This paper proposes a method for estimating the eccentricity that corresponds to the incident angle to a fovea sensor. The proposed method uses the Fourier-Mellin Invariant descriptor to estimate rotation, scale, and translation, by taking both geometrical distortion and non-uniform resolution of a space-variant image from the fovea sensor into account. The following 2 points are focused on in this paper. One is to use multi-resolution images by Discrete Wavelet Transform to properly reduce noise caused by foveation. Another is to use a variable window function (although the window function is generally used for reducing DFT leakage caused by both ends of a signal) to change the effective field of view (FOV) so as not to sacrifice high accuracy. The simulation compares the root mean square (RMS) of the foveation noise between uniform and non-uniform resolutions when a resolution level and a FOV level are changed, respectively. The result shows the proposed method is suitable for the wide-angle space-variant image from the fovea sensor, and, moreover, it does not sacrifice the high accuracy in the central FOV. Another simulation is done to determine a reliable resolution level.
This paper is the full translation from the transactions of JSME Vol.74, No.744.