JP3455078B2 - Image processing apparatus and image processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus for decompressing compressed image data and outputting it to an image output apparatus, and more particularly to an image processing apparatus suitable for color printers, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, there has been used an image processing apparatus for decompressing compressed image data sent from a computer or the like, subjecting it to appropriate processing, and outputting it to an image output apparatus. A conventional image processing apparatus will be described below by taking a printer as an example.

FIG. 21 is a schematic block diagram for explaining a conventional printer.

The computer 8 compresses the bitmap image data 85 to be output to the printer 9 by the compression section 86 realized by a printer driver or the like, and the image memory 8
Store in 7. After that, the data is output to the printer 9 via a data transfer unit (not shown).

In the printer 9, when the printer controller 91 receives the compressed image data from the computer 8, it stores it in the image memory 93. After that, the decompression unit 94 converts the image data into bitmap image data 95,
The image processing unit 96 performs necessary image processing such as color correction, color conversion, or edge processing, and outputs it to the printer engine (image forming portion of the printer) 92. In response to this, the printer engine 92 causes the printer controller 9 to
A printed image is generated according to the image data received from 1.

[0006]

By the way, in the above-mentioned conventional image processing apparatus, color correction or bitmap image data in which the image data of each pixel is multivalued (multiple bits, for example, 8 bits) is used. Necessary image processing such as color conversion or edge processing is performed. Therefore, there is a problem that a large capacity memory is required to store the bitmap image data.

For example, in the conventional image processing apparatus, the edge determination for detecting the edge by checking the gray level difference between the arbitrary pixel and the pixel adjacent to the pixel is performed as follows for the bitmap image data stored in the memory. I'm going to the point.

FIG. 22 is a diagram for explaining the flow of edge determination processing in the conventional image processing apparatus. Here, a case where 8-bit multi-valued image data per pixel is handled will be described.

First, the image data of the pixel for which the edge judgment is performed and the image data of the surroundings are stored in the multivalued memory. Then, the difference between the image data of the pixel for which the edge determination is performed and the image data around it is obtained, and it is determined whether or not this difference is equal to or more than a predetermined amount.

When a 3 × 3 multi-valued memory group as shown in FIG. 23 is used as a memory for storing bitmap image data, the image data of the pixels for which edge determination is to be performed is read out from the multi-valued memory D22 and the edge data is read. The image data around the pixel to be judged is stored in the multi-value memories D11, D13, D31,
Read from D33. Then, the value of the image data of the pixel stored in the multi-valued memory D22 and the multi-valued memories D11, D
The difference from the average value of the image data of the pixels stored in 13, D31 and D33 is calculated, and when the difference is equal to or more than a predetermined amount, the pixel stored in the multi-valued memory D22 is determined to be an edge. Alternatively, as shown in FIGS. 24 and 25, the difference between the image data of the pixel for which the edge determination is performed and the average value of the image data of the eight pixels around the edge is taken, and whether or not the difference is greater than the threshold The edge is determined by checking.

This method is generally used in digital filters.

As described above, in the conventional image processing apparatus, the edge determination is performed by calculating the multivalued image data using the digital filter. Therefore,
A large memory for storing multi-valued image data is required.
Further, in order to perform the edge determination, it is necessary to store at least three lines of image data in the multi-valued memory, which results in a wide bus width for transferring the image data.

Further, in the above conventional image processing apparatus, necessary image processing such as color correction, color conversion, or edge processing is sequentially performed on the bitmap image data for each processing. Therefore, there is also a problem that it takes time to perform all necessary image processing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the capacity of the memory required for image processing and to reduce the bus width for transferring image data, thereby providing a circuit. An object is to provide an image processing device that can be reduced in scale.

[0015]

In order to solve the above-mentioned problems, the image processing apparatus of the present invention provides, for each predetermined image area, specific information for specifying at least one color used to represent the predetermined image. Image processing is performed on compressed image data including a color signal including a color signal and a color selection signal including selection information for selecting the specific information from the color signal for each pixel in the predetermined image area. And the compressed image data that has been subjected to image processing by the image processing means, according to the selection information of each pixel in the predetermined image area included in the color selection signal of the compressed image data. Decompression means for decompressing pixel-based multi-valued image data by adding color data specified by the specification information included in the color signal of the compressed image data selected by the selection information to the pixel , Characterized in that it comprises.

Here, the image processing means changes the arrangement of the selection information of each pixel included in the color selection signal,
It may have a color selection signal processing means for rotating or enlarging / reducing an image.

When the color signal has color data as the specific information, the image processing means performs color correction processing such as color conversion or gamma correction on the color data included in the color signal. It may have signal processing means.

Further, the image processing means is included in the color palette table when the color signal has a color palette number for specifying the color data from the color palette table having a plurality of color data as the identification information. It may have a color palette table processing means for performing color correction processing such as color conversion and gamma correction on the color data.

According to the present invention, with the above configuration, necessary image processing is performed before decompressing the compressed image data. Therefore, the capacity of the memory required for image processing can be reduced, and the circuit scale can be reduced.

Further, according to the present invention, different image processing can be performed in parallel with respect to the color signal and the color selection signal, so that the time required for the image processing can be shortened.

In the present invention, the feature determining means for determining the feature of the target pixel and the determination result of the feature determining means by checking the shade of color between the target pixel and the pixels around the target pixel. And halftone processing means for outputting the multivalued image data in pixel units expanded by the expansion unit, which has been subjected to the halftone processing according to the above.

As the feature determining means, the color shade between the target pixel and the pixels around the target pixel is checked based on the multivalued image data in pixel units expanded by the expanding unit, The feature of the target pixel may be determined.

Alternatively, when the color signal has color data as the specific information, the shading of the color between the target pixel and the pixels around the target pixel is determined by comparing the color data included in the color signal with the color data included in the color signal. The characteristics of the target pixel may be determined by checking based on the selection information included in the selection signal.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below.

Although a case where the image processing apparatus is applied to a printer will be described here, the present invention can be applied to various image output apparatuses such as a facsimile and a monitor in addition to the printer.

FIG. 1 is a schematic block diagram for explaining a printer according to the first embodiment of the present invention.

The computer 1 converts the bitmap image data 21 to be output to the printer 2 into compressed image data composed of a color signal and a color selection signal in a compression unit 22 realized by a printer driver or the like, and an image is obtained. It is stored in the memory 23. Then, the data is output to the printer 1 via a data transfer unit (not shown).

Here, the color signal is a signal for specifying a plurality of colors when various colors used in a predetermined image area (for example, 4 × 4 pixels) are approximated by a plurality of colors. is there. The compression unit 22 approximates various colors in the image area specified by the bitmap image data 21 to a plurality of colors by calculation taking the color space into consideration. Then, data indicating a plurality of approximated colors are arranged in a predetermined order to generate a color signal.

