JP2004088265A - Method for compressing data, image processing apparatus, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To convert data into compression data at a high compression rate which can accurately reproduce multi-value data, for example, multi-value image data in a high compressibility. <P>SOLUTION: The method for compressing data includes the steps of retrieving a series of data transition of a known pattern of a plurality of series of data of a plurality-bit constitution which can display multi-values, and converting the data into compression data including its pattern identity and its starting point data. One of the known data is a pattern B type of a specific distribution of a differential value between adjacent data. Another one is a pattern C type in which the number of data is a known number b and a differential value is a constant a. Another one is a constant differential value, and is converted into compression data including its end point, pattern identity, start point and the differential value. As another one, adjacent data are the same, and is converted into compression data A type including its end point, pattern identity and start data. As the other one, the differential value is changed, and is converted into compression data E type including its pattern identity, start data and respective differential values. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data compression technique, and more particularly, but not exclusively, to image data compression for compressing image data representing a document image. This technique can be used to reduce the amount of data in the transfer and accumulation (storage) of image data. For example, it is used for compression of image data of a document scanner, a digital camera, and CG (Computer Graphics).
[0002]
[Prior art]
Multi-tone (multi-valued) image data has a plurality of bits, such as data representing the luminance or density of one pixel, that is, an image data having an 8-bit configuration capable of expressing 256 tones. The amount of image data representing an image of a document or a single photo is enormous. Accordingly, various data compression methods have been proposed.
[0003]
For example, Japanese Patent Application Laid-Open No. 8-336163 discloses encoding for compressing RGB color image data in units of blocks, and Japanese Patent Application Laid-Open No. 10-191338 discloses a method in which discrete cosine transform is performed on image data to obtain coefficient data. Discloses a DCT compression method in which coefficients are analyzed based on coefficient data, image data is thinned out based on the coefficient analysis data, and the thinned image data and coefficient analysis data are used as compression data. Japanese Patent Application Laid-Open No. 2002-163658 discloses a technique for determining whether an image represented by image data is a natural image or a population image, compressing the image data using JPEG for the natural image area and run-length encoding for the artificial image area. It discloses data compression corresponding to characteristics.
[0004]
By the way, run-length coding is a method in which binary image data such as black and white is converted into a run (number of pixels) in which the same value is continuous, that is, data representing a run from a preceding change point to the next change point of the image data. Since the image data is changed, the binary image data can be compressed at a high compression rate, and the original image can be accurately reproduced. However, in the case of multi-valued image data, the probability of successive image data representing the same value is much smaller than in the case of binary image data, so that the compression ratio is significantly reduced. The run-length encoding disclosed in JP-A-2002-163658 focuses on the point that the number of colors in an artificial image is small and the color switching is sharp, and the colors (characteristic values) represented by the color image data are the same. The color image data of the run is converted into its color and run. That is, run-length encoding is limited to the artificial image area.
[0005]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is a first object of the present invention to convert multi-valued data into compressed data that can be accurately reproduced at a high compression ratio, and for multi-valued image data, black and white multi-valued image data and color component multi-valued image data The second object of the present invention is to convert at high compression ratio into compressed data that can be accurately reproduced.
[0006]
[Means for Solving the Problems]
(1) Search for a series of data transitions of a known pattern in a plurality of series of data having a plurality of bits that can represent multi-values, and if there is, search for it, including its pattern ID and its start point data. A data compression method that converts data to compressed data.
[0007]
In addition, in order to facilitate understanding, parentheses are added, and in them, reference numerals or corresponding elements of the corresponding elements or corresponding items of the embodiment shown in the drawings and described later are shown for reference as examples.
[0008]
Since the start point data is one component of the compressed data, the known pattern is, for example, a type No. shown in FIG. 3 (C type) and the type No. shown in FIG. 5 (B type), the data values of a series of data transitions are not defined, and a difference value distribution that defines a difference value and a run (the number of pixels) can be obtained.
[0009]
In this case, for example, the type No. shown in FIG. The pattern No. 3 (C type) is a pattern in which image data changes with the same difference value over seven pixels, and the pattern No. If there is the difference value (first data) and the run (second data representing seven pixels) in the data defining the number 3, the difference data between the adjacent pixels of the image data continuous on the line is obtained at the time of compression. The first image data of the location where the difference value represented by the first data is continuous in the run (the number of pixels) represented by the second data is set as the starting point data, and the type No. The pattern ID representing 3 is the compressed data of the location. In the decompression, the starting point data is used as the image data of the first pixel (starting point pixel) of the corresponding location, and the difference value represented by the first data defining the pattern of the pattern ID (type No. 3) is expressed by the first pixel (adjacent preceding pixel). ) Is used as the image data of the second pixel (adjacent succeeding pixel) at the corresponding location, and the same image data calculation and assignment to pixels are defined by a pattern of pattern ID (type No. 3). By repeating until the number of runs (7) represented by the second data to be performed, a series of image data before compression is reproduced as it is in decompression.
[0010]
In addition, for example, the type No. shown in FIG. The pattern 5 (B-type) is a pattern in which the transition of image data is represented by six indefinite difference values between a series of eight pixels (eight runs). If there are values 1 to 6, at the time of compression, the difference data between adjacent pixels of the image data continuous on the line is calculated, and the six difference values 1 to 6 are distributed in that order. The image data of the type No. The pattern ID representing 5 is set as the compressed data of the location. In the decompression, the start point data is set as the image data of the first pixel at the corresponding location, and the first difference value 1 of the six difference values 1 to 6 defining the pattern of the pattern ID (type No. 5) is set to the first difference value. The value added to the image data of the pixel (adjacent preceding pixel) is used as the image data of the second pixel (adjacent succeeding pixel) at the corresponding location, and the second difference value 2 is used as the image of the second pixel (adjacent preceding pixel). By making the value added to the data the image data of the third pixel (adjacent succeeding pixel) at the corresponding location and repeating the same image data calculation and assignment to the pixels up to the last sixth difference, A series of image data before compression is reproduced as it is.
[0011]
As described above, the image data before compression can be accurately reproduced. In addition, the transferred data from compression to decompression, that is, the compressed data represents the pattern ID and the starting point data, and a high compression rate can be obtained.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
(1a) One of a series of data transitions of a known pattern is a pattern (B type) in which a distribution in a series direction of a difference value between adjacent data of the series of data becomes a specific pattern (B type). 2. The data compression method according to 1.
[0013]
This corresponds to the type No. shown in FIG. This is an example in which pattern 5 (B type) is described, and as described above, image data before compression can be accurately reproduced, and a high compression ratio can be obtained.
[0014]
(1b) One of a series of data transitions of a known pattern is a pattern (C type) in which the number of the series of data is a predetermined number (b) and the difference value between adjacent data is the same (a). The data compression method according to (1) or (1a).
[0015]
This is the same as the type (1) shown in FIG. This is an example in which pattern 3 (C-type) is described, and as described above, image data before compression can be accurately reproduced, and a high compression rate can be obtained.
[0016]
(2) One of the series of data transitions of the known pattern is a series of data transitions in which the difference value between adjacent data is constant, and if there is, it is determined by the end point (end point X coordinate) of the series and the pattern. The data compression method according to any one of (1) to (1b), wherein the data is converted into compressed data (D type) including an ID, start point data, and the predetermined difference value.
[0017]
Since not only the start point data but also the end point (end point X coordinate) and a certain difference value are used as components of the compressed data, the known pattern is, for example, a type No. shown in FIG. Like 2 (D-type), each data value of a series of data transitions is not specified, and the value is a linear gradation defined by the same difference value (constant gradient) and end point (run: number of pixels). In the case of compression, the difference data between adjacent pixels of the image data continuous on the line is calculated, and the value is the end point at the tail end pixel position where the same difference value (gradient is constant) continues regardless. (Run from top: number of pixels), type No. The pattern ID, the starting point data (the leading image data), and the same difference value (one difference value) representing 2 are used as the compressed data of the location. In the expansion, the starting point data is used as the image data of the first pixel (starting point pixel) of the corresponding location, and the difference value is added to the image data of the first pixel (adjacent preceding pixel). By repeating the same image data calculation and pixel assignment to the end point (run: number of pixels) as the image data of the (row pixel), a series of image data before compression is reproduced as it is in decompression.
[0018]
This compression-encodes linear gradients with various gradients (difference values) and various lengths (runs: the number of pixels). Since gradients (difference values) and lengths (runs) are not specified, Type No. that specifies Versatility is higher than that of Type No. 3 (C type). 3 (C type) is slightly compressed.
[0019]
(3) One of the series of data transitions of the known pattern is that the adjacent data has the same data transition, and if there is, it includes the end point (end point X coordinate), pattern ID, and start point data of the series. The data compression method according to any one of (1) and (2), wherein the data is converted into compressed data (A type).
[0020]
The fact that the image data is the same between adjacent pixels means that the difference value is 0. In this mode, the difference value in the above-described mode (2) is set to 0, and is excluded from the components of the compressed data. This is run-length encoding of multi-valued image data. In a text region or a photograph region on an image, a run in which image data of the same value continues is short and the data compression effect is low, but in a blank region where there is no character or photograph, image data of the same value such as all white continues long. Therefore, the data compression ratio is remarkably high.
[0021]
(4) One of a series of data transitions of a known pattern is a series of data transitions in which a difference value between adjacent data fluctuates. If there is, the pattern transition is performed by using the pattern ID, the starting point data, and each difference value. The data compression method according to any one of (1) to (3), wherein the data is converted into compressed data (E type).
[0022]
This is a pattern for compression-encoding a portion that does not correspond to any of the above (2) to (3), and is a transition of image data that does not match the pattern of the above (2) to (3). At the time of compression, the type ID, the first image data (start point data) immediately before any of the above patterns (2) to (3), and each difference value between adjacent pixels up to the end pixel. Let 1 to n be compressed data. When decompressing, the starting point data is given to the first pixel at the beginning, the value obtained by adding the first difference value 1 to the first pixel is used as the image data of the second pixel, and the value obtained by adding the second difference value 2 to this image data is used as the third data. It is assumed that the image data is pixel data. Similarly, the value obtained by adding the last difference value n is used as the image data of the last pixel. This type of data compression has a relatively low compression ratio, but accurately compresses image data in a random area with a small change in density.
[0023]
When all the patterns (2) to (4) are used, all of a series of multi-valued data can be converted into compressed data.
