Roof edge detection using regularized cubic B-spline fitting

A scheme employing one-dimensional (1-D) Regularized Cubic B-Spline (RCBS) fitting [G. Chen and Y. H. Yang, IEEE Trans. Systems Man Cybernet. 25, 636-693 (1995)] has been used successfully in the task of step edge detection. The regularized fitting is transformed into a quadratic energy equation to simplify the computation. This scheme, however, has three major limitations: it is non-linear, has a limited accuracy and is computationally expensive. This paper presents a modified scheme which overcomes these limitations. The modified scheme employs the I-D RCBS fitting on the horizontal and Vertical orientations of a window of an image to generate two I-D signals, which provide sufficient information about the local property of the sub-image for roof edge detection. Experimental results show that the scheme of roof edge detection is very sensitive to small signals. (C) 1997 Pattern Recognition Society.