The color selection signal is a signal for selecting the color of each pixel in a predetermined image area (for example, 4 × 4 pixels) from the color signals. The compression unit 22 specifies, for each pixel in the image region specified by the bitmap image data 21, information that specifies color data close to the color of the pixel from a plurality of color data included in the color signal (corresponding color data The order (number) in the color signal of is described in pixel order to generate the color selection signal.

FIG. 2 is a diagram for explaining an example of the structure of compressed image data in the case where the colors in the predetermined image area are approximated to a plurality of colors by the calculation considering the color space. Here, 22a shows the data structure of the color signal, and 22b shows the data structure of the color selection signal.

In the example shown in FIG. 2, the color signal approximates the colors used in the predetermined image area to two colors, color 0 and color 1, by the calculation considering the color space.

Specifically, as shown in FIG. 3, each pixel in the predetermined image area is developed in a color space having RGB as coordinate axes (FIG. 3A). Then, by dividing this space into two on a certain surface S, each pixel is classified into two groups, and colors 0 and 1 representing each group (for example, the average value of the pixels belonging to the group) are set. Yes (Fig. 3
(B)). When each RGB color is represented by 8-bit data,
As shown in FIG. 2, the color signal has 24 colors for both color 0 and color 1.
There are 48 bits in total.

When the colors in the predetermined image area are approximated by four colors, the color space may be divided into two arbitrary planes and each pixel in the predetermined image area may be divided into four groups. Then, a color representative of each group may be set.

In the color selection signal, for each pixel in the predetermined image area, information (number) for specifying an approximate color of the pixel (a color representing a group to which the pixel belongs) is arranged in a predetermined order. It is configured. As shown in FIG.
When the color signal is composed of two colors, color 0 and color 1,
The color selection signal has 1 bit per pixel. Further, when the color signal is composed of four colors, the color selection signal has 2 bits per pixel.

When each color of RGB is 8-bit data,
Since the number of bits of 4 × 4 pixel bitmap image data is 24 bits per pixel, 24 × 16 =
It becomes 384 bits. On the other hand, according to the compressed image data shown in FIG. 2, the 4 × 4 pixel bitmap image data can be compressed to a total of 64 bits of the color signal of 48 bits and the color selection signal of 16 bits.

The image data compression / decompression method used in this embodiment is described in detail in Japanese Patent Publication No. 6-7688.

Returning to FIG. 1, the description will be continued.

When the printer 1 receives the compressed image data having the above configuration from the computer 2, the printer 1 operates as follows.

First, in the printer controller 11, the image memory 13 stores the received compressed image data. Then, the image processing unit 16 causes the image memory 13
Necessary image processing such as color correction and pixel rearrangement is directly performed on the compressed image data stored in. After that, the decompression unit 14 decompresses the pixel-based multi-valued image data.

After the expansion processing in the expansion unit 14 is completed, the halftone processing unit 17 reproduces the halftone based on the expanded image data. Then, the data is output to the printer engine (image forming portion of the printer) 12. In response to this, the printer engine 12 generates a printed image according to the data received from the printer controller 11.

In the above-described embodiment, as the compressed image data, a color signal for specifying a plurality of colors that approximate various colors used in the predetermined image area and each pixel in the predetermined image area. The compressed image data composed of a color selection signal in which information for selecting a color from the color signals is arranged in a predetermined order.

Therefore, color conversion from RGB (red, green, blue) to YMCK (yellow, magenta, cyan, black), etc., intermediate color correction, or other color correction can be performed directly from the color signals. it can. In addition, processing involving pixel rearrangement such as image rotation and enlargement / reduction can be performed directly from the color selection signal. Further, the image area separation processing by determining the feature points such as edges can be performed by using both the color signal and the color selection signal. That is, it is possible to use the color signal to determine whether or not there is a shade of an image in the predetermined image area, and it is possible to use the color selection signal to extract the color transition in the predetermined image area. Therefore, by using both of these pieces of information, it is possible to extract the feature points in the predetermined image area.

Therefore, in the present embodiment, the compressed image data having the above-mentioned configuration is used, and necessary image processing is performed before decompressing the compressed image data. Therefore, the capacity of the memory required for image processing can be reduced, and the circuit scale can be reduced. Further, in the present embodiment, since the color correction process and the process involving the rearrangement of pixels can be directly performed from the color signal and the color selection signal, respectively, these processes can be performed in parallel. Therefore, the time required for image processing can be shortened.

Further, the compressed image data having the above-mentioned structure has a feature that the compression efficiency (the data length of the compressed data) is always constant. For example, according to the compressed image data shown in FIG. 2, the 4 × 4 pixel bitmap image data is always compressed to 64 bits.

Therefore, according to the present embodiment, in the printer controller 11, the operations from the reading of the compressed image data from the image memory 13 to the halftone processing in the halftone processing section 17 are performed at the request timing of the printer engine 12. Therefore, it can be performed in synchronization. That is, a speed conversion buffer (memory 95 shown in FIG.
It is not necessary to provide).

As described above, the compression / expansion processing of multi-valued image data in this embodiment is performed in Japanese Patent Publication No. 6-76.
It is based on the one described in Japanese Patent Publication No. 88, and its implementation method may be either hardware or software.

Next, the printer controller 11, which is the main part of this embodiment, will be described in detail. 4 is shown in FIG.
FIG. 3 is a configuration block diagram of the printer controller 11 shown in FIG.

Since the printer engine 12 in the configuration shown in FIG. 1 is the same as that conventionally used in a printer, the details of this part will be omitted.

First, the image processing section 16 will be described.

As shown in FIG. 4, the image processing section 16 includes a color signal calculation section 161, a color selection signal calculation section 162, a color determination section 163, a feature point determination section 164, and an image processing selection section 165. Consists of.

The color signal calculation unit 161 performs color conversion, color adjustment,
Alternatively, color correction such as halftone correction is performed on the color signal. FIG. 5 is a configuration block diagram of the color signal calculation unit 161 shown in FIG. Here, 161a is a color correction unit and 161b.
Is a color conversion unit, 161c is a halftone correction unit, and 161d
Reference numerals ˜161f are memories for storing correction data used by the color correction unit 161a, the color conversion unit 161b, and the halftone correction unit 161c, respectively.

The color correction unit 161a performs processing for correcting the color signal to a color suitable for the printer engine 12.
Generally, the printer engine 12 has color characteristics unique to the device. Therefore, the image output from the printer engine 12 may change from the color specified by the color signal. The color correction unit 161a is for eliminating such a problem. The color data included in the color signal is corrected according to the color characteristics of the printer engine 12. As a color correction method, a matrix calculation method or a table reference method is generally used, but other methods may be used. If the color characteristics change depending on the state of the printer engine 12, the memory 1
It is preferable to refer to and use the color correction data stored in 61d to change.

