A model of wide-angle foveation for all-purpose use

This paper proposes a model of wide-angle spase-variant image that provides a guide for designing fovea sensor. First, Advanced Wide-Angle Foveated (AdWAF) model is formulized taking all-purpose use into account. This proposed model uses both linear coordinates and logarithmic coordinates in both planar projection and spherical projection. Thus, this model divides its 120-degree wide-angle field of view into 4 areas, such that it can represent images by various types of lens, flexibly. The first simulation compares with other lens models, in terms of image height and resolution. The result shows the AdWAF model can reduce image data by 13.5 percent, comparing with a log-polar lens model, when both have the same resolution in the fovea area. The second simulation compares with other foveation models used for the existing wide-angle foveated lens, logpolar chip and vision system. The third simulation estimates scale-invariant property by comparing with the Kuniyoshi's lens and the log-polar lens. The AdWAF model gives its planar logarithmic part complete scale-invariant property, while the Kuniyoshi's lens has about 7.6-percent error at most in its spherical logarithmic part. Moreover, the AdWAF image is extracted from an input image by wide-angle foveated (WAF) lens, based on the proposed model.