EDGE DETECTOR

• Main Author: NISHIGORI YOSHIHISA
• Format: Patent
• Language: English
• Published: 02.02.1989
• Subjects: CALCULATING; COMPUTING; COUNTING; IMAGE DATA PROCESSING OR GENERATION, IN GENERAL; PHYSICS

PURPOSE:To detect only a correct edge by using a value, which is constant- number of times as large as the integral value in an area where the differential value of a video signal is large, as the threshold and comparing this threshold with the integral value in an area where the differential value is small. CONSTITUTION:The video signal from an input terminal 1 is differentiated by a difference circuit 2. This differential signal is inputted to an absolute value circuit 3 and the absolute value is outputted. With respect to this absolute value, the addition value of the absolute value of the differential value in a minute area is obtained by an integrating circuit 5. This addition value is multiplied in a multiplying circuit 6 by a constant value alpha and the result is supplied as the threshold to a threshold circuit 7. Meanwhile, the output of the absolute value circuit 3 is given to an integrating circuit 4, and an integral value A is supplied to the threshold circuit 7. The threshold circuit 7 compares the integral value A with the threshold, and an edge is decided when the integral value A is larger than the threshold. Since edge information obtain in this manner may be broken halfway, the processing to connect broken dot strings is performed in an edge processing circuit 8 to output correct edge information.