The color conversion unit 161b converts the color data included in the color signal into the data of four colors of YMCK, which is mainly used in printers, from the data of three colors of RGB, which is mainly used in monitors and the like. Convert to structured data. This conversion process is a process of generating one color of YMCK based on the data of the three colors of RGB. The color conversion process is a technique that has been conventionally used, but as a general method, there is a method that uses RGB as a complementary color of CMY. In this method, the undercolor removal processing (UCR) and the black generation processing (BG) are performed by combining the three colors of CMY. In addition, a method of performing color conversion by storing a color conversion table in the memory 161e and referring to this table,
There is a method of color conversion by matrix calculation.

In this embodiment, the case where the present invention is applied to the printer controller is explained.
If the output destination of the image data does not need to perform color conversion, such as a monitor, the color conversion unit 161b may not be provided.

The halftone correction unit 161c is a color correction unit 161.
In the a and color conversion unit 161b, processing for improving halftone reproducibility is performed on the color signal subjected to color correction and color conversion processing. This process is generally called gamma correction.

The color data included in the color signal is formed in full scale in order to faithfully reproduce the color. For example, if each color of CMYK has a bit number of 8 bits, each color has 256 levels of data from 0 to 255. However, an image forming apparatus such as a printer may be able to reproduce halftones only within an arbitrary range. For example, in a printer, halftones can be expressed only in the range of 50 to 200 out of 256 levels of 0 to 255, and when it is 50 or less, it becomes pure white, and when it is 200 or more, the color does not increase any more. There is. In such a printer, when one color (one of CMYK) forming a certain color data has a value of 208, it is necessary to prevent the color from becoming a color whose density does not increase any more. . The halftone correction unit 161c converts the color data having 256 gradations for each color into the halftone reproduction range (50 to 20) of the printer.
By correcting so that it is assigned to 0), the above-mentioned problems are prevented from occurring.

As a method of halftone correction, a method of matrix calculation or a method of referring to a table is generally used, but another method may be used. When the halftone characteristic changes depending on the state of the printer engine 12, it is preferable to refer to and use the halftone correction data stored in the memory 161f.

Next, the color selection signal calculation section 162 will be described.

The color selection signal calculation unit 162 performs processing involving pixel rearrangement such as image rotation and enlargement / reduction.

Regarding the rotation of the image, the order of the data of each pixel forming the color selection signal may be exchanged. For example, the data of each pixel forming the color selection signal is exchanged according to the rotation angle and the rotation direction of the image such as 90 degrees, 180 degrees, and 270 degrees. This process is basically the same as the technique conventionally used for image rotation, but in the past, each pixel processed bit map image data having color data. This embodiment is different in that each pixel processes a color selection signal including only color data selection information from the color signal. It is easier to replace the color selection signal with less bits than to replace the data using the bitmap image data. Therefore, the circuit scale can be reduced in this embodiment. Regarding the image rotation processing, the color selection signal calculation unit 162 replaces the data of each pixel forming the color selection signal, and the decompression unit 14 stores the color selection signal from the image memory 13. Call order,
A method of changing it according to image rotation information is also conceivable.

The image enlargement is performed by inserting the same data as the data of the adjacent pixels between the data of the pixels forming the color selection signal. Further, regarding image reduction, for example, a method of reconstructing a color selection signal by extracting data of pixels corresponding to the respective reduced pixels from the data of each pixel forming the color selection signal, or a color selection signal There is also a method of reconstructing the color selection signal after the reduction so that the data distribution on the map when the data of each pixel constituting the above is expanded as much as possible. Alternatively, a method using dither processing can be used. These processes are basically the same as the technique conventionally used for image enlargement / reduction, but conventionally, the process was performed on bitmap image data in which each pixel has color data. On the other hand, the present embodiment is different in that each pixel processes a color selection signal including only color data selection information from the color signal.
In the present embodiment, the number of bits to be handled is smaller than that in the case of using bitmap image data, so that the circuit scale can be reduced.

Next, the color determination unit 163 will be described.

The color determination unit 163 determines whether or not the color in the image region specified by the color signal has a shade by referring to each color data included in the color signal. FIG. 6 shows the color determination unit 163 and the feature point determination unit 16 shown in FIG.
4 is a schematic block diagram of FIG.

As shown in FIG. 6, the color determination unit 163 has a color difference calculation unit 163a and a grayscale determination unit 163b.

The color difference calculator 163a calculates the color difference between a plurality of color data included in the color signal. For example, in the case of the compressed image data shown in FIG. 2, the color difference between the two colors of color signals, color 0 and color 1, is calculated.

The light and shade judging means 163b includes a color difference calculating section 16
The shade of the color is judged based on the color difference obtained in 3a. And
For each of the color data included in the color signal, identification information (binary data) indicating whether the color specified by the data is a dark color or a light color is used as the characteristic determination unit 16
Send to 4.

Next, the feature determining section 164 will be described.

As shown in FIG. 6, the feature point determination unit 164 includes a grayscale binary data memory 164a and a feature point extraction unit 1.
64b.

The grayscale binary data memory 164a stores the grayscale determination result (determination of dark color or light color) of each color data included in the color signal sent from the color determining unit 163.

The feature point extraction unit 164b outputs the grayscale result of the color data corresponding to the data of each pixel (the number for selecting the color data from the color signal) included in the color selection signal as the grayscale 2
By using the value data memory 164a to check, a pixel serving as a feature point is determined.

In general, the edges extracted as feature points are
It is composed of darker pixels than the surroundings. Therefore, the feature point extraction unit 164b obtains the grayscale result of the pixel for which the feature point is determined and the grayscale result of the pixels around it from the grayscale binary data memory 164a, so that the pixel for which the feature point is determined is It is determined whether the color is darker than the surrounding pixels.

Here, the processing in the color judging section 163 and the characteristic point judging section 164 will be described in more detail.

First, the case where the color signal includes two color data will be described.

FIG. 7 shows a color determination section 163 and a feature point determination section 16 in the case where the color signal contains two color data.
FIG. 4 is a diagram for explaining the flow of processing in No. 4.

First, the color difference calculation processing unit 163a calculates the color difference between the two color data included in the color signal for each color of RGB (difference detection).

Next, the gradation determining unit 163b examines the sign (positive or negative) of the color difference obtained by the color difference calculating unit 163a,
The shade of the color of the two color data included in the color signal is determined. It is also determined whether the absolute value of each color difference is larger than a predetermined threshold value (shade determination).

Next, the feature point determination unit 164 determines the data of each pixel included in the color selection signal (the number for selecting the color data included in the color signal) from the color data corresponding to the data. It is replaced with the gray scale result in the section 163.
Then, using a digital filter, feature points are extracted in consideration of the grayscale result between adjacent pixels and the comparison result of the absolute value of the color difference between the pixels and a threshold value (edge determination).

FIG. 8 is a diagram showing a more detailed processing flow of the color determination unit 163 shown in FIG.

