An automatic measurement device for the evaluation of the print quality of printed characters

摘要

When using OCR equipment (OCR = Optical Character Recognition) it is necessary to define shape and print quality of the characters in national and international standards.The paper gives a review of the standardization of the character fonts OCR A and OCR B for optical character recognition. All relevant parameters are discussed which define the print quality of printed characters. A critical review of two measurement methods used so far for the evaluation of print quality parameters is given. The improvement of the measurement methods led to the development of an automatic measurement device which is described in detail.The automatic measurement device consists of a high precision scanning device to digitize the printed characters and a computer program for the evaluation of the data. The mechanical construction and the properties of the scanning device are explained. The computer program consists of two main parts for preprocessing of the scanned data and for the evaluation of the different print parameters.Test results are reported and possible applications of the measurement device are discussed.