(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2003/0194135 Al
Wenzel (43) Pub. Date: Oct. 16,2003
(54) INCREASING ACCURACY OF DISCRETE CURVE TRANSFORM ESTIMATES FOR CURVE MATCHING
(75) Inventor: Lothar Wenzel, Round Rock, TX (US)
Jeffrey C. Hood
Meyertons, Hood, Kivlin, Kowert & Goetzel PC
P.O. Box 398
Austin, TX 78767 (US)
(73) Assignee: National Instruments Corporation
(21) Appl. No.: 10/430,546
(22) Filed: May 6, 2003
Related U.S. Application Data
(63) Continuation-in-part of application No. 10/263,560, filed on Oct. 3, 2002.
(60) Provisional application No. 60/371,474, filed on Apr. 10, 2002.
System and method for estimating a rotational shift between a first discrete curve and a second discrete curve, where the second discrete curve is a rotationally shifted version of the first discrete curve. First and second discrete curves are received. A rotational shift between the first discrete curve and the second discrete curve is estimated based on the first discrete curve and the second discrete curve. A cumulative rotational shift is updated based on the estimated rotational shift. A rotationally shifted version of the second discrete curve is generated based on the cumulative rotational shift. The estimating, updating, and generating are performed in an iterative manner using the respective rotationally shifted discrete curve for each iteration until a stopping condition occurs, thereby determining a final estimate of the rotational shift between the first discrete curve and the second discrete curve. The final estimate may be used to perform curve matching.