Patent ID: 9721180
Date: 2017-08-01
CPC Classifications: A61B,G06K,G06T

Claim:
1. A computer implemented method for respiratory phase estimation from a video of a subject for respiratory function assessment, the method comprising: receiving a video of a subject, said video comprising image frames of a region of said subject where a signal corresponding to said subject's respiratory function can be registered by at least one imaging channel of a video imaging device used to capture said video; processing pixels in said image frames to identify a respiratory pattern for said subject, said respiratory pattern comprising a respiratory signal with temporally successive peak/valley pairs; selecting a peak/valley pair of interest for which respiratory phase is desired to be determined; generating an array of optical flow vectors between a window of pixel locations in a reference image frame corresponding to a peak of said selected peak/valley pair and a substantially same window of pixel locations in each of a pre-defined number of image frames corresponding to said respiratory signal between said peak and ending at a preselected point in said valley, said optical flow vectors having a direction corresponding to motion caused by temporal variations in intensity and a magnitude corresponding to an amount of said variation; determining a ratio of optical flow vectors having an upward pointing direction to optical flow vectors having a downward pointing direction; and determining, based on said ratio, that said respiration phase for said selected peak/valley pair is one of: inspiration and expiration.