JPH04185058A - Handy scanner - Google Patents

Abstract

PURPOSE:To accurately read an image on an original by performing the reading of the image while automatically varying the linear density according to a scan mode. CONSTITUTION:A pulse is outputted from an encoder 2 according to the movement distance of an image sensor 1 by scanning the actuating image sensor 1 in the reading direction against the original where the reading image is drawn. Synchronized with this pulse, the data is processed. When the scan speed is higher than data processing speed, a command is outputted from a microprocessor 5, and this pulse is cancelled at a pulse canceller 9. The microprocessor 5 returns the pulse canceller 9 after the data processing by one line, receives the next pulse, and starts the reading of the next one line while taking this pulse as a trigger.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a handy device that manually scans a document to be read, reads an image on the document, and converts it into an electrical signal.
It is related to scanners.

[Prior Art] An image scanner that reads an image on a document and converts it into an electrical signal uses a scanner that manually scans the document.
There is a small scanner called a so-called handy scanner that reads an image on a document and converts it into an electrical signal.

Figure 2 is a block diagram showing the general configuration of a conventional handy scanner. In the figure, (1) is an image sensor that reads an image on a document, performs photoelectric conversion, and outputs the read image as an electrical signal; 2) is an encoder that outputs the scan speed and moving distance of the image sensor (1) as a pulse signal, and (3) is an encoder that converts the analog signal from the image sensor (1) into a digital signal, and also performs various functions such as shading. (4) is a digital processing unit that processes halftones, etc.; (5) is a microprocessor that controls the whole;
6) is an I10 interface, and (7) is a memory in which control programs and image data for the processor (5) are stored. (8) is a display section that displays the scan speed of the image sensor (1) to notify the user.

Next, the operation will be explained. When the image sensor (1) is in an operating state and scans a document on which a read image, such as a character image, is drawn in the reading direction, the encoder (2) generates pulses according to the moving distance of the image sensor (1). is output. When the so-called fine mode, that is, the mode for reading the read image in detail, is selected, the output of this pulse is 1/7.
It is output once every 7 mm (l click) scan (by CCITT), and using this pulse as a trigger, the microprocessor (5) issues a request to the analog processing section (3) and digital processing section (4), and processes one line. Minute read command, A/D conversion, binarization.

Various processes such as dither conversion are executed, and one line of image data is stocked in the memory (7) (the line density of the stocked image data is 7°7 lines/mm).

In addition, when the standard reading mode is selected, 1 pulse is output every time the image sensor (1) scans 1/3.85 mm, and the linear density is 3.85 lines/3.85 mm.
The image data of m m is read and stored in the memory (7)
will be stocked in

The microprocessor (5) sequentially performs this series of operations until the document is finished reading, and therefore, the encoder (2) outputs one pulse and the next one. The data processing of the image data for each line is completed one by one.

[Problems to be Solved by the Invention] Since the conventional handheld scanner described above is configured and operates as described above, data processing of one line of image data must be completed during the trigger pulse from the encoder. If the scan speed is high even though fine mode is selected, data processing may not be completed in time, causing problems such as stopping the reading operation or stocking and outputting data that has not been processed yet. There was a point.

This invention has been made to solve this problem, and aims to provide a handy scanner that can accurately read images on a document even when the scanning speed is faster than the data processing speed when fine mode is selected. .

[Means for Solving the Problems] The handy scanner according to the present invention is equipped with a pulse canceller, and when the scan speed is too fast and data processing cannot be completed in time, the handheld scanner according to the present invention scans the pulses from the encoder pulse by pulse according to instructions from the processor. It was decided that one or more pulses would be canceled.

[Function] The handy scanner of the present invention is equipped with a pulse canceller, and when the scanning speed is too high for data processing, the encoder generates one or more pulses for each pulse according to instructions from the processor. Since it is decided to cancel the reading, if the data processing cannot be completed in time, it becomes possible to automatically switch the reading speed and perform the reading.

[Example] An example of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 2 indicate the same or corresponding parts.
9) The microprocessor (
5) shows a pulse canceller that cancels the pulses from the encoder (2) by one or more pulses every l pulse.

Next, the operation will be explained. When the image sensor (1) is in an operating state and scans a document on which a read image, such as a character image, is drawn in the reading direction, the encoder (2) generates pulses according to the moving distance of the image sensor (1). is output.

The output of this pulse is 1/7.7 when the so-called fine mode is selected.
It is output once every mm (1 click) scanned (by CCITT), and using this pulse as a trigger, the microprocessor (5) issues a request to the analog processing section (3) and digital processing section (4), and one line is output. Each line of image data is stored in the memory (
7) (the linear density of the stocked data is 7.7 lines/mm).

However, if the scan speed is faster than the data processing speed, pulses will be sent from the encoder (2) during data processing, but in this embodiment, in such a case, commands are sent from the microprocessor (5). This pulse is canceled by the pulse canceller (9). When the microprocessor (5) has finished processing data for one line, it returns the pulse canceller (9) to the original, receives the next pulse, and uses this pulse as a trigger to read the next line. Start.

Figure 3 is a diagram showing the relationship between the pulse output of the encoder (2) and data processing for a line.
m/s or more), a state in which data processing for one line is completed between one pulse and the next, Fig. 3 (B)
Because the scanning speed is too fast (encoder (2)
The pulse canceller (9) is canceling the trigger pulse from the encoder (2) once every two times (the pulse width from the encoder (2) is less than 5 m/s), and in this case, fine mode is selected. , even when pulses are output at 1/7.7mm intervals, the pulses are canceled once every two times, so image scanners (
The reading linear density of 1) is 3.85 lines/mm.

Note that the pulse canceller (9) may be configured by H/W or S/W, and the same effects can be achieved.

[Effects of the Invention] As described above, the present invention has the effect of providing a handy scanner that can automatically switch the reading speed and perform reading when data processing cannot be completed in time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a conventional device, and FIG. 3 is a diagram showing the relationship between encoder pulse output and data processing. In the figure, (1) is the image sensor, (2) is the encoder, (3) is the analog processing section, (4) is the digital processing section, (5) is the microprocessor, (6) is the I10 interface, and (7) is the Memory, (8) is the display section, (9
) is a pulse canceller. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claim] In a handy scanner that manually scans an area to be read and reads an image on the area to be read while sequentially performing data processing in synchronization with pulses sequentially output from an encoder, a pulse canceller is provided. and a means for canceling one or more pulses for each pulse using the pulse canceller, and reading an image by automatically varying the linear density according to the scan mode.・Scanner.