A Multi-Chip Analog VLSI Vision Sensor with Selectivity to Orientation and Spatial Frequency

We describe a multi-chip analog VLSI vision sensor consisting of a silicon retina and an orientation chip that is tuned to particular orientations and spatial frequency bands of input image. The silicon retina emulates the neural circuits of the vertebrate retina and exhibits a Laplacian-Gaussian-like receptive field. The orientation chip receives output image of the silicon retina and aggregates multiple pixels in the image to generate a Gabor-like orientation-selective spatial filter. The orientation and spatial frequency properties of the filter is controlled by selecting the pixels to be aggregated using external signals. Multiple orientations and spatial frequency bands were implemented in separate chips that are connected in parallel to the silicon retina to obtain output images tuned to different orientations and spatial frequency bands simultaneously.