ESTIMATION OF ORIENTATION OF IMAGE FEATURES

摘要

Analysis of a digital image to estimate the orientation of image features uses a local-energy, steerable filter to produce a plurality of filter responses oriented in different orientations (step 1). The orientation of image features is estimated from the filter responses using a vector-sum technique (step 2). An error measure between (a) the theoretical responses of the steerable filter to a one-dimensional feature oriented in the estimated orientation, and (b) the actual responses of the steerable filter is calculated (step 3). The error measure provides an exact measure of the uncertainty in the estimated orientation which is sensitive both to features which are not one­-dimensional and to noise. The error measure is independent of the orientation of the image feature, the scale and type of the feature and the exact shape of the filters used.