Method and system to perform optical moving object detection and tracking over a wide area

• US 8,416,298 B2
• Filed: 08/07/2008
• Issued: 04/09/2013
• Est. Priority Date: 08/07/2007
• Status: Active Grant

• Current Assignee: Rafael - Armament Development Authority Ltd.
• Original Assignee: Visionmap Ltd. (Government of Israel)
• Inventors: Pechatnikov, Michael
• Primary Examiner(s): Nguyen, Tammy
• Assistant Examiner(s): BUI, JONATHAN A
• Application Number:
  US12/514,468
• Publication Number:
  US 20100157055A1
• Time in Patent Office: 1,706 Days
• Field of Search: 348/117, 348/144, 348/145, 348/146, 348/147
• US Class Current: 348/144
• CPC Class Codes: G06T 2207/30181 Earth observation
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/254 involving subtraction of images

Abstract

A method for moving object detection, comprising generating a time series of multi-exposures of scenes, each multi-exposure of a scene comprising a sequence of at least two at least partially overlapping images of that scene captured in rapid succession, wherein the time series of multi-exposures periodically revisits substantially the same scenes, detecting moving objects within each multi-exposure by comparing its sequence of overlapping images, and tracking objects by comparing moving objects detected within multi-exposures of substantially the same scenes.

Claims

1. A method for moving object detection, comprising:

in an airborne vehicle;

(a) generating a time series of multi-exposures of scenes, each multi-exposure of a scene comprising a sequence of at least two at least partially overlapping images of that scene captured in rapid succession, wherein the time series of multi-exposures periodically revisits substantially the same scenes;

(b) detecting moving objects within each multi-exposure by comparing its sequence of overlapping images;

(c) generating data characterizing the moving objects; and

(d) transmitting only the data characterizing the moving objects to a ground station; and

in said ground station;

(e) based on the data characterizing the moving objects, tracking the moving objects;

wherein the data characterizing the moving objects comprises, for each moving object, a capture time, object location coordinates, an object velocity vector, and a thumbnail image of the object.

2. The method of claim 1 wherein the at least two overlapping images of the scene are captured within time intervals of 0.1-0.5 sec.

3. The method of claim 1 wherein the time series of multi-exposures revisits the same scene with a revisit period of at least 5 sec.

4. The method of claim 1 wherein the multi-exposures are double-exposures comprising two respective images captured by two respective cameras.

5. The method of claim 1, wherein said detecting included detecting at least one moving object not suspected to be in said each multi-exposure prior to said detecting.

6. A moving object detection system, comprising:

(a) an optical unit comprising at least one camera for capturing images of scenes;

(b) an airborne electronics unit comprising;

(i) a controller coupled with said optical unit for controlling fields of view and image capture times of said at least one camera, wherein said controller controls said at least one camera to capture a time series of multi-exposures of scenes, each multi-exposure of a scene comprising a sequence of at least two at least partially overlapping images of that scene captured in rapid succession, wherein the time series of multi-exposures periodically revisits substantially the same scenes; and

(ii) a moving object detector coupled with said optical unit for detecting moving objects within each multi-exposure by comparing its sequence of overlapping images and for generating data characterizing the moving objects;

(c) an airborne transmitter for transmitting only the data characterizing the moving objects from the airborne vehicle to a ground station via a communication link; and

(d) at the ground station;

a ground processing unit communicatively coupled with said first electronics unit for tracking the moving objects based on the data characterizing the moving objects;

wherein the data characterizing the moving objects comprises, for each moving object, a capture time, object location coordinates, an object velocity vector, and a thumbnail image of the object.

7. The moving object detection system of claim 6 wherein said airborne transmitter transmits data at low bit rate.

8. The moving object detection system of claim 6 wherein said controller controls said at least one camera so as to capture the at least two overlapping images of the scene within time intervals of 0.1-0.5 sec.

9. The moving object detection system of claim 6 wherein said controller controls said at least one camera so as to revisit the same scene with a period of at least 5 sec.

10. The moving object detection system of claim 6 wherein said at least one camera comprises two cameras, and wherein the multi-exposures are double-exposures comprising two respective images captured by said two respective cameras.

11. The moving object detection system of claim 6 wherein each of said at least one camera is mounted rotatably on a gimbal.

12. The moving object detection system of claim 6 further comprising means for controlling lines-of-sight of said at least one camera.

13. The moving object detection system of claim 6 wherein said moving object detector is for detecting moving objects not suspected to be in said each multi-exposure prior to said detecting.