Abstract: In one general aspect, a method of processing surface profile measurements includes obtaining a calibration image, the calibration image including one or more surface profile measurements at one or more discrete points on a surface, performing calibration processing on the surface profile measurements, performing data processing on the surface profile measurements, and providing data output based upon the calibration processing and the data processing.

Abstract: Two light beams from respective light-emitting devices (e.g., lasers or lamps) cross each other and strike a surface (e.g., of a fluid) at respective oblique orientations relative to the surface (e.g., oblique but nearly vertical orientations that are equal and opposite to each other). A camera captures the surface scattering of the beams in a photographic “double-beam” image containing two respective photographic forms corresponding to the two respective surface scattering locations. The measured distance between the two photographic forms is trigonometrically indicative of the height and slope of the surface in the vicinity of the two surface scattering locations. Some inventive embodiments effect “single-beam” images that are trigonometrically indicative of height only. Plural (e.g.

Abstract: An illuminator (e.g., laser) produces a light beam that partially passes through, and is partially blocked by, a mask contrastingly patterned via non-transparent and transparent portions. The mask-conformed light passes through a lens so that the mask's pattern is projected into fluid seeded with a luminescent substance, which illuminatively reveals an image of the mask's pattern. The light beam can also be expanded and/or diffused prior to reaching the mask. Instead of or in addition to transmissive properties, the mask can have reflective properties wherein the illuminator-produced light beam partially bounces off of, and is partially absorbed by, a mask contrastingly patterned via non-reflective and reflective portions. Reflective optics can supplement or replace refractive optics for projecting the mask's pattern into the fluid.