JPH0226265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the side edge position of a form in an optical character reading device or the like.

Generally, in an optical character reading device, a form is run, the direction perpendicular to the form running direction is the main scanning direction, the direction opposite to the form running direction is the sub-scanning direction, and the main scanning direction is from one side edge of the form to the other side. After scanning a certain range that completely includes one line of characters up to the side edge and in the sub-scanning direction, converting the image into binary information and temporarily storing it in the image memory, one of these is scanned.
The image for the characters is cut out, if necessary, preprocessing is performed to facilitate the recognition work described later, the features of the cut out image are extracted, and this is compared with a reference pattern stored separately in advance. This is used to recognize cut-out images, that is, to read characters.
If the form does not travel in the correct position but shifts to one side, an error will occur in each cutting position, so measure the amount of deviation of the form and use this to correct the cutting position. ing. In measuring the amount of deviation, the positions of both side edges of the form are measured, taking into consideration changes in the form width due to humidity and the like. Conventionally, the side edge position of a form has been measured by storing a certain range including one line of characters in an image memory, and then checking the stored image content for one scan on the image memory. I was doing it. However, recently, perforated and separated forms are often used, and as shown in FIG. This irregular portion 3 is usually convex and has a height of up to 2 mm. This causes an error in the measured value of the position of the side edge of the form, and there is a problem in that the image for one character cannot be accurately cut out, and therefore the characters cannot be read accurately.

The present invention has been made to solve these problems, and its purpose is to make it possible to measure the position of the side edge of a form even if the side edge of the form has irregularities due to perforations. To obtain an optical character reading device which can accurately read characters.

In order to achieve the above object, the present invention sets the relative moving direction of a relatively moving form as a sub-scanning direction, arranges a detector so as to intersect with the sub-scanning direction, and detects the form by scanning with the detector. In a method that obtains an image and measures the position of the side edge of a form from the image, each measurement value is obtained by scanning three or more times for the form in which an irregular part of a constant width appears at the side edge position at a predetermined interval. of,
A means is provided for taking a majority vote of the three measurement values obtained by making the interval in the sub-scanning direction at least the width of the irregular part and within the appearance interval of the irregular part, and by the majority vote. The present invention is characterized in that the position of the side edge of the form is determined.

Hereinafter, the present invention will be explained in detail with reference to Examples. FIG. 2 is a block diagram showing the configuration and functions of an embodiment of the present invention. The scanning unit 20 has a main scanning direction that is perpendicular to the scanning direction of the form 10 and a sub-scanning direction that is the opposite direction to the scanning direction of the form. A certain range completely including one line of characters is scanned in the sub-scanning direction, and the image is converted into binary information and stored in the image memory 40 via the gate 30. The microprocessor 50 checks the stored contents of the image memory 40, confirms that the scanning section has scanned the predetermined range, closes the gate 30, and turns on the form running motor 70 via the form running control section 60. It stops and the running of form 10 is stopped. The scanning section 20 has 2048 photodetecting elements arranged in a one-dimensional manner, thereby scanning a maximum length of 215 mm. Therefore, a length of 0.105 mm in the main scanning direction of the form running surface corresponds to one photodetecting element. Also, sub-scanning is performed at a pitch of 0.105mm. Therefore, the image of the document scanning range is divided into squares of 0.105 mm, and one section of each section is stored in one bit of the image memory 40. The position of the side edge of the form is measured after the image of the form scanning range is stored in the image memory 4 as described above.
0 and the microprocessor 50. FIG. 3 is a diagram showing how an image of the scanning range of the form 10 is stored in the image memory 40 and how the microprocessor 50 examines this and measures the position of the side edge of the form. The position of the side edge of the form is measured using the reference line YY' and the image memory of XX' and ZZ' which are 18 scans before and after the reference line YY', and for the left edge of the form, the stored contents of the image memory are scanned and the values A, B and C are measured. The positions of XA, YB, and
Find it as the distance of ZC, and in the example shown, XA=ZC≠
Since YB, XA=ZC is determined as the left end position of the form by majority vote. As mentioned above, XX′ and
The pitch between YY' and YY' and ZZ' is 18 scans, but when converted to the length on the form, it is 0.105 mm x 18 =
It becomes 1.89mm. The image memories of XX′, YY′, and ZZ′ were detected by a detector with a detection width of 0.105 mm. That is, the measurement of the side edge position of the form by the microprocessor 50 described above corresponds to scanning the form three times at a pitch of 1.89 mm using a detector with a detection width of 0.105 mm. On the other hand, in this embodiment, the width of the irregular portion 3 at the side edge of the form was 1 mm, and the arrangement pitch of the irregular portion 3 was 6 mm. Therefore, the scanning pitch of the detector (1.89mm) is longer than the width of the irregularity plus the detection line of the detector (1mm + 0.105mm = 1.105mm), and the width of the irregularity is longer than the width of the irregularity. width minus the detection width of the detector (6 mm - 1 mm - 0.105 mm = 4.895
mm) shorter. Therefore, in Figure 3, XX′,
Although one of YY' and ZZ' may pass through the irregular portion 3 at each side edge of the form, two or more will not pass through the irregular portion 3 at the same time.

As described above, according to the present invention, even if the side edges of the form have irregularities due to perforation, the position of the side edge of the form can be accurately measured.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of a form with irregularities at the edges, FIG. 2 is a block diagram showing the structure and function of an embodiment of the present invention, and FIG. 3 is an explanatory diagram of an embodiment of the present invention. In the figure, 10 is a form, 20 is a scanning unit, 30 is a gate, 40 is an image memory, 50 is a microprocessor, 60 is a form running control unit, and 70 is a form feeding motor.

Claims (1)

[Claims] 1. The direction of relative movement of a relatively moving form is a sub-scanning direction, a detector is arranged so as to intersect with the sub-scanning direction, and an image of the form is obtained by scanning with the detector, In the method of measuring the side edge position of a form from the image, each measurement value obtained by scanning three or more times is calculated in the sub-scanning direction for the form in which irregular portions of a certain width appear at the side edge position at predetermined intervals. A means is provided to take a majority vote of the three measurement values obtained by making the interval at least the width of the irregular part and within the appearance interval of the irregular part, and by the majority vote, the document is A document side edge detection method characterized by determining the side edge position.