[0024]
(4a) In a plurality of runs of data of a plurality of bits that can represent multi-values, adjacent data searches for the same data transition, and if there is, it is identified as the end point of the run (end point X coordinate). ), The data is converted into data (A type) representing the pattern ID and the starting point data, and if there is no data, the difference value between the adjacent data is extracted, and the pattern ID, the starting point data and the data representing each difference value are represented. Data compression method for conversion to (E type) (14 to 16 in FIG. 9).
[0025]
This is done by first searching for the pattern of the run length coding (A type) of the above (3), and if so, performing the run length coding (A type); This is a mode in which compression encoding is performed using a pattern (E type), and is suitable for compressing image data in a blank area other than a character area or a photograph area.
[0026]
(4b) Search for a series of data transitions of a known pattern in a plurality of series of data of a plurality of bits that can represent multi-values, and if there is, search them for data representing the pattern ID and start point data. Conversion (C type), if there is no such data, adjacent data searches for the same data transition, and if there is, it is converted to data representing the end point (end point X coordinate), pattern ID, and start point data of the series (end point X coordinate). A type), and when there is no such data, a series of data transitions in which the difference value between adjacent data is constant is searched, and if there is, it is determined as the end point of the series (end point X coordinate), pattern ID, The data is converted into start point data and data (D type) representing the constant difference value. If there is no data, a difference value between adjacent data is extracted, and a pattern ID, start point data, and the like representing the difference value are extracted. Data compression method for converting each time data representing the difference values (E-type) (22 18 to 10 in FIG. 9).
[0027]
That is, the pattern search for the series of image data is performed by the above-mentioned (1b) pattern (C type) / (3) pattern (A type) / (2) pattern (D type) / (4) In this mode, only patterns (E-type) are searched in this order, and the pattern (1b) (C-type) / (3) (A-type) / (2) has a high compression ratio in the character area. Since the frequency of appearance of the pattern (D type) is high, it is suitable for high-speed compression processing of image data in a character area.
[0028]
(4c) A search is made for a series of data transitions of a known pattern in a plurality of series of data of a plurality of bits that can represent multi-values, and if there is, it is converted into data representing the pattern ID and start point data. Conversion (B, C type), when there is no data, a series of data transitions in which the difference value between adjacent data is constant is searched, and if there is, it is converted to the end point of the series (end point X coordinate), pattern ID, start point data and data (D type) representing the constant difference value. When there is no data, adjacent data searches for the same data transition. The data is converted into data (A type) representing the end point X coordinate), the pattern ID and the start point data. If there is no data, a difference value between adjacent data is extracted, and the pattern ID and the start point data representing this are extracted. And data compression method of converting the data (E type) representing the difference values (24-28 in FIG. 10).
[0029]
That is, a pattern search for a series of image data is performed by using all the patterns (1b) to (4) and the specific pattern (B, C type) / (2) in (1a) and (1b). (D type) / pattern (A type) of the above (3) / pattern (E type) of the above (4). In the halftone dot photographic area, the above (1a), (1 Since the appearance frequency of the specific pattern (B, C type) 1b) / the pattern (D type) of the above (2) is high, it is suitable for high-speed compression processing of image data in a photographic area.
[0030]
(4d) The image data compression method according to any one of (1) to (4c), wherein the data is image data.
[0031]
(5) The feature of each part of the two-dimensional distribution image represented by the multi-valued image data of a plurality of lines is detected to generate region information for each feature, and a series of image data on each line is a series of predetermined lengths. Out of a plurality of known patterns representing the data transition of the image data, whether or not the pattern corresponds to the pattern addressed to the image feature, and convert the corresponding portion into compressed data (B, C type) including the pattern ID and the starting point data. The non-applicable location is searched for any of the transition patterns that take a data transition range of indefinite length, and the compressed data (A, D, E type) including the pattern ID and the start point data and the pattern end point or the difference value is searched. The image data compression method to be converted.
[0032]
In the compression processing of the multi-valued image data, the functions and effects described in the above (1) to (4) are similarly obtained.
[0033]
(5a) Data is image data; an image data compression method in which the data compression method of (4a) is applied to a blank area where there is substantially no image.
[0034]
(5b) Data is image data; an image data compression method in which the data compression method of (4b) is applied to a character area.
[0035]
(5c) Data is image data; an image data compression method in which the data compression method of (4c) is applied to a photograph area.
[0036]
(5d) The data is image data; the data compression method of (4a) is used in a blank area where there is substantially no image, the data compression method of (4b) is used in a character area, and the data of (4c) is used in a photographic area. An image data compression method that applies a compression method.
[0037]
(5e) Character area information is generated by determining whether the image data is of a character area based on the image data, and is included in the determined character area in a plurality of known patterns, each of which represents a series of data transitions. Those that appear frequently are determined as application patterns, and the corresponding parts are converted into compressed data (C type) including the pattern ID and the starting point data.
If the adjacent data has the same data transition, the data is converted into data (A type) representing the end point (end point X coordinate), pattern ID and start point data of the series,
If the difference value between adjacent data is a constant series of data transitions, it is converted into an end point (end point X coordinate), pattern ID, start point data and data (D type) representing the constant difference value of the series,
Otherwise, the difference value between the adjacent data is extracted and converted into a pattern ID representing the difference value, start point data, and data (E type) representing each difference value.
Image data compression method (2 in FIG. 8, 18 in FIG. 9 to 22 in FIG. 10).
[0038]
(5f) Determine whether or not the image data belongs to the photographic area based on the image data to generate photographic area information, and determine the photographic area in a plurality of known patterns each representing a series of data transitions. The one that appears frequently is determined as an application pattern, and the corresponding part is converted into compressed data (B, C type) including the pattern ID and the starting point data.
If the difference value between adjacent data is a constant series of data transitions, it is converted into an end point (end point X coordinate), pattern ID, start point data and data (D type) representing the constant difference value of the series,
If the adjacent data has the same data transition, the data is converted into data (A type) representing the end point (end point X coordinate), pattern ID and start point data of the series,
Otherwise, the difference value between the adjacent data is extracted and converted into a pattern ID representing the difference value, start point data, and data (E type) representing each difference value.
Image data compression method (5 to 9 in FIG. 8, 24 to 28 in FIG. 10).
[0039]
(5g) Determine whether the image data is of a character area or a photographic area based on the image data to generate area information, and determine the determined character in a plurality of known patterns each representing a series of data transitions A pattern having a large number of appearances in the region is defined as a character region application pattern, and a pattern having a large number of appearances in the determined photograph region is defined as a photograph region application pattern;
In an area (blank area) that is neither a character area nor a photograph area, if adjacent data has the same data transition, data representing the end point (end point X coordinate), pattern ID, and start point data of the series (A type) , And if none of the above, the difference value between the adjacent data is extracted and converted into a pattern ID representing the difference value, start point data, and data (E type) representing each difference value;
In the character area, the part corresponding to the character area application pattern is converted into compressed data (C type) including the pattern ID and the starting point data.
If the adjacent data has the same data transition, the data is converted into data (A type) representing the end point (end point X coordinate), pattern ID and start point data of the series,
If the difference value between adjacent data is a constant series of data transitions, it is converted into an end point (end point X coordinate), pattern ID, start point data and data (D type) representing the constant difference value of the series,
Otherwise, the difference value between the adjacent data is extracted and converted into a pattern ID representing the difference value, start point data, and data (E type) representing each difference value;
In the photo area, the portion corresponding to the photo region application pattern is converted into compressed data (B, C type) including the pattern ID and the starting point data.
If the difference value between adjacent data is a constant series of data transitions, it is converted into an end point (end point X coordinate), pattern ID, start point data and data (D type) representing the constant difference value of the series,
If the adjacent data has the same data transition, the data is converted into data (A type) representing the end point (end point X coordinate), pattern ID and start point data of the series,
Otherwise, the difference value between the adjacent data is extracted and converted into a pattern ID representing the difference value, start point data, and data (E type) representing each difference value;
Image data compression method (PAD in FIG. 8, 14 to 1028 in FIG. 9).
[0040]
(6) A series of data transitions of a known pattern in a series of image data of a plurality of bits that can represent multi-values on the same line is searched, and if there is, it is identified by its pattern ID and its starting point. An image processing device having data compression means (166) for converting the data into compressed data including data;
[0041]
This is an image processing apparatus for compressing multi-valued image data by the data compression method of (1), and can obtain the operation and effect described in (1).
[0042]
(7) An imaging device (10) that photoelectrically converts an image or a scene of a document or a scene to generate multi-valued image data representing the image or scene; and the data compression of (6) above that compresses the multi-valued image data Means (166);
[0043]
For example, the image processing apparatus includes an image pickup device (10) such as a document scanner or a digital camera, and compresses multi-valued image data generated by the image pickup device by the data compression method described in (1) above. The effect can be obtained.
[0044]
(8) The above (6) or (7), further comprising a memory means (MEM) for storing the compressed data of the data compression means (166); and a means for transferring the compressed data (CDIC, IMAC). Image processing device.
[0045]
According to this, it is possible to read and write the data compressed by the data compression method (1) with respect to the memory means (MEM), and it is possible to read and write the image data with high memory use efficiency and high reading and writing speed. High data transfer efficiency from the data compression means to the memory means.
[0046]
(9) Further, data decompression means (163) for decompressing the compressed data into image data; image data processing means (IPP) for converting image data into image data for printout; The image processing apparatus according to (8), further comprising: an image forming unit (100) for forming an image to be represented on a sheet.
[0047]
The image data can be directly converted or the compressed data can be restored to multi-valued image data, converted into image data for printout, and printed out by the image forming means (100). In a mode in which the compressed data is read from the memory means and provided to the data decompression means to decompress the multi-valued image data, the data transfer efficiency from the memory means to the data decompression means is high.
[0048]
(10) When continuous information is expressed in one dimension, replaced with numerical values, and processed, stored, or transferred, the starting point data of interest is matched with the degree of change from the starting point data of the preceding and following data. A print processing apparatus that compresses data by treating it as one information unit.
[0049]
By treating the focused data itself and the change of the data before and after as one information unit, the information can be easily handled, and the amount of data can be reduced because the difference information is used.
[0050]
(11) A print processing apparatus according to (1), wherein the ratio of the information amount (bytes or bits) used by the data and the change amount in the information unit can be arbitrarily changed.
[0051]
Since the ratio of the information amount (bytes or bits) used by the data and the change amount can be arbitrarily changed, the data after compression can be configured according to the original data, and there is a useless area in the information unit. There is no need.
