JPH04287566A - Picture processor - Google Patents

Abstract

PURPOSE:To set optimum resolution automatically to send or store required information without leaving judgement to the operator. CONSTITUTION:A control section 15 reads a picture data at a maximum resolution of a picture read section 11 through preliminary scanning, and a binarizing processing section 12 implements nonmagnification resolution conversion, a binarizing processing section 13 binarizes the result and a resolution detection processing section 14 makes calculation for discriminating optimum resolution. When the preliminary scanning is finished, re-reading is started and the resolution conversion processing section 12 applies interleave processing to the picture data based on a magnification resulting from the result of discrimination and a binarizing processing section 13 binarizes the result and it is sent to a picture memory and a communication control section.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus such as a facsimile machine.

0002

2. Description of the Related Art Conventionally, in a facsimile, for example, a G4 facsimile, the resolution of a read image is 400×4.
00DPI (Dot Per Inch), 200×2
It has multiple resolutions such as 00DPI and 200×100DPI, and the operator judges the content of the document to be sent in advance.
Based on the results, the desired resolution is selected and set. For example, if the content is more important than the quality of the image, such as a document image, set a high resolution, or if the document to be sent does not require high resolution, to save communication time. You are setting a low resolution.

0003

However, in the conventional example described above, it is difficult for the operator to always set the optimum reading resolution for the image to be transmitted. For example, if you select a resolution lower than the required reading resolution, information will be lost and become unreadable on the receiving side, and if you select a resolution higher than the required reading resolution, communication time and costs will increase. There were problems such as waste of money.

[0004] Furthermore, in devices that can store image data in memory, it is possible to print out the stored images and check whether the transmission resolution is set correctly, but this is a cumbersome operation. There were also problems such as wasted time. The present invention has been made to solve the above problems, and provides an image processing device that can automatically set the optimal resolution for transmitting or storing necessary information without relying on the operator's judgment. The purpose is to

[0005]

Means and Effects for Solving the Problems In order to achieve the above object, an image processing apparatus of the present invention has the following configuration. That is, it has a setting means for setting a conversion magnification for resolution conversion from binarized image data, and a resolution conversion means for converting the resolution of the read image data using the conversion magnification set by the setting means.

Preferably, the invention further includes a first binarizing means for simply binarizing the image data, and a second binarizing means for performing pseudo-halftone processing on the image data, and the setting means includes: , a conversion magnification is set from the image data binarized by the first binarization means, and the image data converted by the resolution conversion means is binarized by the second binarization means. do.

[0007] More preferably, the apparatus further includes an image reading means capable of re-reading the same original, and the resolution converting means converts the resolution of the image data read by the image reading means. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the basic configuration of an image processing apparatus in this embodiment. In the figure, numeral 11 is an image reading unit with a shape (so-called flat bed type, etc.) that allows the same original to be read again.
It has a function of performing shading correction etc. on analog data read by an image sensor such as D, and then A/D converting the data into digital data and outputting the result. Reference numeral 12 denotes a resolution conversion processing unit, which converts the resolution using a magnification set based on the determination result of the resolution detection processing unit 14 (described later) at the time of rereading (for example, 400 x 400 DPI).
Converts an image read at a resolution of 200 x 200 DPI). A binarization processing section 13 performs simple binarization processing on the multivalued data converted by the resolution conversion processing section 12. Reference numeral 14 denotes a resolution detection processing section, which determines the resolution necessary for transmission from the image data binarized by the binarization processing section during pre-scanning. Reference numeral 15 denotes a control unit, which is composed of a microprocessor (MPU), RAM, ROM, etc., and controls the operation of each processing unit according to a control procedure (program) stored in the ROM.

Next, the processing procedure in this embodiment will be explained below with reference to the flowchart shown in FIG. In this embodiment, a prescan operation (steps S1 to S5) is performed to determine the optimal resolution, and resolution conversion is performed using a magnification based on the determination result obtained in the prescan. .

