Yk. Ryu et Hs. Cho, NEW OPTICAL SENSING SYSTEM FOR OBTAINING THE 3-DIMENSIONAL SHAPE OF SPECULAR OBJECTS, Optical engineering, 35(5), 1996, pp. 1483-1495
A specular surface reflects light only in the direction such that the
angle of incidence equals the angle of reflection. Due to this charact
eristic, conventional approaches to obtain the shape of specular objec
ts have not guaranteed accurate results. Taking into account this char
acteristic, an optical sensing system is proposed to obtain the three-
dimensional surface shape of specular objects. Its principle is that a
highly focused laser beam strikes the object surface and the specular
components of the reflected light are then detected by a beam receivi
ng unit. To achieve this, the system is to be composed of a galvanomet
er that steers the laser beam's direction to the desired surface point
, a parabolic mirror that reflects the specular component of surface r
eflection toward its center line and a beam receiving unit positioned
along the mirror center line. To evaluate the performance of the propo
sed optical sensing system, a series of experiments was performed for
various measurement conditions. The sensing principle and measurement
accuracy are discussed in detail for various objects of simple geometr
ical shapes. (C) 1996 Society of Photo-Optical Instrumentation Enginee
rs.