Exploiting DLP Illumination Dithering for Reconstruction and Photography of High-Speed Scenes

Abstract

In this work, we recover fast moving scenes by exploiting the high-speed illumination "dithering" of cheap and easily available digital light processing (DLP) projectors. We first show how to reverse-engineer the temporal dithering for off-the-shelf projectors, using a high-speed camera. DLP dithering can produce temporal patterns commonly used in active vision techniques. Since the dithering occurs at a very high framerate, such illumination-based methods can be "sped up" for fast scenes. We demonstrate this with three applications, each of which only requires a single slide to be displayed by the DLP projector. The quality of the result is determined by the camera frame-rate available to the user. Pairing a high-speed camera and a DLP projector, we demonstrate structured light reconstruction at 100Hz. With the same camera and three or more DLP projectors, we show photometric stereo and demultiplexing applications at 300Hz. Finally, with a real-time (60 Hz) or still camera, we show that DLP illumination acts as a very fast flash, allowing strobe photography of high-speed scenes. We discuss, in depth, some characteristics of the temporal dithering with a case study of This is an extension and consolidation of our previous work on the active vision systems using DLP projectors ([24], [16]

Programmable Non-Epipolar Indirect Light Transport: Capture and Analysis

“…Researchers have acquired light transport for translucent materials using a scanning laser over rotated samples [40]. For temporally synced projector-camera systems, researchers have modified DLP projectors for fast projection [41].…”

Adaptive fovea for scanning depth sensors

“…MEMS mirror-modulated imaging was introduced through reverse engineering a digital light processing (DLP) projector (Nayar et al, 2006) for tasks such as edge detection and object recognition. Coupling a DLP projector with a high-speed camera allows for fast structured light and photometric stereo (Koppal et al, 2012). Adding a spatial light modulator in front of the camera allows for dual masks enabling a variety of applications (O'Toole et al, 2015), such as vision in ambient light.…”

Deep Separation of Direct and Global Components from a Single Photograph under Structured Lighting

“…Subsequent work extended direct‐global component separation to multiple light sources [GKGN11], to compensate for motion [ANN13], to high‐speed capture [KYN12], to real‐time visualization of indirect‐only images [OANK15], to overcome limitations in depth of field [GTNZ12, AN14], and to further refine the global component in near and far‐range transport [RRC12]. Other work has explored more exotic hardware such as time‐offlight cameras [WVO* 14, OHX* 14], and by adding an additional controllable mask in front of the camera [ORK12, OMK16].…”