[0052]
(12) A print processing apparatus capable of arbitrarily selecting the number of continuous original data that can be represented by one information unit in (11).
[0053]
Since the number of continuous original data can be arbitrarily selected, the same pattern can be combined into one information unit after compression.
[0054]
(13) In the above (12), one information unit is constituted by the value of the data itself and a numerical value indicating a certain characteristic change pattern, not the amount of change of data following or preceding or succeeding it. Print processing device.
[0055]
By registering a pattern of a characteristic change itself such that the same value continues to some extent or decreases in the same manner and manages the pattern by a corresponding number, the compression effect can be further enhanced.
[0056]
(14) A print processing apparatus according to (13), wherein a change pattern is selected from frequently used patterns in accordance with original data to be used.
[0057]
By selecting frequently occurring patterns according to the original data to be processed and registering them separately from the claim 4, the patterns can be handled by classifying each image of the same type, thereby preventing an increase in the number of patterns. In addition, data can be efficiently compressed.
[0058]
(15) The compression side and the decompression (decompression) side each hold a combination of a plurality of patterns for the characteristic patterns used in the above (13) or (14), and target data with a minimum information unit length. A print processing apparatus capable of covering a pattern having a high frequency.
[0059]
By using the pattern in synchronization with the compression side and the decompression side according to the original data to be processed, it is possible to perform the decompression processing at high speed without taking time for pattern search.
[0060]
(16) Of the above methods (12), (13) and (15), a method is selected by which the most efficient compression and transfer of data to be compressed can be performed even in the same continuous information. A print processing apparatus characterized by the above-mentioned.
[0061]
A high compression effect can be achieved by selecting the most efficient format among compression by difference, continuous same difference, registered pattern, and non-compression.
[0062]
(17) The method according to (12) above, which is located between the compression device and the decompression (decompression) device in (16) above and takes into account the compressed data decompression speed and the data transfer speed of the decompression device. Is a print processing apparatus that converts the compression method in the middle if transfer and expansion can be expected at a higher speed.
[0063]
If it is expected that it will take longer than the transfer time to improve due to compression at the time of compression / decompression, expand the compression at a part that can be decompressed at high speed to prevent the overall speed reduction. Prevention efficiency can be maintained.
[0064]
(18) In the above (17), when the efficiency up to transfer and printing is improved by not performing compression, the subsequent processing is performed in an uncompressed state for the entire continuous information or in units of compressed information. Print processing device.
[0065]
If it is expected that it will take longer than the transfer time to improve due to compression at the time of compression / decompression, expand the compression at a part that can be decompressed at high speed to prevent the overall speed reduction. Prevention efficiency can be maintained.
[0066]
Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
[0067]
【Example】
FIG. 1 shows the appearance of a multifunction full-color digital copying machine according to an embodiment of the present invention. The full-color copying machine generally includes units of an automatic document feeder (ADF) 30, an operation board 20, a color scanner 10, and a color printer 100. A finisher 34 with a tray capable of stacking staplers and formed images, a double-sided drive unit 33, an additional paper supply bank 35, and a large-capacity paper supply tray 36 are mounted on the printer 100. Peripheral units that can be separated from the printer 100, each having a control board having a power device driver, a sensor input, and a controller, and being directly connected to (the process controller 131 of FIG. 4) the control board of the printer 100 that is the main body of the image forming apparatus Alternatively, communication is performed indirectly and the paper is fed and conveyed under the timing control. The operation board 20 and the color scanner 10 with the ADF 30 are also units that can be separated from the printer 100, and the color scanner 10 also has a control board having a power device driver, a sensor input, and a controller. The document is read directly or indirectly and the timing is controlled to read the document image.
[0068]
A LAN (Local Area Network) to which a personal computer PC is connected is connected to the in-machine image data processing device ACP (FIG. 4), and a telephone line PN (facsimile communication line) is connected to the facsimile control unit FCU (FIG. 4). Is connected to the exchange PBX. The printed paper of the color printer 100 is discharged onto the paper discharge tray 108 or the finisher 34.
[0069]
FIG. 2 shows a mechanism of the color printer 100. The color printer 100 of this embodiment is a laser printer. In the laser printer 100, four sets of toner image forming units for forming images of each color of magenta (M), cyan (C), yellow (Y), and black (black: K) are arranged in a moving direction of the transfer paper. (From the lower right in the figure to the upper left y), they are arranged in this order. That is, it is a four-drum type full-color image forming apparatus.
[0070]
These magenta (M), cyan (C), yellow (Y), and black (K) toner image forming units include photoconductor units 110M, 110C, 110Y having photoconductor drums 111M, 111C, 111Y, and 111K, respectively. 110K and developing units 120M, 120C, 120Y and 120K. The arrangement of the toner image forming units is such that the rotation axes of the photosensitive drums 111M, 111C, 111Y and 111K in each photosensitive unit are parallel to the horizontal x-axis (main scanning direction), and the transfer paper It is set so as to be arranged at a predetermined pitch in the moving direction y (sub-scanning direction).
[0071]
In addition to the toner image forming unit, the laser printer 100 carries an optical writing unit 102 by laser scanning, paper feed cassettes 103 and 104, a pair of registration rollers 105, and a transfer paper. The image forming apparatus includes a transfer belt unit 106 having a transfer conveyance belt 160 that conveys the paper so as to pass through the transfer position, a fixing unit 107 of a belt fixing type, a paper discharge tray 108, a double-sided drive (surface inversion) unit 33, and the like. The laser printer 100 also includes a manual tray, a toner supply container, a waste toner bottle, and the like (not shown).
[0072]
The optical writing unit 102 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and scatters a laser beam in the x direction on the surface of each of the photosensitive drums 111M, 111C, 111Y, and 111K based on image data. Irradiate while scanning. A dashed line in FIG. 2 indicates a transfer path of the transfer paper. The transfer paper fed from the paper feed cassettes 103 and 104 is conveyed by conveyance rollers while being guided by a conveyance guide (not shown), and is sent to the registration roller pair 105. The transfer paper sent to the transfer / conveyance belt 160 at a predetermined timing by the registration roller pair 105 is carried by the transfer / conveyance belt 160 and conveyed so as to pass through the transfer position of each toner image forming unit.
[0073]
The toner images formed on the photosensitive drums 111M, 111C, 111Y, and 111K of the respective toner image forming units are transferred to transfer paper carried and conveyed by the transfer / conveyance belt 160, and a superimposition of color toner images, that is, a color image is formed. The formed transfer paper is sent to the fixing unit 107. That is, the transfer is a direct transfer system in which a toner image is directly transferred onto a transfer sheet. When passing through the fixing unit 107, the toner image is fixed on the transfer paper. The transfer paper on which the toner image has been fixed is discharged or fed to the discharge tray 108, the finisher 36, or the double-sided drive unit 33.
[0074]
The outline of the yellow Y toner image forming unit will be described below. Other toner image forming units have the same configuration as that of yellow Y. The yellow Y toner image forming unit includes the photoconductor unit 110Y and the developing unit 120Y as described above. The photoconductor unit 110Y includes, in addition to the photoconductor drum 111Y, a brush roller that applies a lubricant to the surface of the photoconductor drum, a swingable blade that cleans the surface of the photoconductor drum, and a static elimination lamp that irradiates light to the surface of the photoconductor drum. And a non-contact type charging roller for uniformly charging the surface of the photosensitive drum.
[0075]
In the photoconductor unit 110Y, a laser beam modulated based on print data and deflected by a polygon mirror on the surface of the photoconductor drum 111Y uniformly charged by a charging roller to which an AC voltage is applied by an optical writing unit 102. When L is irradiated while being scanned, an electrostatic latent image is formed on the surface of the photosensitive drum 111Y. The electrostatic latent image on the photoconductor drum 11IY is developed by the developing unit 20Y to be a yellow Y toner image. At the transfer position where the transfer paper on the transfer conveyance belt 160 passes, the toner image on the photosensitive drum 11IY is transferred to the transfer paper. After the toner image is transferred, the surface of the photoreceptor drum 111Y is coated with a predetermined amount of lubricant by a brush roller, is cleaned by a blade, and is discharged by light emitted from a discharge lamp. It is provided for the formation of an electrostatic latent image.
[0076]
The developing unit 120Y contains a two-component developer containing a magnetic carrier and a negatively charged toner. The developing case 120Y includes a developing roller disposed so as to be partially exposed from the opening on the photosensitive drum side, a conveying screw, a doctor blade, a toner density sensor, a powder pump, and the like. The developer contained in the developing case is frictionally charged by being agitated and transported by the transport screw. Then, a part of the developer is carried on the surface of the developing roller. The doctor blade uniformly regulates the layer thickness of the developer on the surface of the developing roller, and the toner in the developer on the surface of the developing roller is transferred to the photosensitive drum, thereby forming a toner image corresponding to the electrostatic latent image on the photosensitive drum. Appears on drum 111Y. The toner density of the developer in the developing case is detected by a toner density sensor. When the density is insufficient, the powder pump is driven to supply toner.
[0077]
The transfer conveyance belt 160 of the transfer belt unit 106 is connected to four grounded stretching rollers so as to pass through respective transfer positions in contact with and facing the photosensitive drums 111M, 111C, 111Y and 111K of each toner image forming unit. It is hung around. One of the stretching rollers is 109. Of these tension rollers, an electrostatic attraction roller to which a predetermined voltage is applied is disposed so as to face an entrance roller on the upstream side in the transfer sheet moving direction indicated by a two-dot chain line arrow. The transfer paper that has passed between these two rollers is electrostatically attracted onto the transfer / conveying belt 160. The exit roller on the downstream side in the transfer paper moving direction is a drive roller that frictionally drives the transfer conveyance belt, and is connected to a drive source (not shown). In addition, a bias roller to which a predetermined cleaning voltage is applied from a power supply is arranged so as to come into contact with the outer peripheral surface of the transfer conveyance belt 160. The bias roller removes foreign matters such as toner adhered to the transfer / conveying belt 160.
[0078]
Further, a transfer bias applying member is provided so as to be in contact with the back surface of the transfer conveyance belt 160 forming a contact opposing portion that opposes the photoconductor drums 111M, 111C, 111Y and 111K. These transfer bias applying members are fixed brushes made of Mylar, and a transfer bias is applied from each transfer bias power supply. By the transfer bias applied by the transfer bias applying member, transfer charges are applied to the transfer / conveyance belt 160, and a transfer electric field having a predetermined intensity is formed between the transfer / conveyance belt 160 and the surface of the photosensitive drum at each transfer position. .
