JP5106318B2 - Image processing apparatus, image forming apparatus, image storage method, and computer program - Google Patents

Description

  The present invention includes an image processing apparatus applicable to an image processing apparatus such as a copying machine, a facsimile, a scanner, or a digital multifunction peripheral capable of storing image data in an image storage apparatus such as a hard disk, and the image processing apparatus. The present invention also relates to the image forming apparatus, the image processing apparatus or an image storage method executed by the image forming apparatus, and a computer program for executing the storage method by a computer.

  Recent digital copying machines not only copy originals and distribute image data to an external PC via a network, but also read image data read by a scanner and image data input from an external PC via a network. Some have a function of accumulating in a large-capacity storage device such as a hard disk and reprinting or redistributing the accumulated image data.

  If the image data read by the scanner is 8-bit data of 600 dpi RGB signals, the data amount of the A3 size image is about 200 Mbytes, and the data amount becomes very large. For this reason, image data is normally stored in a storage device after being subjected to compression processing such as JPEG. However, the compression rate of the stored image data cannot be increased so much that the image quality does not deteriorate when the image data is reprinted or redistributed. Therefore, if a large amount of images are to be stored, a large-capacity storage device is required, leading to an increase in cost. Conversely, if the capacity of the storage device is reduced, the free space of the storage device becomes insufficient as the number of stored images increases, so it is necessary to select and delete unnecessary images from the stored images There is a burden on the user. Also, once the stored image data is deleted, there is a possibility that if the user wants to reuse the image data at a later date, there is no original and the scanner cannot read it again.

  As a conventional technique related to a method for solving the above-described problem, for example, a technique described in Patent Document 1 is known. In this conventional technique, a retention period of an image file recorded as attribute data of an image file is set, and when this retention period elapses, the image data is reduced in quality to reduce the data amount. This prior art also allows the user to select dot density (resolution), compression rate, and the like as processing contents for reducing the image quality during image accumulation.

As another conventional technique, for example, a technique described in Patent Document 2 is known. This prior art relates to a medical radiographic image filing device, and compresses and refils image data at a timing determined based on the elapsed time from the date of image capture, the search frequency of image data, and the like. That's it.
JP-A-8-212115 Japanese Patent No. 2838521

  However, in the technique described in Patent Document 1, it is necessary for the user to select a method for reducing the image quality for each image, and when a large amount of images are accumulated, the burden on the user becomes large. In addition, this technique is used when the image quality is reduced by a predetermined method, for example, a method of increasing the compression rate of JPEG compression, without the user selecting a method for reducing the image quality. Depending on the type of image quality, the image quality deteriorates, and the reusability of the stored image may be significantly impaired.

  Although the technique described in Patent Document 2 can automatically determine the compression timing, the only way to reduce the size of the image data is to increase the compression ratio. In a system in which various types of images are input, the image quality is greatly deteriorated depending on the type of image, and the reusability of the stored image is significantly impaired, as in the technique described in Patent Document 1. There is.

  Therefore, the problem to be solved by the present invention is to achieve both the reusability of stored images and the securing of free space in the image storage device.

To achieve the above object, an image processing apparatus of the present invention includes a storage unit for storing the digitized image data, image processing means for performing predetermined image processing on the input or stored image data, the an image processing apparatus having an image classifying means for classifying the plurality of categories on the basis of the image data stored in said storage means to the image feature, use history of the image quality adjustment function as an output history information when outputting the image was stored in the storage means together with the image data, of the image data used in accordance with the history stored in the storage means of the image quality adjustment function of images included in the classified category by the image classifying unit data reducing means for reducing a data amount, further comprising a characterized.

In order to achieve the above object, an image storage method of the present invention includes a storage unit that stores digitized image data, and an image processing unit that performs predetermined image processing on the input or stored image data. And storing the inputted image data in the storage means by the image classification means into the image data stored in the storage means into a plurality of categories based on image characteristics. A first step of classifying, a second step of storing, by the data reduction unit, the use history of the image quality adjustment function in the storage unit together with the image data as output history information when the image is output; and data reduction Means for storing the image based on the use history of the image quality adjustment function of the image included in the classified category of the image included in the classified category. And having a third step of reducing the data amount of the stored the image data, to.

