Patent ID: 7813584

Claim:
An image reproducing device comprising: an image signal inputting part for receiving input of a first image signal; a sub image signal generating part for generating a sub image signal from information on a sub image extracted from said first image signal; a main image signal decoding part for extracting a main image signal from said first image signal and decoding said main image signal; a brightness detecting part for detecting a brightness of said main image signal, calculating a brightness average value of each field of the main image signal, and calculating a moving average value of the brightness average values; a brightness adjusting part for adjusting a brightness of said sub image signal; an image signal composing part for composing said main image signal and said sub image signal and generating a second image signal; and an image signal outputting part for outputting said second image signal, wherein, when a difference between a moving average value of the main image signal of a preceding field and a brightness average value of the main image signal of a present field is not greater than a predetermined threshold, the brightness adjusting part adjusts a brightness of the sub image signal of the present field to be a predetermined reference brightness value corresponding to the moving average value of the main image signal of the present field, using a predetermined time constant, and wherein, when the difference between a moving average value of the main image signal of a preceding field is greater than the predetermined threshold, the brightness adjusting part instantly adjusts the brightness of the sub image signal of the present field to be a predetermined reference brightness value corresponding to the brightness average value of the main image signal of the present field.