Abstract: An optoelectronic system for measuring physical parameters comprising: two narrow band light sources with different peak frequencies coupled together into a combined light using a coupler. The combined light is split into a first Fabry-Pérot interferometer arranged to be exposed to both temperature and physical parameter of interest and a second Fabry-Pérot interferometer arranged to be exposed only to temperature. The system further comprises first and second optical detectors arranged to receive light reflected from the cavities of the first and second Fabry-Pérot interferometers respectively through an optical path comprising a combination of lenses and/or mirrors and a Fizeau interferometer. A processor is arranged to analyze the data received by the first optical detector and second optical detector and calculate a value for temperature and the physical parameter of interest.

Abstract: A system for comparing digital images, whereby a first and second data processing block receive respective data streams corresponding to a reference image and a detected image for comparison with the reference image. The data processing blocks detect reference points in the images, and generate data, which is supplied to a block for determining a first approximation of the function A.sub.o relating the two images. The system also presents blocks for successively refining the function relating the reference image to the detected image. (FIG.