JPS63151262A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To reduce the time required for transmission/reception without losing the picture quality at the receiver side by switching the scanning line density automatically in response to the complicateness or size of a character/graph in an original picture. CONSTITUTION:A change point number discrimination section 5 compares a prescribed set value (n) with a count (m) from a change point count section 4 at each provision of the count (m) end in case of m<n, the section 5 outputs a skip signal to apply interlace scanning of succeeding scanning line to a picture read section 1. Thus, the section 1 skips the next scanning line to scan the succeeding scanning line. Thus, even when the scanning line density is selected to be 3/mm being one half of the conventional density, the picture quality at the reception side is not so much deteriorated and the processing time is reduced. In case of m>=n, the section 5 gives no skip signal to the section 1. Thus, the section 1 continues the scanning by the scanning line density of 6 lines/mm being comparatively high.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a facsimile machine, and more specifically, to a facsimile machine that automatically switches scanning line density according to the density of an original image and transmits the facsimile machine.

[Prior art]

A facsimile machine reads a document image by dividing it into pixels, and further converts each pixel into a binary signal of black and white to obtain an image signal. By the way, when transmitting the image signal obtained in this way through a telephone line, etc., it is difficult to transmit information regarding whether each pixel is white or black, which results in redundancy of information. is too high, and as a result, the time required for transmission, that is, the time the line is occupied, becomes very long, resulting in inefficiency and high line usage charges.

Therefore, when transmitting images using a facsimile machine, it is desirable to compress the amount of information as much as possible.

For these reasons, a method is becoming popular that compresses the redundancy by converting the image signal into information representing a run length of consecutive white or black pixels. As a method that can compress l! Focusing on the strong correlation that generally exists between two scanning lines that are in contact with each other, we have determined the change point of the signal value of the scanning line to be encoded (pixel where the signal changes from white to black or from white to white). A modified read (MR) method has also been proposed in which the amount of information is compressed by expressing the information as a relative positional relationship with the change point of the signal value of the immediately preceding scanning line.

On the other hand, in facsimile machines, the scanning line density, that is, the number of scanning lines per unit in the sub-scanning direction perpendicular to the scanning line, is determined by several standards, such as 3 lines/mm, 4 lines/mm,
6 lines/mm, etc. is defined as a standard.

Therefore, when the characters, figures, etc. of the original image are complex and detailed, it is preferable to transmit the scan line at a high density, for example, 6 lines/double, from the viewpoint of image quality on the receiving side. On the other hand, if the characters, figures, etc. in the original image are relatively simple and coarse, the scanning line density may be made coarser, for example, 3 lines/double, and the image will be sent.
It does not have such a negative effect on the image quality on the receiving side, and the time required to read the original image and process the data is shortened, so the time required for sending and receiving is also shortened, which has the advantage of reducing line usage fees. There is.

[Problem that the invention seeks to solve]

By the way, in conventional facsimile machines, the user of the facsimile machine switches the scanning line density as appropriate depending on the original image and performs a forward/backward operation. For this reason, there is a problem in that it is difficult to select an appropriate scanning line density when dense parts of characters and figures are mixed in the same original image.

For the purpose of solving such problems, for example,
The invention disclosed in Japanese Patent No. 9-49750 has been proposed.

According to the present invention, +! Scanning is performed by thinning out the scanning lines that are in contact with J. Then, the image data of the thinned out scanning lines is omitted, and only the line end code, that is, the code indicating the end of one scanning line, is transmitted. Therefore, in this invention, since the line end code cannot be omitted, there is a problem that it cannot be applied to a compression encoding method that does not require a signal similar to the above-mentioned signal indicating the end of an I scanning line.

The present invention has been made with the aim of solving these 11 points, and is applicable in the case of a somewhat coarse original image where the number of signal change points in one scanning line is less than a predetermined value during scanning of the original image. The object of the present invention is to provide a facsimile machine that can always transmit and receive images at an appropriate scanning line density depending on the density of the original image by automatically performing interlaced scanning.

