections can be realized with the same configuration. With the above configuration, the multi-value data I,,Y,,Q. The YIQ/RGB converter 700 inputs these 1., Y, , Q, and outputs multivalued color image data Rz - G z - B x. YIQ/R
Use a GB converter. Note that the possible range of the halftone modulation Qg may be different from the range of the output data of the RGB/YIQ converter 100. In that case, by multiplying the values of the coefficient matrix in YIQ/RGB conversion section 700 by a constant, the two are made to match. Next, the output part of the color image will be explained. The output system of the present invention is basically the same as the one that supports conventional multi-value RGB, but the feature is that it can quickly output monochrome images when examining the contents of images stored on optical discs, etc. The point is that we have a means to output the . Multivalued color image data R, G, B is stored in the memory 21.2.
2.23 or YIQ/RGB converter 700, etc.
Through the signal line bundle 30, three binarization processing units 800, 8
Enter 01,802. Here, 800, 801, and 802 are data R and G, respectively.
, B is binarized. Binarization processing unit 801°802.80
The internal configuration of the unit 3 can be, for example, the same as that of the binarization processing unit 300 described above. The binarization result passes through the selectors 91, 92, 93 and the signal line bundle 40, and is stored, for example, in the bitmap memory of a color CRT or in the color LBP (La5erBeam P).
rinter). This selector 91.9
In addition to R, G, and B data, one of the signal line bundles 30 is connected to 2.93, and the binarization processing result Y3'' of luminance data is input. When outputting a color image according to instructions from
If a monochrome image is to be output, Y' is output. Similarly, by selecting the output light using a selector, it is possible to realize a function of outputting to a device for monochrome images when monochrome output is instructed. Furthermore, the data reading method is changed depending on, for example, the output device connected to the system. In other words, if a monochrome output device is connected, only brightness information can be read out. Further, as described above, when checking the contents of image data stored on an optical disk or the like, only the brightness information can be read out by reading every fifth image from the optical disk. If a monochrome display appears, the luminance data in the signal line bundle 40 is transferred directly to the color CRT 75.
By displaying the data as RGB data, it is possible to output a monochrome image on a color CRT by simply reading out one of the five data sheets. In this case, since halftone conversion, YIQ/RGB conversion, etc. are not required, a display speed similar to that of outputting a monochrome binary image can be obtained. Note that in order to achieve high-speed monochrome output, the recording format of the image data on the optical disc must also be a format that allows efficient reading of the luminance data. FIG. 9 shows an example of a recording format on an optical disc. In the figure, rectangles 911 to 915 in (1) indicate areas where a directory for one binary image is written, and rectangles 921 to 915 in (2)
Reference numeral 925 represents a portion where binary image data for one binary image is written. In the case of this embodiment, one piece of color image data is recorded on an optical disk as five pieces of binary image data. In this case, directories for image data are also recorded on five optical disks. Here, in both the image data and the directory, the luminance data is written at the beginning, and the color difference signals of the four images are written next. FIG. 9(3) shows part of the structure in the directory 911. This configuration is also the same for 912 to 915. In the figure, 9" is a unique number for a binary image, 932 is a pointer indicating the position of the next binary image, 933 is a unique number for each color image, and 934 is a field for entering a pointer indicating the next luminance data position. Therefore, the content of 934 indicates the position of the binary image data after 5 images. Also, 935 is a field where a flag indicating whether the data is luminance data or color difference data is entered.
This flag will hereinafter be referred to as the brightness flag. When reading data, in the case of color display, the data for 5 color images whose unique number matches the instruction is sequentially read out and sequentially written to memories "~35" in Figure 1.On the other hand, if monochrome display is specified, In this case, a directory of images whose color image unique numbers match the instruction is read, and only the data whose brightness flag is "ON" is read out and transferred as is to the display section from the selector 90. With the above configuration, It is possible to realize an image processing device that efficiently stores color image data and has a high-speed monochrome output function in addition to color output.
