Patent ID: 7136066

Claim:
A system for generating portrait video, the system comprising: a general purpose computing device; and a computer program comprising program modules executable by the computing device, wherein the computing device is directed by the program modules of the computer program to, obtain a frame of a video in grayscale format; apply a first threshold T 1 to said grayscale frame to generate two partial grayscale images, a first of which, S 1 , comprises pixels the non-zero valued ones of which have values greater than said first threshold T 1 , and a second of which, S 2 , comprises pixels the non-zero valued ones of which have values less than said first threshold T 1 ; generate a first bi-level image comprising pixels assigned a first binary value whenever the value of the correspondingly located pixel in the grayscale frame exceeds T 1 , and comprising pixels assigned a second binary value whenever the value of the correspondingly located pixel in the grayscale frame is less than T 1 ; apply a second threshold T 21 to the first partial grayscale image, S 1 , to generate a second bi-level image comprising pixels assigned a first binary value whenever the value of the correspondingly located pixel in the first partial grayscale image exceeds T 21 and pixels assigned a second binary value whenever the value of the correspondingly located pixel in the first partial grayscale image is less than T 21 ; apply a threshold T 22 to the second partial grayscale image, S 2 , to generate a third bi-level image comprising pixels assigned a first binary value whenever the value of the correspondingly located pixel in the second partial grayscale image exceeds T 22 and pixels assigned a second binary value whenever the value of the correspondingly located pixel in the second partial grayscale image is less than T 22 ; and combine the first, second and third bi-level images to create a four level grayscale video frame representing a frame of the portrait video by: combining the second and third bi-level images by adding the pixel values of corresponding pixel locations of these images to create a combined bi-level image; generating an array of two bit elements wherein each element corresponds to a different pixel location of said bi-level images, said elements comprising a most significant bit taken from the associated pixel location of the first bi-level image and a least significant bit taken from the associated pixel location of the combined bi-level image; and assigning a different gray scale level to each possible element value.