Patent ID: 6580463
Filing Date: 2003-06-17
Classification: H04N

Abstract:
A film detector for detecting 25 frame/second sources in PAL television signals or for detecting 30 frame/second sources in NTSC television signals, the detector receiving a field motion signal indicating motion from interlaced field to interlaced field, comprisingan accumulator responsive to said field motion signal and outputting an indication of motion during an entire field, a field delay responsive to the accumulator output outputting a one field delayed accumulator output, a comparator responsive to the accumulator output and the field delay output, the comparator comparing the current field motion indicated by the accumulator output to the last field motion indicated by the accumulator output delayed by one field by said field delay, the comparator outputting a binary signal having a first sense when the current field motion (B) is greater than the last field motion (A) and a second sense when the current field motion is less than or equal to the last field motion, an operator responsive to the accumulator output and the field delay output, the operator outputting a signal indicative of the ratio of present field motion to adjacent field motion, a threshold responsive to the operator output, having its threshold set by a minimum motion ration signal, and outputting a binary signal having one sense when the ratio of present field motion to adjacent field motion is above the threshold level and a second sense otherwise, an AND gate receiving the outputs of said comparator and said threshold, said AND gate outputting the comparator output when the threshold output is in said one sense, and a pattern detector receiving the output of said AND gate for determining the occurrence of a predetermined pattern of moving and non-moving fields.