Modelling and Testing the Stability of Edge Segments: Length and Orientation

This paper derives a model for the variance in the length and orientation of edge segments extracted from an image. It is assumed that edge pixel positions are subject to noise. The eeect of this positional uncertainty is propagated all the way to segment length and orientation. The model predicts an approximately constant variance in segment length, whereas the variance in segment orientation decreases with increased segment length. The theoretical model is veriied by experiments on real images and it is shown that segment orientation is more stable (has higher signal to noise ratio) than length for segments longer than 1/10 of the image size.