In FIG. 8, R0, G0 and B0 are
The data forming one color data (color 0) of the two color data included in the color signal is shown.
Symbols B1 and B1 represent data that constitutes the other color data (color 1).

Of the RGB colors forming the color data, the R color will be focused and described.

First, the color difference calculation unit 163a calculates the difference (R0-R1) between the color 0 and the color 1, and the sign of the calculated difference indicates whether the color 0 or the color 1 is a dark color. It is output as a flag indicating that. Also, the absolute value of the difference is output.

Next, the gray level judging section 163b compares the absolute value of the difference sent from the color difference calculating section 163a with a predetermined constant (threshold value). Then, when the absolute value of the difference is larger than the constant, the flag output from the color difference calculation unit 163a is output via the selector, and the flag is set as the addition target in the addition processing described later.

The above processing is similarly performed for the G color and the B color forming the color data. Then, the flags obtained via the selector are added, and depending on whether the addition result is positive or negative,
It is determined which of color 0 and color 1 is a dark color.
For example, when the color difference calculation unit 163a obtains the color difference by subtracting the color 1 from the color 0 for each of the RGB colors, when the addition result is positive, it is determined that the color 0 is a dark color, and the addition result is negative. In the case of, it is determined that the color 1 is a dark color. In addition, when the addition result is 0, it is determined that there is no gray level difference between the color 0 and the color 1 for extracting the feature point.

Next, the case where the color signal includes three or more color data will be described.

FIG. 9 shows a color determination section 163 and a feature point determination section 16 in the case where the color signal contains four color data.
FIG. 4 is a diagram for explaining the flow of processing in No. 4.

First, the color difference calculation processing unit 163a calculates the color difference between the color data in each of the combinations of the two color data for the four color data included in the color signal for each color of RGB (difference detection).

Next, the gradation determining unit 163b examines the sign (positive or negative) of the color difference obtained by the color difference calculating unit 163a,
The shade of color is judged for each combination of the two color data (shade judgment). Then, the shading results of each combination of the two color data are summarized in the inter-color difference table.

Next, the feature point determination unit 164 develops the data of each pixel included in the color selection signal (the number for selecting the color data included in the color signal) on the map. Then, by referring to the inter-color difference table, the gray level result between the adjacent pixels is checked, and the feature point is extracted by this (edge determination).

FIGS. 10 and 11 are diagrams showing a more detailed processing flow of the color determination unit 163 shown in FIG. 9. FIG. 10 shows the processing by the color difference calculation unit 163a, and FIG.
Indicates the processing in the gray level determination unit 163b.

First, as shown in FIG. 10, the color difference calculation unit 1
In 63a, the differences between the respective color data for each of the RGB colors of the four color data are brute force. Note that FIG.
0 indicates a case where the difference between the color data of R colors (R0, R1, R2, R3) of the four color data (color 0, color 1, color 2, color 3) is taken in a brute force manner. However, G color and B color are similarly processed.

Next, as shown in FIG.
63b, between each color data (between color 0 and color 1, color 1
And between colors 2 and 3, between colors 2 and 3, between colors 3 and 0, between colors 0 and 2 and between colors 1 and 3).
Follow the procedure shown in. Then, the result is written in the inter-color difference table. In the inter-color difference table shown in FIG. 11, the number in the left column, for example 01, indicates the shade determination between color 0 and color 1, and the result is written on the right side thereof. For example, when it is determined that the color 0 is darker than the color 1, the determination result “◯” is written on the right side of the column 01.
In the opposite case, the judgment result "x" is written.

Note that, in the above, for the plurality of color data included in the color signal, the density determination between each color data is performed, but the density can be obtained by other methods.

FIG. 12 is a diagram for explaining another shade determination method in the case where the color signal includes four color data. Here, the four color data (color 0 to color 3) included in the color signal are rearranged in order of darkness. Then, these color data are divided into two, a dark color and a light color. For example, a dark color threshold value (for example, an average value of four color data) is set, and with this density threshold value as a reference, four color data are divided into a dark color and a light color.
Divide into two. Alternatively, when the absolute value of the color difference between adjacent color data is the largest and is equal to or larger than a predetermined value, the color is divided into two, a dark color and a light color.

Next, the image processing selection section 165 will be described.

The image processing selection unit 165 is the feature point determination unit 1
Image area determination is performed based on the determination result in 64. It is preferable to perform different image processing, in particular, halftone processing on the pixel serving as the feature point, the pixels around it, and the pixels farther away from the surrounding pixels. For example, if the feature point is an edge, the pixel that is the feature point is subjected to the line processing, the pixels around the feature point are subjected to the simple dithering process, and the pixel that becomes the feature point is also surrounded by it. It is preferable to perform halftone dot dither processing on pixels that are not certain pixels. In addition, when the color data included in the color signal is a color having a distinct shade such as a text or a line drawing, it is preferable to perform the smoothing process on the pixel serving as the feature point.

Therefore, in the image processing selection section 165,
Image area determination is performed based on the determination result of the feature point determination unit 164, and the type of pixel (a feature point, a pixel in the vicinity thereof, or a pixel farther than the pixels in the periphery thereof), The halftone processing unit 17 is instructed to perform appropriate processing according to the color difference between the color data included in the color signal.

Next, the expansion section 14 will be described.

The decompression unit 14 generates multivalued image data in pixel units based on the color signal sent from the color signal calculation unit 161 and the color selection signal sent from the color selection signal calculation unit 162. First, color data (multivalued data) is acquired from the color signal sent from the color signal calculation unit 161.
Then, each acquired color data is sequentially numbered. Next, the data (the number for selecting the color data from the color signal) assigned to each pixel in the predetermined image area is acquired from the color selection signal. Then, for each pixel, the data assigned to the pixel is replaced with the corresponding color data. As a result, multi-valued image data for each pixel is generated.

Next, the halftone processing section 17 will be described.

The halftone processing section 17 includes an image processing selecting section 16
According to the instruction from 5, the halftone processing such as the halftone dot dither processing, the simple dither processing, and the parallel line processing is performed on the pixel-based multivalued image data output from the decompression unit 14.

FIG. 13 is a block diagram showing the configuration of the halftone processing section 17 shown in FIG.

As shown in FIG. 13, the halftone processing unit 17 performs halftone dot dither processing on the multivalued image data in pixel units output from the decompression unit 14, and the halftone processing A unit 17 is provided.
1 and a halftone processing B unit 172 that performs simple dither processing,
A selector that selects any one output from the halftone processing C unit 173 that performs line processing, the smoothing processing unit 174 that performs smoothing processing, and the processing units 171 to 174 according to an instruction from the image processing selection unit 165. 175
And a halftone reproducing unit 176 that reproduces a halftone based on the multi-valued image data received via the selector 175.

Although the four halftone processes are performed here, the number of processes is not limited to this number, and the contents of the process are not limited to this. For example, when the feature point determination unit 164 determines only which of the two image areas, the edge portion and the non-edge portion, the pixel belongs to, the halftone processing needs to be two.