Furthermore, in order to achieve the above object, a computer program according to the present invention includes a storage unit that stores digitized image data, and an image processing unit that performs predetermined image processing on the input or stored image data. A computer program for executing control by the computer to store the input image data in the storage unit, and a plurality of the image data stored in the storage unit by the image classification unit based on image characteristics The procedure of the first step for classifying the image data into the category and the data reduction means store the use history of the image quality adjustment function in the storage means together with the image data as output history information when outputting the image. The image quality adjuster for images included in the classified category by a step procedure and data reduction means It characterized by having a a procedure for the third step of reducing the data amount of the stored the image data in the storage means based on the usage history.

  According to a seventh means, in any one of the first to sixth means, the data reduction means reduces the data amount of the image stored in the storage means based on the data amount that can be stored in the storage means. It is characterized by determining whether or not to perform the processing.

  According to an eighth means, in any one of the first to sixth means, the data reduction means reduces the data amount of the image data based on an elapsed time since the image data was stored in the storage means. It is characterized by determining whether to perform.

In the embodiments described below, the storage means HDD 5, the image processing means is the first image processing device 2 or the second image processing apparatus 4, the image classifying means, and data reduction means to CPU 6, the amount of data The means for setting whether or not to reduce the image data corresponds to the operation display device 10, and the image output device corresponds to the plotter device 9 .

  According to the present invention, it is possible to achieve both reusability of stored images and securing free capacity of a storage device that stores image data, and to reduce the amount of image data to be stored in an optimum manner for each image. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a digital multifunction peripheral (MFP-Multi Function Peripheral) according to an embodiment of the present invention. This digital multi-function peripheral has a plurality of image processing functions.

  In FIG. 1, a digital multi-function peripheral includes a reading device (scanner) 1, first and second image data processing devices 2 and 4, a bus control device 3, an HDD 5, a CPU 6, a memory 7, a plotter I / F device 8, a plotter. Device 9, operation display device 10, line I / F device 11, external I / F device 12, S.P. B. (South Bridge) 13 and ROM 14 are provided.

  The reading device 1 is a scanner that generates and outputs 8-bit 600 dpi digital image data based on RGB signals from the density information of the original obtained by scanning the original. The first image data processing device 2 performs image processing described later on the digital image data from the reading device 1 and outputs the result. The bus control device 3 controls transmission / reception of various data such as image data and control commands required in the digital multi-function peripheral. The second image data processing unit 4 performs image processing described later on the digital image data processed by the first image data processing device 2 and outputs the result. The HDD 5 is a mass storage device such as a magnetic disk device for storing digital image data and accompanying information of the digital image data.

  The CPU 6 is a microprocessor as a control unit that controls the entire control of the digital multi-function peripheral. The memory 7 is a volatile memory used for temporarily storing programs and intermediate processing data when the CPU 6 controls the digital multi-function peripheral. The CPU 6 is also responsible for drive control and memory control of the HDD 5, and the control described below is performed by the CPU 6 reading out a program stored in a ROM (not shown), developing it in the memory 7 and executing it.

  The plotter I / F device 8 is a dedicated interface device that receives CMYK digital image data sent from the CPU 6 and outputs the digital image data to the plotter device 9. The plotter device 9 is a device that receives CMYK digital image data and outputs the received image data to transfer paper. As the plotter device 9, in addition to an electrophotographic process using a laser beam, etc., there are provided printing means of a known system such as an apparatus that prints out using a liquid medium such as an ink jet printer or a gel jet printer. Includes printing device.

  S. B. Reference numeral 13 denotes a general-purpose circuit that is a bridge function of a bus called South Bridge. The ROM 14 is a memory that stores a program when the CPU 6 controls the digital multifunction peripheral according to the embodiment of the present invention. The operation display device 10 is a part that performs an interface between the digital multifunction peripheral and the user, and is composed of an LCD (liquid crystal display device) and a key switch, and displays various states and operation methods of the device on the LCD. Detects input from the key switch.

  The line I / F device 11 exchanges image data via a telephone line or the like between the digital multifunction peripheral (MFP) and the FAX 15 existing outside the digital multifunction peripheral. The external I / F device 12 inputs various control data and image data between the digital multifunction peripheral (MFP) and the PC 16 outside the digital multifunction peripheral via a network (Ethernet (registered trademark)). Output.