The first purpose is to process Q data at high speed. However, this method requires a large number of binarization processing sections and halftone conversion sections. On the other hand, it is also possible to temporarily hold the data in memory and perform the conversion of each data in chronological order. FIG. 10 shows a block diagram of an example of the configuration of this method. In the figure, devices with the same numbers as in FIG. 1 are the same devices as in FIG. 1. The input multivalued RGB data is RGB/YI
After being converted into multi-valued YIQ data by the Q conversion unit 100, Y remains unchanged, and
After being separated into positive and negative signals at 201, the signals are stored in memories 61, 62, 63, and 64, 65 via the signal line bundle 60. The memories 61 to 65 are memories that store multivalued image data. The data stored in the image memories 61 to 65 are selected one by one by the selector 620, input to the binarization processing section 300, and binarized. The binarized image data passes through the signal line 39, is encoded by the encoder/decoder 530 in the same manner as in the above case, and is stored on an optical disc or the like. Further, when calculating multivalued RGB data from binary image data stored or input from the outside by the communication terminal 570, processing is performed in the following order. Now, from the optical disc 560, Y'”1’3”T’”
The binary images are read in the order of 11 Q'3"Q':Ill and decoded by the sequential code decoding unit 530. The decoded binary image data is converted into multi-value data by the halftone conversion unit 400. , are sequentially written into the memories 61 to 65 by the selector 630 via the signal line bundle 60. Five types of multivalued data Y4yI4'' are stored in the memory. gQ
4p* After 4 types of Q411 are written, the last data Q 4 n is output, and at the same time, the 4 types in the memory are
The type data is also sent to the positive/negative combining units 610, 611 and
It is output to the Q/RGB conversion section 700. On the other hand, the output system for multivalued RGB data can also be configured as follows. Among the three types of multivalued data in the signal line bundle 20, one type is selected by the selector 95 and inputted to the binarization processing section 800. After binarization, the data passes through the selector 90 and is sequentially recorded in the binary image memories 621, 622, and 623. here,
The memories 621, 622, 623 are R, G,
Record B data. On the other hand, in the case of monochrome output, the selector 90
Output the binary image data Y′, transferred by 3.
Y' is simultaneously written into memories 621, 622, and 623 at locations. According to the above configuration, the number of binarization processing units and halftone processing units can be reduced compared to the above-described configuration without reducing the speed during monochrome output. Next, a means for further enhancing the functions of the present invention will be explained. First, means for improving encoding efficiency will be explained. In this embodiment, a luminance signal Y and a color difference signal I are used. The configuration when Q has the same resolution has been explained. However, as described above, human vision has lower resolution for color differences than for luminance. Therefore, as one of the embodiments, processing related to I and Q is performed in both the main scanning line direction and the sub-scanning line direction.
It is also effective to thin out the data to 1/2 and execute it. Since there are no particular restrictions on the method of reducing the processing to 1/2, any known method can be used. In this case, the memories related to I and Q (".32, 33, 34, 35, 10th
The capacities of 61.62, 63, 64.65) in the figure can be reduced to 1/4 of the above. A means for improving the image quality of a binary image when dealing with a document containing a mixture of images will be described. The present invention binarizes and stores YIQ signals. In this embodiment, there are two binarization methods: (a) binarization using a fixed threshold; (b) I-like halftone processing using a systematic dither method; and (c) pseudo-halftone processing using the minimum average error method. Binarization processing unit (300 in FIG. 1, etc.) that can be switched according to instructions
This was explained using an example. Therefore, it is possible to improve the image quality and coding efficiency by switching the binarization method depending on the content of the image. An example of means for realizing this function will be explained using FIG. 11. In the figure, 810 is an area determination unit, 811, 812° 823.8
14 is a comparator, 820 is a logic gate, and 829 is a signal line to the binarization processing section 302. From the RGB/YIQ conversion unit 100, the area determination unit 810
An area where multivalued luminance data Y is input and it is determined by known means whether each part of the input image should be binarized using a fixed threshold value or pseudo halftone processing. This is the judgment section. In the present invention, multivalued luminance information is used. For this reason, until now, when converting images such as documents into binarized images, pseudo-halftone processing has been applied to halftone areas such as photographs.
