<title>Remote 3-D laser topographic mapping with dental application</title>

Abstract

In 1979 we first reported progress on a unique 3-D quantitative mapping structured light method to rapidly and remotely interrogate an unknown surface with an array of laser beams, and to observe and measure the 3-D surfaces off-axis with one or more videocameras.-'2 Significant progress has occurred recently to make this method practical and cost-effective.The system consists of: 1) at least one passive sensor--typically a 512 X 512 square pixel low-light-level CID image intensified progressive scan videocamera operating at 30 Hz; 2) an off-axis active structured laser projector using a 532nm doubled YAG solid state polarized laser, beam formers and a prismatic optic, to simultaneously generate a 128 X 128 square laser beamlet array; 3) a spatially programmable light modulator to block or transmit selected sets of 128 rows (or 128 columns) of laser beams (corresponding to the generated array) at millisecond frame rates; 4) optics to project the structured light sets onto the object; 5) optics at the sensor end; 6) positioning equipment to manipulate the object as required; 7) suitable image processors, array processors, and computers for signal and image processing, calculation of tables of X,Y,Z numerical data, interactive display, and archiving; 8)interfaces to other CAD/CAM systems for the replication of surfaces, or the reconstruction of multiple surfaces into geometric forms..