JPH03216774A - Picture reading device - Google Patents

Abstract

PURPOSE:To perform the reduction processing via a proper thinning operation accordant with a reading section by producing a picture element thinning signal in the main scanning direction with a reading section signal of the main scan defined as a reference signal and therefore producing the proper thinning signals in regard to various set reading sections and thinning rates. CONSTITUTION:A 1st signal generating means A produces a reading section signal of the main scan, and a 2nd signal generating means B produces a thinning signal of the picture data synchronously with the reading section signal. Then the reading section signal of the main scan is defined as a reference signal for production of a picture element thinning signal in the main scanning direction. Thus the proper thinning signals are produced in regard of various set reading sections and thinning rates. The reduction processing through a thinning operation accordant with the reading section is properly performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an image reading device, and particularly to an image reading device that can specify a reading range on a document and performs reduction processing by thinning out.

[Prior Art] Conventionally, image information reduction processing in an image reading device is generally performed by coarsely thinning out the image information.

In addition, thinning processing in the main scanning direction is performed using a main scanning synchronization signal (H
SYNC) or the main scanning effective period signal (ARE) synchronized with this }IsYNc signal as a reference signal.

[Problems to be Solved by the Invention] However, in the conventional example as described above, since the main scanning synchronization signal is used as a reference signal for thinning processing, there are the following problems.

In other words, as shown in FIG. 6, the read interval signal (ARWE) is
) is specified as shown in the same figure (B) or the same figure (C), regardless of the position of the reading section of the ARWE signal,
Only pixels at a certain position of the image information (VDI) are thinned out. For this reason, the image effective area (ARE) and
Depending on the relationship between the reading period (ARWE) and the output timing of the thinning signal (CKWE), ineffective pixels (D) may be read out as shown in FIG. 6(C).

In view of the above-mentioned points, an object of the present invention is to provide an image reading device that generates a thinning signal appropriate for a set reading interval and thinning rate, and obtains reduction processing by appropriate thinning according to the reading interval. There is a particular thing.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an image reading apparatus that reads an original image line by line while moving a reading optical system in a predetermined direction. The present invention is characterized in that it comprises a first signal generating means for generating a reading interval signal, and a second signal generating means for generating an image data thinning signal in synchronization with the reading interval signal.

[Function] In the present invention, the main scanning reading interval signal (ARWE) is used as a reference signal, and the pixel thinning signal (CKWE) in the main scanning direction is
Since a signal generating means is provided to generate a signal, appropriate thinning signals are generated for reading sections and thinning rates of various settings, and as a result, reduction processing by thinning is performed appropriately depending on the position of the reading section. can be done.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

② Go Book Figure 1 shows the basic configuration of an embodiment of the present invention. In the figure, if A is a document, A is a first signal generating means for generating a main scanning reading period signal in an image reading device that reads a document image line by line while moving a reading optical system in a predetermined direction. be. Reference numeral B designates a second signal generating means for generating an intermittent signal for image data in synchronization with the reading interval signal.

Figure 2 shows a schematic internal configuration of an image reading device according to an embodiment of the present invention (hereinafter referred to as the first embodiment). In the figure, 101 is a housing of an image reading device (hereinafter referred to as a reader).

102 is a platen glass on which a document is placed with its reading surface in contact with it. 103 is a reference density surface (also referred to as a white reference plate) for reading the shading reference signal;
Reference numeral 4 denotes a light source lamp that illuminates the reference density surface 103 or the reading position of the document, and 105 represents a reflective shade that effectively concentrates the light of the light source lamp 104 onto the reading position. 106, 10
7 and 108 are lens units 109 from the reading position, respectively.
These are the first, second and third mirrors that form the optical path up to. The lens unit 109 includes mirrors 106 and 107.
, 108 is formed on an image sensor 204. The image sensor 204 converts the luminance information of the imaged original image into an electrical signal for each pixel.

In the above configuration, the first optical system unit (104, 10
5, 106) and the second optical system unit (107, 1
08) is driven by an optical system drive motor (not shown) in the direction of A indicated by an arrow in FIG.
Read the original on 02.

FIG. 3 shows an example of the circuit configuration of the control system of the image reading apparatus shown in FIG. 2 of this embodiment. In the figure, 201 is a CPU in the form of a microcomputer, for example, which controls the entire device.
(Central Processing Unit) and ROM (Read-Only Memory) that stores the operating procedures of this device (reader)
201A, a working RAM (random access memory) 201B, etc.

