Contactless subject monitoring system

A contactless subject monitoring system adapted to monitor at least one skin region of a subject movable relative to an ambient light source is disclosed. The system comprises: a light emitter; an image capturing unit; and a processing system configured to: receive a sequence of video frames of the subject captured by the image capture unit while the light emitter provides varying illumination to the subject; generating a first ambient light corrected image using a varying exposure between video frames of a first portion of the sequence of video frames caused by the varying illumination during capture of the first portion; segmenting the first ambient light corrected image to generate a first segmented image in which at least one skin region is identified; generating a second ambient light corrected image using a varying exposure between video frames of a second portion of the sequence of video frames caused by the varying illumination during capture of the second portion, the second portion being temporally