Patent ID: 7705914

Claim:
A pull-down signal detection apparatus comprising: a first difference circuit which provides a first difference between a current field signal of an input video signal and a 1-field delay signal of the current field signal; a first inter-field comparison unit configured to compare the first difference from the first difference circuit with a first comparison value, add comparison results on a field-by-field basis, compare an addition value of the added comparison results with a second comparison value on a field-by-field basis, and provide a first inter-field comparison result; a second inter-field comparison unit configured to compare the first difference from the first difference circuit with a third comparison value that is less than the first comparison value, add comparison results on a field-by-field basis, compare an addition value of the added comparison results with a fourth comparison value on a field-by-field basis, and provide a second inter-field comparison result; an inter-field correlation determination circuit which determines an inter-field correlation on the basis of the first inter-field comparison result and the second inter-field comparison result, and provides a determination result which indicates one of “strong”, “middle” and “weak” levels; a second difference circuit which provides a second difference between the current field signal of the input video signal and a 2-field delay signal of the current field signal; an inter-frame correlation determination circuit which determines an inter-frame correlation on the basis of the second difference from the second difference circuit, and provides a determination result; and a pull-down signal determination circuit which determines whether the input video signal is a pull-down signal or not, on the basis of the determination results of the inter-field correlation determination circuit and the inter-frame correlation determination circuit.