Method of edge direction detection based on the correlation between pixels of a vector and an edge direction detection system

Abstract

A method for edge direction detection at a selected pixel on a center-line between two lines of an image includes defining two vectors using certain pixels on the two lines. A vector norm is defined which gives an indication of the correlation of between pixels of one vector and pixels of the other vector. If a vertical vector norm value indicates a low correlation in the vertical direction, then it can be assumed that the selected pixel is in a non-vertical edge area. Vector norm values associated with small angles from the vertical direction are used to determine candidate directions for the non-vertical edge. If a candidate direction is verified as being a preferred direction, then a direction-fine tuning process is performed in which vector norm values associated with big angles from the vertical direction are calculated in order to find a more accurate direction for the non-vertical edge.

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