Patent ID: 7587121
Filing Date: 2009-09-08
Classification: H04N

Abstract:
1. A method for detecting a signal presence in a modulated video signal, the modulated video signal having a plurality of encoded fields and a plurality of unencoded fields, the plurality of unencoded fields having a first field, the method comprising: decoding the first field of the modulated video signal to determine a previous field signal strength; comparing the previous field signal strength with a current field signal strength for the plurality of unencoded fields and the plurality of encoded fields by alternating between a reference detection step and an auxiliary detection step to generate an encoded average intensity value for the plurality of the encoded fields and an unencoded average intensity value for the plurality of the unencoded fields; and verifying a signal presence in the modulated video signal by determining whether the encoded average intensity value is greater than the unencoded average intensity value plus a significance value in the modulated video signal.