Feature Extraction and Image Processing for Computer Vision, 4th Edition

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Low-level feature extraction (including edge detection)

Abstract

We shall define low-level features to be those basic features that can be extracted automatically from an image without any shape information (information about spatial relationships). As such, thresholding is actually a form of low-level feature extraction performed as a point operation. Naturally, all of these approaches can be used in high-level feature extraction, where we find shapes in images. There are very basic techniques and more advanced ones and we shall look at some of the most popular approaches. The first order detectors are equivalent to first order differentiation and, naturally, the second order edge detection operators are equivalent to a one-higher ...