Split-screen, single-camera, laser-matrix, stereogrammetry instrument for topographical water wave measurements

Measurements of water wave shapes with stereogrammetry methods require the identification of key features from a minimum of two viewpoints to determine surface topography. A technique that produces a matrix of laser beams from a single source through the use of a holographic lenslet array is described. The beams were used to produce a matrix of highlights on the water wave surface. Stereogrammetry techniques were then employed to calculate the surface shape from the matrix of imposed highlight features. A laboratory demonstration of the technique is presented, and a discussion of its extension to field conditions is given. A split-screen viewing system was devised to permit the highlights from different angles to be viewed simultaneously with a single camera.