Image brightness control on lined monitor screen - uses copy compensation signal for brightness proportional image signal to equalise ambient and/or stray light

摘要

The controlled monitor image screen is written in lines and carries a visible image in a room with ambient brightness. For the compensation of the latter and/or the stray light of brightness proportional image signals, supplied by the image writing device, a compensation signal is copied as it is derived from the average brightness of the image to be written and/or the room brightness. In front of the CRT is fitted a device recognising its characteristic. An adding stage (18) is located in the region of a brightness proportional signal, contg. a signal mixer (15) with an input for a signal with a mean brightness of the image to be reproduced, and an input for a room brightness signal. ADVANTAGE - Monitor image impression irrespective of interference effects for final image on recording paper.