Range and/or profile of a test surface, particularly a submarine surface, are determined by passing a laser beam through a holographic grating structured to emit a divergent light beam defining a two dimensional array of dots in a predetermined pattern and projecting such beam on the test surface. A receiving device, e.g., video camera, ascertains the positions of the dots in the pattern reflected from the test surface and comparison is made of such positions relative to the positions of the respective dots previously reflected in like manner from a datum surface. The values of the displacements of test surface dots from datum surface dots are used to determine the range or orientation of the test surface relative to the grating or the profile of the test surface.
An optical position detector is provided with an image forming member 1, a scale plate 2, and an image pickup 3, which are disposed sequentially along an optical axis in the order mentioned, and a position computing unit 10 connected to the image pickup 3. The scale plate 2 has a plurality of pattern elements arranged periodically along a front coordinate plane perpendicularly intersecting the optical axis. The image forming member 1 condenses a light beam emitted from an object point 4 and converts the same into a reference light converging into an image forming point and, at the same time, spot-illuminates a part, of the scale plate 2 with the reference light, and projects a certain pattern element in a magnified scale. The image pickup 3 has a light receiving surface disposed along a rear coordinate plane perpendicularly intersecting the optical axis and picks up the shadow of the pattern clement projected in the magnified scale and outputs corresponding image data. The position computing unit 10 processes the image data and derives rear coordinate value of the shadow of the projected pattern element, and further determines a position of the image forming point on the basis of the rear coordinate value of the shadow and a front coordinate value of the certain pattern element, and thereby determines the position of the object point on the basis of the position of the image forming point.
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. Indication of fluid flow and/or fluid concentration change is afforded through perceived distinctions between the illuminatively revealed images obtained at the same location at different times.
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., numerous) individual or paired light-emitting devices can be arranged so that a camera snaps an instantaneous photograph containing corresponding forms that are mathematically informative of a surface's configuration at plural (e.g., numerous) locations.
Disclosed herewith is an optical triangulation displacement sensor using a diffraction grating. The optical triangulation displacement sensor includes a light source element, a condenser, a light-receiving element, an image formation lens, a transmission grating and a light-receiving element. The light source element generates light of certain intensity. The condenser receives the light from the light source element and transmits the light to the surface of measurement. The image formation lens receives the light reflected by the surface of measurement. The transmission grating converts the reflected light having passed through the image formation lens into a plurality of diffracted light rays. In the light-receiving element, an image is formed by the diffracted light rays incident from the transmission grating.
The dimensions of a countersunk hole, or of a fastener head, are determined accurately and rapidly by a nondestructive measurement system. At least one laser projects spots of light onto the surface being analyzed. From knowledge of the projection angle, and of the lateral displacement of the spots of light caused by variations in the depth of the surface, one can calculate an actual depth of each point on the surface. A set of parameters defining a mathematical model of the hole or fastener head are fitted to a set of measured coordinates of points on the surface being analyzed, using conventional numerical techniques. The optimized parameters define the dimensions of the countersunk hole or fastener head. The present invention operates independently of the coordinate system used to perform the measurements, so the invention eliminates errors caused by misalignment of optical components. The invention can also provide automatic warnings when the dimensions of a particular countersunk hole or fastener heads exceed predetermined tolerances.
