An Analog Multimode Visual Feature Extraction Retina

We propose a multimode retina integrating image sensing, normalization, smoothing, differentiation and visual feature extraction by incorporating: 1) a histogram equalization function onto the sensor focal plane, which normalizes the image signal at the same dynamic range under different illumination conditions and results a constant signal amplitude facilitating the post processing; 2) a capacitive Gaussian network and a spatial differentiator, which offer a bandpass filtering on the normalized image; 3) a visual feature extraction, which extracts and localizes the areas enveloping objets of interest. This novel multimode retina, when interfaced with a digital processing unit, does a first step processing and information salient region extraction suited for many real-time vision tasks.