초록 ▼

Optical triangulation is used for determining the profile of a surface with only two photomultiplier tubes needed for optical sensing in a flying spot camera system. A feedback arrangement varies the angle at which a laser beam is applied to the surface such that the image of the beam on the surface

Optical triangulation is used for determining the profile of a surface with only two photomultiplier tubes needed for optical sensing in a flying spot camera system. A feedback arrangement varies the angle at which a laser beam is applied to the surface such that the image of the beam on the surface tends to be maintained constant with respect to a linear reference position parallel to a scanning direction. Deviations in the image from its reference position as caused by surface height variations are used in the feedback arrangement to change the deflection angle. The deflection angle is in turn detected and is indicative of the variations in surface height. As an anti-noise feature, amplitude modulation is impressed upon the laser beam directed towards the surface and a filter network is used to filter photomultiplier response so as to exclude response to background optical noise. In order to maintain a very wide dynamic range, the modulation amplitude of the light applied to the surface is varied in inverse relationship to the intensity of reflected light sensed by the photomultipliers.

대표청구항 ▼

A system for determining profile information from a surface of an object comprising: (a) an optical beam source for generating an optical beam for application to the surface; (b) an image stabilization beam adjustor operable to receive the beam from said optical beam source and alter a beam deflecti

A system for determining profile information from a surface of an object comprising: (a) an optical beam source for generating an optical beam for application to the surface; (b) an image stabilization beam adjustor operable to receive the beam from said optical beam source and alter a beam deflection angle; and (c) sensor system means adapted to sense reflected optical energy corresponding to an image from the beam hitting the surface, and operable to sense any changes in the image position which are caused by variations in surface height, and connected to said image stabilization beam adjustor and being operable for causing the image stabilization beam adjustor to alter the beam deflection angle dependent on the sensed changes in the image position from a reference position in a Y-direction, said system tending to maintain the image in its reference position independent of variations in surface height, and wherein said sensor system means determines the surface height by detecting the amount of the beam deflection alteration.