Sine Sectioning Illumination Method
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
The topology of a surface can be determined by projecting a sinusoidal light pattern to the target surface at a determined incident angle. The reflected image is viewed from a different angle revealing lateral displacements and frequency changes related to the Z or elevation component of the topology. Basic Image Function I (x, y) The projected image (Fig. 1) contains two intensity component functions. The first function is: I1 (x, y) = K1 where K1 is a constant which sets the average intensity value I (x, y). The second function is a sine function: I2 (y) = K2 x sine (wy + K3) where K2 is a constant which controls the peak to peak value of intensity I (x, y), w is the frequency with respect to y and K3 is the phase angle with respect to y.