202 is a timing signal generator that generates various timing signals such as a main scanning synchronization signal (HSYNC), a main scanning reading effective period signal (ARE), and a main scanning reading period signal (ARWE), which serve as operation standards according to the settings of the CPU 201. It is a circuit. 203 is this timing signal generation circuit 202
This is an image sensor drive circuit that receives an output signal from the image sensor 204 and drives the image sensor 204. 205 is an amplifier that amplifies the analog image signal output from the image sensor 204, and 206 is an A/D that converts the analog image signal amplified by the amplifier 205 into a digital signal such as 8 bits.
(analog/digital) converter. 207 is A/
A gamma (γ) correction circuit performs density conversion on the digital image signal from the D converter 206, and 208 is a binarization circuit that performs binarization processing on the multivalued image information after γ correction from the correction circuit 207. be. 209 converts the image information that has been binarized into 1 bit per pixel by the binarization circuit 208 into 8 pixels.
This is a packing circuit that packs data into one byte.

A decimation signal generation circuit 210 generates a decimation signal (CKWE) that designates pixels to be used for binarization processing in the binarization circuit 208 or packing processing in the packing circuit 209. 211 is a selector that selects either multivalued image information after γ correction or binary image information packed by packing circuit 209 in response to a command from CPU 201; 212 is an external device (for example, a printer, C
An image buffer memory temporarily stores the image data sent from the selector 211 in order to synchronize with the RT display, etc.); 213 is a write counter that controls the write address to the image buffer memory 212; 214 is the image buffer memory 212; This is a read counter that controls the read address to. 215 is image buffer 2
This is an interface circuit through which the CPU 201 sends image data read from the CPU 12 to an external device, or through which the CPU 201 communicates with the external device.

FIG. 4 shows the operation timing of the thinning signal in this embodiment. That is, it shows the thinning timing for one period of the main scanning synchronization signal. The thinning is performed by selecting one pixel out of every three pixels, and operates using the read interval signal (ARWE) as a reference signal.

In the same figure, a valid section of 12 pixels width (#O to #11)
Two types of reading sections (ARWE (1): #O
~#lO and ARWE (2): 1 1~#11
), it is shown that four pixels, the first pixel, the fourth pixel, the seventh pixel, and the tenth pixel, are selected from the leading end side of the reading section.

As described above, according to this embodiment, since the thinning process is performed using the reading section signal as the reference signal, it is possible to thin out from an appropriate position within the reading section.

FIG. 5 shows a circuit configuration of a control system of an image reading apparatus according to another embodiment (hereinafter referred to as a second embodiment) of the present invention.

The functions of the respective components denoted by the same reference numerals as in FIG. 3 are similar to the functions of the corresponding components in the first embodiment, but only particular differences will be described below.

The image information output from the γ correction circuit 207 is such that only the information within the main scanning effective section or the reading section is stored in the image buffer memory 21.
Written to 2. Which section is selected is set in advance by the CPU 201. Image information is read from the image buffer memory 212 in accordance with a data request from an external device through the interface circuit 215, and thinning processing is performed at this time.

The read counter 214 counts only the addresses corresponding to the read section, and the thinning signal generating circuit 210 synchronized with the read counter 214 generates an appropriate thinning signal for the image data within the reading section.

[Effects of the Invention] As explained above, according to the present invention, a signal generating means for generating a pixel thinning signal in the main scanning direction using the main scanning reading interval signal as a reference signal is provided, so that various An effect can be obtained in that an appropriate thinning signal is generated for the set reading interval and thinning rate.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention. FIG. 2 is a perspective view showing a schematic internal structure of an image reading device according to a first embodiment of the present invention. A block diagram showing the circuit configuration of the control system of the first embodiment. FIG. 4 is a timing chart showing the thinning timing of the first embodiment of the present invention. FIG. 5 is a control system of the second embodiment of the present invention. FIG. 6 is a timing chart showing the timing of the thinning operation in the conventional example. 101 102 109 201 202 203 204 205 206 207 208 209 ... Housing, ... Platen glass, ... Optical imaging lens, ... CPU, ... Timing generation circuit, ... Image sensor drive Circuit, ...Image sensor, ...Amplification circuit, ...A/D converter, ...Correction circuit, ...Binarization circuit, ...Packing circuit, 210 211 212 213 214 215 ・...Thinning signal generation circuit, ...Selector, ...Image buffer memory, ...Memory write address counter, ...Memory read address counter, ...Interface circuit. Real lrI column err pregnancy m 'fN B i 1 i'o
y') 'IA Figure 1

Claims (1)

[Claims] 1) In an image reading device that reads a document image line by line while moving a document or a reading optical system in a predetermined direction, a first signal generating means for generating a main scanning reading interval signal; , a second signal generating means for generating an image data thinning signal in synchronization with the reading interval signal.