Helix derivative and low-cut filters' spectral feature
and application

Yi Zhao

yi@sep.stanford.edu

ABSTRACT

A helix derivative filter can be used to roughen an image and thus enhance its details. Unlike the conventional derivative operator, the helix derivative filter has no direction orientation. I present the enhanced helix/low-cut derivative filters, in which the zero frequency response is adjustable. I analyze the quantitative effects of the adjustable parameters on the filter spectrum and propose guidelines for choosing parameters. I also show some roughened images created by the enhanced filters.