First, in step S1, the control section 15
instructs the image reading unit 11 to start reading, and reads the image data at the highest resolution that the image reading unit 11 has. Then, in step S2, the read image data is sent to the resolution conversion processing section 12, where it is converted to the same resolution. Next, when the resolution conversion process is completed, the process proceeds to step S3, and the converted image data is sent to the binarization processing unit 13 to be binarized, and in the next step S4, the resolution detection processing unit 14 Perform calculations to determine the optimal resolution. Next, when the processing in the resolution detection processing unit 14 is completed, the process advances to step S5, and it is checked whether the processing has been completed for all pixels, and if it has not been completed, the process returns to step S1, Repeat the above process.

On the other hand, when the pre-scan is completed, the process advances to step S6 and re-reading is started. In the next step S7, the image data is thinned out using a magnification based on the determination result obtained during pre-scanning by the resolution detection processing section 14. This thinning process is performed by the resolution conversion processing unit 12, and when the process is completed, the process advances to the next step S8, and the resolution-converted image data is sent to the binarization processing unit 13, where it is binarized. Then, in the next step S9, it is checked whether the processing has been completed for all pixels, and if it has not been completed, step S9 is performed.
The process returns to step 6, and the above-described process is repeated until the process is completed for all pixels. Thereafter, when the process is finished, the resolution-converted binary image data is sent to the image memory and communication control section.

Next, the specific configuration of each of the above-mentioned processing sections will be explained in detail. First, FIG. 3 shows the image reading section 11
FIG. 3 is a diagram illustrating an example of the timing of an image signal read in FIG. As shown in the figure, the image data 34 is stored in the image clock 3
One pixel data is input in synchronization with line synchronization signal 32, and becomes image data for one line in synchronization with line synchronization signal 32.
Then, it is input as image data for one page in synchronization with the page synchronization signal 31.

FIG. 4 shows the resolution conversion processing section 1 in this embodiment.
2 is a block diagram showing the configuration of No. 2. FIG. In this embodiment, a case where thinning is simply performed as resolution conversion processing will be described. In the figure, 41 is a magnification setting section, in which the conversion magnification obtained by the resolution detection processing section 14 is set. 42 is a line synchronization signal control section, which thins out the line synchronization signal 32 according to the value set by the conversion setting section 41, and outputs the thinned out converted line synchronization signal 32'. For example, when performing 1/2 conversion, the line synchronization signal 32 is thinned out every other line synchronization signal. Reference numeral 43 denotes an image clock control section, which thins out the image clock 33 according to the value set by the conversion setting section 41 and outputs a converted image clock 33'.

In this way, by thinning out each control signal, the resolution of image data is converted. Figure 5
2 is a diagram showing each synchronization signal when the main scanning and sub-scanning are each reduced to 1/2. As shown in the figure, when both the main scanning and sub-scanning are converted to 1/2, the amount of data becomes 1/4 (if not compressed and encoded). FIG. 6 is a block diagram showing the configuration of the binarization processing section 13 in this embodiment. In the figure, reference numeral 61 denotes an edge enhancement processing section, which enhances the edges of image data using a Laplacian filter, which is a spatial filter, or the like. A comparator 61 compares the input signal with a predetermined threshold value and performs binarization.

In this embodiment, edge enhancement processing is performed to perform binarization, but the configuration of the binarization processing section 12 is not limited to this, and various modifications are possible. FIG. 7 is a block diagram showing the configuration of the resolution detection processing section 14 in this embodiment. In the figure, 71a and 71b are line buffers for one line, and 72a to 72f are one-pixel delay elements. Reference numeral 73 denotes a pattern matching processing section, which is composed of, for example, a ROM or the like. 74 is a counter that counts pattern matching results. Reference numeral 75 denotes a resolution determining unit that determines high resolution and low resolution (both main scanning and sub scanning resolutions are 1/2 of the high resolution) as the optimum resolution based on the result of the count 74.

In the above configuration, the binarized image data is extracted as nine pixels A to I as shown in FIG. 8 by line buffers 71a-b and one-pixel delay elements 72a-72f. Then, in the pattern matching processing section 73, a match is made with a preprogrammed thin line pattern, and if there is a match, "1" is output, and if none of them match, "0" is output. The pattern matching results are input to a counter 74, and the matching results are counted for one page of image data. When the processing for one page is completed, the resolution determination unit 7
5, the resolution determination result based on the count value of the counter 74 is output.

