JPH02215268A - Image transmitter - Google Patents

Abstract

PURPOSE:To speed up the read/transmission of image data by providing the head scanning line deciding means of an original, a means to decide a reading area and a total transmission data quantity or the total number of transmission lines, and a means to send the image data of respective scanning lines in the reading area to an external part. CONSTITUTION:A reader 1 scans a reading area 5 and outputs digital image data. An original 6 is aligned to a final scanning line. A head detecting part 2 detects the scanning line to pass the original head from the data from the reader 1. By detecting the black and white density change of a ground, the head is stably detected, a control part 4 decides a reading area 7 from the signal of the detecting part 2, and the total number of lines or the product of the total number of lines and the data quantity per scanning line is obtained. Such header information is prepared, it is sent through a transmission control part 3 to the external part, and the transmission control part 3 is instructed to send the image data after the head line of the reading area 7. By such constitution, the necessary time of the original read/transmission can be remarkably shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image transmission device such as a photo facsimile device that reads multivalued image data of a document containing halftone density such as a photograph and digitally transmits this image data. .

2. Description of the Related Art Conventionally, this type of image transmission apparatus has been configured to perform the operations shown in FIG.

That is, when instructed to start reading, the document reading device performs reading scanning (prescanning) of the entire effective reading area IO shown in FIG. 5 (step [phase] to step @).

From the image data read by this pre-scan,
Original 1 set at any position within the effective reading area IO
The reading area 12 is determined by detecting the leading edge position S and the ending position E of the reading area 1, the total number of transmission lines or the total amount of transmitted data (the total number of lines or the total amount of data in the reading area 11), and the header information containing this is determined. Create (Step ◎).

Next, the document reading device performs a reading scan (main scan) of the reading area 12, and the read image data is read as header information and transmitted to the outside (from step ① to step O).
).

Problem to be Solved by the Invention However, blisscanning for determining the reading area and the total number of transmission lines or the total amount of transmitted data requires a considerable amount of time no matter how fast it is done. There has been a problem in that the total reading time, which is the sum of the time for the main scan and the time for the main scan, becomes long. Another problem is that the operation control of the document reading device is complicated.

The present invention has been made in view of the above-mentioned problems, and provides an image transmission device that transmits header information including the total number of transmission lines or the total amount of transmission data and effective image data by one reading multiple scan. The purpose is to provide.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides information on the effective reading area based on image data output from the original reading device during one reading scan of the effective reading area by the original reading device. A means for detecting a scanning line at the leading edge of a set document, and determining a reading area and a total amount of transmitted data or a total number of transmission lines from the position of the scanning line detected by this means and the final scanning line position of the effective reading area. and means for externally transmitting image data of each scanning line within the reading area that is outputted from the document reading device in large numbers following the header information including the determined total transmission data amount or total number of transmission lines. It is equipped with a configuration that has the following.

Operation The present invention has the above-described configuration, and during one reading scan,
For example, the range from the scanning line position next to the scanning line at the leading edge of the document to the final scanning line position of the document effective area is set as the reading area, and the total number of lines in this reading area is set as the total number of transmission lines; The product of the total number of lines and the amount of data per scanning line is the total amount of transmitted data, and header information including this and image data of the reading area are transmitted.

It is clear that such a reading area and the total number of transmission lines or the total amount of transmission data are appropriate if the document is set close to the final scanning line position of the effective reading area.

In this way, there are some restrictions on the position where the document can be set, but it is possible to create and create header information with one reading scan.
The time required for reading and transmitting image data of a document is significantly reduced compared to conventional devices that perform multi-scanning twice, dividing it into a bliss scan and a main scan. It is possible to shorten the time, and the control of the document reading device is simplified.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an image transmission device according to an embodiment of the present invention, in which 1 is a document reading device, 2 is a document leading edge detection unit, and 3 is a device that controls external transmission of image data and header information. A transmission control unit 4 is a control unit that not only controls each unit but also determines a reading area and creates header information including the total number of transmission lines or the total amount of transmission data.

The document reading device 1 performs multiple reading scans within the effective reading area 5 shown in FIG. 2, decomposes the density of the effective reading area 5 into pixels, reads the data, and outputs digital multi-valued image data. The original 6 is set close to the lower end of the effective reading area 5, that is, at the final scanning line position, as shown in the figure.