As described above, the image processing selection section 165.
Instructs to select an appropriate process for the multi-valued image data of the pixel that is the determination target of the determination unit 164, according to the determination result of the feature point determination unit 164. In response to this, the selector 175 selects any one output from the processing units 171 to 174 as the multivalued image data of the pixel which is the determination target in the feature point determination unit 164.

For example, when the determination result of the feature point determination section 164 indicates that the pixel to be determined is an edge, the selector 175 causes the halftone processing C section 173.
Is selected. As a result, the multi-valued image data of the pixel to be determined, which has been subjected to the parallel line processing, is output to the halftone reproduction unit 176. If the pixel to be determined indicates that the pixel is around the edge, the selector 175
The halftone processing B section 172 is selected by. As a result, the multi-valued image data of the pixel to be determined is subjected to the simple dither processing, and is output to the halftone reproduction unit 176. If the pixel to be determined is a pixel far away from the edge, the selector 175 selects the halftone processing A unit 171. As a result, the multi-valued image data of the pixel to be determined, which has been subjected to the halftone dot dither processing, is output to the halftone reproduction unit 176. In addition, the determination result by the feature point determination unit 164 indicates that the pixel to be determined is an edge and that it has a clear shade of color such as a text or a line drawing (this). Can be determined from the color difference between the color data obtained by the color determination unit 163).
5, the smoothing processing unit 174 is selected. As a result, the multi-valued image data of the pixel to be determined is subjected to smoothing processing, and is output to the halftone reproduction unit 176.

The halftone reproducing section 176 reproduces a halftone based on the multi-valued image data in pixel units sequentially received through the selector 175. As a result, the multi-valued image data in pixel units is converted into an output signal suitable for the printer engine 12.

For example, a laser printer generally outputs serial data to the printer engine. In this case, the multi-valued image data is converted into serial data having a pulse amplitude and a pulse application time according to the gradation indicated by the data. That is, the pulse amplitude is changed to change the light amount of the laser light, or the pulse application time is changed to change the light emission time of the laser light. The gradation is set according to the value image data. If the number of gradations that can be reproduced in units of pixels of the printed image is small, halftone reproduction using spatial modulation such as dither processing performed in the previous halftone processing may be used together.

In the first embodiment of the present invention, as described above, color correction processing such as color conversion and pixel rearrangement processing such as image rotation are performed on compressed image data. Therefore, the number of bits to be handled can be significantly reduced as compared with the case where the above processing is performed on the decompressed image data, that is, the multi-valued image data in pixel units. Therefore, according to the present embodiment, it is possible to reduce the memory capacity and the data bus width required for the above processing. As a result, the circuit scale can be reduced. Also,
The time required for processing can be shortened.

Further, in the present embodiment, color correction processing such as color conversion and pixel rearrangement processing such as image rotation are performed in parallel for the color signal and the color selection signal, respectively. Therefore, the time required for image processing can be further shortened.

Further, according to the present embodiment, since the compressed image data whose data length is always constant is used, the operations from the reading of the compressed image data from the image memory 13 to the halftone processing in the halftone processing section 17 are performed. Printer engine 1
It can be performed in synchronism with the request timing of 2. Therefore, it is not necessary to provide a buffer for speed conversion.

In the above embodiment, the color signal and color selection signal calculation unit 16 processed by the color signal calculation unit 161.
The color selection signal processed in 2 is directly output to the decompression unit 14. However, as shown in FIG. 14, the color signal processed by the color signal calculation unit 161 and the color selection signal processed by the color selection signal calculation unit 162 are temporarily stored in the image memory 18, and then stored in the decompression unit 14. You may make it output.

By doing so, even if the color signals and the color selection signals stored in the image memory 13 are not read in the order (for example, the order of input to the image memory 13), the color signals and the color selection signals are read from the image memory 18. By adjusting the reading, the color signal and the color selection signal can be sequentially output to the decompression unit 14. For this reason, it is possible to execute the processing of the color signal, which takes a long processing time, in advance.

In the above embodiment, the compressed image data sent from the computer 2 is temporarily stored in the image memory 13 and then the image processing section 16 performs image processing. However, the compressed image data sent from the computer 2 may be directly input to the image processing unit 16 without passing through the image memory 13. In the present embodiment, since compressed image data having a constant data length is used, even if the image memory 13 is not provided,
The image processing in the image processing unit 16 can be smoothly performed.

Further, in the above embodiment, the color signals of the compressed image data sent from the computer 2 are:
The one including the color data composed of RGB has been described. However, the color data is not limited to this. For example, as the color signal of the compressed image data sent from the computer 2, one containing color data of CMYK may be used. In this case, the color signal calculation unit 161
The color conversion process in is unnecessary.

Further, in the above embodiment, as the color conversion processing in the color signal calculation unit 161, the color conversion of RGB color data into CMYK color data has been described. However, the color conversion processing in the color signal calculation unit 161 is not limited to this. The color data of the color signal of the compressed image data sent from the computer 2 may be converted into color data according to the characteristics of the printer engine 12. For example, the color data composed of RGB may be converted into color data composed of 6 colors obtained by adding light magenta and light cyan to CMYK.

Here, a specific circuit configuration example of this embodiment will be described.

FIG. 15 is a diagram showing a circuit configuration of a printer controller to which the first embodiment of the present invention is applied.

In FIG. 15, among the compressed image data stored in the image memory 50, the color signal composed of the color data of a plurality of colors approximated to the color in the predetermined image area by the calculation using the color space is a color signal. It is input to the correction circuit 51. The color correction circuit 51 refers to the color correction table stored in the memory 52 and performs color correction according to the printer engine. Then, it is input to the color conversion circuit 53.

The color conversion circuit 53 refers to the color conversion UCR table stored in the memory 55 and the color conversion BG table stored in the memory 54 to convert the color data included in the color signal from RGB data into YMCK data. Convert. After that, the color data of the color signal is gamma-corrected by the gamma correction circuit 56. Here, the printer engine 12
In order to perform halftone reproduction suitable for the gamma correction, gamma correction is performed with reference to the gamma correction table stored in the memory 57.

On the other hand, among the compressed image data stored in the image memory 50, a color selection in which a number for selecting one color data included in the color signal is described for each image in the predetermined area. The signal is input to the image rotation circuit 60,
If necessary, image rotation processing is performed by rearranging the pixels.

As described above, the color signal subjected to the color correction and the color selection signal subjected to the pixel rearrangement processing are input to the decompression circuit 58, where they are decompressed into multivalued image data in pixel units. It

The color signals stored in the image memory 50 are input to the color difference calculation circuit 61, and the color difference between the plurality of color data included in the color signals is calculated for each color of RGB. The shade determination circuit 62 determines the shade of a plurality of color data included in the color signal based on the result of the color difference calculation circuit 61, and stores the result in the shade memory 63. The color selection signal output from the image rotation circuit 60 is also stored in the density memory 63.