  When a user scans a document with the reading device 1, an image output from the plotter device 9 such as an image background removal function or a soft / sharp function (whether to make the image smoother) from the operation display device 10. It is possible to adjust the image quality of an image distributed to an external PC 16 or the like through a network. These image quality adjustment functions are realized in the color conversion processing and filter processing of the first image data processing apparatus 2. These image quality setting function settings, output color mode settings, and output resolution (magnification) settings are stored in the HDD 5 as output history information together with image data.

  The image data stored in the HDD 5 is not subjected to processing according to the image quality adjustment function, output color mode, and output resolution settings set when scanning the document. It is also possible to reuse the image stored in the HDD 5 with different settings. The settings of the image quality adjustment function, output color mode, and output resolution at the time of reuse are also stored in the HDD 5 as output history information together with image data.

  FIG. 2 is a block diagram showing a configuration of the first image data processing apparatus 2. The first image data processing apparatus 2 is configured to include each processing means of a scanner γ conversion 21 and a color conversion 22.

  As described above, the scanner γ conversion unit 21 performs γ conversion on each 8-bit read image data based on RGB signals to adjust the gray balance and convert the gradation characteristics. The color conversion unit 22 converts the input image data into RGB data in a color space having a predetermined characteristic and outputs the converted data. This color space is, for example, an Adobe-RGB space defined by Adobe.

  Image data based on 600 dpi RGB signals output from the reading device 1 is compressed by a compression technique such as JEPG and stored in the HDD 5. In compression by JEPPG, the compression rate and image quality are determined by the quality factor (Q value), and the larger the Q value, the better the image quality but the worse the compression rate. The image data processing device according to the embodiment of the present invention compresses the image data output from the reading device 1 at a low compression rate (for example, Q value = 90), and stores it in the HDD 5 while suppressing image quality deterioration.

  The second image data processing device 4 receives image data based on a 600 dpi RGB signal subjected to the decompression process. Note that the compression and decompression processing by JPEG in the embodiment of the present invention is performed by the CPU 6 executing a program.

  FIG. 3 is a block diagram showing the configuration of the second image data processing device 4. The second image data processing device 4 includes a background removal processing unit 31, a filter processing unit 32, a scaling unit 33, a color conversion unit 34, and a gradation processing unit 35.

  In FIG. 3, the background removal processing unit 31 removes the background portion of the image when the background removal processing is set. Specifically, the background removal processing unit 31 removes only the low density portion of the image. The filter processing unit 32 performs smoothing for smoothing the pattern portion of the image and edge enhancement for sharpening the character portion. The scaling unit 33 performs image enlargement / reduction processing for converting the output resolution and image size of the image data. The color conversion unit 34 converts each 8-bit image data based on RGB signals into 8-bit data (only K signals for monochrome output) based on CMYK signals, which are the color space of the plotter device 9. The gradation processing unit 35 converts each 8-bit data based on the CMYK signal into the number of gradations of the plotter device 9 (for example, 2 bits each based on the CMYK signal). Process.

  In addition, when distributing as a color image to external PC etc. via a network, in the color conversion 34, it converts into RGB data, such as sRGB space, and distributes the RGB data. When the image is distributed as a monochrome binary image to an external PC or the like through the network, the color conversion 34 converts the image into a gray scale, and the gradation processing 35 performs pseudo halftone processing such as dither processing or error diffusion processing. Alternatively, simple binarization processing is performed and the monochrome binary image data is distributed.

  When the user scans a document with the reading device 1 configured as described above, an image output from the plotter device 9 such as a density adjustment function or a sharpness adjustment function from the operation display device 10, or even externally through a network It is possible to adjust the image quality of an image distributed to the PC 16 or the like. This image quality adjustment function is realized in the filter processing unit 32 and the color conversion processing unit 34 of the second image data processing device 4.

  These image quality adjustment function settings, output color mode settings, and output resolution (magnification) settings are stored in the HDD 5 as output history information together with image data. Also, since the HDD 5 is not subjected to processing according to the image quality adjustment function, output color mode, and output resolution settings set when scanning the document, the settings are different from the settings when scanning the document. The image stored in the HDD 5 can be reused. The settings of the image quality adjustment function, output color mode, and output resolution for reuse are also stored in the HDD 5 as output history information together with image data.

  Hereinafter, processing for reducing the amount of image data stored in the HDD 5 for each embodiment will be described.

