JPH02130076A - Picture reader - Google Patents

Abstract

PURPOSE:To obtain the averaging processed data in a short time by providing an adding averaging circuit to add and average the picture information of a reading point in a main scanning direction read by an image scanner on an original and the picture information of the reading point read by a fore- adjoining reading element. CONSTITUTION:A CCD image sensor 4 responds to a scanning clock signal, successively outputs data A to An of respective reading elements and the data A to An are successively stored into one picture element delaying circuit 104. At such a time, the one picture element delaying circuit 104 simultaneously outputs the preceding picture information read by a fore-adjoining reading element and stores new picture information. In short, concerning the first reading point, data A are outputted from the one picture element delaying circuit 104 and simultaneously, data A1 are stored. Next, an adding averaging circuit 105 adds and averages the picture information of a present reading point and the picture information outputted from the one picture element delaying circuit 104. Thus, the averaged data for one picture element in the main scanning direction can be outputted in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an image reading device for reading image information used in a digital LV imprinter or facsimile machine 5 and outputting it as multi-tone data.

<Prior Art> Conventionally, a CCD image sensor has been used which reads one line of image information and sequentially outputs the image information read by each reading element using a charge-coupled device (hereinafter referred to as COD).

A conventional image reading device will be described below.

FIG. 2 is a block diagram of a conventional general image reading device, where 1 is a document, 2 is a light source, and 3 is a rod-shaped lens in the direction of arrow A (hereinafter referred to as the main scanning direction) shown in FIG. 4 is a CCD image sensor.

FIG. 3 is a perspective view of a conventional general image reading device, in which the carriage 5 includes a light source 2 and a rod lens 7L/I 3.
and CCD image sensor 4 t-tower 1ffl, and slide in the direction shown by arrow B (hereinafter abbreviated as sub-scanning direction). 6 is a belt that drives the carriage 5; 7 is a coupling member that connects the carriage 5 and the belt 6; 8 is a drive pulley; 9 is a driven googly; 1O is a drive motor.

FIG. 4 is a circuit block diagram of a conventional image reading device.
An amplifier 103 that amplifies the output of the image sensor 4 to an appropriate voltage is an analog-to-digital converter (hereinafter abbreviated as A/D converter) that converts the output of the amplifier l(]2 into a multivalued digital value.

Their general operation is as follows.

A light source 2 irradiates light onto a document l. The light reflected from one surface of the original is collected by the rod lens array 3 and imaged on the reading υ element of the CCD image sensor 4. An output voltage corresponding to image information at each position on the document appears on the reading element of the CCD image sensor 4. The COD image sensor 4 sequentially outputs data from each reading element in response to a scanning clock signal. This output voltage is amplified to a sufficient level by an amplifier 102 for each data of each reading element, and converted into a digital value corresponding to the brightness level by an A/D converter 103. By performing this over one line in the main scanning direction, multi-gradation image information for one line can be obtained. Next is Carriage 5! The image information of the next line is read after moving by the amount of life. By performing this over the entire surface of the document 1, image information for one screen is read. The above-described image reading device is also used when reading halftone dot printing.

In halftone dot printing, even the image that appears continuous is a collection of minute dots, which may interfere with the original and generate false signals commonly referred to as a moiré phenomenon, which can significantly degrade reading quality. For this reason, conventional methods have been used to prevent the moiré phenomenon by averaging the image information of four or nine adjacent points at the expense of some reading accuracy.

<Problems to be solved by the invention> However, in the conventional configuration, the data of the read l line was once stored in memory, read out, and averaged, so that it was difficult to output the data after reading. It took a lot of time.

Means for Solving Problems〉 The present invention uses image information of one point read in the main scanning direction by an image scanner on a document and image information of one point read by an element adjacent to the front of the notable point. The apparatus is equipped with an averaging circuit that adds and averages image information from a delay circuit that outputs , in response to a clock signal. In the sub-scanning direction, since the image scanner is reading while moving, the image information is averaged, and the moire phenomenon is not as noticeable as in the main-scanning direction. Therefore, it is sufficient to average the information of two adjacent points in the main scanning direction.

Effects> With the above configuration, it is possible to prevent the chipotle phenomenon by adding and averaging the image information of a certain reading point in the main scanning direction and the image information of the reading point adjacent to the image information of interest.

<Embodiment> An image reading device according to an embodiment of the present invention will be described below.

FIG. 1 is a circuit block diagram of an image reading device 9 according to the present invention. lOl is a driver, 102 is an amplifier, 1
03 is an A/D converter, and these have the same configuration as the conventional example. 104 is a CCD image sensor 4
The data for one pixel output by the CCD image sensor 4 is stored, and after a delay of the time necessary for the CCD image sensor 4 to output image information for one pixel, the reading element next to the front of the CCD image sensor 4 reads the data read one pixel before. The output one-pixel delay circuit 105 is an averaging circuit that adds and averages the output of the A/D converter 103 and the output of the one-pixel delay circuit 104.

The operation of the image reading apparatus of this embodiment configured as described above will be explained below using the timing chart shown in FIG.

When reading an image, the light source 2 first irradiates the document 1 with light as in the conventional example. The light reflected from the document surface is collected by the rod lens array 3 and sent to the CCD image sensor 4.
imaged on the reading element. CCD image sensor 4
An output voltage corresponding to image information at each position on the document appears on the reading element. As shown in Figure 5, the CCD
The image sensor 4 sequentially outputs data A''An of each reading element in response to the scanning clock signal. This data A''An is sequentially stored in the one-pixel delay circuit 104. At this time, the pixel delay circuit 104 simultaneously outputs the previous image information read by the previous reading element and stores new image information. In other words, regarding the first reading point, data A is output from the one-pixel delay circuit 104 and data A1 is stored at the same time.

Next, the averaging circuit 105 adds and averages the image information at the current reading point and the image information output from the one-pixel delay circuit 104. Therefore, in response to the clock signal, the averaging circuit +05 outputs (A+A 1)/2°(A I +A2
)/2-=(An-1+An)/2 are output one after another.

In this manner, in this embodiment, the averaged data for one pixel in the main scanning direction (average data of the image information of the current reading point and the image information of the previous adjacent reading point) can be sequentially output in response to the scanning clock.

<Effects of the Invention> The present invention includes an averaging circuit that adds and averages the image information of the reading point υ in the main scanning direction read by the image scanner on the document and the image information of the reading point read by the previous reading element. This eliminates the need to temporarily store the data in a memory and then read it out for calculation as in the past, and it is possible to obtain averaged data in a short time.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram of an embodiment of an image reading device 9 according to the present invention, FIG. 2 is a block diagram of a conventional image reading device, FIG. 3 is a perspective view of the same, and FIG. 4 is a circuit block diagram of the same. , FIG. 5 is a timing chart. In the figure, 1... Original, 2... Light source, 3...
Rod lens array, 4... COD image sensor-5... Carriage, 6... Belt, 7
...Connection member. 8... Drive pulley, 9... Driven boo! I-10
... Drive motor, 101 ... Driver,
102... IA, 103... A/D converter, 104... 1 pixel delay circuit, 105...
・Averaging circuit.

Claims (1)

[Claims] 1. An image scanner having a plurality of reading elements, inputting image information for one line and sequentially outputting image information of each element according to a clock signal, and a reading line of the image scanner. In an image reading device equipped with a moving means for moving the image, the image information from a delay circuit that outputs the image information of the reading point in the main scanning direction and the image information of the previous reading point is sequentially added and averaged in response to a clock signal. An image reading device characterized by comprising an averaging circuit.