e are the photoreceptors, horizontal cells, and bipolar cells. The electronic photoreceptors, which make up the first layer, are like the rod and cone cells in the eye. Their job is to accept incoming light and transform it into electrical signals. In the second layer, horizontal cells use a neural network technique by interconnecting the horizontal cells and the bipolar cells of the third layer. The connected cells then evaluate the estimated reliability of the other cells and give a weighted average of the potentials of the cells around it. Nearby cells are given the most weight and far cells less weight.(251) This technique is very important to this process because of the dynamic nature of image processing. If the image is accepted without testing its probable accuracy, the likelihood of image distortion would increase as the image changed. The silicon chip that the two professors developed contains about 2,500 pixels photoreceptors and their associated image-processing circuitry. The chip has circuitry that allows a professor to focus on each pixel individually or to observe the whole scene on a monitor. The professors stated in their paper, "The behavior of the adaptive retina is remarkably similar to that of biological systems" (qtd in Thompon 251). The retina was first tested by changing the light intensity of just one single pixel while the intensity of the surrounding cells was kept at a constant level. The design of the neural network caused the response of the surrounding pixels to react in the same manner as in biological retinas. They state that, "In digital systems, data and computational operations must be converted into binary code, a process that requires about 10,000 digital voltage changes per operation. Analog devices carry out the same operat...
