SA_evaluateEdgeSum


Usage:

GreyStrings = SA_evaluateEdgeSum(GreyImg, Boundaries, PolarScale, Distance)

GreyImage: SA_Image; The corresponding grey value image.
Boundaries: SA_VectorArray; The boundaries of the segmented patches of the image.
PolarScale: SA_VectorArray; The polar scale or log polar scale defining the sectors of interest. (see SA_getPolarScale, SA_getLogPolarScale)
Distance: Uint; The delta in positions on which the polarscale should be applied to the boundaries.

GreyStrings: SA_VectorArray; A list of strings for the boundaries.


Description

SA_evaluateEdgeSum extracts grey value information from GreyImg along the given boundaries using the parameters PolarScale and Distance.
It iterates over all positions in all boundaries applying the polar scale to positions that lie Distance apart from each other.

The PolarScale contains itself local positions that are used as offset to the specific positions of the boundaries to get the positions of interest in the image. Then for all ofset positions in one element of the polar scale all values in GreyImg are summed up. This creates for each boundary a matrix of size [N x k]. N is the number of times the polar scale is evaluated along the boundary (size(boundary) mod Distance). k is a constant value and is the number of sectors the polar scale has. This is the length of each vector in the strings.

The return parameter GreyStrings is of type SA_VectorArray. Each element in the vector array is the resulting string for the corresponding boundary in Boundaries. The element is exact this [N x k] matrix that results at the extraction phase. Thus every element in GreyStrings is the information string for the boundary in Boundaries.




Copyright © 2007 Thomas Oskam, ETH Zürich. All rights reserved.