The feature point determination circuit 64 is based on the grayscale result of the color data used in the predetermined image area stored in the grayscale memory 63 and the selection number of the color data used for each pixel in the predetermined image area. Then, the feature points are extracted and the image area is determined. Then, an instruction is issued to select an appropriate halftone process according to the result.

The halftone reproduction processing circuit 59 performs a plurality of halftone processing (halftone dot dither processing, simple dither processing, line processing, etc.) in parallel on the multivalued image data expanded by the expansion unit 58. Then, according to the instruction of the feature point determination circuit 64, an appropriate result is selected from a plurality of halftone processing results, and based on this, a halftone is reproduced and output.

In the first embodiment of the present invention described above,
The case where the color signal of the compressed image data is one in which the color in the predetermined image area is approximated to a plurality of colors by the calculation considering the color space has been described.

However, the compressed image data used in the present invention includes, for each predetermined image area, a color signal containing identification information for identifying at least one color used to represent the predetermined image, and a predetermined image area within the predetermined image area. For each pixel, a color selection signal including selection information for selecting the specific information from the color signals.

As a second embodiment of the present invention, a case where the color signal of the compressed image data approximates the colors in the predetermined image area to a plurality of colors by using the color palette table will be described below.

First, the compressed image data used in this embodiment will be described.

FIG. 16 is a diagram for explaining an example of the structure of compressed image data when the colors in a predetermined image area are approximated to a plurality of colors using a color palette table. Here, 22c shows the data structure of the color signal, and 22d shows the data structure of the color selection signal.

In the example shown in FIG. 16, the color signal approximates the colors used in the predetermined image area to two colors, color 0 and color 1, using the color palette table.

Specifically, as shown in FIG. 17, the color data of each pixel in the predetermined image area is referred to, and two approximate colors are selected from the color palette table. And selected 2
Information (pallet number) for specifying a color is arranged in a predetermined order and is generated as a color signal. As shown in FIG.
If the number of colors on the color palette table is 256,
The palette number can be represented by 8 bits. Therefore, the color signal has a total of 16 bits as shown in FIG.

The color selection signal is formed by arranging, for each pixel in the predetermined image area, information (number) for specifying the palette number indicating the approximate color of the pixel, in the pixel order. As shown in FIG. 16, when the color signal is composed of two colors, color 0 and color 1, the color selection signal has 1 bit per pixel.

Therefore, according to the compressed image data shown in FIG. 16, 4 × 4 pixel bitmap image data (8 bits for each color of RGB, 24 bits for each pixel, 384 bits in total) are converted into 16 bits of color signals and color selection. Signal 16
A total of 32 bits can be compressed.

Next, the configuration of this embodiment will be described.

FIG. 18 is a block diagram showing the configuration of the printer controller 11a, which is the main part of this embodiment. The rest of the configuration is similar to that of the first embodiment shown in FIG.

The printer controller 11a of this embodiment
Is different from the printer controller 11 shown in FIG.
As shown in FIG. 18, an image processing unit 16a is used instead of the image processing unit 16, and an expansion unit 14a is used instead of the expansion unit 14.

The image processing section 16a has a color palette table calculation section 166, a color selection signal calculation section 162, a feature point determination section 167, and an image processing selection section 165. Here, the color selection signal calculation unit 162 and the image processing selection unit 1
65 is the same as that used in the first embodiment.

The color palette table calculation unit 166 performs color conversion from RGB to YMCK and color conversion to a color palette table (the same table as the color palette table used when compressing image data) prepared in the memory in advance. Adjust or perform color correction such as halftone correction. In the above-described first embodiment, color correction is performed on the color signal, but the color signal used in this embodiment is composed of a palette number on the color palette table for each of a plurality of approximate colors. That is, unlike the color signal of the first embodiment, the color signal itself does not have color data. For this reason,
It is not possible to directly perform color correction on color signals. Therefore, in this embodiment, color correction is performed on the color palette table. The content of the color correction itself is basically the same as that of the first embodiment.

The feature point determination unit 167 is the expansion unit 1 described later.
A feature point such as an edge is determined based on the pixel-based multivalued image data expanded in 4a. This processing is basically the same as the edge determination described with reference to FIGS.

The decompression unit 14a receives the color signal sent from the image memory 13, the color selection signal sent from the color selection signal calculation unit 162, and the color palette table calculation unit 166.
Multi-valued image data in pixel units is generated based on the color palette table that has been subjected to color correction in.

FIG. 19 is a block diagram showing the structure of the expansion section 14a shown in FIG. Here, when the data shown in FIG. 16 is used as the compressed image data, that is, when the color signal includes two color palette numbers, the decompression unit 1
4a shows a configuration example of 4a.

In the example shown in FIG. 19A, the image memory 1
3 and the color selection signal calculation unit 162
The color selection signal sent from the above is sent to the separation storage unit 142 via the buffer 141. The separation storage unit 142 is
Two color palette numbers are acquired from the color signal and are sequentially stored in the memories 142a and 142b. In addition, the data of each pixel (the number for selecting the color palette number from the color signal) included in the color selection signal is expanded into a bitmap in pixel order and stored in the memory 142c.

Then, in the selector 143, the memory 14
The data of each pixel is sequentially read from 2c, and the data (color palette number) stored in either the memory 142a or the memory 142b is read according to the number indicated by the read data. Then, in the conversion unit 144,
The color palette table 144a that has been color-corrected by the color palette table calculation unit 166 is referred to, and the color palette number sent from the selector 143 is converted into the corresponding color data. As a result, the compressed image data is expanded into multivalued image data in pixel units.

In the example shown in FIG. 19B, the color selection signal sent from the color selection signal calculation unit 162 is stored in the buffer 14.
The color signal sent from the image memory 13 is sent to the converter 144 via the buffer 141. The conversion unit 144 acquires the color palette number from the color signal. Then, the acquired color palette number is converted into color data by referring to the color palette table 144a that has been color-corrected by the color palette table calculation unit 166, and this is sequentially sent to the separation storage unit 142.

The separation storage unit 142 acquires the color data sent from the conversion unit 144, and sequentially stores the color data in the memory 142.
d, 142e. In addition, the data of each pixel included in the color selection signal sent from the buffer 141 is expanded on the map and stored in the memory 142c.

Next, in the selector 143, the memory 14
The data of each pixel is sequentially read from 2c, and the data (color data) stored in one of the memory 142d and the memory 142 is read according to the number indicated by the read data. As a result, the compressed image data is expanded into multivalued image data in pixel units.

In the second embodiment of the present invention, the color correction is performed not on the color signal read from the image memory 13,
This is performed on a color palette table prepared in advance (the same table as the color palette table used to compress the image data). Therefore, it is possible to execute the color correction process in advance.

