Method and system for moving object detection

• US 5,309,159 A
• Filed: 02/19/1992
• Issued: 05/03/1994
• Est. Priority Date: 02/19/1991
• Status: Expired due to Fees

• Current Assignee: Israel Aerospace Industries Limited (Government of Israel)
• Original Assignee: Israel Aerospace Industries Limited (Government of Israel)
• Inventors: Meidan, Moshe, Shahaf, Nahum
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US07/838,363
• Time in Patent Office: 804 Days
• Field of Search: 342/90, 342/94, 342/95, 342/96, 342/97, 342/53, 342/56, 342/176, 342/179, 342/197
• US Class Current: 342/90
• CPC Class Codes: G01S 3/7864 T.V. type tracking systems
• CPC Class Codes: G01S 3/789 using rotating or oscillating beam systems, e.g. using mirrors, prisms
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51

Abstract

A method of and a system for scanning a scene for the purpose of classifying a plurality of moving objects located in the scene and having an average distance between them, including the steps of performing a sweep of the scene, during the sweep, producing a multiplicity of detections of at least one portion of the scene at a rate such that a distance traveled by the moving objects between detections is small with respect to the average distance, and calculating, from the multiple detections, two-dimensional motion information for at least some of the moving objects.

Claims

1. A method of scanning a scene for the purpose of classifying a plurality of moving objects located in the scene and having an average distance between them, the method comprising the steps of:

performing a sweep of said scene in steps defining portions of said scene;

during each step, producing a multiplicity of images of at least one portion of said scene at a rate such that a distance traveled by said moving objects between images is small with respect to said average distance; and

calculating, from the difference between said multiple images, two-dimensional motion information for at least some of said moving objects.

2. A method according to claim 1 and wherein said step of calculating includes the step of producing a velocity vector generally for each moving object.

3. A method according to claim 2 and wherein said steps of performing, producing and calculating are repeated a plurality of times and also including the step of predicting from first velocity vectors of a first sweep the expected locations of second velocity vectors of a second sweep consecutive with said first sweep.

4. A method according to claim 3 and including the step of matching said first velocity vectors of said first sweep to said second velocity vectors of said second sweep.

5. A method according to claim 4 and wherein said step of matching includes the step of producing forward gates corresponding to said first velocity vectors.

6. A method according to claim 4 and wherein said step of matching includes the step of producing backward gates corresponding to said second velocity vectors.

7. A method according to claim 5 and wherein said step of matching includes the step of defining a match if a second velocity vector is in a forward gate of a first velocity vector and said first velocity vector is in a backward gate of said second velocity vector.

8. A method according to claim 6 and wherein said step of matching includes the step of defining a match if a second velocity vector is in a forward gate of a first velocity vector and said first velocity vector is in a backward gate of said second velocity vector.

9. A method according to claim 4 and wherein said step of matching is performed after said step of producing a velocity vector is performed.

10. A system for scanning a scene for the purpose of classifying a plurality of moving objects located in the scene and having an average distance between them, the system comprising:

a sensor system for scanning a portion of said scene;

a motor for sweeping said sensor system through said scene in steps defining portions of said scene;

a sensor controller for producing a multiplicity of images of at least one portion of said scene at a rate such that a distance traveled by said moving objects between images is small with respect to said average distance; and

a processor for producing, from the difference between said multiple images, two-dimensional motion information for at least some of said moving objects.

11. A system according to claim 10 and wherein said sensor controller first indicates to said sensor system to scan a first portion of said scene a multiplicity of times and later moves said sensor system to aim towards a second different portion of said scene.

12. A system according to claim 10 and wherein said sensor system is one of the following group:

night vision systems, vidicon cameras or CCD cameras.

13. A system according to claim 10 and wherein said sensor system is a FLIR system.

14. A system according to claim 13 and wherein said FLIR system includes means for internal scanning.

15. A system according to claim 10 and wherein said sensor system is a positional sound detector.