JP2007005949A - Image forming apparatus, method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform high quality print out without degrading the image quality even in network copy processing while emphasizing the print out processing speed. <P>SOLUTION: The image forming apparatus 2 comprises an image output means 24 for outputting image data, a means 25 for determining whether image data to be outputted has a format of raster image data having hierarchic structure or not, and a means 26 for converting resolution of the image data to be outputted and switching execution of resolution conversion depending on the determination results from the determination means 25. Resolution conversion for reducing resolution of image data while emphasizing the output processing speed is performed for the image data other than the raster image data having hierarchic structure, but resolution conversion is not performed while emphasizing the output image quality for the raster image data having hierarchic structure and it is outputted as a visible image. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming method, and an image forming program for converting image data into a visible image and outputting the image.

  In recent years, with the development of network-related technology, in a network system in which a scanner device and a printer device are connected via a network line, so-called network copy processing is performed, that is, image data read by the scanner device is transferred to the printer device. It is widely performed to send and print out. However, in the network copy process, unlike the copy process using the copying machine, the image data passes through the network line. Therefore, it has been proposed that image data to be transmitted is converted into, for example, MRC (Mixed Raster Contents) format data, thereby reducing the communication load on the network line (see, for example, Patent Document 1). .

  The MRC format is a raster image that expresses characters, line drawings, etc., in a relatively high resolution bitmap, and a raster image that expresses natural images, gradation images, etc., in a relatively low resolution, by color and area. Each image plane has a hierarchical structure and is an image format in which each image plane is compressed by a compression method optimum for the image type and wrapped into one file. In other words, by dividing the image data into “image elements that require low resolution” and “image elements that require high resolution”, and applying the optimal resolution and compression method to each, it is possible to achieve both high image quality and low file size. It is a thing.

  By the way, when printing output of image data in a printer apparatus, it is common to perform resolution conversion that lowers the resolution of image data to be output with emphasis on the speed of the print output processing. This is because a high-resolution raster image has a large file size and requires a long transfer time, but the image quality that requires high-resolution processing in print output processing is rarely required. Such resolution conversion processing is performed as part of image data decomposing processing in the printer apparatus, or as part of driver processing in a client computer (PC) that issues a print output job to the printer apparatus.

JP 2001-136361 A

  However, in the case of network copy processing, the user is expected to expect the same output image quality as in the case of copy processing using a copying machine, and image data in MRC format transmitted via a network line is also character, line drawing, etc. Can be output at the same high resolution as normal copy processing, but if the resolution conversion processing described above is performed when printing image data, the high image quality expected by the user may not be achieved. Also, the characteristic of the MRC format that achieves both high image quality and low file size is lost. This point may be dealt with by not performing the resolution conversion process. However, if the resolution conversion process is not performed uniformly even in the case of a print output job other than the network copy process, the print output job This is not preferable because the processing speed is reduced.

  Therefore, the present invention focuses on the speed of print output processing, and can perform high-quality print output without impairing image quality even when performing network copy processing, for example. It is an object to provide a method and an image forming program.

  The present invention is an image forming apparatus devised to achieve the above object, wherein image output means for converting image data into a visible image and outputting, and the format of image data to be output by the image output means has a hierarchical structure. It is possible to perform resolution conversion on the image data to be output by the image output means and determination means for determining whether or not the image data is raster image data, and perform the resolution conversion according to the determination result in the determination means. And a resolution conversion means for switching whether to perform or not.

  The present invention also relates to an image forming method devised to achieve the above object, wherein the image data is output as a visible image, and the format of the image data to be output is a hierarchical structure. A determination step for determining whether or not the image data is composed of raster image data, and resolution conversion for the image data to be output can be performed, and whether or not the resolution conversion is performed according to the determination result in the determination step And a resolution conversion step for switching between them.

  In addition, the present invention provides an image forming program devised to achieve the above object, a computer connected to an image forming apparatus for converting image data into a visible image and outputting the image data, or a computer functioning as the image forming apparatus. A discriminating means for discriminating whether or not the format of image data to be output by the image output device is composed of raster image data having a hierarchical structure, and resolution conversion for the image data to be output by the image output device can be performed. , And functioning as resolution conversion means for switching whether or not to perform the resolution conversion in accordance with the determination result of the determination means.