[0079]
The sheet on which the toner images of the respective colors formed on the photosensitive drums 111M, 111C, 111Y, and 111K are transferred by the transfer and transfer belt 160 is sent to the fixing device 107, where the toner image is heated and pressed to form a sheet. Is heat-fixed. After the heat fixing, the sheet is sent to the finisher 34 from a discharge port 34ot to the finisher 34 on the upper portion of the left side plate. Alternatively, the paper is discharged to a paper discharge tray 108 on the upper surface of the printer body.
[0080]
Of the four photosensitive drums, the photosensitive drums 111M, 111C, and 111Y for forming a magenta image, a cyan image, and a yellow image are one electric motor (color drum motor; color drum motor) for driving a color drum (not shown). M: not shown), and is driven at a one-step speed reduction via a power transmission system and a speed reducer (not shown). The photosensitive drum 111K for forming a black image is driven by a single electric motor (K drum motor: not shown) for driving the black drum at a one-step speed reduction via a power transmission system and a speed reducer (not shown). You. The transfer conveyance belt 160 is rotated by driving a transfer drive roller via a power transmission system by the K drum motor. Accordingly, the K drum motor drives the K photoconductor drum 11K and the transfer / transport belt 60, and the color drum motor drives the M, C, Y photoconductor drums 11M, 11C, 11Y.
[0081]
The K developing device 120K is driven by an electric motor (not shown) driving the fixing unit 107 via a power transmission system and a clutch (not shown). The M, C, Y developing units 120M, 120C, 120Y are electric motors (not shown) for driving the registration rollers 105, and are driven via a power transmission system and a clutch (not shown). The developing units 120M, 120C, 120Y, 120K are not always driven, but receive drive transmission by the clutch so that they can be driven at a predetermined timing.
[0082]
FIG. 1 is referred to again. The finisher 34 has a stacker tray, that is, a stacking and lowering tray 34hs and a sort tray group 34st. It has a sorter discharge mode.
[0083]
The paper fed from the printer 100 to the finisher 34 is conveyed in the upper left direction, passes through an inverted U-shaped conveyance path, switches the conveyance direction downward, and then discharges the paper in the stacker according to the set mode. In the mode, the sheet is discharged from the discharge port to the loading and lowering tray 34hs. In the sorter discharge mode, the sheet currently discharged in the sorter tray group 34st is discharged to the assigned sorter tray.
[0084]
When the sorter discharge mode is designated, the discharge controller in the finisher drives the sort tray group 34st placed at the lowermost stacking and retract position to the use position indicated by the two-dot chain line in FIG. Increase the interval. In the sorter discharge mode, a single (one) copy or print of the set number of sheets is performed. When the sorter discharge mode is set for the set sort, each transfer sheet on which the same original (image) is printed is sorted by the sort tray group 34st. Sorted and stored in each tray. When the sorter discharge mode is set for page sorting, each tray is assigned to each page (image), and each transfer sheet on which the same page is printed is stacked on one sort tray.
[0085]
FIG. 3 shows a document image reading mechanism of the scanner 10 and the ADF 30 attached thereto. The original placed on the contact glass 231 of the scanner 10 is illuminated by the illumination lamp 232, and the reflected light (image light) of the original is reflected by the first mirror 233 in parallel with the sub-scanning direction y. The illumination lamp 232 and the first mirror 233 are mounted on a first carriage (not shown) driven at a constant speed in the sub-scanning direction y. The second carriage (not shown), which is driven at the half speed in the same direction as the first carriage, has the second and third mirrors 234 and 235 mounted thereon, and the image light reflected by the first mirror 233 is The light is reflected by the second mirror 234 in the downward direction (z), is reflected by the third mirror 235 in the sub-scanning direction y, is converged by the lens 236, is irradiated on the CCD 207, and is converted into an electric signal. The first and second carriages are driven forward (scanning original) and backward (return) in the y direction by the driving motor 238 as a driving source.
[0086]
The scanner 10 is equipped with an automatic document feeder ADF 30. The document stacked on the document tray 241 of the ADF 30 is sent between the conveyance drum 244 and the pressing roller 245 by the pickup roller 242 and the registration roller pair 243, and passes over the reading glass 240 in close contact with the conveyance drum 244. Then, the paper is discharged onto the paper discharge tray 248 below the original tray 241 by the paper discharge rollers 246 and 247. When the document passes through the reading glass 240, the document is illuminated by the illumination lamp 232 moving immediately below the document. The reflected light of the document is radiated to the CCD 207 via the optical system below the first mirror 233 and photoelectrically converted. You.
[0087]
A white reference plate 239 and a base point sensor 249 for detecting the first carriage are provided between the reading glass 240 and the scale 251 for positioning the start of the document. The white reference plate 239 reads the original with a uniform density due to variations in the individual light emission intensities of the illumination lamps 232, variations in the main scanning direction, and unevenness in sensitivity of each pixel of the CCD 207. It is provided for correcting a phenomenon in which the read data varies (shading correction). In this shading correction, first, the white reference plate 239 is read for one line in the main scanning direction before scanning the document, the read white reference data is stored in a memory, and when reading a document image, The image data is divided by the corresponding white reference data in the memory.
[0088]
FIG. 4 shows a system configuration of an image processing system of the copying machine shown in FIG. In this system, a color document scanner 12 composed of a reading unit 11 and an image data output I / F (interface) 12 is connected to an image data interface control CDIC (hereinafter simply referred to as CDIC) of an image data processing device ACP. I have. A color printer 100 is also connected to the image data processing device ACP. The color printer 100 receives recording image data from the image data processor IPP (Image Processing Processor; hereinafter simply referred to as IPP) of the image data processing device ACP to the writing I / F 134, and prints out the image at the image forming unit 135. . The image forming unit 135 is as shown in FIG.
[0089]
An image data processing device ACP (hereinafter simply referred to as ACP), which is an image processing device, includes a parallel bus Pb, an image memory access control IMAC (hereinafter, simply referred to as IMAC), and a second memory module MEM2 (hereinafter, simply referred to as IMAC) which is an image memory. MEM2), a system controller 1, a RAM 4, a nonvolatile memory 5, an operation board 20, a font ROM 6, a first memory module MEM1 (hereinafter simply referred to as MEM1), a CDIC, an IPP, and the like. The facsimile control unit FCU (hereinafter simply referred to as FCU) is connected to the parallel bus Pb.
[0090]
The reading unit 11 that optically reads a document generates a R, G, B image signal by photoelectrically converting the reflected light of the lamp irradiation on the document by the CCD, and A / D converts the image signal by the sensor board unit SBU. The data is converted into image data, subjected to shading correction, and transmitted from the output I / F 12 to the CDIC.
[0091]
The CDIC performs image data transfer between the output I / F 12, the MEM 1, the parallel bus Pb, and the IPP, and communication between the process controller 131 and the system controller 1 that controls the overall control of the ACP. The RAM 132 is used as a work area of the process controller 131, and the nonvolatile memory 133 stores a boot program and the like of the process controller 131.
[0092]
IPP is a programmable arithmetic processing unit that performs image processing. Image data written from the output I / F 12 to the MEM 1 and input to the CDIC from the MEM 1 is transferred to the IPP via the CDIC, and the IPP performs signal degradation (scanner) accompanying quantization into an optical system and digital signals. (System signal degradation) is corrected and output (transmitted) to the CDIC again.
[0093]
The image memory access control IMAC (hereinafter simply referred to as IMAC) controls writing / reading of image data to / from the MEM 2. The system controller 1 controls the operation of each component connected to the parallel bus Pb. The RAM 4 is used as a work area of the system controller 1, and the nonvolatile memory 5 stores a boot program and the like of the system controller 1.
[0094]
The operation board 20 inputs a process to be performed by the ACP. For example, the type of process (copying, facsimile transmission, image reading, printing, etc.), the number of processes, and the like are input. Thereby, the input of the image data control information can be performed.
[0095]
The processing of the image data read by the reading unit 11 includes a job for storing and reusing the read image data in the MEM2 and a job for not storing the read image data in the MEM2. Each case will be described. As an example of storing the read image data in the MEM 2, there is a case where a plurality of sheets are copied for one document. In this case, the reading unit 11 is operated only once, and the image data read by the reading unit 11 is read. Writing to MEM1, reading from MEM1, printing the first sheet, and accumulating in MEM2. Then, the image data stored in the MEM 2 is read a plurality of times and the second and subsequent sheets are printed.
[0096]
As an example where MEM2 is not used, there is a case where only one document is copied. In this case, it is only necessary to reproduce the read image data as it is, and thus it is not necessary to access MEM2 by IMAC. When the MEM2 is not used, the image data output from the document scanner 10 is written to the MEM1 via the CDIC and then input to the IPP. Then, after performing “scanner image processing” 190 (FIG. 6) by IPP, the image is transferred to the CDIC. The data transferred to the CDIC is returned from the CDIC to the IPP again. In the IPP, “image quality processing” 300 (FIG. 6) is performed. In the “image quality processing” 300, the RGB signals are color-converted into YMCK signals, and printer γ conversion, gradation conversion, and gradation processing such as dither processing or error diffusion processing are performed.
[0097]
The image data after the image quality processing is transferred from the IPP to the write I / F 134. The write I / F 134 performs laser control on the signal subjected to the gradation processing by pulse width and power modulation. Thereafter, the image data is sent to the image forming unit 135, and the image forming unit 135 forms a reproduced image on transfer paper.
[0098]
Next, a description will be given of a flow of image data when the image data is stored in the MEM 2 and additional processing such as image direction rotation and image synthesis is performed at the time of image reading. When transferred from the IPP to the CDIC, the image data is primarily compressed by the CDIC. The primary compressed image data is sent from the CDIC to the IMAC via the parallel bus Pb. The IMAC is for controlling access to image data and the MEM 2 based on the control of the system controller 1, developing print data of a personal computer PC (hereinafter simply referred to as a PC) connected to the LAN, and effectively utilizing the MEM 2. Performs secondary compression / expansion of the image data.
