Digital Micromirror Device Based Phase Measuring Profilometry

Non-contact optical three-dimensional (3D) sensing is a very important research field in which many three-dimension sensing methods with structured illumination such as phase-measuring profilometry (PMP), Fourier transformation profilometry (FTP), and modulation measuring profilometry (MMP) have received great attention in recent years. Digital Micromirror Device(DMD) and Digital Light Processor(DLP) used as a new type of spatial light modulator has play a wide foreground in optical information processing and structured illumination three-dimensional sensing. This doctoral thesis focus on the study on DMD-based PMP, analysis the spatial-temporal characteristic , the light intensity transfer characteristic and the chroma transfer characteristic of DMD. The main results obtained can be summarized as follows:1. The spatial-temporal characteristic of DMD has been extensively studied and the role of the spatial-temporal characteristic taken in the application of structured illumination three-dimensional sensing has been discussed. The experimental results have also been demonstrated.2. Intensity transfer function(ITF) of DMD has been introduced ,ITF is important for the quantity of projected sinusoidal fringe and the accuracy of phase measurement. A auto-adapted error correction method by means of the intensity transfer function has been developed , which may improve the phase measurement accuracy andthe automatization degree obviously.3. A fast phase measuring profilometry using RGB tricolor structured illuminationwith a digital micro-mirror device(DMD) has been developed. In this system, a DMD is used for projecting only one complex color distribution on the surface of the measured object. In the distribution , three interlaced RGB basedtricolor sinusoidal fringe patterns are synchronously coded by which the phase difference of the patterns are 120 degree one another. The detector to capture only one frame of the deformed complex color distributions without phase stepping device . By using image separating techniques to obtain 3D profile data.4. A high resolution PMP system with Digital Camera has been developed, this system improves measuring precision largely, with lower poles in phase unwrapping .It has used in the bottom model of a well measurement, human heart measurement and so on ,the practicability of such system has been approved.5. From the applicable point of view, the instrumental design of DMD-based PMP system have been considered, which may transform to be productivity.