The document leading edge detection section 2 detects a scanning line passing through the leading edge of the document 6 by examining the image data of each scanning line input from the document reading device 1. This detection can be performed by various methods, but when the document is read in the document reading device 1 against a background (a sheet or plate provided on the document holding cover, a carrier sheet, etc.) that has a pattern of shading at a constant period. The document leading edge detection unit 2 detects the document leading edge by the following method, for example.

For each scan line, by comparing the image data with a threshold in the black density range and a threshold in the white density range,
It detects density changes such as edges in the underlying shading pattern and counts the number of times they occur. In the scanning line in the area where there is no document, the density pattern of the background is detected as a density change, so the number of detections exceeds a certain value. However, in the original part, the background is almost completely blocked by the original, so the number of times density changes are detected does not reach a certain value. Therefore, the scan line in which the number of density change detections falls below a certain value for the first time after the start of multiple reading scans by the document reading device 1 is detected as the scan line at the leading edge of the document, and a detection signal is sent to the control unit 4.

Note that this method is not easily affected by the positional shift of the shading pattern of the base, so it is possible to stably detect the leading edge of the document even if a carrier sheet is used as the base. Further, since a line memory for storing image data is not required, the circuit configuration of the document leading edge detection section 2 can be simplified.

The control unit 4 determines that the area from the next scan line (or the scan line after two or more lines) of the scan line for which the detection signal was output from the document leading edge detection unit 2 to the last scan line of the effective reading area 5 is the reading area 7. , the total number of lines in this reading area 7 is calculated as the total number of transmission lines. Alternatively, the total amount of transmitted data is calculated as the product of this total number of lines and the amount of data per scanning line. Then, header information including the total number of transmission lines or the total amount of transmission data is created and sent to the transmission control unit 3 to be sent to the outside. In addition, the entire transmission control unit 3 sends out image data after the first line of the reading area 7.
instruct.

The overall operation of this image transmission device is shown in FIG. That is, when the document reading device 1 is instructed to start reading by the control unit 4, it starts reading scanning from the upper end of the effective reading area 5.

The document leading edge detection section 2 sequentially checks whether the image data of each scanning line outputted from the document reading device 1 is the image data of the scanning line of the leading edge of the document (step 2).

When the multiple reading scans of the document reading device 1 reach the leading edge of the document 6, a detection signal is sent from the document leading edge detecting section 2 to the printing section 4. The control unit 4 determines the reading area 7, calculates the total number of transmission lines or the total amount of transmission data, creates header information including this, and causes the transmission control unit 3 to send this header information to the outside (step ①). , ■). Sending this header information is
The process ends before the reading of the reading area 7 starts.

Next, the control section 4 causes the transmission control section 3 to sequentially transmit the image data of each scanning line within the reading area 7, and monitors the end of the reading scan (steps ①, ①).

Effects of the Invention As is clear from the above description, the present invention detects the scanning line at the leading edge of the document during one reading scan of the effective reading area by the document reading device, and detects the position of this scanning line and the effective reading area. The reading area and the total amount of transmitted data or the total number of transmission lines are determined from the final scanning line position of Because it is transmitted externally, compared to conventional devices that separate the reading scan twice into pre-scan and main scan, it is possible to significantly reduce the time required to read and transmit the image data of the document. Control of the document reading device becomes simple. Note that although there is a restriction that the originals are set in the final scanning line position of the effective reading area, this does not pose any particular problem in terms of the operation of the apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a document transmission device according to an embodiment of the present invention, FIG. 2 is a diagram for explaining document reading in the document transmission device, FIG. 3 is an operation flowchart of the document transmission device, and FIG. FIG. 4 is an operational flowchart of the conventional document transmission device, and FIG. 5 is a diagram for explaining the document reading process in the conventional document transmission device. 1... Document reading device, 2... Document leading edge detection section, 3.
...Transmission control unit, 4...Control unit, 5...Reading effective area, 6...Document, 7...Reading area. Name of agent: Patent attorney Shigetaka Awano and one other person (Fig. 4)

Claims (1)

[Scope of Claims] A document reading device that performs reading power scanning of an effective reading area in which an original is set and outputs image data; means for detecting a scanning line at the leading edge of a document set in the effective reading area from image data output from the device; and reading from the position of the scanning line detected by the means and the position of the final scanning line in the effective reading area. means for determining the area and the total amount of transmitted data or the total number of transmission lines; header information including the total amount of transmitted data or the total number of transmission lines determined by the means; 1. An image transmission device comprising means for sequentially transmitting image data of each scanning line to the outside.