According to the image forming apparatus having the above-described configuration, the image forming method having the above-described procedure, and the image forming program having the above-described configuration, when the image data is converted into a visible image and output, the format of the image data to be output is a hierarchical structure. It is determined whether or not it is composed of the raster image data. “Hierarchical raster image data” is a hierarchical structure having a plurality of image planes, and is composed of raster image data to which an optimal resolution is applied for each image plane. A typical example is image data in the MRC format. For example, this determination may be performed by recognizing information related to the format of the header portion of the image data to be output.
When the format is discriminated, whether to perform resolution conversion on the image data to be output is switched according to the discrimination result. For example, if the raster image data is not hierarchically structured, the resolution conversion is performed by reducing the resolution of the image data to be output with an emphasis on the speed of output processing. However, if the raster image data is hierarchically structured, the output image quality is emphasized. Thus, resolution conversion of image data to be output is not performed. In other words, resolution conversion for the image data is performed according to the format of the image data to be output without preparing a signal for instructing the necessity of resolution conversion separately from the image data or including it in the image data. It is possible to switch whether or not to perform.

  As described above, the image forming apparatus, the image forming method, and the image forming program of the present invention can switch whether or not resolution conversion is performed on the image data depending on the format of the image data to be output. In the case of a format that should be emphasized, it is possible to improve the processing speed by performing resolution conversion that lowers the resolution. In the case of a format that emphasizes output image quality, resolution conversion is not performed. High-quality output can be performed. In other words, high-quality image output can be performed without impairing the image quality in some cases while placing importance on the speed of the print output processing. Moreover, since such switching is performed based on the format of the image data, it is necessary to prepare a signal for instructing whether or not resolution conversion is necessary separately from the image data or to include it in the image data. Thus, the processing load (especially signal communication load etc.) can be reduced.

  Hereinafter, an image forming apparatus, an image forming method, and an image forming program according to the present invention will be described with reference to the drawings.

First, a schematic configuration of a system including an image forming apparatus will be described.
FIG. 1 is a block diagram showing an example of a system configuration to which the present invention is applied. In short, the network system described here is configured such that the scanner device 1, the printer device 2, and the client PC 3 are connected via the network line 4 and can perform network copy processing. It is a thing. In the example shown in the figure, there is one scanner device 1, one printer device 2, and one client PC 3, but it is needless to say that there may be a plurality of them on the network line 4.

The scanner device 1 includes an image reading unit 11 that optically reads image data from a document and a data transmission unit 12 that transmits the image data read by the image reading unit 11 to the network line 4 in order to perform a network copy process. And. Further, in the scanner device 1, in order to reduce the communication load on the network line 4, the format conversion unit 13 that converts the format of the image data to be transmitted by the data transmission unit 12 and the data amount are reduced. Data compression means 14 for performing the processing.
The format conversion means 13 converts the image data to be transmitted into a format composed of raster image data having a hierarchical structure, specifically, an MRC format whose details will be described later.
Further, the data compression unit 14 compresses the image data after the format conversion by the format conversion unit 13 by an optimal compression method for each image plane constituting the image data.
As a result, the scanner device 1 divides the image data to be transmitted into “image elements that require low resolution” and “image elements that require high resolution”, and applies the optimum resolution and compression method to each. Therefore, both high image quality and low file size can be achieved.

  The printer device 2 receives image data transmitted through the network line 4 and prints out the image data. In other words, the printer apparatus 2 functions as an image forming apparatus that converts the image data into a visible image and outputs it. For this purpose, in the printer apparatus 2, a data acquisition unit 21 that receives image data transmitted through the network line 4, a data expansion unit 22 that performs expansion processing on the image data received by the data acquisition unit 21, and an image after expansion processing The image development unit 23 develops (decomposes) the data into a printable format, and the image output unit 24 prints out the developed image data on a recording sheet using, for example, an electrophotographic method.

In addition, the printer apparatus 2 includes a determination unit 25 and a resolution conversion unit 26 in addition to these units 21 to 24.
The discriminating unit 25 determines whether or not the format of the image data acquired by the data acquiring unit 21, that is, the image data to be output by the image output unit 24, is a raster image data having a hierarchical structure. It is determined whether or not it is of the MRC format whose details will be described later. This determination result is notified to the resolution conversion means 26.
The resolution conversion unit 26 reduces the resolution of the image data to be output as part of the decomposing process performed by the image development unit 23 in order to improve the processing speed when the image output unit 24 prints out the image data. Can be done. However, the resolution conversion unit 26 does not always perform resolution conversion for all image data, but switches whether to perform resolution conversion according to the determination result of the determination unit 25.