  FIG. 4 is a flowchart illustrating a processing procedure for reducing the data amount of the image stored in the HDD 5 according to the first to fourth embodiments. In this flowchart, first, a so-called stored image stored in the HDD 5 is determined which category is included among a plurality of categories based on predetermined image characteristics (step S1). This category determination is performed at the time when an image (data thereof-the same applies hereinafter) is stored in the HDD 5, and is stored together with the image as one of accompanying information. In this embodiment, the document is classified into three types of document types, that is, a text document, a photo document, and a mixed document. Details of this category determination will be described later.

  The date and time when the image is stored in the HDD 5 is also stored in the HDD 5 as one of the supplementary information together with the image. Based on this date and time, it is determined whether the elapsed time from the accumulation time is a predetermined time T1 (for example, one month) or more (step S2). The longer the elapsed time since the image was accumulated, the lower the possibility that the accumulated image will be reused. This processing is finished without performing processing for reducing the data amount with emphasis (step S2-no).

For an accumulated image that has been accumulated for a predetermined time or longer (step S2-yes), the CPU 6 obtains output history information of all accumulated images included in the determined category (step S3). As described above, the HDD 5 stores the output history information together with the image (data thereof). In this embodiment, only output resolution history information is acquired from the output history information. Specifically, the following number of outputs is obtained from the history information of the output resolution of the stored image included in the determined category. That is,
(1) Number N1 of “output resolution ≦ 200 dpi”
(2) Number N2 of “200 dpi <output resolution ≦ 400 dpi”
(3) Number N3 of “400 dpi <output resolution”
It is. Then, based on the history information of the output resolution for each category thus obtained, a process for reducing the data amount of the accumulated image is performed (step S4). Details of the method for reducing the data amount will be described later. In this way, the image with the reduced data amount is stored in the HDD 5.

The category determination in step S1 is performed as follows.
As described above, in this embodiment, the document is classified into three types of document types, that is, a character document, a photo document, and a mixed document. This classification can be performed by performing layout analysis on the stored image. Layout analysis is often used in pre-processing of OCR processing and the like, and various methods for that purpose are disclosed. These layout methods can be used for layout analysis. For example, as disclosed in Japanese Patent Application Laid-Open No. 2001-297303, a background color of a document image is specified, pixels other than the background region are extracted from the document image using the background color, and the connected components are integrated by integrating the pixels. Is generated, and the connected component is classified into a predetermined region using at least a shape feature, whereby a character region or a photographic region can be identified.

  For character area identification, for example, a method for identifying a character area using the shape of a circumscribed rectangle after performing an adaptive binarization process as disclosed in JP-A-7-73271. It can also be used. Further, for example, as disclosed in Japanese Patent Application Laid-Open No. 7-221968, the adjacent relationship of the black area of the image is analyzed and separated into rectangles, and the character of the image is based on the size of the rectangle and the distribution density of the black areas. It is also possible to use a technique for identifying regions of photographs, graphics (graphics), and tables. By using such a known method (or a combination thereof), it is possible to divide into areas for each attribute such as a character area, a photograph area, a graphic area, and a table area.

  An example of layout analysis is shown in FIG. In the example of (a), the area is divided into three areas including only the character areas L1, L2, and L3. In the example of (b), it is divided into six areas, character areas L11, L12, L13, and L14, a graphic area D1, and a photo area P1. In the example of (c), it is divided into two areas, a graphic area D11 and a photograph area P11. Based on the layout analysis result, the document type of the stored image is determined. As a result of the layout analysis, if only a character area exists as shown in FIG. If the character area and other areas (graphic area and photo area) are mixed as shown in FIG. If the character area is not included and only other areas (graphic area or photo area) exist as in (c), it is determined as “photo document”.

The processing for reducing the amount of data in step S4 is performed as follows.
In step S4, the data amount is reduced as follows from the history information of the output resolution for each category acquired in step S3.

(1) When the number N1 of “output resolution ≦ 200 dpi” is the highest The resolution of the 600 dpi accumulated image is converted to 200 dpi.
(2) When the number N2 of “200 dpi <output resolution ≦ 400 dpi” is the highest In the case of a text document, the resolution conversion of the 600 dpi accumulated image is performed to 400 dpi.
In the case of a mixed document, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
In the case of a photographic document, the resolution of the 600 dpi accumulated image is converted to 200 dpi.
(3) When the number of times N3 where “400 dpi <output resolution” is the highest In the case of a character document, resolution conversion is not performed with 600 dpi.
In the case of a mixed document, the resolution of the 600 dpi accumulated image is converted to 500 dpi.
In the case of a photographic document, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
This resolution conversion can be performed by operating only the scaling unit 33 of the second image data processing device 4 or by executing a program with the CPU 6.