Various means used for performing binarization processing using a fixed threshold value can be used for line figures such as characters. On the other hand, 811, 812, 813, and 814 are input multivalued color difference data I2p+Ln+QxPrQ2n and preset threshold values T11'r, l'r
, is a comparator that compares IT4. In the monochrome part of the input image, the color difference signal I z
p p I z n * Q 2p p Q z n
takes a value near O, but when m is measured in units of pixels, it does not necessarily become exactly 0. Therefore, if all of these four types of multi-valued data are below a specific threshold, it is assumed that the image is a monochrome image. - As an example, the operation of the comparator 811 is expressed by the following equation. S = 1: Izp≧T = Izp < T - The other three comparators operate in the same way. The logic circuit 820 includes the four comparators 811 and 812 described above.
．． 813, 814 and the output of the area determination unit 810, the final determination result is output. The outputs of the four comparators are all 1 (O11, and the output of the area determination unit 810 is "line figure").
In this case, the input image is a monochrome line figure. Therefore, for example, for monochrome line figures, binarization processing is performed using a fixed threshold, and for color line figures,
It is possible to perform pseudo halftone processing using the minimum average error method, and for halftone regions, pseudo halftone processing using a systematic dither method. Further, it is also possible to not only make a judgment for each part of one image, but also to execute judgment for each image and select a binarization power formula. Third, compatibility with devices that handle monochrome binary images will be explained. For example, electronic file devices and the like have conventionally been designed for monochrome binary images. A case will be described in which images input and accumulated using these devices are outputted by this device. Image data input by a conventional device that handles monochrome images is a binary image of brightness information. As described above, the present invention includes means for directly outputting a binary image of brightness information stored on an optical disk or the like. Therefore, the following method allows an image input by a conventional monochrome image device to be output. An example of the internal structure of the directory 911 in this case is shown in the first example.
The diagram shown in FIG. 2 is a directory for binary image data for luminance signals, similar to FIG. 9, but the directory for image data for color difference signals is also the same as in FIG. 9. Here, a unique number entry field 9'' for a binary image.A part 940 for entering each item as a binary monochrome image, including a pointer 932 indicating the position of the binary image, is a part 940 for entering each item as a binary monochrome image. Make it in the same format as the directory structure.As a result, 1. Image data recorded on an optical disk using the device described in the present invention can be searched and output using conventional monochrome devices.Entering data with this device In addition to the above items,
The unique number of each color image is entered in the entry field 933, and the pointer address indicating the next luminance data position is entered in the entry field 934. Note that even if the input image is a monochrome image, a new color image unique number is assigned, and the location of the next data is entered in 934. And furthermore, entry 41! The data corresponding to #1936 is 5 types of data Ip, I-, Y = Qp
- Fill in the contents of the flag indicating which data out of Qo. This flag is called a data flag.The data is a luminance signal,
Alternatively, in the case of a monochrome image, nothing is entered in this column 936. As a result, even image data entered using a conventional monochrome device can be output as a monochrome image using the device of the present invention. Furthermore, in entry 41937, a flag indicating whether the entered data is a color image or a monochrome image is entered. Hereinafter, this flag will be referred to as a color flag. When instructed to output a certain image in color, the device first reads the directory on the optical disk and prints 933.
The image ordered to be displayed is searched based on the unique number of the color image entered in . As a result of the search, five pieces of data are selected for one color image. Next, if the color flag is checked and it is confirmed that the image is a color image,
The selector 510 is driven according to the contents of the entry column 936 or the order of entry, and the data of these five sheets is transferred to the corresponding memory. On the other hand, if the image instructed to be output is a monochrome image, the color flag indicates that it is a monochrome image. In this case, the image is directly output as a monochrome image through the same process as the high-speed display described above. Finally, as an application example of the present invention, a device and method for inputting a document as digital image data and accumulating its luminance signal and color difference signal will be reviewed. FIG. 13 is a block diagram of an application example of the present invention. In FIG. 0, parts labeled with the same numbers as in FIGS. 1 and 10 represent the same devices as in the figures. In the figure, the rabbit 92 is Y
RGB data input from the IQ/RGB conversion unit 700 and luminance signal Y input from one of the signal line bundles 60
It has a function to select one of the two. This selector 92 is
It can also be applied to the embodiments shown in FIGS. 1 and 10 described above, and similar effects can be obtained. The process of inputting a document or the like as digital data of the three primary colors of RGB, converting it into a YIQ signal, and storing it in the memories 61 to 65 is the same as the embodiment shown in FIG. 10 described above. Here, the selector 625 has a function of bidirectional input/output. When storing data, one of the 60 signal line bundles
Select a book and input the brightness/brightness from memories 61 to 65.
