Dual-frequency Phase Multiplexing (DFPM) and Period Coded Phase Measuring (PCPM) Pattern Strategies in 3-D Structured Light Systems, and Lookup Table (LUT) Based Data Processing

摘要

A computer-implemented process, system, and computer-readable storage medium having stored thereon, program code and instructions for 3-D triangulation-based image acquisition of a contoured surface/object-of-interest under observation by at least one camera, by projecting onto the surface-of-interest a multi-frequency pattern comprising a plurality of pixels representing at least a first and second superimposed sinusoid projected simultaneously, each of the sinusoids represented by the pixels having a unique temporal frequency and each of the pixels projected to satisfy; $$ \begin{array}{cc}{I}_n^p=A^p+\sum _{k=1}^KB_k^p\cos \left(2\pi f_ky^p+\frac{2\pi \mathrm{kn}}{N}\right)& \mathrm{Eq}.\left(1.1\right)\end{array}$$ ;where I_n^p is the intensity of a pixel in the projector for n^th projected image in a particular instant in time; K is an integer representing the number of component sinusoids (e.g., K=2 for a dual-frequency sinusoid pattern, K=3 for a triple-frequency sinusoid, and so on), each component sinusoid having a distinct temporal frequency, where K is less than or equal to (N+1)/2. Images then captured by the camera are defined according to:; $$ \begin{array}{cc}{I}_n^c=A^c+\sum _{k=1}^KB_k^c\cos \left(2\pi f_ky^p+\frac{2\pi \mathrm{kn}}{N}\right)+\eta & \mathrm{Eq}.\left(1.2\right)\end{array}$$ ;To obtain phase terms from the pixels projected in accordance with Eq. 1.2, for each k:; $$ \begin{array}{cc}2\pi f_ky^p=\arctan \left(\frac{\sum _{n=0}^{N-1}I_n^c\times \cos \left(\frac{2\pi \mathrm{kn}}{N}\right)}{\sum _{n=0}^{N-1}I_n^c\times \sin \left(\frac{2\pi \mathrm{kn}}{N}\right)}\right).& \mathrm{Eq}.\left(1.3\right)\end{array}$$