JP3809764B2 - Color mode determination apparatus and image processing apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color mode determination apparatus that determines a color and a monochrome image used in an image processing apparatus such as a printer.
[0002]
[Prior art]
In an image processing apparatus (image recording apparatus) such as a color printer, various inconveniences may occur if an image that is originally supposed to be monochrome output is erroneously determined to be a color image. For example, in the case where the device charges for colors that are to be charged in black and white, it is necessary to pay for the charges separately. Some apparatuses change the process speed between color and black and white. In such a case, the printing speed of color is generally slower. Therefore, if the apparatus erroneously determines black and white as a color, there is a problem that printing productivity is reduced. Furthermore, some devices change the parts (parts) used for color and black and white. In such a case, if the device mistakenly determines black and white as a color, a component (part) used only during color printing is also used during monochrome printing, leading to a reduction in the life of the component.
[0003]
In view of this, it has been proposed to incorporate a color mode determination device for determining color and monochrome images into an image processing device. Here, the identification of whether or not the original image is a color image is determined by the presence or absence of each color signal component of Y (yellow), M (magenta), and C (cyan), as described in, for example, Japanese Patent Laid-Open No. 10-93829. ,It can be carried out.
[0004]
[Problems to be solved by the invention]
However, in order to determine the presence or absence of these color components, a process for scanning all the pixels of each color component is required. This process can be executed using software or dedicated hardware. However, when using software, there is a problem that a great deal of processing time is required. On the other hand, when dedicated hardware is used, high-speed processing is possible, but there is a problem that costs increase.
[0005]
Accordingly, an object of the present invention is to provide a color mode determination apparatus and an image processing apparatus using the same that can easily reduce the determination time of the color mode.
[0006]
[Means for Solving the Problems]
The object is to provide a compression unit that compresses input image data for each color component, and determines whether the image data is color based on the data compressed for each color component by the compression unit This is achieved by the mode determination device.
[0007]
That is, the color mode determination apparatus of the present invention includes a compression unit that compresses input image data for each color component of Y (yellow), M (magenta), C (cyan), and K (black), and the compression unit. A comparison means for comparing the data of each compressed color component with the compressed data of blank paper prepared in advance in order to determine the presence or absence of the data of each color component compressed in step 1, the result of comparison by the comparison means , YMC determines that the input data is color data when at least one component is not blank.
[0008]
Further, as a result of the comparison by the comparison means, it is possible to determine that the input data is black and white data when all the components of YMC are blank and the K component is not blank.
[0009]
Such a color mode determination apparatus can be used in an image processing apparatus such as a printer, a copier, or a scanner.
[0010]
Furthermore, in the determination device, the compressed data of the blank paper may be held in advance for each paper size or each band size.
[0011]
According to the color mode determination method of the present invention, the input image data is compressed for each color component of Y (yellow), M (magenta), C (cyan), and K (black), and the compression step A comparison step of comparing the data of each compressed color component with the compressed data of blank paper prepared in advance in order to determine the presence or absence of the data of each color component compressed in step 1, the result of comparison by the comparison step , YMC determines that the input data is color data when at least one component is not blank.
[0012]
Further, as a result of the comparison in the comparison step, when all the components of YMC are white paper and the K component is not white paper, it can be determined that the input data is black and white data.
[0013]
In the above determination method, the compressed data of the blank paper may be held in advance for each paper size or each band size.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an example of an image processing apparatus to which a color mode discrimination apparatus according to the present invention is applied. In the figure, a CPU 1 has a central function of various controls of the image processing apparatus, and is connected to various circuit devices through a bus 2 as follows. The host interface circuit 3 is a circuit for interfacing with a host device 4 such as a host computer. For example, the circuit configuration is such that print data input from the host device is received based on the RS-232C standard or the Centronics standard. It has become. Further, the host interface circuit 3 may be connected to a network and supplied with print data from a plurality of devices (workstations or the like) on the network (Ethernet or the like).
[0015]
The RAM 5 is a working memory, and functions as a reception buffer that temporarily holds data necessary for the image processing apparatus to perform various controls and print data input from the host interface circuit 3. The RAM 5 includes a page memory 5a. The ROM 6 is a memory that stores a program for controlling the image processing apparatus. The compression / decompression unit 7 compresses the bitmap information of one page, stores it in, for example, the RAM 5, decompresses it during printing, and outputs it to the recording unit interface circuit 9.
[0016]
The character pattern memory 8 is a so-called font memory, and stores a character pattern when printing out. The recording unit interface circuit 9 converts the data decompressed by the compression / expansion unit 7 into raster data and supplies it to the recording unit 10, and various signals (synchronization pulse, recording unit) with the recording unit 10. The state signal, the operation command signal to the recording unit, etc.) are transmitted / received to function as an interface between each unit in the apparatus and the recording unit 10. The recording unit 10 is constituted by a laser printer, for example.