[0099]
The image data sent to the IMAC is stored in the MEM 2 after secondary compression of the data, and the stored data is read out as needed. The read data is expanded to primary compressed data, returned from IMAC to CDIC via parallel bus Pb, and expanded to original image data by CDIC. After the transfer from the CDIC to the IPP, the image is processed and output to the write I / F 134, and the image forming unit 135 forms a reproduced image on transfer paper.
[0100]
In the flow of image data, the function of the digital multifunction peripheral is realized by the bus control by the parallel bus Pb and the CDIC.
[0101]
Facsimile transmission is performed by performing image processing on the read image data by IPP and transferring it to the FCU via the CDIC and the parallel bus Pb. The FCU converts the data into a communication network and transmits it to the public line PN as facsimile data. Facsimile reception is performed by converting line data from the public line PN into image data by the FCU and transferring it to the IPP via the parallel bus Pb and CDIC. In this case, the image is output from the writing I / F 134 without performing any special image quality processing, and the image forming unit 135 forms a reproduced image on transfer paper.
[0102]
In a situation where a plurality of jobs, for example, a copy function, a facsimile transmission / reception function, and a printer output function operate in parallel, the right to use the reading unit 11, the imaging unit 135, and the parallel bus Pb is assigned to the job by the system controller 1 and the process. Control is performed by the controller 131. The process controller 131 controls the flow of image data, the system controller 1 controls the entire system, and manages the activation of each resource. The function selection of the digital multi-function peripheral is performed on the operation board 20, and the processing contents such as the copy function and the facsimile function are set by the selection input of the operation board 20.
[0103]
The system controller 1 and the process controller 131 communicate with each other via the parallel bus Pb, the CDIC, and the serial bus Sb. Specifically, communication between the system controller 1 and the process controller 131 is performed by performing data format conversion for a data interface between the parallel bus Pb and the serial bus Sb in the CDIC.
[0104]
Various bus interfaces, for example, a parallel bus I / F 7, a serial bus I / F 9, a local bus I / F 3, and a network I / F 8, are connected to the IMAC. The controller unit 1 is connected to related units via a plurality of types of buses in order to maintain independence in the entire ACP.
[0105]
The system controller 1 controls other functional units via the parallel bus Pb. The parallel bus Pb is used for transferring image data. The system controller 1 issues an operation control command for accumulating image data in the MEM 2 to the IMAC. This operation control command is sent via the IMAC, the parallel bus I / F 7, and the parallel bus Pb.
[0106]
In response to this operation control command, the image data is sent from the CDIC to the IMAC via the parallel bus Pb and the parallel bus I / F7. Then, the image data is stored in the MEM 2 under the control of the IMAC.
[0107]
On the other hand, the system controller 1 of the ACP functions as a printer controller, a network control, and a serial bus control in the case of calling from a PC as a printer function. In the case of the connection via the network, the IMAC receives the print output request data via the network I / F 8.
[0108]
In the case of a general-purpose serial bus connection, the IMAC receives print output request data via the serial bus I / F 9. The general-purpose serial bus I / F 9 supports a plurality of types of standards, for example, an interface of a standard such as USB (Universal Serial Bus), 1284, or 1394.
[0109]
The print output request data is developed into image data by the system controller 1. The development destination is an area in MEM2. Font data necessary for development can be obtained by referring to the font ROM 6 via the local bus I / F 3 and the local bus Rb. The local bus Rb connects the controller 1 to the nonvolatile memory 5 and the RAM 4.
[0110]
As for the serial bus Sb, besides the external serial port 2 for connection with the PC, there is also an interface for transfer with the operation board 20 which is the operation unit of the ACP. It communicates with the system controller 1 via IMAC instead of print development data, accepts processing procedures, displays system status, and the like.
[0111]
Data transmission and reception between the system controller 1 and the MEM 2 and various buses are performed via the IMAC. Jobs using MEM2 are centrally managed in the entire ACP.
[0112]
FIG. 5 shows the configuration of the CDIC shown in FIG. The CDIC inputs the document data by the image data input control 161a and the memory input / output control 161b, and stores the image data in the input side memory MEM1. Thereafter, in synchronization with the write synchronization signal of the write I / F 134, the original data is read from the input side memory MEM1 by the memory input / output control 161b and the image data output control 161c, and output to the IPP. The data after the scanner image processing is received by the image data input control 161g, and the image data for transfer is again transmitted to the IPP by the image data output control 161e via the multiplexer MUX162. Alternatively, the data after the scanner image processing is received by the image data input control 161d, sent to the data compression 166, and sent to the IMAC side via the post-compression data conversion 164 and the parallel data interface 165.
[0113]
Since there is a first path from the memory input control to the IPP of the image data output control 161c and a second path from the memory input / output control 161b to the IPP of the image data output control 161f, the MEM1 is accumulated from the MEM1 through the P1mm path. It is not necessary to synchronize the image data with the write synchronizing signal of the printer 100, and the image data can be transmitted at high speed as long as the transfer capability of the parallel bus Pb permits.
[0114]
FIG. 6 shows an outline of the image processing function of the IPP. IPP is a separation generation (determination of whether an image is a text area or a photograph area: image area separation) 192, background removal 193, scanner gamma conversion 194, filter 195, color correction 302, scaling 303, image processing 304, printer gamma conversion 305 And a gradation process 606 is performed. IPP is a programmable arithmetic processing unit that performs image processing. Image data input to the CDIC from the output I / F 12 of the scanner 10 is transferred to the IPP via the CDIC, and the IPP performs signal degradation due to quantization into optical systems and digital signals (signal degradation of the scanner system). Is corrected and output (transmitted) to the CDIC again. In the IPP, “image quality processing” 300 is performed on the image data returned from the CDIC to the IPP. In the “image quality processing” 300, the RGB signal is color-converted into a YMCK signal by a color correction 302, and a scaling 303, image processing 304, printer gamma conversion 305, and gradation processing such as gradation conversion, dither processing, or error diffusion processing are performed. 306 and so on.
[0115]
FIG. 7 shows an outline of the configuration of the IMAC. IMAC includes access control 172, memory control 173, secondary compression / decompression module 176, image editing module 177, system I / F 179, local bus control 180, parallel bus control 171, serial port control 175, serial port 174, and network. Control 178 is provided. The secondary compression / decompression module 176, the image editing module 177, the parallel bus control 171, the serial port control 175, and the network control 178 are connected to the access control 172 via DMAC (direct memory access control).
[0116]
The system I / F 179 sends and receives commands or data to and from the system controller 1. Basically, the system controller 1 controls the entire ACP. Further, the system controller 1 manages the resource allocation of the MEM 2, and controls other units via the system I / F 179, the parallel bus control 171 and the parallel bus Pb.
[0117]
Each unit of the ACP is basically connected to the parallel bus Pb. Therefore, the parallel bus control 171 controls transmission and reception of data to and from the system controller 1 and the MEM 2 by controlling the bus occupation.
[0118]
The network control 178 controls connection with the LAN. The network control 178 manages transmission and reception of data to and from an external extension device connected to the network. Here, the system controller 1 does not participate in the operation management of the connected devices on the network, but controls the IMAC interface. Although not particularly limited, in the present embodiment, control for 100BASE-T is added.
[0119]
The serial port 174 connected to the serial bus has a plurality of ports. The serial port control 175 has a number of port control mechanisms corresponding to the types of buses provided. Although not particularly limited, in the present embodiment, port control for USB and 1284 is performed. In addition to the external serial port, it controls transmission / reception of data related to command reception or display with the operation unit.
[0120]
The local bus control 180 interfaces with a local serial bus Rb to which a RAM 4 and a nonvolatile memory 5 necessary for activating the system controller 1 and a font ROM 6 for developing printer code data are connected.
[0121]
The operation control executes command control by the system controller 1 from the system I / F 179. Data control manages MEM2 access from external units, centering on MEM2. The image data is transferred from the CDIC to the IMAC via the parallel bus Pb. Then, the image data is taken into the IMAC by the parallel bus control 171.
[0122]
The memory access of the fetched image data is separated from the management of the system controller 1. That is, the memory access is performed by direct memory access control (DMAC) independently of system control. For access to the MEM2, the access control 172 arbitrates access requests from a plurality of units. Then, the memory control 173 controls the access operation of the MEM2 or the reading / writing of data.
[0123]
When accessing the MEM2 from the network, the data taken into the IMAC from the network via the network control 178 is transferred to the MEM2 by the direct memory access control DMAC. The access control 172 arbitrates access to the MEM 2 in a plurality of jobs. The memory control 173 reads / writes data from / to the MEM2.
[0124]
When accessing the MEM2 from the serial bus, the data taken into the IMAC by the serial port control 175 via the serial port 174 is transferred to the MEM2 by the direct memory access control DMAC. The access control 172 arbitrates access to the MEM 2 in a plurality of jobs. The memory control 173 reads / writes data from / to the MEM2.
[0125]
Print output data from a PC connected to a network or a serial bus is developed by the system controller 1 in a memory area in the MEM 2 using font data on a local bus.
[0126]
The system controller 1 manages the interface with each external unit. For the data transfer after being taken into the IMAC, each DMAC shown in FIG. 7 manages the memory access. In this case, since the DMACs execute data transfer independently of each other, the access control 172 performs job collision regarding access to the MEM 2 or prioritizes each access request.
[0127]
Here, the access to the MEM 2 includes an access from the system controller 1 via the system I / F 179 for bitmap expansion of the stored data, in addition to the access by each DMAC. In the access control 172, the DMAC data permitted to access the MEM2 or the data from the system I / F 179 is directly transferred to the MEM2 by the memory control 173.
[0128]
IMAC has a secondary compression / decompression module 176 and an image editing module 177 for data processing therein. The secondary compression / decompression module 176 compresses and decompresses data so that image data or code data can be effectively stored in the MEM2. The secondary compression / decompression module 176 controls an interface with MEM2 by DMAC.
[0129]
The image data once stored in the MEM 2 is called from the MEM 2 by the direct memory access control DMAC to the secondary compression / decompression module 176 via the memory control 173 and the access control 172. Then, the converted image data is returned to the MEM 2 or output to an external bus by the direct memory access control DMAC.
[0130]
The image editing module 177 controls the MEM 2 by the DMAC, and performs data processing in the MEM 2. Specifically, the image editing module 177 performs not only the clearing of the memory area, but also the rotation processing of the image data and the synthesis of different images as data processing. The image editing module 177 reads the secondary compressed data from the MEM 2 and decompresses it into the primary compressed data by the secondary compression / decompression module 176. In the module 177, the primary compression is performed by the same decoding logic as the data decompression 163 of the CDIC. The data is expanded to image data, expanded in the memory in the module 177, and processed. The processed image data is primarily compressed by the same encoding logic as the CDIC's primary compression logic, further secondary-compressed by the secondary compression / decompression module 176, and written to the MEM2.