Also in this embodiment, as in the first embodiment, the pixel rearrangement processing such as image rotation can be directly performed on the color selection signal, so that the memory required for the processing can be saved. The capacity and the like can be reduced.

In the above embodiment, the color palette table (the color palette table in which each color data included in the table is RGB) used when the computer compresses the image data is prepared in advance on the printer controller side. The color palette table calculation unit 166 converts each color data included in this table from RGB data into CMYK data. However, the color palette table prepared in advance on the printer controller side is not limited to this. A color palette table obtained by converting each color data included in the color palette table used when the image data is compressed by the computer into color data according to the characteristics of the printer engine may be prepared in advance on the printer controller side. . For example, when each color data included in the color palette table used when the image data is compressed by the computer is RGB, the color palette table color-converted into CMYK is provided on the printer controller side. You may prepare in advance. In this case, the color conversion process in the color palette table calculation unit 166 is unnecessary.

In the above first and second embodiments, the case where the present invention is applied to the printer has been described, but the present invention is not limited to this. As described above, the present invention can be applied to various image output devices such as a facsimile and a monitor as well as a printer.

As an example, a case where the present invention is applied to a display controller will be described. FIG. 20 is a diagram showing a circuit configuration of the display controller 70 to which the present invention is applied.

In FIG. 20, the CPU in the computer
A pixel 80 compresses the multi-valued image data in pixel units into compressed image data composed of a color signal and a color selection signal in the same way as described in each of the above embodiments, and stores the compressed image data in the memory 81.

The memory address generation circuit 75 generates the address of the data to be read from the memory 81 in accordance with the scan address generated by the scan address generation circuit 77 based on the clock output from the oscillator 78. In response to this, the compressed image data is sequentially read from the memory 81.

The compressed image data sequentially read from the memory 81 is input to the image processing circuit 72 via the register 71. When the color signal of the compressed image data is composed of color data of a plurality of colors approximated by the calculation using the color space, the color signal is color-coded with respect to the color signal in the same manner as described in the first embodiment. Make a correction. However, the color conversion process from RGB to YMCK is not performed. Further, when the color signal is composed of the color palette numbers on the color palette table of a plurality of colors, the color correction is performed on the color palette table prepared in advance according to the procedure described in the second embodiment. However, in this case as well, similar to the above, the color conversion processing from RGB to YMCK is not performed. Further, the image processing circuit 72 responds to the color selection signal of the compressed image data by pixels for image rotation, enlargement / reduction, etc. Processing that involves sorting,
Do as needed.

The color signal and the color selection signal output from the image processing circuit 72 are expanded by the expansion circuit 73 into multivalued image data in pixel units in the same manner as described in each of the above embodiments, and then D / It is converted into an analog signal by the A converter. Then, the synchronizing circuit 76 outputs the same to the display 82 together with the synchronizing signal generated based on the scan address generated by the scan address generating circuit 77.

[0156]

As described above, according to the present invention,
The capacity of the memory required for image processing can be reduced, and the bus width for transferring image data can be reduced, so that the circuit scale can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic block diagram illustrating a printer according to a first embodiment of the invention.

FIG. 2 is a diagram for explaining a configuration example of compressed image data when a color in a predetermined image area is approximated to a plurality of colors by calculation considering a color space.

FIG. 3 is a diagram for explaining a color signal generation process of the compressed image data shown in FIG.

FIG. 4 is a configuration block diagram of a printer controller 11 shown in FIG.

5 is a configuration block diagram of a color signal calculation unit 161 shown in FIG.

6 is a schematic block diagram of a color determination unit 163 and a feature point determination unit 164 shown in FIG.

7 is a diagram illustrating a color determination unit 163 and a feature point determination unit 16 illustrated in FIG. 4 in the case where the color signal includes two pieces of color data.
FIG. 4 is a diagram for explaining the flow of processing in No. 4.

FIG. 8 is a diagram showing a more detailed processing flow of the color determination unit 163 shown in FIG.

9 is a diagram illustrating a color determination unit 163 and a feature point determination unit 16 illustrated in FIG. 4 in the case where the color signal includes four pieces of color data.
FIG. 4 is a diagram for explaining the flow of processing in No. 4.

10 is a color difference calculation unit 16 of the color determination unit 163 shown in FIG.
It is a figure for demonstrating the flow of a more detailed process in 3a.

11 is a shade determination unit 16 of the color determination unit 163 shown in FIG.
It is a figure for demonstrating the flow of a more detailed process in 3b.

FIG. 12 is a diagram for explaining another shading determination method in the case where a color signal includes four color data.

13 is a configuration block diagram of a halftone processing unit 17 shown in FIG.

FIG. 14 is a diagram for explaining a modified example of the first embodiment of the present invention shown in FIG.

FIG. 15 is a diagram showing a circuit configuration of a printer controller to which the first embodiment of the invention is applied.

FIG. 16 is a diagram for explaining a configuration example of compressed image data when colors in a predetermined image area are approximated to a plurality of colors using a color palette table.

FIG. 17 is a diagram for explaining a color signal generation process of the compressed image data shown in FIG. 16.

FIG. 18 is a configuration block diagram of a printer controller 11a which is a main part of the second embodiment of the present invention.

FIG. 19 is a block diagram showing the configuration of an expanding section 14a shown in FIG.

FIG. 20 is a diagram showing a circuit configuration of a display controller 70 to which the present invention is applied.

FIG. 21 is a schematic block diagram for explaining a conventional printer.

FIG. 22 is a diagram for explaining the flow of edge determination processing in the conventional image processing apparatus.

FIG. 23 is a diagram showing a memory that stores bitmap image data in a conventional image processing apparatus.

FIG. 24 is a diagram for explaining edge determination processing in the conventional image processing apparatus.

FIG. 25 is a diagram for explaining edge determination processing in the conventional image processing apparatus.

[Explanation of symbols]

1 Printer 2 Computer 11 Printer Controller 12 Printer Engine 13, 18, 21, 23, 50 Image Memory 14, 14a Decompression Unit 16, 16a Image Processing Unit 17 Halftone Processing Unit 22 Compression Unit 51 Color Correction Circuits 52, 54, 55, 55, 57, 81, 142a-14
2e, 144, 161d to 161f Memory 53 Color conversion circuit 56 Gamma correction circuits 58, 73 Expansion circuit 59 Halftone reproduction processing circuit 60 Image rotation circuit 61 Color difference calculation circuit 62 Grayscale determination circuit 63 Grayscale memory 64 Feature point determination circuit 71 Register 72 Image processing circuit 74 A / D conversion circuit 75 Memory address generation circuit 76 Synchronization circuit 77 Scan address generation circuit 76 Oscillator 80 CPU 82 Display 141 Buffer 142 Separation storage unit 161 Color signal calculation unit 161a Color correction unit 161b Color conversion unit 161c Intermediate Length correction unit 162 Color selection signal calculation unit 163 Color determination unit 163a Color difference calculation unit 163b Grayscale determination units 164 and 167 Feature point determination unit 164a Grayscale binary data memory 164b Feature point extraction unit 165 Image processing selection unit 166 Color palette table calculation unit 171 middle Tone processing unit A 172 halftone processing section B 173 halftone processing section C 174 smoothing processing unit 175,143 selector 176 halftone reproduction unit

