Formation of a time-varying signal representative of at least variations in a value based on pixel values

A method of forming a time-varying signal representative of at least variations in a value based on pixel values from a sequence of images, the signal corresponding in length to the sequence of images, the method comprising acts of:

• obtaining the sequence of images;
• forming a plurality of groups of sub-sets of pixel values by selecting a sub-set of at least one pixel value from each of at least two images defining an interval to form a group of associated sub-sets,
• wherein, for any pair of groups with only sub-sets from the same images, the sub-sets from more than one image are different;
• and
• selecting groups of sub-sets to form the signal in accordance with at least one selection criterion, wherein the selected groups of sub-sets cover different intervals, shorter than a length of the sequence and groups are formed by obtaining spatio-temporal volumes of pixel values from a sequence of images at least based on the obtained sequence of images, each volume comprising pixel values within a spatial aperture from each image within an interval of the sequence, the method including using one of a different aperture and a different interval length for groups defined on different intervals of the sequence.

A method of forming a time-varying signal representative of at least variations in a value based on pixel values from a sequence of images, the signal corresponding in length to the sequence of images, the method comprising acts of:

• obtaining the sequence of images;
• forming a plurality of groups of sub-sets of pixel values by selecting a sub-set of at least one pixel value from each of at least two images defining an interval to form a group of associated sub-sets,
• wherein, for any pair of groups with only sub-sets from the same images, the sub-sets from more than one image are different;
• and
• selecting groups of sub-sets to form the signal in accordance with at least one selection criterion, wherein groups are formed by obtaining spatio-temporal volumes of pixel values from a sequence of images at least based on the obtained sequence of images, each volume comprising pixel values within a spatial aperture from each image within an interval of the sequence, wherein evaluation of the at least one selection criterion includes at least one of determining a measure of spatial uniformity and determining a measure of temporal uniformity.

A method of forming a time-varying signal representative of at least variations in a value based on pixel values from a sequence of images, the signal corresponding in length to the sequence of images, the method comprising acts of:

• obtaining the sequence of images;
• forming a plurality of groups of sub-sets of pixel values by selecting a sub-set of at least one pixel value from each of at least two images defining an interval to form a group of associated sub-sets,
• wherein, for any pair of groups with only sub-sets from the same images, the sub-sets from more than one image are different;
• and
• selecting groups of sub-sets to form the signal in accordance with at least one selection criterion, wherein groups are formed by obtaining spatio-temporal volumes of pixel values from a sequence of images at least based on the obtained sequence of images, each volume comprising pixel values within a spatial aperture from each image within an interval of the sequence, and the method further includes extracting a signal section from each selected group by combining multiple pixel values from each aperture into a value.

A system for forming a time-varying signal representative of at least variations in a value based on pixels and corresponding pixel values from a sequence of images, the signal corresponding in length to the sequence of images, the system comprising:

• a processor configured to:
• produce an interface for obtaining the sequence of images;
• form a plurality of groups of sub-sets of pixels and corresponding pixel values by selecting a sub-set of at least one pixel and corresponding pixel value from each of at least two images defining an interval to form a group of associated sub-sets, such that images are covered by at least two intervals;
• and
• select groups of sub-sets to form the signal in accordance with at least one selection criterion,
• wherein the selected groups of sub-sets cover different pixels and intervals, shorter than a length of the sequence.