Patent ID: 7397394
Filing Date: 2008-07-08
Classification: G01D

Abstract:
1. A method for determining the absolute value of a rotational angle, the method comprising: imaging a continuous segment of a code track of a code carrier on a sensor array such that the sensor array generates a corresponding output signal, wherein the code track has a light and dark transition pattern over an angular range of 360°; subjecting the sensor array output signal to a convolution operation with a reference signal in a first correlation filter to reconstruct the light and dark transition pattern of the imaged segment of the code track as a first correlation function signal, wherein the reference signal represents a segment of the light and dark transition pattern of the code track, wherein extrema of the first correlation function signal are indicative of the light and dark transition pattern of the imaged segment of the code track and are indicative of the position of the light and dark transition pattern of the imaged segment of the code track relative to the sensor array; and processing the first correlation function signal to determine a code word and a predetermined angle corresponding to the code word.