Color difference signal Y 21 I 2 P I I 2 n l
QZPIQ@n is sequentially transferred to encoder 540. On the other hand, when reading images, signals stored as multivalued image data for five discs on the optical disc 560 or the like are sequentially read out, subjected to decoding processing, and stored in the memories 61 to 65. The subsequent operation is basically the same as the example described in FIG. 10. At two points, the selector 92 selects the Y IQ/RGB converter 70
Either the RGB signal output from 0 or the luminance signal Y passing through the signal line bundle 60 is selected and transferred to the signal line bundle 20. Here, if the luminance signal Y is selected, the signal line bundle 2
The image in 0 is a monochrome image in which each of RGB is a luminance signal Y. Furthermore, when a method for encoding mixed positive and negative data is used as the encoding method for multivalued data, it is also possible to omit the positive/negative separation and combination processing. FIG. 14 shows an embodiment of an apparatus for encoding color difference signals with both positive and negative signals. In the figure, the memories 66, 67, and 68 have luminance/
The color difference signal Y, Ill, Ql is accumulated. The operations of other parts are similar to those shown in FIG. 13. Finally, the 0-hydro type, which describes an example of the image processing method proposed by the present invention, efficiently handles monochrome mixed images by applying processing similar to the operation of the image processing device described above to color image data. It is characterized by being able to FIG. 15 is an example of a processing flow for accumulating color image data using the image processing method proposed by the present invention. Color image data input as multivalued data in RGB format is converted into luminance information Y and two types of color difference information 2 and Q by RGB/YIQ conversion. After the conversion, I and Q, which are multi-value data containing a mixture of positive and negative values, are separated to produce four types of multi-value data Ip and I. and Q P I
Output Q11. After that, five types of multivalued data Y,
Ip. In, Qp, and Qn are each independently binarized. Binarization is performed using pseudo halftone processing. Through the series of processes described above, multivalued color image data is converted into five pieces of binary image data. These five pieces of binary image data are encoded using a known method and stored on an optical disk or the like. here,
If the input image is a monochrome image, of the five types of signals, only the luminance signal is accumulated, and if it is a color image, all five types are accumulated, and it is also recorded that it has a color difference signal. Next, regarding the method of outputting the accumulated image data,
This will be explained using FIG. 16. First, the case of outputting a color image will be described. The luminance signal Y' and the color difference signals Ip, I, Q, l, Q, stored on an optical disk as five pseudo-halftone images,
l is read out and each is decoded to obtain five pseudo halftone image data. Next, each binary data is subjected to halftone conversion using the method described above, and five multivalued image data Y, IP, In
, QF, and Qo are restored. Of the four restored color difference signals, I- and In, and Qp and Qn are synthesized, respectively, and multi-valued data (1) and (Q) in which positive and negative values are mixed are output. Finally, the multivalued data Y, I, and Q are converted and multivalued RGB data is output. Through the above processing, the accumulated 5
Multivalued color image data can be output from multiple pseudo-halftone images. On the other hand, when displaying the contents of each image in a short time, only the luminance data Y' is read out from the five pseudo halftone image data stored, decoded, and output. The luminance data Y' is a monochrome image of target color data. The device and method described above have the ability to efficiently accumulate color images, especially images with monochrome parts such as documents, and display monochrome images at high speed when searching for content. It is possible to realize a color image processing device that maintains compatibility with other devices.