  As described above, the degree of reduction of the data amount is determined depending on how images of the same document type are often output. In addition, when the resolution of a character document is lowered, the readability of the character is deteriorated. Therefore, in order to ensure reusability, the degree of resolution reduction is suppressed as much as possible.

As described above, according to this embodiment,
(1) Analyzing output history information of images with similar image characteristics and performing control to reduce the amount of data of the stored image based on how it is actually used (usage tendency). Thus, it is possible to secure the free capacity of the storage device such as the HDD 5 while ensuring the reusability.
(2) Since a document having similar image characteristics is considered to have a similar usage tendency, not only output history information of the target accumulated image but also output history information of an accumulated image having the same image characteristics as the image By using, reusability can be ensured more reliably.

There are effects such as.

  In this embodiment, the document type is classified into three types of character document, photo document, and mixed document from layout analysis. For example, whether or not a table is included or the ratio of character areas in the case of a mixed document. You may classify more finely using.

  In step S2, the elapsed time from the start of image accumulation is used as a criterion for determination. However, the elapsed time from the last output of the image can also be used as a criterion for determination. Alternatively, it is possible to determine whether or not the free capacity of the HDD 5 is equal to or smaller than a predetermined capacity, and to perform the process of reducing the data amount of the image after step S2 only when the HDD 5 is equal to or smaller than the predetermined capacity. Further, it may be configured to determine whether or not to perform the process of reducing the data amount of the accumulated image by a user's selection input from the operation display device 10. At this time, by making it possible to set the processing for each image, it is possible to leave an important image that is reused over a long period of time without degrading the image quality.

  Example 2 will be described below.

  In FIG. 4, first, it is determined which category of a plurality of categories based on predetermined image characteristics is included in a so-called accumulated image accumulated in the HDD 5 (step S1). This category determination is as described in the first embodiment, and is classified into three types of document types, that is, a text document, a photo document, and a mixed document. Next, as in the first embodiment, the elapsed time since the image was accumulated is compared with a predetermined (reference) time T1, and when the accumulation time has passed the predetermined time T1, all of the categories included in the determined category are determined in step S3. As the output history information of the accumulated image, a ratio A% (= number of outputs at 300 dpi or less / total number of outputs) at which the output resolution is 300 dpi or less is acquired.

In step S4, based on the output ratio A% of 300 dpi or less,
(1) When the category of the stored image is a character document When A> 80%, the resolution of the 600 dpi stored image is converted to 300 dpi.
When 80% ≧ A> 50%, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
In other cases, resolution conversion is not performed with 600 dpi. (2) When the category of the accumulated image is a photographic document When A> 50%, the resolution of the 600 dpi accumulated image is converted to 200 dpi.
In other cases, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
(3) When the category of the stored image is a mixed document When A> 50%, the resolution of the 600 dpi stored image is converted to 300 dpi.
In other cases, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
Thus, the data amount of the stored image is reduced.

  Through the control as described above, as in the first embodiment, it is possible to secure the free capacity of the storage device such as the HDD while ensuring the reusability of the stored image.

  Example 3 will be described below.

  In FIG. 4, first, it is determined which category of a plurality of categories based on predetermined image characteristics is included in a so-called accumulated image accumulated in the HDD 5 (step S1). This category determination is as described in the first embodiment, and is classified into three types of document types, that is, a text document, a photo document, and a mixed document. Next, the elapsed time since the image was accumulated in step S2 is compared with a predetermined (reference) time T1, and when the accumulation time has passed the predetermined time T1, the determined category is determined in step S3. As output history information of all the stored images included, a ratio A% (= number of outputs at 300 dpi or less / total number of outputs) where the output resolution is 300 dpi or less, and a ratio B% (= monochrome mode) where the output color mode is the monochrome mode Output count / total output count), use ratio C% of image quality adjustment function such as density adjustment function or sharpness adjustment function (= output count using image quality adjustment function / total output count).

