JPS5852781A - Linear scanner - Google Patents

Abstract

PURPOSE:To improve the character recognition precision of an OCR by storing slanting and position shift data on plural solid-state image pickup elements, and correcting the storage address signal of an input image signal on the basis of the stored data. CONSTITUTION:The scanning widths and left-end positions of plural position-shift reference marks detected by an optical scanning system 7 are detected by an edge detecting circuit 8 and transferred to an arithmetic circuit 9. The arithmetic circuit 9 calculates an evaluation function of the slanting and position shift of the solid-state image pickup elements and on the basis of it, correction parameters are selected selectively from a correction parameter storage memory 13, and stored in a parameter storage register 10. On the basis of the correction parameters stored in the parameter storage register 10, an address generating circuit 11 generates a correction address to store a one-line scanning pattern, obtained through the linear scanning of the optical scanning system 7, in a pattern memory 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line scanning position shift detection device used in an optical character reading device (hereinafter referred to as OCR). In particular, it is a device that directly reads characters, etc.

At present, solid-state imaging devices such as CCDs are often used as light devices for scanning forms and converting them into electrical signals.

Furthermore, the reading field of view is expanded using a single solid-state image sensor. When reading a form using such multiple solid-state image sensors, even a slight positional shift of the solid-state image sensors may cause the images of characters, etc. included in the reading field to tilt or shift, making it difficult for OCR to recognize the characters. Accuracy may deteriorate. On the other hand, it takes time and labor to accurately correct such slight positional deviation of the solid-state image sensor in advance through adjustment work.

An object of the present invention is to provide a round line scanning device that solves the above-mentioned conventional drawbacks by providing a plurality of misalignment marks with specific shapes within the field of view of each solid-state image sensor. .

Another object of the present invention is to improve character opening accuracy by correcting image signals of characters and the like using the line scanning position deviation values detected by the present invention.

According to the present invention, in a scanning device that performs line scanning within the field of view of each of a plurality of solid-state image sensors, a plurality of sawtooth-shaped positional deviation basic marks are placed on a preset reference line within the field of view of each of the solid-state image sensors. a means for line-scanning an area including the reference line to obtain a scanning signal of the misaligned basic mark;
Based on the position of the tortoise and left end on the scanning line of the misaligned basic mark obtained from the scanning signal of the misaligned basic mark,
A line scanning device is provided which includes means for detecting the tilt and positional deviation of a solid-state image sensor, and means for correcting a storage address signal of an input image signal based on the detected tilt and positional deviation values of the solid-state image sensor. The present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an optical scanning system in OCR.

In the figure, a form 1 is being transported by a transport device 2 at a constant speed. 6 is a conveyance device [located in the conveyance direction of 12,
This is a reference mark plate on which a plurality of positional deviation reference marks 61, which will be described later, are printed. 3 is a light source. The light emitted from the light source 3 illuminates a plurality of misaligned reference marks 61 arranged on the reference mark plate 6 or the reading line on the form 1, and the reflected light is collected by two lenses 4. It is installed so as to lead to the two solid-state image sensors 5. The two solid-state image sensors 5 are installed so that one end of their field of view is superimposed so that the entire area of the reading line can be imaged. During a period in which the form 1 is not transported onto the reference mark plate 6 by the transport device M, the solid-state image sensor 5 images one line on the plurality of misaligned reference marks 61 on the reference mark plate.

FIG. 2 111(2)(3)(4) shows an example of a line scanning signal obtained using a solid-state image pickup device installed with a positive siren in line scanning of a plurality of misaligned reference marks according to the present invention. FIG. FIG. 2 (1) shows, as an example, a case in which three positional deviation reference marks having a sawtooth shape are arranged at equal intervals as positional deviation reference marks in the present invention, and line scanning is performed in the direction shown by the arrow. Figure 2 (1) is obtained by scanning the line shown in Figure 2 (1).
A scanning signal as shown in 2) can be obtained.

By performing differential processing on the signal obtained by scanning shown in Figure 2 (2), both ends of the scanning of the positional deviation reference mark as shown in Figure 2 (3) and Figure 2 (4) are calculated. A signal is obtained when the signal is displayed. By these signals, the scanning width /S of the misaligned reference mark shown in FIG. 2 and the position P81. which indicates the left end of the misaligned reference mark shown in FIG. P82. P8. can be detected.

Figure 3 (11 + 21 ( 31 ( 41 ( 51) indicates that during line scanning of the multiple positional deviation reference marks shown in Figure 2, a slight inclination of the solid-state image sensor or a positional deviation between the two solid-state image sensors may occur). FIG. 4 is a waveform diagram showing an example of a scanning signal obtained in such a case.

When line scanning is performed with an inclination upward to the right as in the direction of the arrow shown by the solid line in FIG. 3(1), a 12-scan signal as shown in FIG. 3(2) is obtained. Note that the arrow direction Fi indicated by the dotted line in FIG. 3(1) shows line scanning when using a solid-state image pickup device that is accurately installed as shown in FIG.

For example, when a solid-state image sensor as shown in FIG. 3 (1) is first used, the left end position PS1, PS2 and P 1 , P 2 of the positional deviation reference mark shown in FIG. It is obtained by calculating the ratio of relative positions.

