Abstract: In this paper, we propose a method for detecting
circular shapes with subpixel accuracy. First, the geometric properties
of circles have been used to find the diameters as well as the
circumference pixels. The center and radius are then estimated by the
circumference pixels. Both synthetic and real images have been tested
by the proposed method. The experimental results show that the new
method is efficient.
Abstract: Linear approximation of point spread function (PSF) is a new method for determining subpixel translations between images. The problem with the actual algorithm is the inability of determining translations larger than 1 pixel. In this paper a multiresolution technique is proposed to deal with the problem. Its performance is evaluated by comparison with two other well known registration method. In the proposed technique the images are downsampled in order to have a wider view. Progressively decreasing the downsampling rate up to the initial resolution and using linear approximation technique at each step, the algorithm is able to determine translations of several pixels in subpixel levels.