In step S4, based on these information,
(1) Case where the category of the stored image is a photographic document When A> 50%, the resolution of the 600 dpi stored image is converted to 200 dpi.
If A ≦ 50%, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
When C ≦ 50%, recompression is performed with a Q value = 80.
If C> 50%, the Q value remains at 90.
(2) When the category of the stored image is a text document When A> 80%, the resolution of the 600 dpi stored image is converted to 300 dpi.
When 50% <A ≦ 80%, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
When A ≦ 50%, the resolution is not converted at 600 dpi.
When B> 50%, color conversion to a monochrome image is performed.
When 30% <B ≦ 50%, color conversion to an index color image is performed.
When B ≦ 30%, color conversion is not performed for a full-color image.
When C ≦ 50%, recompression is performed with a Q value = 50.
If C> 50%, recompress with Q value = 70.
(3) When the category of the stored image is a mixed document When A> 50%, the resolution of the 600 dpi stored image is converted to 300 dpi.
In the case of A ≦ 50%, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
When B> 80%, color conversion to a monochrome image is performed.
When B ≦ 80%, color conversion is not performed for a full-color image.
When C ≦ 50%, recompression is performed with a Q value = 60.
If C> 50%, recompress with Q value = 80.
Thus, the data amount of the stored image is reduced.

  Here, in the output history information, the compression rate is changed based on the usage ratio of the image quality adjustment function when the image is output using the image quality adjustment function such as the density adjustment function or the sharpness adjustment function. This is because the demand for image quality is considered high. Therefore, when the usage rate of the image quality adjustment function is high, the compression rate is not lowered so much.

  In addition, if the resolution of a character document is lowered, the readability of the character is deteriorated. However, even if the compression rate is increased (even if the Q value is reduced), the compression noise increases, but the readability of the character is maintained. Moreover, even if it becomes a monochrome image, there is no influence on the readability of a character. On the other hand, even if the resolution of a photographic document is lowered, there is little influence. However, if the compression rate is increased, compression noise (particularly block noise in JPEG compression) becomes conspicuous and the image quality deteriorates greatly. Considering these points, the processing method for reducing the amount of image data and the degree thereof are changed depending on the category of the image.

  As described above, according to the present embodiment, resolution conversion and recompression are performed using output history information of a plurality of items, so that free space in a storage device such as an HDD is ensured while ensuring reusability more reliably. Can be secured.

  Hereinafter, Example 4 will be described.

In FIG. 4, first, category determination in step S <b> 1 is performed on a so-called accumulated image accumulated in the HDD 5. In the category determination of the fourth embodiment, the color ratio is classified into three categories of low / medium / high based on the color ratio in the image. Specifically, first, it is determined whether each pixel of the image is a chromatic color or an achromatic color. S = Max (R, G, B) −Min (R, G, B)
When the saturation S is greater than or equal to a predetermined value, it is determined as a chromatic color, and when it is less than the predetermined value, it is determined as an achromatic color. This determination is performed for all pixels,
Color ratio = (number of chromatic pixels / total number of pixels) x 100 [%]
Calculate the color ratio as

And when the color ratio is (1) less than 10%, the color ratio = low,
(2) When the ratio is 10% or more and less than 30%, the color ratio = medium (3) When the ratio is 30% or more, the color ratio = high.

  Next, the elapsed time since the image was accumulated in step S2 is compared with a predetermined (reference) time T1, and when the accumulation time has passed the predetermined time T1, the same as in example 3 in step S3. Furthermore, as output history information of all accumulated images included in the determined category, a ratio A% (= number of outputs at 300 dpi or less / total number of outputs) where the output resolution is 300 dpi or less, and the output color mode is a monochrome mode. Ratio B% (= output count in monochrome mode / total output count), use ratio C% of image quality adjustment function such as density adjustment function and sharpness adjustment function (= output count using image quality adjustment function / total output count) get.

In step S4, the data amount of the accumulated image is reduced based on such information. That is,
(1) When the color ratio is low Since it is highly possible that the document is a text document,
If A> 80%, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
When 50% <A ≦ 80%, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
When A ≦ 50%, the resolution is not converted at 600 dpi.
When B> 50%, color conversion to a monochrome image is performed.
When 30% <B ≦ 50%, color conversion to an index color image is performed.
When B ≦ 30%, color conversion is not performed for a full-color image.
When C ≦ 50%, recompression is performed with a Q value = 50.
If C> 50%, recompress with Q value = 70.
(2) When Color Ratio = Medium Since there is a high possibility that the document is a mixed document, if A> 50%, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
In the case of A ≦ 50%, the resolution of the 600 dpi accumulated image is converted to 400 dpi.
When B> 80%, color conversion to a monochrome image is performed.
When B ≦ 80%, color conversion is not performed for a full-color image.
When C ≦ 50%, recompression is performed with a Q value = 60.
If C> 50%, recompress with Q value = 80.
(3) When the color ratio is high There is a high possibility that it is a photographic document.
If A> 50%, the resolution of the 600 dpi accumulated image is converted to 200 dpi.
If A ≦ 50%, the resolution of the 600 dpi accumulated image is converted to 300 dpi.
When C ≦ 50%, recompression is performed with a Q value = 80.
If C> 50%, the Q value remains at 90.
Thus, the data amount of the stored image is reduced.