[0131]
FIG. 4 is referred to again. A memory MEM1 is provided on the input side of the document scanner 10, CDIC, IPP, printer 100, etc., beyond the parallel bus Pb, such as IMAC, MEM2, FCU, etc., apart from storage. An original image is read by the original scanner 10, and the image is temporarily stored in the memory MEM1 on the input side via the CDIC. Thereafter, the image data is read out from the input side memory MEM1, and "scanner image processing" is performed via CDIC and IPP. Thereafter, in synchronization with the write synchronization signal on the printer 100 side, the image data is transmitted from the CDIC to the printer 100 via the IPP and the print output path P1mp in line data units to obtain the first transfer image. At the same time, image data is sent from the CDIC to the MEM2 via the parallel bus Pb via the path P1mm to the IMAC and the storage MEM2, and the original image is stored. At this time, the image data is primarily compressed by the CDIC data compression 166.
[0132]
Thereafter, when a second transfer image is obtained, or when a transfer image of the same original image is obtained when a trouble such as a paper jam occurs in the printer 100, the IMAC and the parallel bus Pb are passed from the MEM2 through the path P2mp. Then, a transfer image can be obtained by transferring the image data to the CDIC, the IPP, and the printer 100 via the path P1mp.
[0133]
An image transfer path P1mp for obtaining the first transfer image from the input side memory MEM1 and an image transfer path P1mm for storing the image from the memory MEM1 to the storage memory MEM2 are separately provided. Since there is a transfer path P1mm from the input side memory MEM1 to the storage memory MEM2 separately from the print output image data transfer path P1mp, there is no need to synchronize with a write synchronization signal when transmitting image data to the storage MEM2. When the image data read by the scanner 10 is stored in the MEM 2 and when the image data is transferred to the FCU, PC, or an external device via the external serial port 2, the data is transmitted at high speed as long as the transfer capability of the parallel bus Pb permits. It is possible to do.
[0134]
As the flow of the document image data in FIG. 4, the data is read from the input side memory MEM1 and then transferred to the CDIC, IPP, CDIC, IPP, and the printer 100. Since the data transfer path is shorter than in the conventional example, It is possible to reduce the time from reading the original to obtaining the first transfer paper, that is, the time until the first copy.
[0135]
In FIG. 4, when only one original is to be copied, the original image data is not transmitted to the storage MEM2, but is transmitted from the input side memory to the VDC and the image forming unit via the CDIC and the IPP to obtain a transfer image. be able to. In this case, in the CDIC, the path of the image data input control 161g / multiplexer 162 / image data output control 161e is selected to bypass the primary compression / primary expansion 166 and 163 of the image data. As a result, not only the task of the CDIC is reduced, but also the data transfer on the parallel bus Pb is reduced, and the data transfer on the parallel bus Pb of another unit connected to the parallel bus Pb is not delayed, and the system efficiency is reduced. Can be improved.
[0136]
When the image data of MEM1 is sent to MEM2, FCU, PC or external serial port 2, the image data read from MEM1 is primarily compressed by CDIC data compression 166. Conversely, when the primary compressed data is transferred from the MEM2, FCU, PC or the external serial port 2 to the IPP via the CDIC and subjected to image quality processing 300 and printed out by the printer 100, the data expansion 163 of the CDIC requires The primary compressed data is decompressed into image data and output to the IPP, and the image data for recording, which has undergone image quality processing by the IPP, is output to the printer 100.
[0137]
FIG. 8 shows an outline of data compression (primary compression) in the CDIC data compression 166. Here, first, a characteristic area (character area / photograph area / blank area) on the image (page 1) represented by the image data of MEM1 is detected (step 1).
[0138]
In the following, the word “step” is omitted in parentheses, and step No. Write only numbers.
[0139]
In the detection (1) of the image characteristic region Ari, in this embodiment, the distributions (b), (c) and (d) of the density levels represented by the raster image data in the main scanning direction X are shown in FIG. In the sub-scanning direction Y, the maximum density (e) on the line of each raster image data is obtained. Then, as shown in FIG. 15, for each raster image data, the continuation amounts a to g of pixels having a density higher than a certain fixed threshold and pixels having a lower density are obtained. FIG. 15 shows the continuous amount in the main scanning direction X. In the sub-scanning direction Y, the continuous amount in the sub-scanning direction Y is calculated based on the maximum density on the line ((e) in FIG. 14). Then, from the periodicity of the continuation amounts a to g on the current scanning line, main scanning direction feature amount data representing the likelihood of a character region and the likelihood of a photograph region, whether the current main scanning position is a character region or a photograph region, is generated. From the periodicity of the continuous amount in the sub-scanning direction, whether the current sub-scanning position is a character area or a photograph area, generates sub-scanning direction characteristic amount data representing the likeness of a character area and the likeness of a photograph area, and from both characteristic amount data, A character area and a photograph area are determined, and an area that cannot be determined as any of them is determined as a blank area. Then, area information representing each area is generated.
[0140]
FIG. 8 is referred to again. Next, for the determined character area and photograph area, an on-line image data transition pattern with a high appearance frequency is detected, and an application pattern is determined for the area information (PAD). In the present embodiment, the following five types of patterns are scheduled to be applied to the primary compression.
[0141]
Type A: One-dimensional continuous pattern of the same image data
Continuous image data of image data representing the same value on the same line is represented by an end point X coordinate (the number of pixels: may be a run), a type ID (type No. 1), and a start point data (the first image data of the series). Is converted to data representing. Type No. There is only one.
[0142]
Type B: Regular one-dimensional change patterns that appear frequently in photographic image data expressed in halftone dots
The difference values are distributed in a fixed pattern. If the data values of all the pixels in the pattern are described for each pixel, the appearance frequency will be low and the pattern matching process will be complicated. Therefore, this pattern is a set of difference values between adjacent pixels (difference value group), the starting point data is given to the first pixel, and each difference value is sequentially added thereto, so that the image data of the second and subsequent pixels is sequentially obtained. To play. However, data (one-point data and each difference value) corresponding to each pixel in the pattern on a one-to-one basis uniquely represents the image data of each part of the pattern. Since the difference value group (type definition data) is assigned (linked) to the type ID, all the image data of the one-dimensional change pattern may be converted into data representing the type ID and the starting point data. 12 and FIG. 5, Type No. Although it is indicated as 6, any number of images having a high frequency of appearing in the halftone dot photographic image may be prepared.
[0143]
C type: regular fixed pattern often appearing in photograph area and character area
This pattern is a linear gradient of fixed gradient and fixed run. Since the gradient (difference value) is fixed and the run is also fixed, that is, since the difference value and the run (type definition data) are assigned to the type ID, all the image data of this pattern is converted to the type ID and the start point data. Just convert it. 12 and FIG. Although 3 is shown, there are various gradients (difference values) and runs. That is, it is not limited to one type (type No. 3).
[0144]
D type: linear gradation often appears in photographic area and character area
This pattern is an indefinite but linear gradient (one difference value) and an indefinite run of linear gradation. Since the gradient (difference value) is indefinite and the run is also indefinite, all image data of this pattern must be converted into data representing its end point X coordinate (or run), type ID, start point data, and difference value. No. 12 and FIG. There is only one type indicated as 2.
[0145]
E type: Image data distribution pattern that does not correspond to any of the above A to D types
All the image data of this pattern is converted into a difference value between the starting point data and adjacent pixels. That is, data compression by differential conversion is used. All image data of this pattern is converted into data representing a type ID, start point data, and a difference value group between adjacent pixels. FIG. There is only one type designated as 4. Since the data compression rate of this pattern is low, the end point of this pattern must be set immediately before any of the A-type to D-type patterns appear. Since the position at which the value becomes the starting point, the search is easy. Therefore, in this embodiment, the end point of the E type is determined to be the start pixel of the A type (as a result, the pixel next to the end point may not be the start point of the A type).
[0146]
The CDIC data compression 166 has an encoding table in which type definition information and a compressed data segment generation program used for matching search of all types described above are stored for a type ID, and is applied to a blank area. Type IDs (A type type No. 1 & E type type No. 4) applied to the character area, type IDs (C type number type, A type type No. 1, D type type 2 & E type) Type No. 4) and the type ID (number of B type, number of C type, type of D type 2, type No. 1 of A type & type No. of E type) applied to the photograph area. .4) is stored in the order of priority.
[0147]
Here, an outline of the primary compression 166 will be described. When data of two or more dimensions is treated as one-dimensional data, a difference between a point of interest (pixel: pixel) and data immediately behind can be used (FIG. 13 (a), (b)). A series of pieces of the difference information from the next one (right) is treated as a unit (FIG. 12). In particular, when the color changes in the horizontal direction in image data representing gradation, almost the same difference often continues ((a) in FIG. 13; type Nos. 2 & 3). In addition, there is a mode in which the difference value changes. In this case, for example, information indicating that the change in the value continues to 2, 2, 1, 1, 2, 2 is collected into one unit ((a) in FIG. 13; type No. 4). There is also a pattern in which the difference value changes unique to the halftone dot expression ((b) in FIG. 13; type Nos. 5 & 6). In addition, by giving a type ID (type identification information: type No.) to the information unit after compression (compressed data segment: FIG. 12), the change amount (difference value) itself is not described. By assigning a number (type ID: type No.) corresponding to the frequently occurring change pattern, a higher compression effect can be obtained if the pattern is checked in advance for each target data. When the change amount (difference value) is constant and continuous, image data is regarded as a set of horizontal lines, and a unit obtained by adding a change amount to a run length is applied so that run-length encoding is applied to multi-valued data. (Type No. 1 in FIG. 12).
[0148]
These processes can be applied to monochrome image data, RGB color image data, or YMCK image data for color recording by performing each of the color component image data.
