Identifying living skin tissue in a video sequence using color and spatial similarities

A method for identifying living skin tissue in a video sequence, the method comprising:

• obtaining a video sequence, the video sequence comprising a plurality of image frames;
• dividing each of the image frames into a plurality of frame segments by grouping pixels into frame segments based on color and spatial similarities of the pixels, wherein each frame segment is a group of neighboring pixels in the image frame;
• forming a plurality of video sub-sequences, each video sub-sequence comprising a frame segment from two or more of the plurality of image frames, by for each video sub-sequence, selecting frame segments from each of the plurality of image frames such that a difference between the chrominance of the frame segments in the video sub-sequence is minimized;
• analyzing the plurality of video sub-sequences to determine a pulse signal for each video sub-sequence;
• determining a similarity matrix based on pairwise similarities for each determined pulse signal with each of the other determined pulse signals;
• and
• identifying areas of living skin tissue in the video sequence from the similarity matrix.

A non-transitory computer readable medium having computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform a method comprising:

• obtaining a video sequence, the video sequence comprising a plurality of image frames;
• dividing each of the image frames into a plurality of frame segments by grouping pixels into frame segments based on color and spatial similarities of the pixels, wherein each frame segment is a group of neighboring pixels in the image frame;
• forming a plurality of video sub-sequences, each video sub-sequence comprising a frame segment from two or more of the plurality of image frames by, for each video sub-sequence, selecting frame segments from each of the plurality of image frames such that a difference between the chrominance in the chromatic plane of the frame segments in the video sub-sequence is minimized;
• analyzing the plurality of video sub-sequences to determine a pulse signal for each video sub-sequence;
• determining a similarity matrix based on pairwise similarities for each determined pulse signal with each of the other determined pulse signals;
• and
• identifying areas of living skin tissue in the video sequence from the similarity matrix.