JPS57207933A - Reader for picture information on cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain picture information of accurate location with simple constitution when picture information on a cathode-ray tube is read, by correcting location information read by a light pen, etc., based on delay correction values. CONSTITUTION:To read and store a delay time which is the most suitable for the conditions of use in advance of actual use, an image which is to be used as a reference is displayed on a cathode-ray tube (CRT)33 and information on the CRT33 is optically read through a light pen 34. A signal d0 is obtained by amplifying the read signal c3 by an amplifier 35A and a location reading signal d3 is obtained by shaping the signal d0. At a read location detecting means 36, a delay time is obtained based on the read signal d3 and a scan location signal e3 from a CRT controlling section 32. The delay time thus obtained is introduced into a switch 37 as a signal f3. When the switch 37 is switched to a location A in advance, a delay time tDY can be supplied to and stored in a delay time storing section 38 as a signal i3 which shows a delay time correction value. Moreover, when the switch 37 is switched to another location B, a location read signal g3 can be supplied to a delay time correcting section 39.