An OPTICRAM camera contain a 64 KB dynamic RAM.The cover of the dynamic RAM is made of glass instead of metal or plastic.An image of an object is directly focused onto the glass surface of dynamic RAM by the lens on the front of the camera.The dynamic RAM contains 65,536(64 KB) memory cells.These cells are divided into two sections.Each section is a matrix of 128 X 256 cells.Each cell functions as a pixel.
In a dynamic RAM 0 and 1 are stored as charge on tiny capacitors.As the charge gradually change due to leakage,a dynamic RAM has to be be refreshed periodically.If light falls on a dynamic RAM cell,the stored charge on the tiny capacitor changes at a faster rate as compared to the usual condition when there is no light falling on the memory cells.A dynamic RAM can be used as an image sensor.For this purpose all memory cells,are first charged to logic 1 level.After certain predetermined interval of time the logic level has changed from 1 to 0 represents a light spot.The logic level of an OPTICRAM can be read and stored directly in the microcomputer memory for processing.The light sensitivity of the camera can be adjusted.It is done by adjusting the time interval between charging up all the cells and reading out the logic levels on the cells.foe example for brighter light a shorter time interval is used.
A Micron Eye camera employing an OPTICRAM has been developed by Micron Technology.It contains a printed circuit board with suitable interfacing circuit board with suitable interfacing circuitry so that it can be interfaced to a microcomputer.With this type of sensors bit pattern of images are stored in the computer memory.
An OPTICRAM camera is relatively inexpensive.It can easily be interfaced to a microcomputer.It has enough resolution to be applied to robots and other similar applications.a
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