Patent attributes
A picture of 625/50 format is converted to a picture of 525/60 format by a format converter provided halfway of the transmission link (1). By thinning scanning lines from the 625/50 format with a scanning line thinning means (2) on an input side of the transmission link (1) and then thinning fields from the format of 525/60 with a field (frame) thinning means (4) on an output side, the formats are matched with each other. After that, a picture quality characteristic amount is extracted by picture quality characteristic amount extracting portions (3), (5) and transmitted to a central monitoring room (6). A comparing means (7) of the central monitoring room (6) compares received picture quality characteristic amount so as to monitor a transmitted picture quality on a transmission link.
