Patent ID: 6271889
Filing Date: 2001-08-07
Classification: H04N

Abstract:
A method for detecting horizontal synchronization pulses of a sequence of video signals, each one of the video signals having video information subsequent to the horizontal synchronization pulse, such horizontal synchronization pulse having a substantially non-time varying tip portion disposed between a pair of substantially time varying transition portions, such method comprising:producing a first detection signal in response to a comparison between actual time variations in the video signal and a predetermined time variation criterion representative of one of the substantially non-time varying and the substantially time varying portions of the horizontal synchronization pulse;producing, in response to the first detection signal, a second detection signal in response to a comparison between actual time variations in the video signal and a predetermined time variation criterion representative of another one of the substantially non-time varying and the substantially time varying portions of the horizontal synchronization pulse;producing, in response to the first detection and second detection signals, output pulses when such comparisons indicate the level-detection and transition detection signals meet the criteria;determining time duration between output pulses and comparing such time duration with a predetermined time duration representative of the expected time duration of the video signal;determining a minimum value of the video signal for each one of the video signals and for determining whether the determined value representative of the level portion of one of the video signals is within a predetermined window about the lowest determined value of a preceding one of the video signals; andproducing a sync pulse in response to the determined time duration and the determined minimum value.