Patent ID: 7489341

Claim:
A method for stabilizing digital video motion comprising: selecting a current video frame and a previous video frame from a video stream; 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, wherein the first-order autoregression comprises: multiplying the frame motion vector of the current frame by a first constant; multiplying the steady motion vector of the previous video frame by a second constant, wherein the first constant is a floating-point value in a range of 0-1 inclusive, the second constant is calculated by subtracting the first constant from 1, and the first constant is chosen to be a lesser of a third constant and a correlation value; computing an estimated hand motion vector of the current video frame by subtracting the steady motion vector of the previous video frame from the frame motion vector of the current video frame; and calculating the correlation value between the estimated hand motion vector and the steady motion vector by taking an absolute value of an inner product of the estimated hand motion vector of the current video frame and steady motion vector of the previous video frame, and dividing the absolute value by a product of a 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 and a 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 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; cropping a selected video frame from the current video frame, wherein a center of the selected video frame is offset from a center of the current video frame by the hand motion vector; and recording the selected video frame to a storage device.