【Effect of the invention】

According to the present invention, it is possible to efficiently store color images, especially images containing a mixture of monochrome parts such as documents and thin patterns such as characters, and to display monochrome images at high speed when searching for content. A color image processing device that is also compatible with devices for value images can be realized.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the basic configuration of the device, Fig. 2 is a block diagram showing an example of the internal configuration of the positive/negative separator, and Fig. 3 is a block diagram showing an example of the configuration of the binarization processing unit. 4 is a block diagram showing an example of weighting coefficients used in the minimum average error method. FIG. 5 is a diagram showing an example of a reference scanning window for explaining the principle of halftone conversion. FIG. 6 is a diagram showing an example of weighting coefficients for halftone conversion, FIG. 7 is a block diagram showing an example of the configuration of the halftone conversion section, and FIG. 8 is a diagram showing an example of the configuration of the -order addition section. 9 is a diagram illustrating an example of the recording format in an optical disc. FIG. 10 is a block diagram illustrating an example of application of the present invention. FIG. 11 is a diagram illustrating automatic switching of the binarization processing method. Block diagram for realizing the 12th
The figure shows an example of a color image data recording format to maintain compatibility with an image processing device for monochrome images, and FIG. FIG. 14 is a diagram showing an example of the configuration of a system that handles halftone data. As an example of the present invention, FIG. FIG. 15 is a diagram showing the flow of processing for accumulating color image data, and FIG. 16 is a diagram showing the flow of processing for outputting the accumulated color image data. Explanation of symbols 10... Image input section, 15... Selector, 21...
・Memory (R), 22...Memory (G), 23...
Memory (B), 20, 30, 40, 50.60...
Signal wire bundle, ", 32, 33, 34. 35... memory,
61.62,63,64.65...Memory, 70...
・Full color CRT, 75...Color CRT, 80・
...Color printer, 90...Selector. 100...RGB/YIQ conversion unit, 200.201...Positive/negative separation unit, 220...Differentiator, 230...Comparator, 240, 250...Selector, 300...Binarization processing part, 330, 390...adder. 340... Comparator, 347... ROM, 355...
・Differentiator, 335, 345, 350...Selector. 360.377.395...shift register, 370
．． 380... line memory, 361,375°378
... Latch, 400 ... Halftone conversion section, 411.4
12,413,414...Line memory, 421.4
22,423,424,425...-Next addition section, 4"
, 432, 433, 434° 435...Latch, 45
1,452,453°4”.472,473...Shift register, 490...Adder, 510...Selector, 530...Coding/decoding unit, 560...Optical disk, 570...Communication Terminal, 610... Positive/negative combining section, 7
00...YIQ/RGB conversion section, 800, 801, 8
02. Binarization processing unit, 810... area determination unit, 81
1,812°813.814... Comparator, 820...
・Logic circuit. Figure 2 Figure 75

Claims (1)

[Claims] 1. In an image processing device that handles document images including color images as digital data, input multi-value color image data in RGB format is processed by multi-value luminance information Y and a plurality of multi-value data. means for converting the luminance information Y and the color difference information I and Q into color difference information I and Q;
means for encoding the binarized luminance information Y' and color difference information I' and Q' as a pseudo halftone image; means for accumulating as a pseudo halftone image, means for reading out the accumulated luminance information and color difference information, means for decoding the read luminance information and color difference information, and the decoded binary luminance. A means for inputting information Y' and color difference information I' and Q' and outputting multivalued luminance information Y" and color difference information I" and Q', and a means for simulating only the decoded binary luminance information Y'. A color image processing device characterized by having means for displaying a halftone image. 2. As a method for storing or transmitting a document image including a color image as digital data, the image is displayed as multi-valued color image data in RGB format. input, convert it into multivalued luminance information Y and multivalued color difference information I and Q, binarize the luminance information Y and the color difference information I and Q by pseudo halftone processing, and convert the binarized luminance A method of encoding information Y' and color difference information I' and Q' as a pseudo-halftone image, and storing the encoded luminance information and color difference information as separate pseudo-halftone images, and the accumulated luminance information. and chrominance information, decode the read luminance information and chrominance information, and obtain the decoded binary luminance information Y' and chrominance information I'.