Next, the above pattern matching process will be explained in detail. First, when the document to be read requires high resolution (for example, when there are many small characters, line drawings, etc.), many thin line patterns as shown in FIG. 9 are detected. If an image having many such thin lines with a width of one pixel is thinned out by resolution conversion, there is a high possibility that the thin lines will disappear. In other words, in this case, if the read original is converted to a resolution lower than this, information will be lost, and for example, there is a possibility that the received original cannot be read by facsimile.

Therefore, in this embodiment, blocks containing thin lines are detected by pattern matching (blocks in which a 3×3 matching block is matched as a thin line pattern), and the total number of thin line blocks in one page is calculated. Set the resolution as a criterion. That is, in this embodiment, if the sum of the thin line blocks exceeds a preset reference value, it is determined that a high resolution is required, and reading is performed at the same highest resolution as the prescan. For example, facsimile can be transmitted at high resolution (400 x 400 DPI).

On the other hand, if the sum of the thin line blocks is less than the reference value, it is determined that there is redundancy in the reading resolution, the resolution conversion processing unit 15 performs thinning processing, and transmits at a lower resolution (200×200 DPI). . Then, in the facsimile, the image data is sent onto the communication line using the resolution converted as described above as the resolution parameter for actually sending.

[0020]

[Other Embodiments] Next, other embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment described above, when resolution detection processing is performed on a binary image that has been subjected to pseudo-halftone processing, many fine line patterns occur in the read image regardless of the required resolution, making correct determination impossible. .

Therefore, in another embodiment, when a pseudo-halftone image is targeted, the resolution is determined using the simple binarization processing result, and the pseudo-halftone processing is performed when rereading after the resolution determination. It is something. FIG. 11 is a block diagram showing the configuration of an image processing device in another embodiment. Note that processing units similar to those in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted.

As shown in the figure, a pseudo halftone processing section 16 performs pseudo halftone processing on the multivalued data converted by the resolution conversion processing section 12, and a simple binarization processing that performs simple binarization processing on the multivalued data. 17, and a selection section 18 for selecting whether to extract a pseudo-halftone image or a simple binary image according to the operator's settings. FIG. 12 is a diagram showing a detailed configuration of the pseudo halftone processing section 16, and in this example, binarization processing is performed using the textured dither method. A comparator 71 performs binarization processing by comparing the threshold value obtained by the threshold value generator 72 and the input multivalued image data. 72 is a threshold generator, which outputs a dither pattern as shown in 73 by counting the line synchronization signal 32 and image clock 33, and the dither matrix 73 provides a pseudo halftone image of 16 gradations. .

Next, the processing procedure in another embodiment is shown in FIG.
This will be explained below according to the flowchart shown in 3. First, in step S11, the control section 15 controls the image reading section 1.
1 to start reading, and reads the image data at the highest resolution that the image reading unit 11 has. And step S
12, the read image data is sent to the resolution conversion processing unit 1.
2, and converts the resolution to the same size. Next, when the resolution conversion process is completed, the process advances to step S13, the converted image data is sent to the simple binarization processing unit 17, where simple binarization is performed, and in the next step S14, the resolution detection processing unit In step 14, calculations are performed to determine the optimal resolution. Next, when the processing in the resolution detection processing unit 14 is completed, the process advances to step S15, and it is checked whether the processing has been completed for all pixels, and if it has not been completed, the process returns to step S11, Repeat the above process.

On the other hand, when the pre-scan is completed, the process advances to step S16 and re-reading is started. In the next step S17, the image data is thinned out using a magnification based on the determination result obtained during pre-scanning by the resolution detection processing section 14. This thinning processing is performed by the resolution conversion processing section 12, and when the processing is completed, the processing proceeds to steps S18 and S19, respectively, and the resolution-converted image data is processed by the simple binarization processing section 17 and the pseudo halftone processing section 16. and performs binarization of each. Then, in the next step S20, it is checked whether the processing has been completed for all pixels, and if it has not been completed, the processing is returned to step S16, and the above-mentioned processing is continued until the processing is completed for all pixels. repeat. Thereafter, when the processing is completed, the selection section 18 selects the binary image data selected in advance by the operator from among the resolution-converted binary image data and sends it to the image memory and the communication control section.

In the embodiment described above, the setting of whether or not to perform resolution conversion is performed by pattern matching, but the method is not limited to the above-mentioned method. Another possible method is to determine the complexity of the image and set whether or not to perform resolution conversion using the sum of small run lengths as a determination criterion.

In addition, in the embodiment, high resolution and low resolution (
Although two types of automatic determination have been described (both main scanning and sub-scanning resolutions are 1/2 of the high resolution), the present invention is not limited to this, and the type of resolution is arbitrary. For example, high resolution, medium resolution (for high resolution, both main scanning and sub scanning are 1
When performing automatic judgment for three resolutions: 1/2 resolution) and low resolution (1/4 resolution for both main scanning and sub-scanning compared to high resolution), a matching window of the size as shown in Figure 10 is used. It is also possible to detect each thin line having a line width of 1, a line width of 2, and a line width of 3 using the method, and determine an appropriate resolution from the histogram of these thin lines. Specifically, if there are many blocks with a line width of 1, select high resolution and
If there are few blocks with line width 2 and line width 3 and there are many blocks with line width 2 and line width 3, medium resolution may be selected, and when there are few thin lines with line widths 1, 2, and 3, low resolution may be selected.

Further, in the embodiment, the resolution conversion processing section is explained as simple thinning processing, but the present invention is not limited to this, and conventionally proposed interpolation processing or the like may be used. Further, the image memory is not limited to a semiconductor memory, and may be any type of memory such as a hard disk or an optical disk.

[0028]

[Effects of the Invention] As explained above, according to the present invention,
By automatically setting the optimal resolution for transmitting or storing necessary information without relying on the operator's judgment, it is possible to save communication time and memory.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an image processing device in this embodiment.

FIG. 2 is a flowchart showing a processing procedure in this embodiment.

FIG. 3 is a diagram showing the timing of input image signals.

FIG. 4 is a block diagram showing the configuration of a resolution conversion processing section.

FIG. 5 is a timing signal showing resolution conversion.

FIG. 6 is a block diagram showing the configuration of a binarization processing section.

FIG. 7 is a block diagram showing the configuration of a resolution detection processing section.

FIG. 8 is a diagram showing reference pixels for pattern matching in this embodiment.

FIG. 9 is a diagram showing an example of a thin line detection pattern.

FIG. 10 is a diagram showing a matrix for determining three types of resolution.

FIG. 11 is a block diagram showing the basic configuration of an image processing device in another embodiment.

FIG. 12 is a block diagram showing the configuration of a pseudo halftone processing section.

FIG. 13 is a flowchart showing a processing procedure in another embodiment.

[Explanation of symbols]

11 Image reading section 12 Resolution conversion processing section 13 Binarization processing section 14 Resolution detection processing section 15 Control section 16 Pseudo halftone processing section 17 Simple binarization processing section 18 Selection section

Claims (3)

[Claims] 1. A setting means for setting a conversion magnification for resolution conversion from binarized image data, and a resolution conversion means for converting the resolution of read image data using the conversion magnification set by the setting means. An image processing device characterized by: [Claim 2] A first method for simply binarizing image data.
a value converting means, and a second unit for performing pseudo halftone processing on the image data.
further comprising a binarization means, and the setting means includes a first binary
A conversion magnification is set from the image data binarized by the digitization means, and the image data converted by the resolution conversion means is converted into a second image data.
2. The image processing apparatus according to claim 1, wherein the image processing apparatus performs the binarization using a binarization means. 3. The image reading apparatus further comprises an image reading means capable of re-reading the same document, and the resolution converting means converts the resolution of the image data read by the image reading means. 2. The image processing device according to 2.