Patent ID: 7417688

Claim:
An apparatus for detecting and selecting progressively scanned signals and interlaced signals including: input video signal means; de-interlacer means connected to said input video signal means to de-interlace an applied interlaced signal; compensating delay means connected to said input video signal means to provide a delay in dependence upon a latency of the de-interlacer means; frame detector means connected to said input video signal means to detect whether an input video signal applied to said input video signal means is a progressively scanned signal or an interlaced signal; said frame detector means being a progressive frame detector means comprising: first and second conditional accumulator means which are each arrange to receive said input video signal and each of which are at-ranged to perform, for each video field the function: If ((x>y AND x>z) OR (x<y AND x<z)) then field_sum=field_sum+|x−y|+|x−z| where x, y and z are a conditional accumulation of video luminance samples of the applied video signal; AND and OR are Boolean operators; and |x| is the absolute of view sample x; where the samples are applied to the first conditional accumulator means with the delays: sample x —zero delay; sample y—312 line delay; sample z 313 line delay; and the samples are applied to the second conditional accumulator means with the delays: sample x—625 line delay; sample y—312 line delay; sample z—313 line delay; and an output of each of the first and second conditional accumulator means is connected to comparator means arranged to detect whether the input video signal is progressive or interlaced scanned in dependence upon the conditions: Condition Result next_field_sum/previous_field_sum > 0.25 current field is part AND of an interlaced frame next_field_sum/previous_field_sum < 4 next_field_sum/previous_field_sum >= 4 current field is part of a progressive frame with the previous field next_field_sum/previous_field_sum <= 0.25 current field is part of a progressive frame with the next field wherein if the current field is detected to be part of an interlaced frame the frame detector means selects an output from said de-interlacer means, otherwise an output from said compensating delay means is selected.