Abstract: A spectrophotometer useful for spectral analysis of light emanating from one or more targets within an image is described. The apparatus comprises a diffractive lens having an optical axis, a planar array of photodetector elements (pixels), a means for changing the distance between the photodetector array and the diffractive lens along the optical axis and a signal processor. If either the photodetector array or the lens is moved along the optical axis, different wavelengths of light from each target within the image come into and out of focus on particular photodetector elements in the plane of the photodetector array generating sequential images corresponding to different wavelengths. By tracking each pixel's output in the photodetector array as a function of lens position relative to the photodetector array, the spectral composition of each target within the image is generated.

Abstract: Images having specified illumination intensity distributions are used at low light levels to produce photoevents which are electronically detected to generate random numbers having probability density distributions which correspond to the specified illumination intensity distribution and at very high rates, e.g., one hundred thousand numbers per second. These random numbers are used to operate the systems which are based upon random processes such as can be expressed in Monte Carlo algorithms, for example using a Markov process, which systems include computers to carry out the random processes.