According to an aspect, there is provided an apparatus for identifying living skin tissue in a video sequence, the apparatus comprising a processing unit configured to obtain a video sequence, the video sequence comprising a plurality of image frames； divide each of the image frames into a first plurality of frame segments； form a first plurality of video sub-sequences, each video sub-sequence comprising a frame segment from the first plurality of frame segments for two or more of the image frames； divide each of the image frames into a second plurality of frame segments, the second plurality of frame segments comprising a greater number of frame segments than the first plurality of frame segments； form a second plurality of video sub-sequences, each video sub-sequence comprising a frame segment from the second plurality of frame segments for two or more of the image frames； analyze the video sub-sequences in the first plurality of video sub-sequences and the second plurality of video sub-sequences to determine a pulse signal for each video sub-sequence； and analyze the pulse signals to identify areas of living skin tissue in the video sequence.
