JPS5941088A - Method for reading out picture - Google Patents

Abstract

PURPOSE:To prevent disabled reading or a reading error and to improve the reliability of picture reading by changing the incident angle of irradiated light at the detection of abnormal reflection from a form and reading out the form again. CONSTITUTION:Reflected light obtained at a reading position on the form 3 is guided to an image sensor 5 through a reflector 4 and converted into an electric signal corresponding to the quantity of photodetection. The converted electric signal is amplified by an amplifier 6. A detecting circuit 8 detects abnormal reflection on the form by comparing a value obtained by dividing a video signal, an output from the amplifier 6, by resistances 1, 2 with the output of a white level follower 7 following the reflected light of a white part on the form 3. When the abnormal reflection is detected, the incident angle of a light guide 2 is changed by a cam 12 driven by the detection signal and the form 3 is read out again by the control of a motor through a controller 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to improving the reliability of an OCR/OMR# optical reader.

(+3) Background of the technology Optical reading devices read images of characters, marks, etc. written on a form using reflected light obtained by illuminating the form, and a threshold value is used to binarize the read signal. In order to suppress the A' movement of the output of the white level follower due to ridges on the form surface, a white level follower that follows the 41 bladder increase signal corresponding to the white area on the form is usually installed for illumination. The light source is such that the irradiation light beam is 4
It is set at an angle of 5 degrees or more and 21 degrees.

On the other hand, when writing letters on a form, a 22mm pencil is usually used.
Alternatively, a ballpoint pen is used, but when writing with a hard pencil and using strong pressure, specular reflections are likely to occur on the handwriting, especially when four marks are created on the handwriting.
This may result in unreadability or corruption, and there is a need for effective countermeasures to improve reliability.

(C) Prior art and problems Self-reading capability or v
l; In order to prevent mistakes, conventionally, to prevent specular reflection, there have been methods such as distributing the illumination light beams or using ground glass in front of the illumination light source to scatter the irradiated light. For abnormal values in the read signal due to specular reflection, this is detected 17 and electrically ai1? Various methods are used to correct this. However, it is very difficult to completely prevent specular reflection using the part name method, and errors in correction were often made when using the method of Gonagisa.

G)) Object of the Invention The object of the present invention is to read EI5! by specular reflection on a form in an optical reading/taking device. The object of this invention is to improve reliability by preventing cine performance or dust removal errors.

@ Structure of the Invention The most obvious image reading method is to scan a form illuminated by irradiated light and read the information written on the paper using reflected light (C). - A white level follower that follows the reflected light from the white background part of 1, and a detection circuit 11 that detects abnormal reflection on eaves etc. by comparing the video 1 obtained by reading the form with the output of the white level follower. In preparation, when an abnormal reflection is detected in the front panel 4, the incident angle of the irradiation beam L is changed and the document is read again.

V) Implementation 1-0 of Issue 11 Next, the gist of the present invention will be specifically explained using a practical example.

The figure shows a configuration diagram of one embodiment of the present invention. 1, 2 indicates an illumination light source, and 2 indicates a light guide that guides the irradiation light generated by the illumination light source 1 to the reading position fil (1/C) on the form. , 3 is a form,
5 is a reflecting mirror that transmits the reflected light obtained at the H, /, 5 position on the 4-digit form 3 to the image sensor described below. 5 is the reflecting mirror 4.
The image sensor 6 amplifies the output No. 3 of the image sensor 5, which receives the reflected light reflected by the sensor and converts it into an aether signal according to the receiving prisoner.'' Soichisagi, 7 H11jl
t, Man: 141 forces of ÷ 6 1 ℹ 1 on H] Also plate part reflection no? White level follower, 8 is i so lj
By comparing the output of the white level follower 7 with the partial pressure value by the resistor R1 and the resistor R2 and the output of the white level follower 7 by using the comparator 9, the furnace IJ.・Detection circuit for detecting abnormal reflection on vote 1, 1
0 is a control 1j that controls a motor described later by the output signal of the detection circuit 8 and also controls the wt collection of the form again; iiL f is a motor that drives a cam described later; 12 is a control that moves one end of the light guide 2; This is a cam that changes the excess I angle of the irradiation light by changing the angle of the irradiation light.

The video signal generated when specular reflection occurs due to the concave trace of the lead mark shows an abnormally large value compared to the video obtained for the white background, and therefore can be reliably detected by the detection circuit 8. can do.

In OCR/OMR%, characters or marks on the same document are always entered by the same person. Therefore, the concave mark 17 (
Therefore, if muscle reflexes occur at t, they will also occur repeatedly on other parts of the form.

In addition, such specular reflections i,;l can all be removed at once by simply reducing the incident angle of the irradiated light slightly. Therefore, when extracting the specular reflection as before, 1. By changing the incident angle of the irradiation light to a small angle of 41 and performing the Taji and document reading, normal removal can be achieved. There are many cases where this occurs.

It should be noted that since the decrease in the incident angle is only a small amount, there is very little adverse effect on the output of the white level follower 7, etc.

(2) As described in detail, according to the present invention, it is possible to eliminate specular reflections on forms, thereby preventing reading errors or reading errors caused by specular reflections, thereby improving the reliability of optical reading devices. can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The figure shows a configuration diagram of an embodiment of the present invention, where 7 is a white level follower and 8 is a detection circuit.

Claims (1)

[Claims] scanning the Ii+ form illuminated by irradiation light; 17 optical reading for reading tW M written on the form using reflected light;
In the scanning device, errors on the form are confirmed by comparing the video signal obtained by the white level follower that follows the reflected light of the white area on the form and the output of the white level follower with the output of the white level follower. - An image v5 capturing method comprising: a detection circuit for detecting the abnormal reflection, and changing the incident angle of the irradiation light and reading the form again when the abnormal reflection is detected.