Method and system for image-sequence-based target tracking and range estimation

United States Patent m

Choate et al.

[54] METHOD AND SYSTEM FOR

IMAGE-SEQUENCE-BASED TARGET
TRACKING AND RANGE ESTIMATION

[76] Inventors: William C. Choate, 6247 Twin Oaks Cir., Dallas, Tex. 75240; Rajendra K. Talluri, 7131 Woodhollow Dr., Apt. 108, Austin, Tex. 78731

[21] Appl. No.: 810,745

[22] Filed: Dec. 18,1991

[51] Int. C1.6 G01S 13/00

[52] U.S. CI 364/516; 342/458;

342/64

[58] Field of Search 364/516, 174; 382/16,

382/37, 54, 10,14, 23, 25, 28; 342/126, 458, 64;

250/201.6, 201.8, 202

[56] References Cited

U.S. PATENT DOCUMENTS

4,004,852 1/1977 Pentecost 250/201.6

4,700,307 10/1987 Mons et al 342/64

4,855,932 8/1989 Cangiani et al 364/516

4,916,302 4/1990 Sorimachi 250/201.6

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US005422828A

[ii] Patent Number: 5,422,828 [45] Date of Patent: Jun. 6, 1995

4,954,837 9/1990 Baird et al 342/458

Primary Examiner—Emanuel T. Voeltz

Assistant Examiner—Thomas Peeso

Attorney, Agent, or Firm—Robert L. Troike; Richard L.

Donaldson

[57] ABSTRACT

A method of tracking targets across a sequence of images estimates the range of these tracked objects from the camera. The method assumes the motion of the camera between the successive frames is known. The distance from the sensor to the object is assumed to be much larger than the physical dimensions of the object. The method and system make use of the known sensor motion to generate "expected images" that are then used to establish a reliable correspondence and track the targets across the image sequence. The method and system use a mean/energy-normalized area correlation technique to establish inter-frame correspondence. With this correspondence, two new methods can estimate the range of the target from the sensor.

11 Claims, 5 Drawing Sheets