[0017]
FIG. 2 is a diagram for explaining an embodiment of the color mode discriminating apparatus according to the present invention, and FIG. 3 is a process flow diagram thereof. Hereinafter, the present embodiment will be described with reference to FIG. Note that the processing program used in this embodiment can be stored in, for example, the ROM 6.
[0018]
First, drawing information is input from the host device 4 such as a host computer via the host interface circuit 3 (step 111). Subsequently, a drawing process is performed on this information (step 112), and the inputted drawing information is converted into image data 21 (raster data) for each color component and stored in, for example, the page memory 5a of the RAM 5 (FIG. 2). (1)). At this time, color conversion (RGB → YMCK conversion) and screen (dither) processing are performed as necessary. Then, it is determined whether or not the input of the drawing information has been completed (step 113). If the drawing information has not been completed yet, the process returns to step 111 and the input of the drawing information is continued. On the other hand, when the input of the drawing information is finished, the creation of the image data of four components of K (black), Y (yellow), M (magenta), and C (cyan) is finished (step 114).
[0019]
The four-component one-page image data 21 (raster data) is read from the RAM 5 by, for example, the DMA method ((2) in FIG. 2), and then compressed by the compression / decompression unit 7 in order to reduce the data storage capacity. In the device 22, each component is compressed (step 115). The compressed data 24 is temporarily stored in the memory (RAM 5) ((3) in FIG. 2, step 116). This accumulation operation is performed until the accumulation of all the four component compressed data is completed (step 117).
[0020]
In the present embodiment, this compressed data 24 is compared with the compressed data of blank paper (raster data does not exist) prepared in advance (step 118). Then, the color mode is determined as follows. First, it is determined whether at least one of the YMC components is not blank (step 119). If at least one component is not blank, the page is determined to be color (step 120). Conversely, when all of the YMC components are blank, it is further determined whether or not the K component is blank (step 121). If the K component is blank, this page is determined to be blank (step 122). On the other hand, if the K component is not blank, this page is determined to be a black and white image (step 123).
[0021]
The above-mentioned blank compressed data is, for example, as follows. Now, in the case of a compression technique of an algorithm for converting into compressed data such as “how many 0 or 1 bits continue when the same bit continues,” a blank sheet is “0x00, 0xFF, 0x00, 0xFF,. .., 0x00, 0xFF "compressed data, one page of the compressed data is analyzed, and the compressed data from the beginning to the end is blank from" 00FF ".
[0022]
This type of white paper compression data can be prepared for each paper size or band size, for example. Here, the band size indicates a unit for holding raster data. Normally, raster data is stored in units of pages for each component of YMCK, but the pages may be divided into strips and stored. This one strip is called a band. By performing processing in units of bands (decompression → compression), it is possible to perform processing with a small amount of memory.
[0023]
In this manner, the apparatus notifies the recording unit 10 of the color mode when a certain page is determined to be color, and similarly notifies the recording unit 10 of the determination when it is determined to be blank or black and white.
[0024]
Returning to the description of FIGS. 2 and 3, the compressed data 24 once stored in the RAM 5 is read out from the RAM 5 by DMA processing ((4) in FIG. 2), and then the compression / expansion unit 7. Is expanded in the expansion device 23 (step 124). The expanded image data is output to the recording unit 10 via the recording unit interface circuit 9 ((5) in FIG. 2). In response to the notification of the color mode determination result, the recording unit 10 discharges the image data by color or monochrome processing or blank paper (step 125).
[0025]
FIG. 4 is a diagram for explaining another embodiment of the color mode discriminating apparatus according to the present invention, and FIG. 5 is a process flow diagram thereof. Hereinafter, this embodiment will be described with reference to FIG. Note that the processing program used in this embodiment can be stored in the ROM 6.
[0026]
First, drawing information is input from the host device 4 such as a host computer via the host interface circuit 3 (step 211). Subsequently, a drawing process is performed on this information (step 212), and the inputted drawing information is converted into image data 41 (raster data) for each color component and stored in, for example, the page memory 5a of the RAM 5 (FIG. 4). (1)). At this time, color conversion (RGB → YMCK conversion) and screen (dither) processing are performed as necessary. Then, it is determined whether or not the input of the drawing information has been completed (step 213). If the drawing information has not been completed yet, the process returns to step 211 to continue the input of the drawing information. On the other hand, when the input of the drawing information is finished, the creation of the image data of the four components K, Y, M, and C is finished (step 214).
[0027]
The four-component one-page image data 41 (raster data) is read from the RAM 5 by, for example, the DMA method ((2) in FIG. 4) and then compressed by the compression / expansion unit 7 in order to reduce the data storage capacity. In the device 43, each component is compressed (step 215). In parallel with this compression, the image data is checked for the presence or absence of raster data. In other words, the presence or absence of raster data is detected for each component using the raster data detection device 42 (step 216). FIGS. 6A to 6C are diagrams showing the relationship between raster data detection, compression, and decompression in the conventional and the present invention, respectively. FIG. 4A shows an example in which pages overlap in the conventional method, FIG. 5B shows the method of the present invention, and FIG. This detection result is used in a later step. On the other hand, the compressed data 45 of each component is temporarily stored in the memory (RAM 5) ((3) in FIG. 4, step 217). This accumulation operation is performed until the accumulation of all the four component compressed data is completed (step 218).
[0028]
In this embodiment, the color mode is determined as follows using the above-described detection result relating to the raster data of each component (step 219). First, it is determined whether there is data in at least one of the YMC components (step 220). If there is data for at least one component, this page is determined to be color (step 221). Conversely, when there is no data in all of the YMC components, it is further determined whether there is no data in the K component (step 222). If there is no data in the K component, this page is determined to be blank (step 223). On the other hand, when there is data in the K component, this page is determined to be a black and white image (step 224).
[0029]
In this manner, the apparatus notifies the recording unit 10 of the color mode when a certain page is determined to be color, and similarly notifies the recording unit 10 of the determination when it is determined to be blank or black and white.
[0030]
Returning to the description of FIGS. 4 and 5, the compressed data 45 once stored in the RAM 5 is read from the RAM 5 by, for example, the DMA method ((4) in FIG. 4), and then decompressed by the compression / decompression unit 7. The device 44 is decompressed (step 225). The expanded image data is output to the recording unit 10 via the recording unit interface circuit 9 ((5) in FIG. 4). In response to the notification of the color mode determination result described above, the recording unit 10 discharges the image data by color or monochrome processing or blank paper (step 226).
[0031]
As described above, in the present invention, since the color mode is determined using the compressed data, the amount of inspection data for determination is greatly reduced, and the determination time of the color mode can be significantly shortened. As a result, there is no need for dedicated hardware for high-speed processing as in the prior art, and the product cost can be reduced. Further, by performing the raster data detection and the compression process in parallel, the processing time can be similarly reduced.
[0032]
【The invention's effect】
According to the present invention, it is possible to obtain a color mode determination apparatus and an image processing apparatus using the same that can easily reduce the determination time of the color mode.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of an image processing apparatus to which a color mode discrimination apparatus according to the present invention is applied.
FIG. 2 is a diagram for explaining an embodiment of a color mode discrimination device according to the present invention.
FIG. 3 is a process flow diagram of the embodiment of FIG. 2;
FIG. 4 is a diagram for explaining another embodiment of the color mode discriminating apparatus according to the present invention.
FIG. 5 is a processing flow diagram of the embodiment of FIG. 4;
FIGS. 6A to 6C are diagrams showing the relationship between raster data detection, compression, and decompression in the prior art and the present invention, respectively.
[Explanation of symbols]
1 CPU
2 Bus 3 Host interface circuit 4 Host device such as host computer 5 RAM
6 ROM
7 Compression / Expansion Unit 8 Character Pattern Memory 9 Recording Unit Interface Circuit 10 Recording Unit 21 Image Data 22 Compression Device 23 Expansion Device 24 Compression Data

Claims (7)

  Compression means for compressing the input image data for each color component of Y (yellow), M (magenta), C (cyan), and K (black), and presence / absence of data of each color component compressed by the compression means A comparison means for comparing the compressed data of each color component with the compressed data of blank paper prepared in advance for determination, and as a result of comparison by the comparison means, at least one component of YMC is not blank paper And determining that the input data is color data.   2. The color mode determination according to claim 1, wherein, as a result of the comparison by the comparison means, if all the components of YMC are blank and the K component is not blank, it is determined that the input data is monochrome data. apparatus. The blank of the compressed data, the color mode determination apparatus according to claim 1 or 2, wherein the stored in advance for each sheet size or each band size.   An image processing apparatus comprising the color mode determination apparatus according to claim 1.   A compression process for compressing the input image data for each color component of Y (yellow), M (magenta), C (cyan), and K (black), and the presence / absence of data of each color component compressed in the compression process A comparison step of comparing the compressed data of each color component with the compressed data of blank paper prepared in advance for determination, and as a result of comparison by the comparison step, at least one component of YMC is not blank paper And determining that the input data is color data.   6. The color mode determination according to claim 5, wherein when all the components of YMC are blank and the K component is not blank as a result of the comparison in the comparison step, it is determined that the input data is monochrome data. Method.   The color mode determination method according to claim 5 or 6, wherein the compressed data of the blank paper is stored in advance for each paper size or each band size.

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