Abstract
Optical mutual intensity can be controlled by the variable intensity distribution of an extended quasi-monochromatic incoherent source. A point source with a conceptually variable intensity, moving stepwise over the source plane, is capable of providing an equivalent extended incoherent source. This idea can be realized by an opto-electronic hybrid system. The intensity pattern of an object illuminated stepwise by a movable point source with unit intensity is recorded at every step by a CCD TV camera and held in a computer memory. All the memorized intensity patterns are multiplied successively with a series of weighting values from a suitable function generated in the computer. This generated function can take the same formula as the required intensity distribution of an extended incoherent source. The sum total of all the weighted elementary patterns results in an intensity pattern of the object equivalent to that formed by spatially coherence-controllable illumination. The computer-generated image patterns for a knife-edge object are in good agreement with the measured image patterns. The image pattern can be shaped with the help of such a function generated in the computer.