[Means for solving problems]

In the facsimile machine of the present invention, when encoding one scanning line, the number of signal change points in the I scanning line is counted, and if the number is less than a predetermined number, the scanning line is considered to be a relatively coarse image part and W& Interlaced scanning is performed, and when decoding during reception, if the number of signal variations in one scanning line is less than a predetermined value, it is assumed that interlaced scanning was performed during encoding, and the scanning line of the same image information is The scanning line of the image information is printed in duplicate, or the scanning line of image information interpolated based on the correlation with the scanning line immediately before it is printed.

The present invention provides a facsimile apparatus that encodes and transmits an image signal obtained by scanning an original image with a reading means, and also decodes a received signal into an image signal and prints it with a printing means. a change point counting means for counting the number of change points of an image signal of a scanning line; and a change point counting means for counting the number of change points of the image signal of a scanning line, and a step for causing the reading means to skip the next scanning line if the counted value of the change point number counting means is less than a predetermined value during encoding. and means for causing the printing means to print the same image signal as the scanning line as the next scanning line when the count value of the change point counting means is less than or equal to a predetermined value during decoding. It is characterized by having the following.

[Effect]

In the device of the present invention, the scanning line density is automatically switched according to the density of the original image, and the scanning line density becomes dense for complex and detailed image parts, so transmission and reception are performed with high image quality. Since the scan line density is coarse in both image areas, rapid transmission and reception is performed.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a block diagram showing the configuration of an encoding section for image transmission of a facsimile apparatus according to the present invention, and FIG. 2 is a block diagram showing the configuration of a decoding section for reception. In addition, the same reference numerals are attached to the members that are commonly used in both.

In FIG. 1, reference numeral 1 denotes an image reading section composed of, for example, a one-dimensional image sensor. The image signal as an optical signal read by the image reading section 1 is converted into a digital electrical signal and provided to the image memory 2. Note that the scanning line density when reading the original image by the image reading section 1 is set to 6 lines/l, which is a relatively high density.

The image memory 2 stores the image signal given from the image reading section 1 in units of one scanning line. The image signal stored in the image memory 2 is output to the change point detection section 3 in units of one scanning line.

Note that this image memory 2 only stores the image signals sequentially read by the image reading section 1 for each scanning line during encoding during transmission, but as will be described later, during decoding during reception, the image memory Since it is necessary to store image signals for one image, it has a corresponding storage capacity.

The change point detection unit 3 detects the address of the change point included in each scanning line segment of the image data successively outputted from the image memory 2, outputs this result to the encoding unit 6, and also detects the change point address. Every time a point is detected, a predetermined change point detection signal is sent to the change point counter 4.
Output to.

The encoding unit 6 uses a predetermined compression encoding method, such as a run length (M I+) method or a modified read (MR) method, based on the address of the change point of each scanning line given from the change point counter 4. The image signal of one scanning line is compression-encoded and output to the encoder sofa memory 7.

The code buffer memory 7 sequentially stores the compressed code of one scanning line Q1 given from the encoding unit 6.

On the other hand, each time a change point detection signal is given from the change point detection unit 3, the change point counting unit 4 counts the number of change points and calculates the count value m.
hold as. Then, when the change point detection unit 3 finishes detecting the change point in the image data of one scanning line,
The change point counting section 4 outputs the current H-ten value m to the change point number determination section 5, and resets the count value m to O.

Every time the change point determining section 5 receives the count value m from the change point counting section 4, it compares it with a predetermined set value n. As a result of the comparison, if m<n, the number of change points determining unit 5
outputs a skip signal that causes the image reading section 1 to interlace scan the next one scanning line.

As a result, the image reading section 1 skips the next scanning line and scans the next scanning line. That is, m<n means that the number of changing points in one scanning line is relatively small, in other words, the portion of the scanning line of the original image is a relatively simple and rough image.

Therefore, even if the scanning line density is reduced to 1/2 of the normal scanning line density, the image quality on the receiving side does not deteriorate significantly, and the processing time can be shortened.

On the other hand, when m≧n, the number of change points determining unit 5 does not output a skip signal to the image reading unit 1. As a result, the image reading section I continues scanning at a scanning line density of 6 lines/fl, which is a relatively high density.

