Method for boundary positioning and quality identification of watermark of paper

Abstract

The invention discloses a device for boundary positioning and quality identification of a watermark of paper. The paper travels in a mounting frame; two symmetrical reflective optical fiber sensors are arranged at positions above two sides of the paper on the mounting frame; a charge coupled device (CCD) sensor is arranged at a position above the center of the paper, light sources are arranged at positions below the center of the paper; a diffusely reflecting plate which is parallel to the paper is arranged between the light sources and the paper; the reflective optical fiber sensors are connected with a computer; and the CCD sensor is connected with the computer through an image acquisition card. A method for the boundary positioning and quality identification of the watermark of the paper by using the device comprises the following steps of: acquiring a watermarked paper image by using the CCD sensor, transmitting to the computer, and processing the image; and matching a processed watermark pattern contour and a standard watermark pattern contour, marking the unmatched image, and displaying and storing result information. The device can automatically position boundaries of watermarks and extract watermark patterns and realizes automatic identification.

Description

technical field [0001] The invention relates to a paper watermark identification device and method, in particular to a paper watermark boundary location and quality identification method. Background technique [0002] The watermark pattern in paper is a pattern of special optical properties formed by controlling the density of local paper fibers during the papermaking process. [0003] During printing, due to the influence of many conditions, the watermark pattern may have quality problems such as incompleteness; at present, most of the quality problems of paper watermarks are judged by human eyes, and subjective factors are greatly affected, so the accuracy of judgment is difficult to guarantee. [0004] Generally, light sensors are used in watermark pattern detection, and the light-emitting element and light-receiving element are arranged at intervals. Due to the aging of the light-emitting element and changes in ambient temperature, the light irradiated on the paper will ...

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Problems solved by technology

[0003] When printing, due to the influence of many conditions, the watermark pattern may have quality problems such as incompleteness; at present, most of them rely on human eyes to judge the quality of paper watermarks, subjective factors have a great influence, and the accuracy of judgment is difficult to guarantee

[0004] Generally, light sensors are used in watermark pattern detection, and the light-emitting element and light-receiving element are arranged at intervals. Due to the aging of the light-emitting element and changes in ambient temperature, the light irradiated on the paper will be uneven, which will affect the watermark pattern of the image in the later stage. processing, resulting in misrecognition of the watermark pattern

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