Method and system for stabilizing video data

• US 20070085927A1
• Filed: 12/17/2004
• Published: 04/19/2007
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Goodix Technology Co., Ltd. (Shenzhen Goodix Technology Co., Ltd.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Auberger, Stephane
• Granted Patent: US 7,436,984 B2
• Time in Patent Office: Days
• US Class Current: 348/402.100
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6811 based on the image signal
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors

Abstract

The invention relates to a method for stabilizing a video recording of a scene made by a video camera and represented by video data, said method comprising the steps of subdividing said video data into a plurality of successive frames themselves divided into a plurality of blocks, determining for each block of each frame a motion vector representing the direction and magnitude of the motion in said block, said vector at an instant t being called global motion vector GMV(t) and representing said motion at the instant t with respect to the previous frame, defining a modified vector called integrated motion vector IMV(t) at the instant t and designating the final motion vector correction to be applied to the current frame in view of its motion correction, said integrated motion vector being given by the expression:IMV(t) = GMV(t)+a(E). WIV(t−1) where a(E) is a variable adaptive factor depending on an expression E and IMV(t−1) is the integrated motion vector corresponding to the previous current frame, and modifying the video data according to the modified integrated motion vectors defined for each successive current frame.

Claims

1. A method for stabilizing video data, said method comprising the steps of:

subdividing said video into a plurality of successive frames

dividing each of said successive frames into a plurality of blocks;

determining for each block of each frame a motion vector representing the direction and magnitude of the motion in said block, said vector GMV at an instant t being called global motion vector GMV(t) and representing said motion at the instant t with respect to the previous frame;

defining a modified vector, called integrated motion vector IMV(t) at the instant t and designating the final motion vector correction to be applied to the current frame in view of its motion correction, said integrated motion vector being given by the expression;

IMV(t)=GMV(t)+a(E) . IMV(t−

1)

where GMV(t) is the global motion vector of the current frame at the instant t, a(E) is a variable adaptive factor depending on an expression E and IMV(t−

1) is the integrated motion vector corresponding to the previous current frame; and

modifying the video data according to the modified integrated motion vectors defined for each successive current frame.

2. A stabilizing method according to claim 1, in which said variable adaptive factor depends on the sum of the two last global motion vectors.

3. A stabilizing method according to claim 2, in which the variable damping factor a(E) is determined independently for the horizontal and vertical coordinates of the vectors.

4. A stabilizing method according to claim 1, comprising an additional correction step, provided for checking if the correction of motion vector is not above a given threshold and, if yes, modifying said correction so that it stays within a predetermined allowed range.

5. A system for stabilizing video data, said system comprising:

a frame storage for storing a plurality of successive frames of video data of the video recording;

a processor coupled to said frame storage for dividing each frame into a plurality of blocks, determining for each block of each frame a motion vector which represents the direction and magnitude of the motion in said block, said vector at an instant t being called global motion vector GMV(t) and representing said motion at the instant t with respect to the previous frame, defining a motion vector, called integrated motion vector IMV(t) at the instant t and designating the final motion vector correction to be applied to the current frame in view of its motion correction, said integrated motion vector being given by the expression

IMV(t)=GMV(t)+a(E) . IMV(t−

1)

where GMV(t) is the global motion vector of the current frame at the instant t, a(E) is a variable adaptive factor depending on an expression E and IMV(t−

1) is the integrated motion vector corresponding to the previous current frame, and modifying the video data according to the modified integrated motion vectors defined for each successive current frame.