(The denominator of the evaluation function J1 shown in equation 4 represents the distance between the left end positions of adjacent positional deviation reference marks when the solid-state image sensor is installed in a positive RVC, and is a constant value set in advance.

In equation (2), if the tilt of the fixed J image element is in the upward-right direction, the evaluation function J1 satisfies 0<Jl-1, and as the degree of upward slope to the right increases, the evaluation function Jq becomes smaller; As the degree becomes smaller, the evaluation function 51 approaches 1.

In addition, in equation (2), if the tilt of the solid-state image sensor is downward to the right, the evaluation function J1 satisfies 14J1, and if the degree of downward slope to the right becomes thicker, the evaluation function J1 becomes larger; It can be said that the evaluation function Jl approaches 1 as the value becomes smaller.

Note that the evaluation function Jl described above uses the left end positions 1d of adjacent misalignment reference marks, but may also use the left end positions of any two misalignment reference marks.

Fig. 3 (31f41 (51) indicates 2 in line scanning of multiple positional deviation reference marks using two solid-state image sensors.
This figure shows an example of a case where a vertical positional shift occurs between two solid-state image sensors. .

Accurately installed solid-state camera II in Figure 3 (3) of the whistle! By line-scanning the field of view A1 of the element, the image shown in FIG.
) was obtained, while the scanning shown in FIG. 3 (51 I get a signal.

Note 1. /s, / in Figure 3 (3), (4), (5)
7+/9 indicates the positional deviation reference mark width, and PS4. P.S.
5. PS6゜PS7 is the position I road deviation reference mark run 6;
The position ft indicating the left end obtained by .

Detection of vertical deviation as shown in FIG. 3(5) is determined by equation (2) shown below.

That is, the evaluation function expressed by equation (2), step 2, is defined as the positional deviation reference mark width/'7 when the positional deviation occurs in the downward direction. 3, 0<J2<1
When the above is satisfied and no upward positional deviation occurs, the positional deviation reference mark width/7 becomes larger than the positional deviation reference mark width is, causing J2>1.

FIG. 4 is an X-Program diagram showing a specific example of the present invention.

7 is the optical scanning system explained in FIG.
As shown in Figures and Figure 3, the positional deviation standard for bubble number 11! A scanning signal is obtained by line-scanning the area.

8 is an edge detection circuit, which detects the scanning width and left end position of a plurality of positional deviation reference marks detected in the optical scanning system, as shown by +3) and +41 in Fig. 2;
It is transferred to the arithmetic circuit 9.

The arithmetic circuit 9 detects the tilt and positional deviation of the solid-state image sensor as explained in FIG. 1 evaluation function Jl to check
and J2, and based on the values of the calculated #f1JEJ functions Jl and J2, correction parameters for tilt and positional deviation are selected from the correction parameter storage memory 13 and stored in the parameter storage register 10. In addition, the correction parameters are the evaluation functions Jl and J2 described above for each 9th performance.
The value of is quantized into N stages, and the quantized evaluation function, TI
and J2 from the hn positive parameter storage memory 13.

A pattern memory 12 stores a pattern including a character area for one line of the form 1 shown in FIG. Reference numeral 11 denotes an address generation circuit, which stores a one-line scanning pattern line-scanned by the optical scanning system 7 in the pattern memory 12 based on the correction parameters stored in the address generation circuit 11u parameter storage register 10.
Generate a corrected address.

According to the addresses generated by the address generation circuit 11, the one-line scanning pattern described above is sequentially stored in the pattern memory 12.

As described below, by applying the present invention, it is possible to correct and store the inclinations and positional deviations of a plurality of solid-state image sensors, and improve the character recognition accuracy of the QCI (which is subsequently processed).

[Brief explanation of the drawing]

FIG. 1 shows an example of an optical scanning system in OCR. Figures 2 (1), (21, (31, and 4) show line scanning signals obtained using a solid-state image pickup device that is precisely installed for one moment in virtual scanning of a plurality of misaligned reference marks in the present invention. FIG. 3 is a waveform diagram showing an example. FIG. It is a waveform diagram showing an example when singing or positional shift occurs in the solid-state image sensor.W, 4 is a logical block diagram showing a specific embodiment of the present invention.In the figure, 1 is the book festival, 2 is the transport device, 3 is the light source, 4#
5 is a solid-state image sensor, 6 is a reference mark plate, 7 is an optical scanning system, 8 is an edge detection circuit, 9Fi,
10 is a parameter storage register, 11 is an address generation circuit, 12 is a pattern memory, and 13 is a correction parameter storage memory. Figure 1 Figure 2 (1) Figure 3 (I) (2) (3) (4) (5) r, :IbP57 Figure 4

Claims (1)

[Claims] In a scanning device that performs line scanning within the field of view of each of a plurality of solid-state image sensors, a plurality of sawtooth-shaped positional deviation basic marks are provided on a preset reference line within the field of view of each of the solid-state image sensors, and the means for obtaining a scanning signal of the misaligned basic mark by scanning an area including the reference line; and a means for obtaining a scanning signal of the misaligned basic mark by scanning an area including the reference line; and a means for obtaining a scanning signal of the misaligned basic mark based on the scanning signal of the misaligned basic mark; a positional deviation detection means for detecting the tilt and positional deviation of the solid-state image sensor; 1. A line scanning device comprising: means for correcting a signal.