EXTRACTION SYSTEM FOR FEATURE POINT IN RECOGNITION OF ONLINE HAND-WRITTEN CHARACTER

摘要

PURPOSE:To approximate strokes constituting a character by reduced number of points without missing a feature point by extracting a local acute angle inflection point by a direction angle tracing method of the first step and extracting a feature point representing a global inflection point and a smooth curve by a recurrent remotest point extracting method of the second step. CONSTITUTION:When stroke data is inputted to a stroke storing circuit 11 and a counter 12 indicating the position of a present pen point is set to '2', coordinate data of the pen point ai indicated by the counter 12 and pen points ai-1, ai+1 before and after it is read to registers 21, 22, 23 and fed to subtraction circuits 24, 25. Values of vectors ai-1ai and aiai+1 are set to the registers 22, 23. An inner product calculation circuit 28 calculates the inner product of the vectors ai-1ai and aiai+1 and a positive and negative decision circuit 29 decides a positive and negative of the calculation result. When it is negative, a data circuit 30 is opened and the value of the counter 12 is outputted as the data for indicating the position of the inflection point. Then, the value of the counter 12 is increased by 1 and a similar operation is repeated until the end point.