IMAGE FORMAT CONVERSION PREPROCESSOR AND IMAGE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an image format conversion preprocessor which can accurately detect the image format of a digital image signal whatever image format the digital image signal has as a preprocessor for an image format converting device for the digital image signal. SOLUTION: The preprocessor is equipped with a horizontal pixel number calculating means 1 which extracts a horizontal synchronizing signal HD and a dot clock signal CLK from the digital image signal and calculates the number N of horizontal pixels of one horizontal line from both the signals and an all-horizontal-line-number calculating means 13 which counts the dot clock signal CLK, generates horizontal reference pulses PS when the counted value reaches the number N of horizontal pixels, and calculates the number M of all horizontal lines from the horizontal reference pulses PS and a vertical synchronizing signal VD extracted from the digital image signal.