Abstract: An apparatus for determining the fluorescence of materials in a scene which includes optical means to collect radiation from the scene. Means are provided to divide the collected radiation into first and second beam paths. The first beam path traverses a first filter centered on a Fraunhofer line and having a passband which extends into the solar continuum on either side of the Fraunhofer line. The second beam path traverses the first filter and a second filter, also centered on the Fraunhofer line, with a passband on the order of half the bandwidth, at half-depth, of the Fraunhofer line. Means are provided to image the first and second beams onto first and second detector arrays, respectively. The image on the first detector array is registered with the image on the second detector array. Co-adding means are provided whereby successive detector pixels at successive time intervals corresponding to a single point on the ground are added and averaged.

Abstract: A spherical lens has a surface whereon a dichroic coating reflects light of known wavelength, substantially all other light being transmitted therethrough. Within the focal plane of the surface at fixed locations are respective proximal ends of a plurality of fiber light pipes. The distal ends of the fiber pipes are respectively connected to light emitting diodes whereby each diode is associated with one of the locations. In response to light being provided by a first diode, from the location associated therewith a light image of a first proximal end is transmitted to a first small region on the surface. The image of the first proximal end is collimated at the first small region and reflected therefrom. In response to light being provided by a second diode, from the location associated therewith a light image of a second proximal end is transmitted to a second small region on the surface. The image of the second proximal end is collimated at the second small region and reflected therefrom.