System and method for determining respiration rate from a video

A system for determining respiration rate from a video of a subject being monitored for respiratory function, the system comprising:

• a video imaging device for capturing video comprising a plurality of time-sequential image frames of at least one region of interest of a subject's body where a signal corresponding to respiration can be registered by at least one imaging channel of said video imaging device;
• a processor in communication with a memory and executing machine readable instructions for performing:
• receiving said video of a subject;
• extracting, from said region of interest from said plurality of image frames, features of pixels and forming vectors of length N from said extracted features;
• constructing a N×M video matrix of temporally sequential feature vectors, a total number of columns M in said video matrix corresponding to a time duration over which a respiration rate for said subject is to be determined;;
• processing said video matrix to obtain a matrix of eigenvectors, said eigenvector matrix being such that principal axes of variations due to motion associated with said subject's respiration are contained in a first few eigenvectors;
• selecting one eigenvector from said first few eigenvectors;
• and
• extracting a respiration rate for said subject from said selected eigenvector.