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

Claim 8:
9. A method for performing ambient light image correction, the method comprising:
providing pulsed illumination to a subject;
capturing, while the subject is illuminated by the pulsed illumination, a plurality of images of the 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 is not a multiple integral of a frame rate at which the plurality of images are captured, 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;
obtaining a predetermined number n of a plurality of candidate images, wherein the plurality of candidate images are n sequential images of the plurality of images;
generating, for each pixel location of every pixel location in the plurality of candidate images, a respective sorted list of pixels by sorting the 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;
applying, 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
generating 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.