JPH05182019A - Marking character recognition device - Google Patents

Abstract

PURPOSE:To improve the recognition rate of a character by providing a first illumination means having two illumination bodies which are arranged so that an angle that the both illumination bodies make becomes a prescribed angle and a second illumination means having the other two illumination bodies which are arranged so that they make the same prescribed angle. CONSTITUTION:The image of a marking character 19 marked on a measured object 18 is inputted from an image pickup means 11 by a synchronizing signal in a state where it is illuminated by the first illumination means 16 lighted by the synchronizing signal generated by a synchronizing signal generation means 15. Then, the image of the marking character 19 is inputted from the image pickup means 11 by the synchronizing signal in the state where it is illuminated by the second illumination means 17 lighted by the synchronizing signal generated by the synchronizing signal generation means 15. An image processing means 12 generates the image where the minimum value of image element values in the same position in the two images obtained by the image pickup means 11 is set to be an image value. Furthermore, a character extraction means 13 extracts a character area from the image and generates the character image. Then, the character image is inputted to an image recognition means 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marking character recognizing method and apparatus for recognizing marking characters stamped on a metal surface or the like.

[0002]

2. Description of the Related Art Conventionally, in a stamp character recognizing device, a stamp character 26 stamped on a measuring object 25 as shown in FIG.
Was illuminated by the illumination means 24 and was taken in by the imaging means 21. The captured grayscale image is converted into a binary image by the image processing means 22 to extract a character area, and the extracted character area is input to the character recognition means 23 to recognize the engraved character.

[0003]

However, in the past, when it was attempted to illuminate well in order to extract the area of the engraved character,
Depending on the surface material and finish of the engraved characters, there may be a bright spot or a dark shadow depending on the illumination, and it is difficult to extract only the engraved letters by binarizing this image. As described above, the conventional techniques have a problem that it is difficult to accurately and stably extract a character area, and it is difficult to accurately recognize a character.

Therefore, an object of the present invention is to eliminate the influence of the reflection of illumination in order to solve the above-mentioned conventional problems.
In addition, by brightly illuminating only the engraved character, the area of the engraved character is accurately and stably extracted, and the character recognition rate is increased.

[0005]

In order to solve the above problems, the present invention illuminates illumination means A, illumination means B, image pickup means for picking up an imprinted character, and illumination means A, B alternately. Timing, a synchronization signal generating means for controlling the timing of the image pickup of the image pickup means, an image processing means for processing an image signal from the image pickup means, a character extracting means for extracting a character area, and a character area for extracting the character area. The character recognition means for recognizing the engraved characters is provided to enable accurate and stable recognition of the engraved characters.

The illumination means A and B use a plurality of sets of illumination means arranged at a certain angle or a plurality of sets of illumination means for illuminating a certain angle range in order to illuminate the engraved characters brightly. I made it a structure.

[0007]

In the marking character recognizing device constructed as described above, the first image is captured from the image pickup means by the synchronizing signal while the illumination means A is turned on by the synchronizing signal generated by the synchronizing signal generating means. Next, the second image is captured from the image pickup means by the synchronizing signal while the lighting means B is turned on by the synchronizing signal generated by the synchronizing signal generating means. Similarly, a plurality of images are captured below. The image processing means generates an image in which the pixel value is the minimum pixel value of the plurality of images for each pixel at the same position of the plurality of images. Further, a character image is generated by extracting a character area from the image. By inputting the character image generated in this way into the character recognition means, a high character recognition rate is achieved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the system configuration of the present invention. In FIG. 1, an image of an engraved character 19 stamped on a measurement object 18 is input from the image pickup means 11 by the synchronization signal while being illuminated by the illumination means A16 which is turned on by the synchronization signal generated by the synchronization signal generation means 15. To do. Next, the image of the engraved character 19 is input from the image pickup means 11 by the synchronization signal while being illuminated by the illumination means B17 which is turned on by the synchronization signal generated by the synchronization signal generation means 15. The image processing means 12 generates an image in which the minimum pixel value of the two images obtained by the image pickup means 11 at the same position is used as the pixel value. Further, the character extracting means 1
In step 3, a character area is extracted from the image to generate a character image. A high character recognition rate is achieved by inputting the character image into the character recognition means 14.