and a method of outputting multilevel luminance information Y'' and color difference information I'' and Q'' by performing arithmetic processing on and Q', and displaying only the decoded binary luminance information Y' as a pseudo halftone image. 3. In an image processing device that handles a document image including a color image as digital data, input multivalued color image data in RGB format is converted into luminance information Y. means for converting into a plurality of color difference information I and Q; means for binarizing the luminance information and color difference information by pseudo halftone processing; and the binarized luminance information Y' and color difference information I" and Q". multiple 2
A color image processing device characterized by having means for outputting, displaying, or storing a value image. 4. The color image processing apparatus according to claim 1 or 3, further comprising means for converting the multivalued color difference signals I and Q into a multivalued signal consisting only of 0 or positive values. color image processing device. 5. In the color image processing device according to claim 4,
As means for converting the multi-value color difference signals I and Q into multi-value signals consisting only of 0 or positive values, the color difference signals are inputted and converted into two types of multi-value image data I_p, I_n and Q_p, Q_n, respectively. A color image processing device characterized by having means for separating and outputting. 6. In the color image processing device according to claim 1 or 3, the binarized luminance information Y' and the binarized color difference information I' and Q' are each independently encoded. and means for accumulating only the binarized luminance information Y' when the input image is a monochrome image, and in other cases, the luminance information Y' and the color difference information I' and Q'.
What is claimed is: 1. A color image processing device, comprising means for accumulating a color image and recording that an input image is a color image. 7. The color image processing device according to claim 6,
means for comparing the values of the multivalued color difference information I and Q with a predetermined value, and when the value of the color difference signal is within a specific range in a certain portion or more of the input image as a result of the comparison; means for determining that the input image is a monochrome image; means for accumulating only the binarized luminance information Y' when the input image is a monochrome image based on the determination result; A color image forming apparatus comprising means for accumulating the luminance information Y' and the color difference information I' and Q' when the input image is not a monochrome image, and means for recording that the input image is a color image. Image processing device. 8. The color image processing device according to claim 3,
means for comparing the multivalued color difference signals I and Q with a predetermined specific value for each pixel; and means for determining, for each pixel, whether the input image is a color image or a monochrome image based on the comparison result. A color image processing device comprising: 9. The color image processing device according to claim 3,
Means for binarizing the luminance information Y and the color difference information I and Q includes means for executing a plurality of types of binarization processing methods including pseudo halftone halftone processing; A color image processing device comprising means for selecting one of the types. 10. In the color image processing apparatus according to claim 9, the means for selecting the binarization processing method includes means for determining the feature amount of each part of the input image, and means for determining the area of each part of the image based on the feature amount. and a means for switching the binarization method based on the determination result. 11. In the color image processing apparatus according to claim 10, the means for determining the area of each part of the input image includes means for extracting feature amounts from luminance information, means for extracting feature amounts from color difference information, and A color image processing device characterized by having means for determining an area based on two types of feature amounts. 12. In an image processing device that handles document images including color images as digital data, one sheet of color image data brightness information Y' and multiple types of color difference information I' and means for reading out the luminance information Y' and color difference information I' and Q' into multi-valued luminance information Y" and color difference information I" and Q'; Multi-value color difference information is multi-value R
A color image processing device characterized by having means for converting and outputting color image data in GB format. 13. In an image processing device that handles document images including color images as digital data, luminance information Y of one sheet of color image data stored or transmitted in the form of a binary image.
