Patent ID: 7768551
Filing Date: 2010-08-03
Classification: H04N

Abstract:
1. A method for calculating an estimated hand motion vector of a plurality of images, comprising: selecting a current video frame and a previous video frame from a video stream generated by a video camera; dividing the current video frame into a plurality of macroblocks; selecting a subset of macroblocks from the current video frame; comparing the subset of macroblocks to the previous video frame within a two dimensional comparison range to generate a set of motion vectors; calculating a frame motion vector for the current video frame; estimating a steady motion vector for the current video frame by a first-order autoregression; calculating a hand motion vector for the current video frame by taking a difference between the steady motion vector and the frame motion vector of the current video frame; estimating the steady motion vector for the current video frame by summing a product of a first variable and the steady motion vector for the previous video frame with a product of a second variable and the frame motion vector of the current video frame, wherein the sum of the first variable and the second variable equals a first constant, wherein the second variable is set to be a minimum of a smoothing value or a correlation value; and calculating an estimated hand motion vector by subtracting the steady motion vector of the previous video frame from the frame motion vector of the current video frame; wherein the correlation value is calculated by: taking a first square root of an inner product of the estimated hand motion vector of the current video frame and the estimated hand motion vector of the current video frame; taking a second square root of an inner product of the steady motion vector of the previous video frame and the steady motion vector of the previous video frame; calculating a dividend value by multiplying the first square root by the second square root; calculating a divisor value of an inner product of the estimated hand motion vector of the current video frame and the steady motion vector of the previous video frame; and calculating the correlation value by taking an absolute value of the divisor value divided by the dividend value.