DYNAMIC THRESHOLDING
Macro: PROATHDTH
Function: Input image is divided into blocks of the size specified by user. A threshold for each block is calculated by the differnce histogram method. Using these threshold values for each block, a threshold reference plane of the input image size is created by interpolating other values. The resultant image is thresholded with respect to the reference plane.
Parameters:
1. Input, output and reference image planes.
2. Block size to consider.