  As described above, according to the present embodiment, the determination of the image category based on the color ratio is simpler than the determination using the layout analysis. Therefore, the resolution similar to that of the third embodiment is determined based on the simple determination process. Conversion and recompression can be performed, and the free space of the HDD 5 (storage device) can be ensured while ensuring reusability more reliably.

  Example 5 will be described below.

  The fifth embodiment is an example in which the data amount reduction method is determined only from the usage history of the target stored image when the target stored image is output many times. FIG. 5 is a flowchart showing a processing procedure in the fifth embodiment.

  In FIG. 5, first, it is determined which category of a plurality of categories based on a predetermined image feature is included in a so-called accumulated image accumulated in the HDD 5 (step S <b> 11). This category determination is as described in step S1 of the first embodiment, and is classified into three types of document types, that is, a text document, a photo document, and a mixed document. Next, in step S12, the elapsed time since the image was stored in the same manner as in the first embodiment is compared with a predetermined (reference) time T1, and when the predetermined time T1 has elapsed, in step S13, the target stored image It is determined whether the number of outputs is a predetermined number M or more. When it is less than M, the process proceeds to steps S16 and S17. Steps S16 and S17 are the same as the processes in steps S3 and S4 in FIG. 4, and output history information of all accumulated images included in the determined category is acquired, and the data amount of the accumulated images is reduced based on the information. To do.

  On the other hand, when the number of outputs of the target accumulated image is M or more in step S13, the process proceeds to steps S14 and S15. In step S14, output history information of the target accumulated image is acquired, and in step S15, the data amount of the accumulated image is reduced based on the information. The specific image data reduction processing in steps S15 and S17 appropriately employs the processing described in the first to fourth embodiments.

  As described above, when the number of outputs of the target accumulated image is large, it is clear how the accumulated image is often output, so the data amount can be reduced only from the output history information of the image. By determining the method and its degree, it is possible to secure the free capacity of the storage device such as the HDD while ensuring the reusability of the stored image (steps S13-yes, S14, S15). Conversely, if the number of outputs of the target stored image is small, it is unclear how the stored image is often output, so the output history information of the stored image having the same image characteristics as that image is used. By determining the method for reducing the data amount of the target image and its degree, reusability can be ensured reliably (steps S13-no, S16, S17).

  In addition, this invention is not limited to this embodiment, It cannot be overemphasized that all the technical matters contained in the technical idea described in the claim are object.

As described above, according to the present embodiment,
(1) Since the data amount of the stored image is reduced based on the usage history including other stored images with similar image characteristics, it is possible to achieve both reusability of the stored image and securing of free space in the HDD 5. .
(2) Since data is classified into categories based on the document type of the stored image, the data amount can be reduced by an optimum method or degree for each document type.
(3) Since data is classified into categories based on the color ratio of the stored image, the data amount can be reduced by an optimal method or degree for each color ratio.
(4) Since the degree to which the data amount is reduced is set for each category based on the image characteristics of the stored image, the data amount can be reduced to an optimum degree for each image.
(5) Since a process for reducing the data amount is set for each category based on the image characteristics of the stored image, the data amount can be reduced by an optimum process for each image.
(6) When the number of reuses of the stored image is large, the data amount is reduced based only on the use history of the image regardless of the use history of other stored images having similar image characteristics. The amount of data can be reduced by a method or degree optimal for reuse.
(7) Since it is determined whether or not to perform the process of reducing the data amount of the stored image based on the data amount that can be stored in the image storage device, only when the HDD 5 has a small free space, the image data amount Can be reduced.
(8) Since it is determined whether or not to perform the process of reducing the data amount of the accumulated image based on the elapsed time after the image is stored, only for an image having a long time since being accumulated in the HDD 5 The amount of image data can be reduced.
(9) Since it is possible to set in advance whether or not to reduce the data amount of the stored image, it is possible to leave an important image without degrading the image quality.
There are effects such as.

