METHOD AND SYSTEM FOR MEASURING VEHICLE SPEED BASED ON MOVEMENT OF VIDEO CAMERA
First Claim
1. A method for measuring movement of a video camera placed on a moving vehicle, the method comprising:
- (a) acquiring a sequence of digital frames of the earth surface;
(b) correcting distortions of each frame;
(c) correlating adjacent frames, wherein the frames have maximum coincidence; and
(d) measuring off-set values between the adjacent frames,wherein;
a simplified frame is created for each frame by approximation and filtering of the frame;
distortions are corrected for each simplified frame based on the camera parameters associated with each frame;
correlations of adjacent frames having maximum coincidence, are found;
correction off-set value is calculated based on changes in the camera parameters during generation of the frames; and
an actual off-set of portion of the surface is based on the off-set of the adjacent simplified frames corrected by the correction off-set value.
1 Assignment
0 Petitions
Accused Products
Abstract
A digital video camera is placed on a vehicle. The video camera is attached to the vehicle and is directed to a surface at a certain angle to the surface. The camera angle can change while vehicle is in motion. The camera angle is constantly measured by angular sensor (i.e., inclinometer). Images of the surface are projected onto a video matrix and transformed into a sequence of digital frames that are formed at a pre-set time interval. A speed of the video camera relative to the surface is calculated as a ratio of an off-set between the adjacent frames and the time interval between the frames. Then a known relative speed of the vehicle can be corrected by multiplication of the height of the camera (above the surface) by a coefficient that equals a ratio of the known vehicle speed and the measured camera speed.
-
Citations
19 Claims
-
1. A method for measuring movement of a video camera placed on a moving vehicle, the method comprising:
-
(a) acquiring a sequence of digital frames of the earth surface; (b) correcting distortions of each frame; (c) correlating adjacent frames, wherein the frames have maximum coincidence; and (d) measuring off-set values between the adjacent frames, wherein; a simplified frame is created for each frame by approximation and filtering of the frame; distortions are corrected for each simplified frame based on the camera parameters associated with each frame; correlations of adjacent frames having maximum coincidence, are found; correction off-set value is calculated based on changes in the camera parameters during generation of the frames; and an actual off-set of portion of the surface is based on the off-set of the adjacent simplified frames corrected by the correction off-set value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A system for measuring movement of a vehicle, the system comprising:
-
a video camera on the vehicle for generating images of an earth surface, wherein the video camera changes its angle relative to the earth surface as the vehicle moves over the earth surface; a processing unit connected to the camera for processing the frames; and a device for measuring camera angles relative to the earth surface, wherein the processing unit approximates and filters the frames and calculates off-sets of earth surface images caused by changes in the camera angles relative to the earth surface, and wherein; a simplified frame is created for each frame by approximation and filtering of the frame; distortions are corrected for each simplified frame based on camera parameters; correlations of adjacent simplified frames, wherein frames having maximum coincidence, are found; a correction off-set value is calculated based on changes in the camera angle; and an actual off-set of a portion of the surface is calculated based on the off-set of the adjacent simplified frames corrected by the correction off-set value.
-
Specification