[0149]
The data compression ratios of the A type to E type vary depending on the characteristics of the image represented by the image data, but generally, in the blank area, the A type is the highest, and the appearance probabilities of the other types B to D are almost 0. It is. Therefore, in the present embodiment, the A-type is assigned to the blank area, and the E-type, which has a low compression rate but is versatile, is used complementarily in the places where the A-type cannot be applied. In the character area, the appearance rate of the C-type, which has a high compression ratio, is high. Therefore, the application of the C-type is in the first rank, and the application of the A-type is in the second rank because of the large space between characters. Assuming that gradation appears, the application of the D-type is set in the third rank, and the universal E-type is used complementarily in places where none of them is applied. Furthermore, in the photographic area, the appearance probability of the B type is high due to the halftone dot expression. Therefore, the application of the B type having a high compression ratio is ranked first, and the appearance probability of the linear gradation (C type) of the specific run is also high. The application of type C having a high rate is set in the second rank, the application of type D is set in the third rank on the assumption that various linear gradations appear, and the type A is set in the fourth rank on the assumption that there is a density flat region. In addition, where there is no application of any of them, the universal E-type is used complementarily.
[0150]
In order to realize this, as described above, an A-type type number is assigned to a blank area in the allocation table. 1 & E type No. 4 is assigned to the character area, and the C type number type and the A type type No. 1, D type 2 & E type No. 4 to the photograph area, a number of B-type, a number of C-type, a type of D-type 2, and a type No. of A-type. 1 & E type No. 4 are stored in this notation order.
[0151]
In the feature pattern detection PAD of FIG. 8, first, the appearance frequency of each of the C-type numbers applied to the character area on the allocation table is measured, and only the type having a frequency equal to or higher than the set frequency is determined as the character area application (2 to 2). 4). Specifically, an image data extraction area having a predetermined area is defined in the character area, and how many C-type patterns are present in the area is searched by pattern matching, and a counter associated with the pattern is counted. Up, and only the type whose count value is equal to or greater than the set value is determined as the character area application. If any of the character areas on the one-page image is smaller than the image data extraction area having a predetermined area, the C type is not applicable. That is, it is not determined to apply to the character area.
[0152]
Next, the appearance frequency of each of several types of B type and C type addressed to the photographic area is measured on the allocation table, and only the types whose frequency is equal to or higher than the set frequency are determined to be applied to the photographic area (5-9). This content is the same as the setting of the character area application type described above.
[0153]
As described above, when the character area application type (within the C type) and the photograph area application type (within the B and C types) are determined, the CDIC data compression 166 performs the “compression processing” (10) and performs one page of MEM1. Is read line by line, scanner image processing 190 is performed through the IPP, and compression processing for primary compression is started by the CDIC data compression 166, and the primary compressed data is transferred to the transfer destination ( MEM2, FCU, PC or external serial port 2) (10).
[0154]
9 and 10 show the contents of the "compression process" (10). First, refer to FIG. In the "compression process" (10), the image data of the first line is first read from the MEM1, subjected to scanner image processing by the IPP, and written into the input line buffer memory of the data compression 166 of the CDIC (11, 12). Then, the difference calculation of the one-line image data in the input line memory is performed, and the difference value for one line is written in the difference line memory. Note that the difference calculation here uses difference (data) obtained by subtracting image data of a preceding pixel from image data of a succeeding pixel of two pixels adjacent on one line.
[0155]
Next, the difference data at the head position of the one-line difference data in the difference line memory is determined as the attention data, and the image data of the adjacent preceding pixel is determined as the start point data with respect to the difference data, and the position is within the blank area. And the information (first order: pattern matching of type A No. 1 of the A type, second order: pattern matching of type No. 4 of the E type) given the blank area information to the allocation table. The type definition information and the compressed data segment generation program of the read and assigned type are read from the encode table, and data compression is performed according to the read. That is, first, whether the distribution of the difference data after the position is a continuation of the same difference value, that is, the type No. 1 is searched, and if so, type No. One compressed data segment is generated using the type ID representing 1, the start point data, and the x-coordinate (end point X-coordinate: pixel position on one line) of the succeeding pixel in contact with the end point of the distribution, and the output line buffer Write to memory (13, 14, 15).
[0156]
In this case, since it is the head of the line, the compressed data segment No. shown in FIG. 1, the information "line head header ID" indicating the head of the line, the Y coordinate (line No.), the end point X coordinate, the type ID, and the compressed data segment No. having the start point data. 1 is generated and written at the head of the output line buffer memory.
[0157]
A type No. In the case where the distribution is not the distribution of type A, A type A starting point position (the starting point where the same difference data continues) that is the A type 1 is searched for, and a pixel immediately before the starting point position (A type starting pixel: E type end point pixel) is searched for an E type No. In step 4, the data is compressed, a compressed data segment is generated, and written to the output line buffer memory at a position corresponding to the original image data position (16). This type E type No. 4 is of type No. 4, the difference data (difference value 1, difference value 2,...: A difference data group) up to the start point data and the E-type end point pixel. At the beginning, a compressed data segment (No. 1) at the head of the line is generated by adding information “line header ID” indicating the head of the line and the Y coordinate (line No.) to the output line buffer memory. Write to the first area.
[0158]
Reference is also made to FIG. Next, the image data of the pixel next to the end point (end point X coordinate, end point pixel) of the area in which the generation of the compressed data segment has been completed is determined as start point data, and the next pixel and its adjacent succeeding pixel are determined. The difference data between the two is determined as the data of interest (29), and if it is a blank area, A-type or E-type data compression is performed as described above, and the compressed data segment No. 2 is generated and written in the output line buffer memory (29-30-14 to 16).
[0159]
Note that, at a part of the line other than the head of the line, the compressed data segment is the compressed data segment No. of FIG. As shown in 2, the "header ID in the line" indicating that the line is in the line is placed at the head, and has no Y coordinate data.
[0160]
Type No. When a pixel (target pixel) serving as a starting point of data compression of a section is determined (13-14 / 29-30-14), if it is a character area, character area information is given to the allocation table and Assigned information (first rank: C-type pattern matching, second rank: A-type type No. 1 pattern matching, third rank: D-type type No. 2 pattern matching, fourth rank: E-type pattern No. 4 pattern matching) is read, and the type definition information of the assigned type and the compressed data segment generation program are read from the encoding table, and data compression is performed according to the read data. That is, first, the C-type type No. determined in the character pattern application PAD in FIG. If there is (for example, No. 3), it is searched whether there is a difference data distribution of that type, and if so, a compressed data segment of that type is generated and written to the output line buffer memory (18, 19). C-type type No. specified for character area application When there is no A, or when the difference data distribution does not match even if there is, the type No. 1 is searched, and if so, the type A of the type A described above is searched. No. 1 compressed data segment (No. 1 / No. 2) is generated and written to the output line buffer memory (20). A type No. 1 is not the difference data distribution, the D-type type No. Then, a search is made for the difference data distribution of No. 2 and, if so, a compressed data segment of that type is generated and written to the output line buffer memory (21). D type type No. 2 is not the difference data distribution, the type E type No. 4 is generated and written into the output line buffer memory (21).
[0161]
Type No. When a pixel (target pixel) serving as a starting point of data compression of a section is determined (13-14 / 29-30-14), if the pixel is a photographic area, photographic area information is given to the allocation table, and Assigned information (first order: pattern matching of B type, second order: pattern matching of C type, third order: pattern matching of type No. 2 of D type, fourth order: type No. of A type .1, pattern matching of the fifth type: pattern matching of the E type No. 4), and read out the type definition information of the assigned type and the compressed data segment generation program from the encode table, and read the data accordingly. Perform compression. That is, first, the B-type type No. determined to apply to the photographic area by the feature pattern detection PAD in FIG. If there is (for example, No. 5), it is searched whether there is a difference data distribution of that type, and if so, a compressed data segment of that type is generated and written to the output line buffer memory (24). Type B type no. If there is no, or if the difference data distribution does not match even if there is, the C-type type No. defined for the photographic area application. If there is (for example, No. 3), it is searched whether there is a difference data distribution of that type, and if so, a compressed data segment of that type is generated and written to the output line buffer memory (25). C-type type No. specified for application of photographic area Is not present, or even if the difference data distribution does not match, the D-type type No. A search is made for a differential data distribution of 2, and if so, a compressed data segment of that type is generated and written to the output line buffer memory (26). D type type No. 2 is not the difference data distribution, the above-mentioned type A type No. 1 is searched, and if so, the type A of the type A is searched. No. 1 compressed data segment (No. 1 / No. 2) is generated and written to the output line buffer memory (27). A type No. 1 is not the difference data distribution, the E-type type No. 4 is generated and written into the output line buffer memory (28).
[0162]
Type No. When the pixel (target pixel) serving as the starting point of the data compression of the section is updated (29), if the updated pixel position X is outside the tail end of the line, the data compression 166 performs the processing for one line of the output line buffer memory. The compressed data is transmitted (30-31), and the Y coordinate value is advanced (32: the line number is incremented by 1). If the Y coordinate value is outside one page (page end), Then, the compression process (10) is ended, but if it is not the page end, the process proceeds to step 12, where the image data of the next line is written into the input line buffer memory 12 (12). Data compression of this line is performed in the same manner as described above. FIG. 12 schematically shows the distribution of compressed data for one line.
[0163]
FIG. 11 shows an outline of the expansion processing “data expansion” (163P) of the primary compressed data in the data expansion 163 shown in FIG. The data decompression 163 includes a decoding table corresponding to the encoding table in the data compression 166. The decoding table includes data distribution definition data and image data corresponding to generation of all types of compressed data segments in the encoding table. A playback program is stored.
[0164]
When the compressed data for one line is written into the input line buffer memory, the compressed data segment No. at the head of the line is written. 1 is extracted (41-43). That is, from the data following the line head header ID, data up to the data immediately before the next “header ID in the line” is extracted, and the start data in the data is written to the line head pixel data storage area of the input line buffer memory. , The data distribution definition data and the image data reproduction program corresponding to the type ID are read from the decode table, and each image data from the second pixel to the end pixel (end point X coordinate) of one type of image data is reproduced and output. The data is written in the memory area below the second pixel position in the line buffer memory (45).
[0165]
Here, type ID of type A whose type ID is A type. If it is 1, the start point data is written from the second pixel position to the end point X coordinate position.
[0166]
If the type ID is B type, the start point data is written at the head (first pixel) of the X coordinate area where the decoded image data of the type is written, and the corresponding type read from the decode table is written at the next position. No. Is added to the image data (start point data) of the adjacent preceding pixel (first pixel) of the difference data group in the data distribution definition data of It is written at the corresponding position as pixel image data. Next, the second one of the difference data group is added to the image data of the adjacent preceding pixel (second pixel), and the obtained sum is used as the image data of the (third) pixel of the adjacent succeeding row. Write to. Such data processing is repeated until the last difference data of the difference data group is used.