  The client PC 3 issues a print output job for the printer apparatus 2. For this purpose, the client PC 3 transmits the image data generated or acquired by the client PC 3 to the printer device 2 through the network line 4 in a predetermined format while following the instructions from the application program or operation system installed in the client PC 3. Printer driver means 31 is provided. The predetermined format here may be a format used for general printout processing, but is assumed to be composed of only raster image data having a hierarchical structure, specifically, not the MRC format.

  Here, the format of image data used when performing network copy processing in the network system configured as described above will be described. When performing the network copy processing, the image data read by the image reading unit 11 of the scanner device 1 is converted into a format composed of raster image data having a hierarchical structure by the format conversion unit 13 of the scanner device 1, and further the data It is compressed by the compression means 14 so that both high image quality and low file size can be achieved. A typical example of the format composed of raster image data having a hierarchical structure, which is a format that achieves both high image quality and low file size, is the MRC format.

  FIG. 2 is an explanatory diagram showing an outline of the MRC format. The MRC format is generally divided into two types. As shown in FIG. 2A, one type is a format (hereinafter referred to as “multi-layer format”) in which a multi-layer (Mask 1 to 6) character / line image is superimposed on a single background image (Background). is there. In addition, as shown in FIG. 2B, another type is a format composed of a background image (Background), a surface image (Foreground), and a mask image (Selector) indicating which part is the surface image. (Hereinafter referred to as “three-layer format”).

  FIG. 3 is an explanatory diagram showing a specific example of the multilayer format. As shown in the figure, in the multi-layer format, the background image layer is composed of only a plane of a picture or picture area, which is an image element in which gradation is important and low resolution, and a compression method suitable for the picture / picture area. JPEG (Joint Photographic Experts Group) compression is performed. On the other hand, all the layers other than the background image layer are composed of only a plane of a character or line drawing image area that is an image element requiring high resolution, and are compression methods suitable for the character / line drawing area. MMR (Modified Modified Read) compression is performed. In the multilayer format, the data format in each layer is a raster format. That is, for example, even a layer of a character / line drawing area is represented by raster image data, not a text data format or a vector data format.

  FIG. 4 is an explanatory diagram showing a specific example of the three-layer format. As shown in the figure, in the three-layer format, the background image layer (hereinafter referred to as the “Back layer”) consists of a plane of only a photo / picture area, which is an image element in which gradation is important and low resolution is required. JPEG compression, which is a compression method suitable for the area, is performed. Furthermore, the surface image layer (hereinafter referred to as “Fore layer”) is for characters or line drawings, which are image elements that require high resolution, and corresponds to the color information of the characters / line drawings. Therefore, multi-level JPEG compression is performed. Further, the mask image layer (hereinafter referred to as “Mask layer”) indicates which portion is the Fore layer (character / line image), and high resolution is required, so MMR compression is performed. In the three-layer format, the data format in each layer is a raster format as in the case of the multilayer format. That is, for example, even the Mask layer is represented by raster image data, not a text data format or a vector data format.

  Next, in the printer device 2 of the network system as described above, an example of processing operation when image data transmitted through the network line 4 is received and the image data is printed out, that is, the image forming method according to the present invention. Will be described.

FIG. 5 is a flowchart showing an example of the procedure of the image forming method according to the present invention.
In the printer device 2, when the data acquisition unit 21 receives image data transmitted through the network line 4 (step 101, step is hereinafter abbreviated as “S”), that image data, that is, an image to be output by the image output unit 24. The determination means 25 determines whether the format of the data is the MRC format (S102). It is conceivable to determine whether or not the format is the MRC format as follows.

  For example, for a multi-layer format, first, it is determined whether or not an object (image element) in one page of image data to be output is composed of only raster image data. For example, if the image data is a PDF (Portable Document Format) file, this determination may be made with reference to header (attribute) information about each object constituting the PDF file. If there is at least one other than raster image data (such as vector data), it is determined that it is not in the MRC format.

  If the object is composed only of raster image data, then, referring to the attribute information of each object, the compression method for each raster image data is recognized, and the compression methods are JPEG compression and MMR compression. It is judged whether it is comprised only by. If there is a compression method other than JPEG compression or MMR compression, it is determined that it is not in the MRC format.

  In the case where the compression method is configured only by JPEG compression and MMR compression, whether or not there is only one object by JPEG compression among the compression methods configured only by JPEG compression and MMR compression. Judging. If there is only one object by JPEG compression, it is determined that the image data received by the data acquisition unit 21 is in the MRC format by the multilayer format.