1 is a block diagram showing an overall configuration of a digital multifunction peripheral (MFP) according to an embodiment of the present invention. It is a block diagram which shows the structure of a 1st image data processing apparatus. It is a block diagram which shows the structure of a 2nd image data processing apparatus. 6 is a flowchart illustrating a processing procedure in the first to fourth embodiments. 10 is a flowchart illustrating a processing procedure in the fifth embodiment. It is a figure for demonstrating layout analysis when classifying into the category of the document type of a text document, a photograph document, and a mixed document.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reading apparatus 2 1st image data processing apparatus 3 Bus control apparatus 4 2nd image data processing apparatus 5 HDD
6 CPU
7 Memory 8 Plotter I / F Device 9 Plotter Device 10 Operation Display Device

Claims (12)

An image processing apparatus comprising storage means for storing digitized image data, and an image processing means for performing predetermined image processing on the input or stored image data,
An image classifying means for classifying the plurality of categories on the basis of the image data stored in said storage means to the image feature,
The use history of the image quality adjustment function as an output history information when outputting the image together with the image data is stored in the storage means, of the image quality adjustment function of images included in the classified category by the image classifying unit data reducing means for reducing a data amount of the image data stored in the storage means based on the use history,
The image processing apparatus characterized by comprising a. The image processing apparatus according to claim 1.
The image processing unit is characterized in that the image classification means classifies the image based on a document type of the image. The image processing apparatus according to claim 1.
The image processing device according to claim 1, wherein the image classification means classifies based on a color ratio that is color information of an image. The image processing device what Re one Kouki placement of claims 1 to 3,
The image processing apparatus according to claim 1, wherein the data reduction means switches a degree of reducing the data amount of the image data stored in the storage means for each category classified by the image classification means. The image processing device what Re one Kouki placement of claims 1 to 3,
The image processing apparatus, wherein the data reduction unit switches processing for reducing the data amount of image data stored in the storage unit for each category classified by the image classification unit. The image processing device what Re one of claims 1 to 3,
Said data reduction means, when the output number of the image data stored in the storage means is equal to or more than a predetermined number of times, the use history of the image quality adjustment function of images included in the classified category by the image classifying unit regardless of, based on only the use history of the image quality adjustment function of the image, the image processing apparatus characterized by reducing the data amount of the image data. The image processing device what Re one Kouki placement of claims 1 to 6,
The data reduction unit determines whether or not to perform a process of reducing the data amount of the image stored in the storage unit, based on the data amount that can be stored in the storage unit. . The image processing device what Re one Kouki placement of claims 1 to 6,
The image processing apparatus, wherein the data reduction unit determines whether or not to perform a process of reducing the data amount of the image data based on an elapsed time since the image data is stored in the storage unit. The image processing apparatus according to claim 7 or 8,
An image processing apparatus comprising: means for presetting whether or not to reduce the amount of image data stored in the storage means. And tens Re one Kouki mounting image processing apparatus according to claim 1-9,
Image output means for outputting a visible image based on the image data processed by the image processing device;
An image forming apparatus comprising: Storage means for storing the digitized image data, input or a stored image processing means for performing predetermined image processing on the image data has, storing input the image data into the storage means In an image storage method for
By the image classifying means, a first step of classifying into a plurality of categories on the basis of the image data stored in said storage means to the image feature,
The data reducing means, a second step of storing in the storage means together with the image data use history of the image quality adjustment function as an output history information when outputting an image,
The data reducing means, reduce the amount of data of the image data stored in said storage means based on the use history of the image quality adjustment function of images included in the classified categories of images included in the classified categories A third step of
An image storage method characterized by comprising: Storage means for storing the digitized image data, and an image processing means for performing predetermined image processing on the input or stored image data, is stored in the storage means the input the image data In a computer program for executing control by a computer,
By the image classifying means, the procedure of the first step of classifying into a plurality of categories on the basis of the image data stored in said storage means to the image feature,
The data reducing means, a procedure of the second step of storing in the storage means together with the image data use history of the image quality adjustment function as an output history information when outputting an image,
The data reducing means, a procedure of a third step of reducing the data amount of the image data stored in the storage unit based on the use history of the image quality adjustment function of the image contained in the classified category,
Computer program characterized in that it comprises a.

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