System and method for detecting a passing vehicle from dynamic background using robust information fusion
First Claim
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1. A method of detecting a passing vehicle comprising the steps of:
- receiving a video sequence comprised of a plurality of image frames;
measuring image intensity and estimating image motion in each image frame;
formulating a hypothesis model describing background dynamics;
using the measured image intensity and motion estimation to determine if the background dynamics has been violated in a given image frame by determining if the difference between the measured image intensity and a predicted image intensity is above a threshold and if the difference between the measured image motion and a predicted image motion of the background is above a threshold; and
if the background dynamics has been violated, using motion coherency to determine whether the violation of the background dynamics is caused by a passing vehicle by performing the following steps;
applying a first subwindow and a second subwindow to the image frame having the violated background dynamics to determine the sequence of motion causing the violation, the motion between the first and second subwindows being measured using robust motion estimation which calculates image flow and their covariances at distributed sample points in an analysis window with multiple image frames;
determining the trajectory of motion of the violated background dynamics by determining which subwindow first indicates a change in image motion; and
if the first subwindow experiences a change in image motion first, determining the violation of background dynamics to be caused by a passing vehicle.
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Abstract
A system and method for detecting a passing vehicle is disclosed. A video sequence comprising a plurality of image frames is received. Image intensity is measured and image motion is estimated in each image frame. A hypothesis model describing background dynamics is formulated. The measured image intensity and motion estimation is used to determine if the background dynamics has been violated in a given image frame. If the background dynamics has been violated, motion coherency is used to determine whether the violation of the background dynamics is caused by a passing vehicle.
39 Citations
24 Claims
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1. A method of detecting a passing vehicle comprising the steps of:
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receiving a video sequence comprised of a plurality of image frames; measuring image intensity and estimating image motion in each image frame; formulating a hypothesis model describing background dynamics; using the measured image intensity and motion estimation to determine if the background dynamics has been violated in a given image frame by determining if the difference between the measured image intensity and a predicted image intensity is above a threshold and if the difference between the measured image motion and a predicted image motion of the background is above a threshold; and if the background dynamics has been violated, using motion coherency to determine whether the violation of the background dynamics is caused by a passing vehicle by performing the following steps; applying a first subwindow and a second subwindow to the image frame having the violated background dynamics to determine the sequence of motion causing the violation, the motion between the first and second subwindows being measured using robust motion estimation which calculates image flow and their covariances at distributed sample points in an analysis window with multiple image frames; determining the trajectory of motion of the violated background dynamics by determining which subwindow first indicates a change in image motion; and if the first subwindow experiences a change in image motion first, determining the violation of background dynamics to be caused by a passing vehicle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for detecting a passing vehicle comprising:
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at least one camera for capturing a video sequence of image frames of background dynamics; a processor associated with the at least one camera, the processor performing the following steps; i). measuring image intensity and estimating image motion in each image frame; ii). formulating a hypothesis model describing the background dynamics; iii). using the measured image intensity and motion estimation to determine if the background dynamics has been violated in a given image frame by determining if the difference between the measured image intensity and a predicted image intensity is above a threshold and if the difference between the measured image motion and a predicted image motion of the background is above a threshold; and iv). if the background dynamics has been violated, using motion coherency to determine whether the violation of the background dynamics is caused by a passing vehicle by performing the following steps; a). applying a first subwindow and a second subwindow to the image frame having the violated background dynamics to determine the sequence of motion causing the violation, the motion between the first and second subwindows being measured using robust motion estimation which calculates image flows and their covariances at distributed sample points in an analysis window with multiple image frames; b). determining the trajectory of motion of the violated background dynamics by determining which subwindow first indicates a change in image motion; and c). if the first subwindow experiences a change in image motion first, determining the violation of background dynamics to be caused by a passing vehicle. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification