Abstract: Apparatus is disclosed to accurately measure and analyze multiple component interfering gases which coexist in the stack gas effluent generated from a combustion process which utilizes a non-dispersive, narrowband infrared absorption technique. The apparatus includes a probe in the stack with an optical measurement cavity (34) through which the stack gases are passed. A transceiver (14) mounted to the probe includes an optical portion operatively associated with the measurement cavity including a chopped light source (54), (60), (62) for projecting beams of light into the measurement cavity and a detector (86) for detecting the attenuation of the gases to provide a measure of the extent of absorption of each gas of interest. A control unit, preferably remote from the transceiver, preferably a programmed digital computer, and preferably via a J-box (18) converts the electric outputs to a corresponding % modulation and in turn corrects for temperature, pressure and interference between gases.

Abstract: Stereoscopic inputs given by a display, where the stereo images are centered on respective intersecting optical axes, which images both stereo inputs on a field lens at the intersecting which forms, in turn, exit pupils at a predetermined focal distance from the field lens on the respective optical axes. The input lenses are spaced such that the distance between the formed pupils is equal to the interpupillary distance of the viewer. The viewer merely positions himself such that his right eye is coincident with the one exit pupil and the left eye becomes coincident with the other exit pupil. Selection of the proper optics for any given stereo application first requires consideration of the parameters involved and their influence on the application at hand. Some of the display parameters are necessarily linked to sensor parameters and vice versa. Also, certain visual system parameters are dictated.