Patent ID: 11871117
Assignee: KONINKLIJKE PHILIPS N.V.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC H

Claim 0:
1. A system for performing ambient light image correction, the system comprising:
a light source configured to provide pulsed illumination to a subject;
an imaging unit configured to capture, while the subject is illuminated by the pulsed illumination provided by the light source, a plurality of images of the subject, wherein each image of the plurality of images is captured at an exposure time shorter than a wave period of the pulsed illumination, wherein a pulse frequency of the pulsed illumination provided by the light source is not a multiple integral of a frame rate at which the plurality of images are captured by the imaging unit, and wherein a total time during which the plurality of images are captured is at least half of the wave period of the pulsed illumination; and
a control unit configured to:
obtain a predetermined number n of a plurality of captured images, wherein the plurality of candidate images are n sequential images of the plurality of images;
generate, for each pixel location of every pixel location in the plurality of candidate images, a respective sorted list of pixels by sorting respective pixels each corresponding to the respective pixel location in the plurality of candidate images, wherein the sorting is based on a pixel value of the respective pixels;
apply, for the each pixel location of every pixel location in the plurality of candidate images, a set of weights to the respective sorted list of pixels to obtain a plurality of weighted and sorted lists of pixels, wherein the set of weights is associated with a least squares approximation of a probability density function of the pixel value over time; and
generate an estimated ambient light corrected image based on the plurality of weighted and sorted lists of pixels by summing the plurality of weighted and sorted lists of pixels.