JPS62236258A - Image reader - Google Patents

Abstract

PURPOSE:To shorten a reading time by preparting the correcting data to an original document density at the time of the forward reading and outputting the gradation data to the original document density by the correcting data at the time of the double reading when an original document reading element is reciprocated and original document is scanned. CONSTITUTION:A reading element 12 controls an optical scanning system 11 and starts the reading action so as to read the home position A of an original document 16. The picture information of the read original document is sent to a CPU 24. The CPU 24 executes the arithmetic processing of the picture information in accordance with the program stored into a ROM 26, prepares the density histogram, etc., of the original document 16, executes the gamma correction and stores gamma correcting data into a RAM 25. The reading element 12 is once stopped at an edge part B of the original document 16 and next, shifted toward the home position A. At such a time, the picture photoelectric-converted by the reading element 12 is inputted through an I/O device to the CPU, the CPU 24 determines the number of gradation of the image information by the gamma correcting data stored into the RAM 25, outputs it through the I/O device, the reading element returns up to the home position A and one reading is completed.

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 scans the surface of a document with exposure and detects the reflected light with an optical reading element to read an image on the surface of the document. Regarding equipment.

[Conventional technology]

Conventionally, in order to express the gradations of highlights, halftones, and black parts of a document in an image reading device, for example, a histogram of the density levels of the document is created, and the gradations of the parts where the density levels occur frequently are calculated. Processing was performed such as gamma correction to increase the gradation and lower the gradation of small areas.

An example of a document reading section of such an apparatus is shown in FIG. In FIG. 3, an original platen glass 45 is provided on the upper surface of the apparatus main body 1, and an original document 45 on the original platen glass 45 is provided inside the apparatus main body 1.
An optical bench 41 including an exposure lamp 43 for scanning 6, a lens 44, and a self-scanning reading element 42 is provided.

The original is illuminated by an exposure lamp 43, and the light reflected by the original 46 forms an image on the reading element 42 via a lens 44, which converts the image information of the original 46 into an electrical signal.

Next, the operation will be explained.

When the reading operation starts, the reading element 42 in the optical bench 41 starts scanning the original from the home position A shown in FIG. Return to home position A.

When performing the above-mentioned gamma correction using the apparatus shown in FIG. 3, first the above-mentioned reciprocating reading operation is performed to read the density information of the document in order to create a density histogram, and then an operation of photoelectrically converting the image information of the document is performed.

[Problem that the invention seeks to solve]

Therefore, in order to read one document in the conventional image reading apparatus described above, the reading element must perform a reciprocating reading operation twice, which has the drawback of taking time.

[Means for solving problems]

The present invention has been made in view of the above points, and includes an optical scanning type mobile document reading device that scans a document by reciprocating a document reading element. This image reading device is characterized in that it performs side 6 reading, sets and reads the gradation of "□" based on density information when reading the image in the backward movement.

〔Example〕

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. Device body 1
A document table glass 15 is provided on the top, and an optical scanning type 11 including an exposure lamp 13 for illuminating the document 16 on the document table 15, a lens 14, and a self-scanning type reading element 12 is provided inside. ing.

The original 16 is irradiated by the exposure lamp 13, and the light reflected by the original 16 is transmitted through the lens 14 to the reading element 1.
2 and converts the image information of the original 16 into an electrical signal.

The optical scanning system 11 is moved by a motor 19 driven by a control unit 17, a belt 20, and a roller 18, and the image from the home position A to the end B of the original 16 is combined with the reading element and converted into an electrical signal. .

FIG. 2 shows a block diagram of the control section 17 of the reading device. Image information from the reading element 12 is input/output (
Ilo) device 21, and the central processing unit (CPtJ)
) 24, where it is processed and stored in the RAM 25. Arithmetic processing by the CPU 24 is performed according to a program stored in the ROM 26, and is output as gradation data through the I10 device 21.

On the other hand, the control program for the motor 19 is also stored in the ROM 26, and the CPU 24 drives the motor 19 with the driver 22 via the I10 device 21.
The movement of the optical scanning system 11 is controlled via the roller 18.

Next, the operation of this image reading device will be explained using FIGS. 1 and 2. The optical scanning system 11 is controlled so that the reading element 12 reads the home position A of the original 16, and a reading operation is started. The optical scanning system 11 moves to the end B of the original 16 under the control of the CPU 24;
At the same time, the image information of the original is photoelectrically converted by the reading element 12 and sent to the CPtJ 24 . The CPU 24 performs arithmetic processing on the image information according to a program stored in the ROM 26, creates a density histogram of the original 16, etc., and performs gamma correction. In this way, the original 1 is stored in the RAM 25.
Increase the number of gradations in the part where density level 6 occurs frequently,
Gamma correction data that lowers the number of gradations in small areas is stored.

The optical scanning system 11 once stops until the reading element 12 reads the edge B of the original 16, and then moves toward the home position A in the opposite direction.

At this time, the image information photoelectrically converted by the reading element 12 is input to the CPU 24 through the I10 device.
Step 4 determines the number of gradations of the image information while referring to the gamma correction data stored in the RAM 25, outputs it through the I10 device, and the reading element returns to the home position A, completing one reading.

In this way, with respect to the planning information of the original document 16, gradation output data is obtained in which the number of gradations is increased in areas where density levels occur frequently, and the number of gradations is decreased in areas where density levels occur less frequently.

〔Effect of the invention〕

As explained above, in an optical system movable image reading device that scans the original by reciprocating the original reading element, correction data for the original density is created during the forward movement of the image reading device, and correction data for the original density is created during the backward movement of the original. Since the gradation data for the density is output, the present invention requires only one reading operation for reading one document, which has the effect of shortening the reading time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram of a control section in FIG. 1, and FIG. 3 is a block diagram of a conventional example. DESCRIPTION OF SYMBOLS 1... Reading device main body, 11... Optical scanning system, 12.
・・Document reading element, 13・・Exposure lamp, 14・
... Lens, 15... Original table glass, 16... Original, 17... Control section, 18... Roller, 19... Motor, 20... Belt, 21... Input/output ( Ilo)
device, 22...driver, 24...CPU, 25.
...RAM, 26...ROM. )mo-2/ Figure 2 Figure 3

Claims (1)

[Claims] In an image reading device that reads a document using a reading element mounted on an optical scanning system that moves back and forth, the density of the original is measured during the reciprocating reading of the reading element, and the gradation of the image reading is determined based on the density information during the backward reading. An excellent image reading device characterized by setting and reading.