[0167]
If the type ID is C type, the start point data is written at the head (first pixel) of the X coordinate area where the decoded image data of the type is written, and the corresponding type read from the decode table is written at the next position. No. Is added to the image data (starting point data) of the adjacent preceding pixel (first pixel) in the data distribution defining data, and the obtained sum is used as the image data of the (second) pixel of the adjacent succeeding row. Write to the corresponding location. Such data processing is repeated the number of times smaller than the number of pixels b in the image data distribution definition data by one.
[0168]
When the type ID is D type, the type No. In the case of 2, the starting point data is written at the head (first pixel) of the X coordinate area where the decoded image data of this type is to be written, and the difference data existing in the compressed data segment is written to the next preceding pixel (the next pixel). The sum is added to the image data (start point data) of the first pixel), and the obtained sum is written in the corresponding position as the image data of the (second) pixel of the succeeding row. Such data processing is repeated up to the end point X coordinate.
[0169]
Type ID of type E is E type. 4, the start data is written at the head (first pixel) of the X coordinate area where the decoded image data of this type is to be written, and the next position in the differential data group in the compressed data segment is written at the next position. The first difference data is added to the image data (start point data) of the adjacent preceding pixel (first pixel), and the obtained sum is written into the corresponding position as the image data of the adjacent second row (second) pixel. Next, the second difference data in the group of difference data is added to the image data of the adjacent preceding pixel (second pixel), and the obtained sum is added to the image data of the (third) pixel of the adjacent succeeding row. To the corresponding position. Such data processing is repeated until the last difference data in the difference data group is used.
[0170]
When the above-mentioned decompression of one compressed data segment, that is, the reproduction of the image data is completed, the data of the next compressed data segment is extracted and the image data is reproduced in the same manner (46-47-44-45). When such image data is reproduced, when the next X coordinate is outside the line end (line end), the image data for one line in the output line buffer memory is transmitted (48). Then, the primary compressed data of the next line is read into the input buffer memory (49-50-42), and the image data of one line is reproduced in the same manner as described above. When the decoding and transmission of the primary compressed data of the last line of one page are finished, the "data decompression" (163P) is finished (50).
[0171]
FIG. 12 shows compressed data on one line when image data of one page per color is compressed in units of one page per color. For example, in a mode in which color component image data such as RGB data or YMCK data is compressed in units of lines, and, for example, compressed data of R, G, and B image data of the same line is sequentially output in units of lines, The compressed data segment No. at the head of the line As shown in (c) of FIG. Immediately before the data (Y coordinate), a color ID representing a color component is inserted, and the number of colors of the line compression data is indicated.
[0172]
In the embodiment described above, the segment division of the compressed data on one line is identified by the "header ID in the line", but this is changed to the data amount (byte number) in the segment. It may be. For example, the compressed data segment No. The “line head header ID” of “1” includes “ID data representing the head of the line” and the compressed data segment No. 1 in the compressed data segment No. 1 For segments that are not the head of the line, ie, 2 or less, the “header ID in the line” is changed to data representing the data amount in the segment. In this mode, at the head of the line, "data representing the data amount" following "ID data representing the head of the line" is extracted, and the data of the data amount represented by the extracted data is referred to as the compressed data segment No. 1 data. Then, the next data segment pointer is placed at the next extracted data. Data segment No. When decoding of the pointer is completed, the pointer reads the data at a certain point, and stores the data represented by the pointer in the data segment No. 2 and the next data segment pointer is placed at the next extracted data. In this manner, data can be sectioned and extracted in segment units.
[0173]
In the above embodiment, the type No. 1 and No. 2 indicates that the end point X coordinate is included in the compressed data, but the X position (the number of pixels from the line head) is counted at the time of decoding, and the position of the reproduced image data (write position on the output line buffer memory) is determined. Since it is always known, the end point X coordinate may be changed to the number of reproduction image data (run; number of pixels).
[0174]
Although the data compression 166 and data decompression 163 are shown only in the CDIC, the internal and external devices which require the above-described primary data compression are similarly provided with the data compression 166, and the primary compressed data is decompressed. Internal and external devices that require (decryption; decompression) are also provided with data decompression 163.
[0175]
Further, in the above-described embodiment, the characteristic region (character region, photograph region, blank region) of the image is automatically detected, the type corresponding to the region and having a high appearance frequency is automatically searched, and the type to be applied to the pattern search is determined ( (B, C types) and several types (A, D, E types) automatically assign their use to areas, but specify them according to the user's feature designation (text, photo). May be determined to be applied to the pattern search.
[0176]
Further, in the above-described embodiment, the type that has a high appearance frequency is applied from the types (B and C types) already prepared, but the difference data having the high appearance frequency is determined based on the image data. Searching the distribution pattern, giving it a type ID, generating type definition information of the type ID and generating a compressed data segment and registering it in the encoding table, and additionally adding the type ID to the allocation table, The data distribution definition data of the type ID and the image data reproduction program may be generated and added to the decode table.
[0177]
【The invention's effect】
The image data before compression can be accurately reproduced. Also, a high compression ratio can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view showing the appearance of a copying machine having a composite function according to a first embodiment of the present invention.
FIG. 2 is an enlarged vertical sectional view schematically showing an image forming mechanism of the printer 100 shown in FIG.
FIG. 3 is an enlarged vertical sectional view showing an outline of a reading mechanism of the original scanner 10 shown in FIG.
FIG. 4 is a block diagram showing an outline of an image processing system of the copying machine shown in FIG. 1;
FIG. 5 is a block diagram showing an outline of a functional configuration of the CDIC shown in FIG. 4;
FIG. 6 is a block diagram showing an outline of a functional configuration of the IPP shown in FIG. 4;
FIG. 7 is a block diagram showing an outline of a functional configuration of the IMAC shown in FIG. 4;
8 is a flowchart showing an outline of a data compression process of the data compression 166 shown in FIG.
FIG. 9 is a flowchart showing a part of the contents of a compression process (10) shown in FIG. 8;
FIG. 10 is a flowchart showing the rest of the contents of the compression processing (10) shown in FIG.
11 is a flowchart showing an outline of a data decompression process of the data decompression 163 shown in FIG.
12 is a block diagram schematically showing the distribution of compressed data on one line, which has been subjected to data compression processing by the data compression 166 shown in FIG. 5;
13A and 13B show the distribution of a specific pattern of image data, FIG. 13A shows gradation, and FIG. 13B shows image data distribution in a halftone dot area. (C) shows a format in which the color component image data is compressed in units of lines, and, for example, the compressed data of the R, G, and B image data of the same line is sequentially output in units of lines, and the compression of the head of the line is performed. Data segment No. FIG. 3 is a block diagram showing data of No. 1;
14A is a plan view showing an image area on a document, and FIGS. 14B, 14C and 14D are multi-tone images obtained by scanning the document shown in FIG. 14A in the main scanning direction. A graph showing the distribution of the reading density level, and (e) is a graph showing the distribution of the highest density on each line in the sub scanning direction.
FIG. 15 is a graph showing the distribution of multi-gradation read density levels and the continuous amount of presence or absence of an image when an original is scanned in the main scanning direction.
[Explanation of symbols]
10: Color document scanner 20: Operation board
30: Automatic document feeder 34: Finisher
34hs: loading and lowering tray 34ud: lifting platform
34st: Sort tray group
100: color printer PC: personal computer
PBX: Switch PN: Communication line
102: Optical writing unit 103, 104: Paper cassette
105: registration roller pair 106: transfer belt unit
107: Fixing unit 108: Output tray
110M, 110C, 110Y, 110K: Photoconductor unit
111M, 111C, 111Y, 111K: photosensitive drum
120M, 120C, 120Y, 120K: developing unit
160: transfer conveyance belt ACP: image data processing device
CDIC: Image data interface control
IMAC: Image memory access control
IPP: Image data processor
231: platen glass 232: illumination lamp
233: First mirror 234: Second mirror
235: Third mirror 236: Lens
207: CCD 238: Running body motor
239: Reference white plate 240: Glass
241: Document tray 242: Pickup roller
243: registration roller pair 244: transport drum
245: Holding roller 246, 247: Discharge roller
248: Pressure plate also used as paper output tray
249: Base point sensor 250: Axis
251: Scale 260: Motor control unit

Claims (9)

A series of data transitions of a known pattern are searched for in a series of data of a plurality of bits that can represent a multi-value, and if there is, it is converted into compressed data including the pattern ID and the starting point data. The data compression method to convert. One of the series of data transitions of the known pattern is a series of data transitions in which the difference value between adjacent data is constant. 2. The data compression method according to claim 1, wherein the data is converted into compressed data including a difference value. One of the series of data transitions of the known pattern is such that adjacent data is the same data transition, and if there is, it is converted into compressed data including the end point, pattern ID and start point data of the series. 3. The data compression method according to 1 or 2. One of a series of data transitions of a known pattern is a series of data transitions in which a difference value between adjacent data fluctuates, and if there is, it is compressed data including its pattern ID, start point data, and each difference value. The data compression method according to any one of claims 1 to 3, wherein the data compression is performed. A feature of each part of a two-dimensional distribution image represented by multi-valued image data of a plurality of lines is detected to generate region information for each feature, and a series of image data on each line is a series of data transitions of a predetermined length. Out of a plurality of known patterns representing the image feature, and converts the corresponding portion into compressed data including the pattern ID and the starting point data. An image data compression method for retrieving which of the transition patterns takes an indefinite length, and converting the data into compressed data including a pattern ID and start point data and a pattern end point position or a difference value. Searches for a series of data transitions of a known pattern in a series of image data of a plurality of bits that can represent multi-values on the same line, and if there is, includes that pattern ID and its starting point data. An image processing device comprising: data compression means for converting the data into compressed data. An image processing apparatus comprising: an image pickup apparatus that photoelectrically converts an image or a scene of a document or a scene to generate multi-value image data representing the image; and a data compression unit according to claim 6 that compresses the multi-value image data. . The image processing apparatus according to claim 6, further comprising: a memory unit that stores the compressed data of the data compression unit; and a unit that transfers the compressed data. 9. The image processing apparatus according to claim 8, data expansion means for expanding the compressed data into image data, image data processing means for converting the image data into image data for printout, and image data for printout. An image forming device for forming an image on paper.

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