Answer sheet identification method

Abstract

The invention relates to an answer sheet identification method, which comprises the following steps: dynamically filtering and obtaining a colorful image of an answer sheet; carrying out gray processing to the image; judging whether a gray image is the processing of a "black" image; carrying out local threshold value binarization processing; looking up to process a convex quadrangle on a binary image, wherein the convex quadrangle has a maximum area and is more than a certain threshold value, and four inner corners of the convex quadrangle are similar to straight angles; carrying out inclination and perspective distortion correction processing; intercepting a rectangular area, and carrying out normalized image processing; identifying student numbers; identifying test paper numbers; and identifying answers. Due to the portability of a mobile terminal, a research that a mobile terminal camera is used for scanning an answer sheet and a relevant algorithm is used for identifying becomes very meaningful, the working efficiency of a teacher can be obviously improved, and the answer sheet identification method is helpful for teaching work. The answer sheet identification method also can be used for reference into the identification statistical processing of information cards, such as questionnaires, votes and the like, and has a wide application value.

Description

technical field [0001] The invention relates to an answer sheet identification method, which requires a mobile intelligent terminal to invoke camera scanning technology, digital image processing and pattern recognition technology. Background technique [0002] According to the different image input devices of the answer sheet, there are generally three types of camera marking systems, scanner marking systems and digital camera marking systems. [0003] The digital camera marking system is inconvenient to operate, and there are few relevant literature reports. A practical scanner marking system generally uses a high-end scanner with an automatic document feeder, but it is not the first choice for individuals to purchase such high-priced scanners. The camera marking system reported in the literature generally does not use the smart mobile terminal camera as the input device for the answer card image, which is inconvenient to carry. [0004] At present, there are few technica...

AI Technical Summary

Problems solved by technology

[0003] The digital camera marking system is inconvenient to operate, and there are few relevant literature reports

A practical scanner marking system generally uses a high-end scanner with an automatic document feeder, but it is not the first choice for individuals to purchase such high-priced scanners

The camera marking system reported in the literature generally does not use the smart mobile terminal camera as the input device for the answer card image, which is inconvenient to carry

[0004] At present, there are few technical reports on the use of mobile terminal cameras as input devices for answer sheet images; moreover, some of these methods require the use of black signature pens for filling, and the use of 2B pencils is not allowed, which limits the practicality of the method

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