  For example, for the three-layer format, first, it is determined whether or not an object (image element) in one page of image data to be output is composed only of raster image data. This determination may be made in the same manner as in the multilayer format. If there is at least one other than raster image data (such as vector data), it is determined that it is not in the MRC format.

  If the object is composed only of raster image data, it is then determined whether the compression method for each raster image data is composed only of JPEG compression and MMR compression, as in the case of the multi-layer format. . If there is a compression method other than JPEG compression or MMR compression, it is determined that it is not in the MRC format.

  In the case where the compression method is composed only of JPEG compression and MMR compression, whether or not each object in one page can be classified into one of Back layer, Fore layer, and Mask layer, that is, It is determined whether or not the page is composed of one page Back layer, Fore layer and Mask layer. This determination may also be made by referring to attribute information about each object. If the image data is composed of the Back layer, Fore layer, and Mask layer, it is determined that the image data received by the data acquisition unit 21 is in the MRC format using the three-layer format.

  However, if the page information in the image data received by the data acquisition means 21 includes tag information specially set in the network system to indicate the MRC format, a series of the above-described series Instead of performing the procedure, it may be determined whether the format is the MRC format based on the tag information.

  If the format of the image data received by the data acquisition unit 21 is not the MRC format as a result of the determination by the determination unit 25 as described above, the image data is transmitted from the client PC 3 for processing the print output job. Is. Accordingly, in the printer device 2, the resolution conversion means 26 performs resolution conversion for reducing the resolution of the image data in order to improve the processing speed when the image data is printed out (S103). Since this resolution conversion may be performed using a known technique, a detailed description thereof is omitted here. Then, when the resolution conversion means 26 performs the resolution conversion, the image output means 24 prints out the image data after the resolution conversion onto the recording paper (S104).

  On the other hand, if the format of the image data received by the data acquisition unit 21 is the MRC format as a result of the determination by the determination unit 25, the image data is transmitted from the scanner device 1 for network copy processing. It is. That is, it is considered that the user expects output image quality similar to that in the case of copy processing using a copying machine, rather than improvement in processing speed when performing print output. Therefore, in the printer device 2, the image output unit 24 prints out the image data on the recording paper without performing resolution conversion by the resolution conversion unit 26 on the image data received by the data acquisition unit 21. (S104). That is, it is possible to switch whether or not the resolution conversion by the resolution conversion unit 26 is performed according to the determination result of the determination unit 25, and for the image data in the MRC format, the resolution conversion is not performed on the image data. In addition, the image data is printed out.

  As described above, according to the printer apparatus 2 and the image forming method performed by the printer apparatus 2 described in the present embodiment, when the image data is printed out, the format of the image data to be printed out is the MRC format. It is determined whether or not there is, and switching whether or not to perform resolution conversion on the image data to be output is switched according to the determination result. Specifically, if the image data to be printed out is not in the MRC format, the resolution conversion is performed to reduce the resolution of the image data to be output with emphasis on the speed of the output process. For example, importance is attached to the output image quality, and resolution conversion of image data to be output is not performed. Therefore, the resolution conversion for the image data can be performed according to the format of the image data to be output without preparing a signal for instructing the necessity of resolution conversion separately from the image data or including it in the image data. It is possible to switch whether or not to perform.

  In other words, since whether or not to perform resolution conversion on the image data is switched depending on the format of the image data to be output, in the case of a format in which the speed of the output processing should be emphasized, the resolution conversion for reducing the resolution is performed, The processing speed can be improved, and in the case of a format where output image quality should be emphasized, high-quality output can be performed without performing resolution conversion. In other words, high-quality image output can be performed without impairing the image quality in some cases while placing importance on the speed of the print output processing. Moreover, since such switching is performed based on the format of the image data, it is necessary to prepare a signal for instructing whether or not resolution conversion is necessary separately from the image data or to include it in the image data. As a result, the processing load (especially signal communication load etc.) can be reduced.

  In particular, as described in the present embodiment, if resolution conversion is not performed in the MRC format, high-quality output is performed without performing resolution conversion on the image data of the MRC format. It is possible to achieve the same output image quality as copy processing using a copier, and the MRC format feature of high image quality and low file size will be utilized. It will be very suitable.

  Further, as described in the embodiment, if the determination as to whether the format is the MRC format is performed based on the compression method of the image data, it is possible to determine whether the format is a multilayer format or a three-layer format. For example, since the determination can be performed by recognizing the compression information included in the header portion of the image data, the determination can be performed easily and reliably.

