5 Transform Filters, Spatial Filters and the Wavelet Transform
5.1 Introduction and Overview
After the image has been transformed into the frequency or sequency domain, we may want to modify the resulting spectrum. Filtering modifies the frequency or sequency spectrum by selectively retaining, removing or scaling various components of the spectrum. High-frequency information can be removed with a lowpass filter, which will have the effect of blurring an image, or low-frequency information can be removed with a highpass filter, which will tend to sharpen the image by emphasizing rapid changes. We may want to extract the frequency information in specific parts of the spectrum by bandpass filtering. Alternately, ...
Get Digital Image Processing and Analysis, 4th Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
