TAPEREDGE
By Vinzenz Unger and Anchi Cheng
This program creates smooth density gradients across the edges of an image to avoid spikes in the calculated Fourier transform. The gradients are calculated using the densities on opposite edges of the inputfile (“$image.img”) and a tapered copy of the image (“$image.tap”) is written out. ITAPER/JTAPER designate the total depth along the x and y axes (in pixel) over which the tapering takes place. The maximal allowed setting have been given in the protocol, any larger values need changes of the program dimension. To make the calculation more efficient, the area is averaged in separate strips of depth IAVER/JAVER. Finally, ISMOOTH/JSMOOTH determine how much of the local environment around each pixel is used to determine its adjusted density. Likely, the given parameter settings will not need to be changed.