  In the present embodiment, the preferred specific examples of the present invention have been described. However, the present invention is not limited to the contents, and can be appropriately changed without departing from the gist thereof.

  For example, in the present embodiment, the MRC format image data has been described in detail as an example of the hierarchical raster image data. However, the present invention is not limited to this, and the scanner device 1 does not always have to be limited to this. Even if the image data to be transmitted is in another format, it is conceivable to apply the present invention in the same manner.

  Further, in the present embodiment, when the printer device 2 determines whether or not it is the MRC format and whether or not resolution conversion is necessary according to the determination, that is, the printer device 2 determines the determination means 25 and the resolution conversion means. In the case of the network copy process, for example, the image data transmitted from the scanner apparatus 1 is a system configured to temporarily pass through the client PC 3 (client PC 3 The client PC 3 may perform at least the determination or both the determination and the resolution conversion switching. In this case, the printer driver unit 31 in the client PC 3 only needs to have functions as the determination unit 25 and the resolution conversion unit 26.

  Each of these means 25 and 26 functions as a computer (for example, the printer device 2 or the client PC 3 has an image when the printer device 2 has the function or the client PC 3 has the function). It may be realized by causing a predetermined program to be processed by a function (CPU or ASIC provided for processing data). In this case, however, the predetermined program is not necessarily installed in advance in the printer device 2 or the client PC 3, and is provided by being stored in a computer-readable storage medium for the printer device 2 or the client PC 3. Or may be distributed via wired or wireless communication means. That is, the functional configuration as the image forming apparatus in the present embodiment described above can also be realized by an image forming program that causes a computer to function as the image forming apparatus.

1 is a block diagram illustrating an example of a system configuration to which the present invention is applied. It is explanatory drawing which shows the outline | summary of a MRC format. It is explanatory drawing which shows the specific example of a multilayer format. It is explanatory drawing which shows the specific example of a three-layer format. 3 is a flowchart illustrating an example of a procedure of an image forming method according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Scanner apparatus, 2 ... Printer apparatus, 3 ... Client PC, 4 ... Network line, 11 ... Image reading means, 12 ... Data transmission means, 13 ... Format conversion means 13, 14 ... Data compression means, 21 ... Data acquisition means , 22 Data decompression means 22, 23 Image development means 23, 24 Image output means 24, 25 Discrimination means 26 Resolution conversion means 31 Printer driver means

Claims (9)

Image output means for converting the image data into a visible image and outputting the image data;
Discriminating means for discriminating whether or not the format of the image data to be output by the image output means is composed of raster image data having a hierarchical structure;
Resolution conversion means that can perform resolution conversion on the image data to be output by the image output means, and that switches whether or not to perform the resolution conversion according to the determination result of the determination means. Forming equipment. The resolution conversion means does not perform resolution conversion on the image data when the determination means determines that the format of the image data to be output by the image output means is a raster image data having a hierarchical structure. The image forming apparatus according to claim 1. The discriminating unit discriminates whether or not the format of the image data to be output by the image output unit is composed of hierarchical raster image data based on the compression method of the image data. The image forming apparatus according to claim 1. An image forming method for converting image data into a visible image and outputting the image,
A discriminating step for discriminating whether or not the format of image data to be output is composed of raster image data having a hierarchical structure;
A resolution conversion step of performing resolution conversion on the image data to be output and switching whether or not to perform the resolution conversion according to a determination result in the determination step. In the resolution conversion step, when the determination step determines that the format of the image data to be output is a raster image data having a hierarchical structure, resolution conversion is not performed on the image data. The image forming method according to claim 4. 5. The determination step according to claim 4, wherein whether or not the format of the image data to be output is composed of hierarchical raster image data is determined based on a compression method of the image data. 6. The image forming method according to 5. A computer connected to an image forming apparatus that converts image data into a visible image and outputs the computer, or a computer that functions as the image forming apparatus.
A discriminating means for discriminating whether or not the format of image data to be output by the image output device is composed of raster image data having a hierarchical structure;
An image characterized by being able to perform resolution conversion on image data to be output by the image output device and functioning as a resolution conversion means for switching whether or not to perform the resolution conversion according to a determination result by the determination means. Formation program. The resolution conversion means does not perform resolution conversion on the image data when the determination means determines that the format of the image data to be output by the image output apparatus is raster image data having a hierarchical structure. The image forming program according to claim 7. The discriminating unit discriminates whether or not the format of image data to be output by the image output apparatus is composed of raster image data having a hierarchical structure based on a compression method of the image data. The image forming program according to claim 7 or 8.

Images