That is, m≧n means that the number of changing points in one scanning line is relatively large, or in other words, the portion of the scanning line of the original image is a relatively complex and detailed image.

Therefore, by keeping the scanning line density at 6 lines/1, high image quality in the reception example is guaranteed.

The operation of the encoding section of the facsimile apparatus of the present invention having the above-described structure will be briefly explained according to flowchart 1 in FIG. 3 showing its operation procedure.

It is assumed that the scanning line density for reading the original image by the image reading section 1 is normally set to 6 lines/frame, which is a relatively high density.

First, the image reading section 1 reads a document image by one scanning line from one end thereof, and stores it in the image memory 2 as an image signal. The changing point detection unit 3 sequentially detects the addresses of changing points in the image data for one scanning line and outputs them to the encoding unit 6, and the changing point counting unit 4 calculates the number of changing points m It is accumulated as . On the other hand, the encoding unit 6 compresses and encodes the image signal for I scanning lines based on the change point address detected by the change point detection unit 3, and stores the result in the code buffer memory 7.

During this period, the change point determining unit 5 calculates the count value m of the change point counting unit 4.
is compared with the set value n, and the counted value m is smaller than the set value n (m<
If n), a skip signal is output to the image reading section 1 to skip the next one scanning line and scan the next one scanning line ii!
ii) The image reading unit 1 is made to perform the process. As a result, the scanning line density becomes 3 lines/I1m, which is relatively coarse.

On the other hand, if the count value m is greater than or equal to the set value n (m≧n), the skip signal is not output from the change point determination unit 5 to the image reading unit 1, and therefore the scanning line density of document reading by the image reading unit 1 is The density remains at 6/■, which is relatively dense.

FIG. 2 is a block diagram showing the configuration of the decoding section of the apparatus of the present invention. For convenience of explanation, the configuration of the device of the present invention is divided into an encoding section shown in FIG. 1 and a decoding section shown in FIG. 2, but in practice, encoding and decoding can be performed simultaneously. Therefore, members that can be used in common are shared by both.

Therefore, common parts are given the same reference numerals in FIG. 1 and FIG. 2.

In FIG. 2, a code memory 7 stores a compressed code signal transmitted from another facsimile machine equivalent to the apparatus of the present invention and received through a line. The compressed code stored in the code buffer memory 7 is output to the decoding unit 8 in units of one scanning line.

The decoding unit 8 decodes the compressed code for each scanning line provided from the code buffer memory 7 into image data, and outputs the image data to the change point detection unit 3.

The change point detection unit 3 detects the change point address in the image data of the scanning line and outputs it to the image signal reproduction unit 9, as in the case of encoding described above, and each time it detects each change point address, , outputs a change point detection signal to the change point counter 4.

Note that the change point counting section 4 and the change point number determination section 5 operate in the same manner as in the above-mentioned encoding, but the change point number determination section 5 determines that the counted value m is smaller than the set value n (m<n). If it is determined that, the change point counting unit 4 determines if! A predetermined signal is given to the ti image signal re-resident section 9.

The image signal reproducing unit 9 reproduces the image signal for one scanning line based on the changing point address given from the changing point detecting unit 3,
The images are sequentially stored in the image memory 2 in units of one scanning line. However, when a predetermined signal is given from the change point counting section 4, the reproduced image signals are recorded in the image memory 2 in duplicate, that is, two scanning lines are treated as the same image signal.

By the way, as a result of the comparison by the change point determination unit 5, m <
If n, interlaced scanning was performed during encoding during transmission and the scanning line density was coarsened to 2, so it is restored during decoding. That is, if interlaced scanning is performed during encoding, the image signal reproducing unit 9
By outputting one scanning line's worth of image signals reproduced by 2 scanning lines redundantly, the scanning line density during decoding is set to 6 lines/11, which is the same as during encoding, to avoid deterioration in image quality. do.

On the other hand, when m≧n, interlaced scanning was not performed during encoding, so no duplicate output of image signals was performed, but the scanning line density during encoding was 6 lines/frame. So,
The scanning line density during decoding also remains at 6 lines/1.

