Ronald J Flower, Robert W Olsen, Michael A Van Ells, Ralph Flatau: Apparatus and method for measuring blood constituents. Mine Safety Appliances Company, Walter G Marple Jr, John E Kidd, Nicholas L Coch, September 5, 1989: US04863265 (298 worldwide citation)

An apparatus for noninvasive determination of constituent concentrations utilizing light wave absorption measurements and methods for processing signals generated by such measurements.

Tzeyang J Chou, Marshall Ma, Ralph Flatau, Fred Elderbroom: Digital radiography with image brightness and contrast normalization. S&S Inficon, Wall and Roehrig, September 19, 1989: US04868651 (29 worldwide citation)

A process for enhancing a still video image can correct digital fluoroscopy images which are under- or overexposed and have their image brightness values concentrated to one end of the gray scale. A pixel histogram is formed, but is clipped at a low value. Then, a cumulative histogram is formed from ...