With the advance of linear CCD arrays and high precision galvanometer design in recent years, triangulation based 3D laser cameras have found wide applications from human contour digitization to object tracking and imaging on the International Space Station.  In most applications, a beam size of 1mm or larger is used to minimize the beam divergence over the entire range.
With a beam diameter of 1mm, the position resolution (X, Y direction) is normally in the order of one millimeter. In the triangulation method, the distance (Z direction) information is extracted from the position of a Gaussian shape peak on a detector array. There are two major sources of error, excessive edge effects and speckle noise caused by a large spot size. Edge effects are produced when parts of the same beam spot fall on surfaces at different distances. This causes the peak shape of the imaging spot on the array to deviate from Gaussian and produces errors in the distance measurement at the edge of an object.
In this paper, modeling of edge effects and speckle noise in an auto-synchronized 3D laser camera in terms of beam size, laser wavelength, optical aperture and geometrical parameters used in the triangulation arrangement are discussed. The methods to mitigate errors from edge effects and speckle noise, and the results showing high resolution in both lateral position and distance on a 3D object are presented.