' and a means for reading out multiple types of color difference information I' and Q', means for reading out only the brightness information among the accumulated brightness information and color difference information, and displaying the brightness information Y' as a monochrome binary image. Alternatively, a color image processing device characterized by having means for printing out. 14. In the color image processing apparatus according to claim 12 or 13, the means for reading out the binary luminance information Y' and the binary color difference information I' and Q' is configured to read out the luminance information Y' and the binary color difference information I' and Q'. It has means for reading out the color difference information I' and Q' and outputting it as a color image, means for reading out only the luminance information Y' and outputting it as a monochrome binary image, and means for switching between the two types of output means. A color image processing device featuring: 15. In an image processing device that handles images such as documents as digital data, means for outputting accumulated image data, means for detecting whether the accumulated image data is a color image or a monochrome image, and the detection result A color image processing apparatus characterized by comprising means for switching the reading method of the stored image data between a color image and a monochrome image. 16. In the color image processing apparatus according to claim 15, the means for detecting whether the stored image data is a color image or a monochrome image includes means for reading a signal recorded in the storage medium; 1. A color image processing device comprising at least one means for inputting an instruction from a color image processing device. 17. In the color image processing device and method according to claim 12, the binary luminance information Y' and the binary color difference information I' and Q' are combined with the multivalued luminance information Y", the color difference information I" and As a means of converting to Q'', Y' arranged in two dimensions
, I', Q' with a scanning window of n x m pixels, and the product of binary data for n x m pixels in the scanning window and a predetermined weighting coefficient for n x m pixels. A color image processing device comprising means for executing a sum operation and means for outputting the result of the product-sum operation. 18. The color image processing apparatus according to claim 1 or 2...The color image processing apparatus according to claim 18, further comprising means for obtaining color difference information at a resolution different from that of the luminance information. 19. As a method for storing or transmitting document images including color images as digital data, input RG
B-format multivalued color image data is converted into luminance information Y and a plurality of color difference information I and Q, the luminance information and color difference information are binarized by pseudo halftone processing, and the binarized luminance information is A color image processing method characterized by outputting, displaying, or storing Y' and color difference information I'' and Q'' as a plurality of binary images. 20. In the color image processing method according to claim 19, the multi-value color difference signals I and Q are converted into two types of multi-value image data I_p and I_ each consisting of only 0 or positive values.
A color image processing method characterized by separating and outputting n, Q_p, and Q_n. 21. In the color image processing method according to claim 2 or 19, the binarized luminance information Y' and the binarized color difference information I' and Q' are each independently encoded. , if the input image is a monochrome image, only the two luminance information Y' are stored; in other cases, the luminance information Y' is stored.
and color difference information I' and Q', and also records that the input image is a color image. 22. In the color image processing method according to claim 2 or 19, the multivalued luminance information Y and the color difference information I and Q are subjected to a plurality of types of binarization processing including pseudo halftone halftone processing. A color image processing method characterized by performing binarization using one method selected from among the methods. 23. In an image processing method that handles document images including color images as digital data, one color image data brightness information Y' and multiple types of color difference information I' and Q stored or transmitted in the form of a binary image. ' and
The luminance information Y' and color difference information I' and Q' are converted into multivalued luminance information Y'' and color difference information I'' and Q'', and further converted into multivalued RGB format color image data and outputted. Characteristic color image processing method. 24. In an image processing method that handles document images including color images as digital data, one sheet of color image data brightness information Y' stored or transmitted in the form of a binary image and multiple As a method for reading and outputting the types of color difference information I' and Q', only the brightness information among the accumulated brightness information and color difference information is read out and displayed or printed out as a monochrome binary image. Image processing method. 25. In the color image processing method according to claim 24 or 25, when reading out the binary luminance information Y' and the binary color difference information I' and Q', the luminance information In the case where Y' and the color difference information I' and Q' are read out to output a color image, and in the case where only the brightness information Y' is read out and a monochrome 2
A color image processing method characterized by switching output as a value image depending on the target image or device. 26. A color image processing device, in an image processing method that handles images such as documents as digital data, which is characterized in that the method of reading out the stored image data is switched between color images and monochrome images. 27. In the color image processing device according to claim 26, it is possible to determine whether the stored image data is a color image or a monochrome image by at least one of reading a signal recorded in the storage medium or an instruction from the outside. A color image processing method characterized by detecting the image data and switching the reading method and output method of the image data. 28. In an image processing device that handles images as digital data, means for generating a plurality of multivalued image data consisting only of 0 and positive values from multivalued image data containing a mixture of positive values and negative values; , a color image processing device comprising means for independently binarizing the plurality of generated multivalued image data. 29. An image processing device that handles images as digital data, having means for generating multi-value image data in which positive values and negative values are mixed from a plurality of multi-value image data consisting only of 0 and positive values. A color image processing device characterized by: