Patent ID: 7910873

Claim:
A system comprising: an array of pixels, each pixel comprising: a first photodetector; a first optical filter having a first passband to pass to the first photodetector a first filtered light having a first intensity; a second photodetector; a second optical filter having a second passband different from the first passband, the second optical filter to pass to the second photodetector a second filtered light having a second intensity; and a first circuit coupled to the first and second photodetectors to provide a voltage indicative of a logarithm of the ratio of the first intensity to the second intensity, wherein the array of pixels has M pixels, where M is an integer greater than one, and the system further comprises a second circuit comprising: a functional unit to store a set of weight vectors {right arrow over (w)} i , i=1, 2, . . . , N, where N is an integer greater than one, each weight vector {right arrow over (w)} i of dimension M, the functional unit to calculate quantities h i , i=1, 2, . . . , N where h i =ƒ({right arrow over (x)},{right arrow over (w)} i ), where {right arrow over (x)} is an M dimensional vector of the voltages provided by the first circuit of each corresponding pixel, and ƒ is a function of two M dimensional vectors; and a set of N neuron processors, each neuron processor to provide a quantity A(h i ) where A is a selectable transfer function.