JPH1051629A - Facsimile equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a facsimile equipment with an image processing part provided with a function judging a halftone area and a non-halftone area included in an inputted original by the variable length block units of plural pixels. SOLUTION: The inputted original is sent to an image processing part for a character original 2 and an image processing part for a photographic original 3 through an image reading part 1 and given image processing respectively optimum for a characteristic part being the non-halftone area and a photographic part being the halftone area. The inputted original is simultaneously sent to an image area judging part 4 to receive judgement on its characteristic and graphic parts by the unit of one pixel, this result is additionally sent to an area judging part 6 to receive final judgement by the unit of a block consisting of plural pixels, and an image processing selection part 5 selects one of the outputs of the parts 2 and 3 from this judging result and makes it an image output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image processing type image area separating function in an image reading section of a facsimile apparatus.

[0002]

2. Description of the Related Art Two examples of read image processing in a conventional facsimile machine are described below. As a first example, the image data of a document to be read is
There is a method of performing an operation with surrounding pixels on a pixel-by-pixel basis, determining a photograph portion and a character portion, and using the results to realize image processing suitable for each. In this method, a small window is formed around a pixel of interest, and the window is moved one after another to determine whether the pixel of interest is a character or a photograph from a group of pixels in the cut region. As a second example, scanning direction 1 of image data of a document to be read is used.
The line is divided into several fixed-length blocks, and in each block, calculation is performed on a per-pixel basis with peripheral pixels to determine a photograph portion and a character portion, and the number of pixels in the block determined to be a photograph is counted. I do. After a while, this number of photo pixels
If the value is larger than a predetermined reference value, the block is determined to be a photo block, and otherwise, the block is recognized as a character block and the process proceeds.

[0003]

Here, in the first example of the above-mentioned prior art, when the text included in the original data to be read is fine, it may be erroneously determined to be a photograph part. In such a case, it becomes impossible to improve the image quality of the character portion. This is because when a fine character is scanned by a reading device, a signal having an intermediate value having a small change amount with respect to an adjacent pixel is transmitted in a small window in a unit of pixel as in the case of reading a photograph portion due to the performance of the reading device. This is because, as a result of the image area determination by, there is a case where it is erroneously determined to be a photograph part. Also, in the second example of the above-described prior art, the method of determining whether a character and a photograph are performed for each fixed-length block is that the area of the character portion or the photograph portion included in the original to be read and the fixed-length block are not necessarily appropriately. If a block is determined to be a photographic area and contains fine characters in the block, the result is an erroneous determination and it is difficult to improve the image quality of the character portion. Also,
Conversely, when there is a photo portion in a block determined to be a character portion, the photo portion may be degraded.

The present invention has been made in view of such circumstances, and a conventional method for determining a photograph portion and a character portion on a pixel-by-pixel basis or on a block-by-block basis has been used. Is intended to improve the image quality by correctly determining the character portion.

[0005]

According to a first aspect of the present invention, there is provided an image reading section for optically reading a transmission original and converting the transmission original into image data of a digital electric signal, and the image as an output of the image reading section. A plurality of image processing circuits that receive data and perform different processing according to the processing classification of the image contents, and are connected in parallel with the image processing circuits, and determine the image data in pixel units according to the processing classifications An image area determination circuit having a function, receiving a determination result of the image area determination circuit,
An area determination circuit that finally determines the image data according to the processing classification by adding an area determination in units of blocks composed of a plurality of pixels based on the relationship and continuity with surrounding pixels, and a result of the area determination circuit. An image processing selection circuit for selectively selecting output results of the plurality of image processing circuits in pixel units in accordance with the processing classification using the obtained selection signal and outputting an image to be transmitted. It is a facsimile machine having a transmission image processing unit.

According to a second aspect of the present invention, in the facsimile apparatus of the first aspect, the plurality of image processing circuits include a photographic image processing circuit for processing a photographic portion which is a halftone area, and a non-halftone area. And a character image processing circuit for processing the character portion.

According to a third aspect of the present invention, in the facsimile apparatus according to the first aspect, in the area determination of the block unit in the area determination circuit, a user can change a parameter group relating to an inter-pixel distance required for the determination. It is characterized by the following.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing apparatus according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. In this figure, reference numeral 1 denotes an image reading unit, which optically reads a document to be transmitted, and converts this analog image data into digital electrical signal image data. Next, a portion surrounded by reference numeral 7 is a transmission image processing unit in the facsimile machine. Reference numeral 2 denotes a character document image processing unit, and reference numeral 3 denotes a photo document image processing unit. Image processing suitable for a character portion and a photograph portion included in the input document is performed. Reference numeral 4 denotes an image area determination unit that determines a character portion and a photograph portion on a pixel-by-pixel basis. Reference numeral 6 denotes an area determination unit, which uses a determination result of a character part or a photograph part output from the image area determination unit 4 to newly determine a character part based on a relationship with surrounding pixels and continuity of pixel data. A determination result for a photo portion is generated. Reference numeral 5 denotes an image processing selection unit. Based on the result of the area determination unit 6, two types of image processing which have been sent from the character document image processing unit 2 and the photo document image processing unit 3 have been completed. Is selected as an output of the transmission image processing unit 7.

Next, the operation of the facsimile machine will be described. First, the image reading section 1 optically reads an input document and outputs image data of a digital electric signal to the transmission image processing section 7. The transmission image processing unit 7
, The input image data is equally supplied to the character document image processing unit 2, the photographic document image processing unit 3, and the image area determination unit 4. Therefore, since the text document image processing unit 2 performs the processing before the type of the given image data is determined to be a text document, the image processing is performed on the assumption that all the data are text documents. Do. The same applies to the image processing unit 3 for a photo original, and given data is assumed to be a photo original, and appropriate image processing is performed. That is, the character document image processing unit 2 and the photo document image processing unit 3 perform different types of image processing on data having exactly the same contents. In the case of a text document, both input and output are two values of white and black with no intermediate value. In contrast, in the case of a photo document, there are gradations, so that the processing suitable for each is different. In both of the two processing units, the output is 1 bit wide.

[0010] The image input data is similarly supplied to the image area determination unit 4. The image area determination unit 4 determines character data and photograph data on a pixel-by-pixel basis. After this processing, the image area determination unit 4 outputs the result to the next-stage area determination unit 6.
Output to The area determination unit 6 is a feature of the present invention, and based on the result obtained by the image area determination unit 4 at the preceding stage, m pixels in the main scanning direction are grouped into a block to determine the relationship with surrounding pixels. Judgment of a character portion and a photograph portion is performed in block units based on the continuity and the continuity, and the result is sent to the image processing selection unit 5. This determination result is the final conclusion of the determination of the character portion and the photograph portion. In the image processing selection unit 5, the result of the output from the character document image processing unit 2 and the photograph document image processing unit 3 is determined in units of one pixel in accordance with the conclusion of the preceding area determination unit 6. After selecting one of them, it is output as the final processing result of the transmission image processing unit 7.

Next, the algorithm of the operation of the area judging section 6, which is the gist of the present invention, will be described in more detail with reference to FIG. In FIG. 2, the horizontal direction corresponds to the main scanning direction of the facsimile, and the left end corresponds to the left end of the document. Also, the pixel groups on the L-th line and the (L + 1) -th line are taken as an example. In the figure, pixels are distinguished from each other using ○ and ●. ○ indicates one pixel determined to be a character part by the above-described image area determination unit 4 at the preceding stage, and ● indicates one pixel similarly determined to be a photograph part. The main area determination unit 6 performs the determination in units of blocks of several pixels based on the result determined by the image area determination unit 4. First, in the L-th line, the image area determination unit 4 determines, for a block that has been determined to be a photograph part continuously for m or more pixels, a position within n pixels from left and right (= front and back) from both ends of the block. , M or more pixels, and if there is no pixel portion determined to be a photograph portion, the position in one scanning line is determined using the block as a character region. In the next L + 1-th line, even if the pixel group located at the same position in the main scanning direction as the above-described character area of the L-th line is determined to be a photograph part by the image area determination unit 4, Forcibly determine the character area.

In FIG. 2, a case where m = 3 and n = 10 is taken as a specific example of the above-mentioned algorithm. First, attention is paid to the block A of ●, which is composed of the six pixels of the second group from the left end of the L-th line and which is determined to be a photograph portion by the image area determination unit 4. Looking at the left and right (= front and back) of the block A, there is no portion that is determined as a photograph continuously at m = 3 pixels or more at positions within n = 10 pixels in the right direction. Next, looking at the left direction of the block A, there is a block C in which three dots (=> m) are continuous at three pixels (= <n) apart from the condition of the above algorithm.
Block A is determined to be a photograph part. Therefore, the lower L +
The block A 'indicated by a circle at the same position in the main scanning direction of the first line is also determined to be a photograph portion. On the other hand, regarding the block B, which is also on the L-th line and is determined to be a photographic part by the image area determination unit 4, first, the number of continuous pixels is 4, but before and after (= left and right) n = Since there is no photo portion within 10 pixels, the block is determined to be a character area, and the next L + 1 line is located at the same position in the main scanning direction.
Is also determined as a character area.

In the above description, the L-th line and L + 1
The determination of the same position of the block in the main scanning direction of the line is regarded as the same block when m or more pixels are overlapped in position, and the block is applied to this processing.

[0014]

As described above, according to the facsimile apparatus of the present invention, the following effects can be obtained. 1. In addition to the function of judging a character part and a photograph part in units of one pixel, it has a function of judging an area. The image quality in the part can be improved. 2. Since the area is determined in units of variable-length blocks composed of a plurality of pixels while being in increments of one pixel, erroneous determination within the fixed block, which is a drawback of the method of determining a fixed-length block, can be prevented. It is possible to determine a text portion and a photo portion with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image processing unit in a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an operation example of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image reading part, 2 ... Text original image processing part, 3 ... Photo original image processing part, 4 ... Image area determination part, 5 ... Image processing selection part, 6 ... Area determination part, 7 ... Transmission image processing part

Claims (3)

[Claims] 1. An image reading unit for optically reading a transmission original and converting the image into digital electric signal image data, and receiving the image data output from the image reading unit according to a processing classification of image contents. A plurality of image processing circuits for performing different processing, an image area determination circuit connected in parallel with the image processing circuits, and determining which of the processing classifications the image data belongs to on a pixel-by-pixel basis; An area determination circuit that receives a determination result of the circuit, adds an area determination in units of blocks composed of a plurality of pixels from the relationship and continuity with surrounding pixels, and finally determines the image data according to the processing classification. Using the selection signal obtained as a result of the area determination circuit, selectively selecting output results of the plurality of image processing circuits in pixel units in accordance with the processing classification, and obtaining an image output to be transmitted. Image processing Facsimile apparatus having a selection circuit, the transmission image processing unit consisting of. 2. The image processing circuit according to claim 1, wherein the plurality of image processing circuits include a photographic image processing circuit that processes a photographic portion that is a halftone region and a character image processing circuit that processes a character portion that is a non-halftone region. Item 1. A facsimile apparatus according to Item 1. 3. The facsimile apparatus according to claim 1, wherein a parameter group relating to an inter-pixel distance necessary for the determination is variable in the area determination in the block determination circuit.