Abstract

It is said that man has five senses—sight, touch, smell, taste, and hearing—at his disposal. Clearly, the one he finds most generally valuable is his sight. This is hardly surprising, as it is excellent for remote sensing, gives an effectively instantaneous response, has truly enormous parallel information capacity, and provides far more reliable and quantitative data than any of the others—it is common to say “you believe the evidence of your own eyes.” Optical sensor technology may still have some way to go to match the same compact design and all-round performance as the eye/brain combination, but the promise is clearly there! As an aside, it is worth noting that we, as humans, are not able to remotely sense electrical or magnetic fields well (although migrational birds are believed to use magnetic sensors), so, if one believes that nature often chooses the best methods, the technology of optical sensors may perhaps evolve to overtake that of electrical ones in time. Modern camera and CD player technologies have shown that even highly complex optoelectronic systems can be manufactured cheaply in volume, so cost should not present a major barrier for large-scale application of standard devices.