As an embodiment specifically showing the illuminating means A and B, the illuminating means 31 and the illuminating means 33, which are installed at an angle of 90 degrees as shown in FIG. At the same time, the first image is input by turning on the lights by the synchronizing signal generated by the generating means 15. An example of this image is shown in FIG. As shown in FIG. 5, the lighting means 31 and the lighting means 3
The reflected light from 3 is reflected radially with an angle of 90 degrees. Next, similarly, the illuminating means 32 and the illuminating means 34 having an angle of 90 degrees are simultaneously turned on by the synchronizing signal generated by the synchronizing signal generating means 15 of FIG. 1, and the second image is input. An example of this image is shown in FIG. As shown in FIG. 6, the reflected light from the illumination means 31 and the illumination means 33 is
The reflected light of the image shown by is shifted by 45 degrees and is reflected radially with an angle of 90 degrees. Lighting means 31 and lighting means 3
The set of 3 and the set of the lighting means 32 and the lighting means 34 are installed at an angle of 45 degrees. An image having a pixel value that is the minimum value of the pixel values at the same positions of the image of FIG. 5 and the image of FIG. 6 is generated. This image is shown in FIG. As shown in FIG. 7, the lighting means 31, the lighting means 32, the lighting means 33, and the lighting means 3
The reflected light by 4 is removed, and the engraved character can be extracted. The lighting means 31 and the lighting means 33 correspond to the lighting means A16 in FIG. 1, and the lighting means 32 and the lighting means 34 correspond to those in FIG.
It corresponds to the illumination means B17. The measurement target 35 corresponds to the measurement target 18 in FIG.

As another embodiment, as shown in FIG. 4, the illumination means 41 having an irradiation range of 90 degrees out of the entire circumference of the object 43 to be measured and the irradiation means having another 90 degrees of irradiation range. The illuminating means 42 is turned on by the sync signal from the sync signal generating means 15 of FIG. In this case, the lighting means 4
1 corresponds to the illumination means A16 in FIG. 1, and the illumination means 42 corresponds to the illumination means B17 in FIG. Further, the measurement target 43 corresponds to the measurement target 18 in FIG.

[0011]

As described above, according to the present invention, two or more sets of illuminating means for illuminating a stamped character, image pickup means for picking up an image of the stamped letter, timing of alternately turning on the illuminating means and the image pickup means. Synchronous signal generating means for controlling the timing of image capturing, image processing means for processing the image signal from the image pickup means, character extracting means for generating a character image from the image, and character recognition for recognizing the extracted character image Since it is configured by means, even if the surface material and finish that can not accurately and stably extract the character area with the conventional technology, by canceling the part that shines by reflection and exposing only the engraved character, accurate Since the character area can be stably extracted, the effect of increasing the character recognition rate is high.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing an embodiment of a conventional method.

FIG. 3 is a view of the illumination means of the embodiment of the present invention as seen from above.

FIG. 4 is a view of the illumination means of another embodiment of the present invention as seen from above.

FIG. 5 is an input image according to the embodiment of the present invention.

FIG. 6 is another input image according to the embodiment of the present invention.

FIG. 7 is an image obtained by taking the minimum value of two images according to the embodiment of the present invention.

[Explanation of symbols]

 11 Image pickup means 12 Image processing means 13 Character extraction means 14 Character recognition means 15 Synchronous signal generation means 16 Illumination means A 17 Illumination means B 18 Measurement target 19 Marked characters 21 Imaging means 22 Image processing means 23 Character recognition means 24 Illumination means 25 Measurement Target 26 Engraved character 31 Illuminating means 32 Illuminating means 33 Illuminating means 34 Illuminating means 35 Measuring object 41 Illuminating means 42 Illuminating means 43 Measuring object

Claims (2)

[Claims] 1. A plurality of illuminating means for irradiating a character or a symbol imprinted on an object to be measured, an imaging means for converting the imprinted character or symbol illuminated by the illuminating means into an image signal, and the illuminating means of the illuminating means. An engraved character and symbol recognition device comprising a synchronization signal generation means for controlling respective lighting timings and a recognition means for processing the image signal and recognizing a character and a symbol has an angle of about 90 degrees with each other. A first illuminating means having two illuminating bodies arranged so as to form a second illuminating body having two illuminating bodies arranged so that an angle between them is approximately 90 degrees.
An engraved character and symbol recognition device comprising: 2. A plurality of illuminating means for irradiating a character or a symbol imprinted on an object to be measured, an imaging means for converting the imprinted character or symbol radiated by the illuminating means into an image signal, and the illuminating means. In a marking character and symbol recognition device composed of a synchronization signal generating means for controlling each lighting timing and a recognition means for processing the image signal and recognizing a character and a symbol, of the entire circumference of the measuring object. The first which makes an angle of 90 degrees or less the irradiation range
And the second illuminating means having an illumination range of 90 degrees or less, and a marking character and symbol recognition device.