When the image memory 2 stores both image signals for one document, it outputs them to the printing section 10 for printing.

The operation of the decoding section of the facsimile apparatus of the present invention having the above configuration will be briefly explained with reference to the flowchart of FIG. 4 showing the operation procedure.

Note that the scanning line density of image printing by the printing unit 10 is set to 6/1n, which is relatively dense.

First, the compressed encoded data recorded in 4.1 in the encoder sofa memory 7 is read out for one scanning line by the decoding section 8 and decoded as image data. Then, the changing point addresses of the decoded one scanning line of image data are sequentially detected by the changing point detecting section 3, and the number is accumulated as a count value m by the changing point counting section 4. On the other hand, the image signal reproducing section 9
reproduces the image data for one scanning line into an image signal, that is, restores it to a white/black dot signal, based on the change point address detected by the change point detection section 3, and stores the result in the image memory 2. Make me remember.

During this period, the change point determining unit 5 calculates the count value m of the change point counting unit 4.
is compared with the set value n, and the counted value m is smaller than the set value n (m<
If n), the image signal reproducing unit 9 is caused to output the same image signal for one more scanning line in duplicate.

The image signal for one scanning line which is output redundantly from the image signal reproducing section 9 is stored in the image memory 2, so that the two scanning lines are stored in the image memory 2 as the same image signal. Therefore, the scanning line density of image printing by the printing unit 10 is 6 lines/dragon, which is the same as that of decoding.

Although a detailed explanation will be omitted, the same one scanning line worth of image signal is duplicated in the image memory 2 by the image signal reproduction section 9 of the decoding section of the apparatus of the present invention shown in the above-mentioned figure 2. Instead of storing, for example, the image signal for one scanning line and the image signal reproduced further earlier are interpolated.
Of course, it is also possible to create an image signal for each scanning line independently and store it in the image memory 2.

〔effect〕

As described in detail above, according to the present invention, the scanning line density is automatically switched according to the complexity or size of characters and figures in the original image, so there is no loss of image quality on the receiving side. , and there is no inconvenience such as unnecessary time required for transmission and reception.

Furthermore, since the apparatus of the present invention does not require a signal indicating the end of each scanning line, it can be applied to any compression encoding method, and there is no need to transmit or receive any special signals.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram showing the configuration of the encoding section of a facsimile apparatus according to the present invention, FIG. 2 is a block diagram showing the configuration of the decoding section, and FIG. FIG. 3 is a flowchart for explaining the operation of the encoding section, and FIG. 4 is a flowchart for explaining the operation of the decoding section. 1... Image reading unit 2... Image memory 3...
- Change point detection section 4... Change point counting section 5...
Change point determination section 6... Encoding section 7... Code buffer memory 8... Decoding section 9... Image signal reproducing section 10... Printing section Patent Applicant: Sanyo Electric Co., Ltd. Agent Patent Attorney Noboru Kono Figure 3 Figure 4

Claims (1)

[Claims] 1. A facsimile machine that encodes and transmits an image signal obtained by scanning a document image with a reading means, and also decodes a received signal into an image signal and prints it with a printing means. The apparatus includes: a change point counting means for counting the number of change points of an image signal of one scanning line; and during encoding, when the counted value of the change point number counting means is less than a predetermined value, the reading means is provided with the following information. means for performing interlaced scanning on a scanning line; and upon decoding, when the count value of the change point counting means is less than or equal to a predetermined value, an image signal identical to that of the scanning line is sent to the printing means as the next scanning line; 1. A facsimile device comprising: means for printing. 2. In a facsimile machine that encodes and transmits an image signal obtained by scanning a document image with a reading means, and also decodes a received signal into an image signal and prints it with a printing means, one scanning line a change point counting means for counting the number of change points of the image signal; and during encoding, if the counted value of the change point number counting means is less than or equal to a predetermined value, the reading means interlace scans the next scanning line. and, upon decoding, when the count value of the change point counting means is less than or equal to a predetermined value, an image signal interpolated based on the correlation between that scanning line and the immediately preceding scanning line is used as the next scanning line. A facsimile apparatus comprising: means for causing the printing means to print.