Patent ID: 6859237
Filing Date: 2005-02-22
Classification: H04N

Abstract:
1. A field motion detector for generating a field motion detection signal from information contained in fields of opposite parity of a 2-1 interlaced format video signal having an input receiving the video signal (F 0 ) from a source, a first delay delaying the video signal at the input by one field period less one half of one scanning line period and providing a first delayed output (F 1 −½H), a second delay delaying the video signal at the input by one field period plus one half of one scanning line period and providing a second delayed output (F 1 +½H), a first subtractor subtracting the first delayed output from the video signal to provide a first difference, a second subtractor subtracting the second delayed output from the video signal to provide a second difference, a keep smaller absolute value comparator selecting and providing, as an output indicator of field motion, the magnitude of field motion the smaller of the first difference and the second difference, the improvement characterized by a single line vertical differentiator responsive to vertical transitions within a field, providing an output indicative of vertical energy, a comparator comparing the magnitude of field motion from said keep smaller absolute value comparator to the vertical energy from said single line vertical differentiator, and a switch controlled by said comparator such that the detector provides as its output an indication of field motion, the magnitude of the field motion taken from the output of said keep smaller absolute value comparator when the field motion magnitude is greater than said vertical energy magnitude, and provides as its output an indication of no field motion when the vertical energy magnitude is greater than the field motion magnitude.