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tamura et al. 1-1-1 Higashitaga-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Electric Appliance Division (72) Inventor Naoyuki Urata 810 Shimoimazumi, Ebina-shi, Kanagawa Stock Office Company, Hitachi, Ltd. (72) Inventor Tadashi Okada 810 Shimoimaizumi, Ebina, Kanagawa Stock Company, Office Systems Division, Hitachi, Ltd. (56) Reference JP 62-175069 (JP, A) JP 5 -211601 (JP, A) JP-A-2-220562 (JP, A) JP-B 6-7688 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/38- 1/393

Claims (15)

(57) [Claims] 1. An image processing apparatus , comprising a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
An image processing apparatus comprising: a decompressing unit for performing the processing for the color signal and the processing for the color selection signal in parallel. 2. An image processing apparatus , comprising a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
The image processing means has a color selection signal processing means for rotating or enlarging / reducing an image by changing the arrangement of selection information of each pixel included in the color selection signal. An image processing device characterized in that. 3. An image processing device , comprising: a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
If, for each pixel of said predetermined image area, prior Symbol color signals
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
The color signal has color data as the specific information, and the image processing means performs color correction processing on color data included in the color signal. An image processing apparatus comprising means. 4. An image processing apparatus , comprising: a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
The color signal is a color palette number for specifying color data from a color palette table having a plurality of color data as the specifying information, and the image processing means is a color palette table. An image processing apparatus having a color palette table processing means for performing color correction processing on the color data included in. 5. The image processing apparatus according to claim 3 or 4, wherein the color correction processing is color conversion. 6. The image processing apparatus according to claim 3, wherein the color correction processing is gamma correction. 7. An image processing apparatus , comprising: a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
The target pixel and the pixel surrounding the target pixel are checked for color shading based on the pixel-valued multivalued image data expanded by the expanding unit, And a halftone processing unit for outputting the multivalued image data expanded by the expansion unit, which has been subjected to halftone processing according to the judgment result of the feature judging unit. An image processing apparatus characterized by being provided. 8. An image processing device , comprising: a small number of images used to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
Image for compressed image data having a color selection signal
Image processing means for performing processing and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
Decompressing means, and the color signal has color data as the specific information, and the color shading between the target pixel and pixels around the target pixel is included in the color signal. By checking based on the data and the selection information included in the color selection signal,
A characteristic determining unit that determines the characteristic of the target pixel; and a halftone processing unit that outputs the multivalued image data expanded by the expanding unit, which has been subjected to the halftone processing according to the determination result of the characteristic determining unit. An image processing apparatus, further comprising: 9. The image processing apparatus according to claim 7, wherein the halftone reproducing unit performs different halftone processing on the multivalued image data in pixel units expanded by the expanding unit. An image having two halftone processing means and a selector for selecting any one of the at least two halftone processing means according to the determination result of the feature point determination means. Processing equipment. 10. The image processing apparatus according to claim 9, wherein the feature determining unit determines the target pixel as a feature point when the target pixel has a darker color than pixels surrounding the target pixel. The image processing apparatus, wherein the selector switches a halftone processing unit to be selected according to whether or not the target pixel is determined to be a feature point. 11. The image processing apparatus according to claim 10, wherein any one of the at least two halftone processing means is a smoothing processing means, and the selector determines that the target pixel is a feature point. If done,
An image processing apparatus for selecting multi-valued image data for the target pixel which has been smoothed by the smoothing processing means. 12. An image forming unit for forming a printed image, and
An image that outputs a signal for forming a printed image to the image forming unit
A printer including a processing unit , wherein the image processing unit uses a small number of images to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
A memory for storing compressed image data having a color selection signal and
And a compressed image data stored in the storage means
Image processing means for performing image processing, and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
Decompressing means and a mark according to the multivalued image data decompressed by the decompressing means.
Outputs a signal for forming a photographed image to the image forming unit.
The image processing means has a color selection signal processing means for rotating or enlarging / reducing an image by changing the arrangement of selection information of each pixel included in the color selection signal. Printer. 13. An image forming unit for forming a printed image;
An image that outputs a signal for forming a printed image to the image forming unit
A printer including a processing unit , wherein the image processing unit uses a small number of images to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
A memory for storing compressed image data having a color selection signal and
And a compressed image data stored in the storage means
Image processing means for performing image processing, and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
Decompressing means and a mark according to the multivalued image data decompressed by the decompressing means.
Outputs a signal for forming a photographed image to the image forming unit.
Input means, the color signal has color data composed of RGB data as the specific information, and the image processing means converts the color data contained in the color signal from RGB data to YMCK data. A printer having color conversion means for converting. 14. An image forming section for forming a printed image;
An image that outputs a signal for forming a printed image to the image forming unit
A printer including a processing unit , wherein the image processing unit uses a small number of images to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
A memory for storing compressed image data having a color selection signal and
And a compressed image data stored in the storage means
Image processing means for performing image processing, and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
Decompressing means and a mark according to the multivalued image data decompressed by the decompressing means.
Outputs a signal for forming a photographed image to the image forming unit.
The color signal has color data as the specific information, and the image processing means adapts the color data included in the color signal to the characteristics of the image forming unit. A printer having gamma correction means for performing gamma correction. 15. An image forming section for forming a printed image;
An image that outputs a signal for forming a printed image to the image forming unit
A printer including a processing unit , wherein the image processing unit uses a small number of images to represent the predetermined image for each predetermined image area.
Color signal including identification information for identifying at least one color
And for each pixel in the predetermined image area, the color signal
Including selection information for selecting the specific information from among
A memory for storing compressed image data having a color selection signal and
And a compressed image data stored in the storage means
Image processing means for performing image processing, and compressed image data subjected to image processing by the image processing means.
Specified in the color selection signal of the compressed image data.
According to the selection information of each pixel in the image area, each pixel
The compressed image data selected by the selection information.
Color data specified by the specific information included in the color signal
Data to add multi-valued image data in pixel units
Decompressing means and a mark according to the multivalued image data decompressed by the decompressing means.
Outputs a signal for forming a photographed image to the image forming unit.
Inputting means, the color signal has color data as the specific information, and the shade of color between the target pixel and pixels around the target pixel is represented by the color data included in the color signal. And by checking based on the selection information included in the color selection signal,
The output unit further includes a feature determining unit that determines a feature of the target pixel, and the output unit performs a halftone process according to a determination result of the feature determining unit, and the multivalued image data expanded by the expanding unit. A printer for generating a signal for forming a printed image based on the printer.