An updatable holographic three-dimensional display

Nature 451, 694-698 (7 February 2008)

Holographic three-dimensional (3D) displays^1,² provide realistic images without the need for special eyewear, making them valuable tools for applications that require situational awareness, such as medical, industrial and military imaging. Currently commercially available holographic 3D displays³ use photopolymers that lack image-updating capability, resulting in restricted use and high cost.

Mephisto 3D Scanning Engine

Mephisto is one of the most flexible and adoptable 3d scanners. Applications include:

3D face capture for films and computer games
3D scanning for reverse engineering
3D scanning for architecture and heritage
3D capture of small objects for model making and jewellery

Scanning principle

gray code

Scanner uses the combination of Gray code and the digital fringe shifting technology. Binary patterns of the gray code are used to index projector image pixels, while phase shifting produces high precision sub-pixel accuracy without ambiguities.Mephisto interface allows us to choose a wide variety of combinations of binary bit words and fringe images. This way we can scan most difficult objects and surfaces, and it is possible to choose high pattern frequencies for unbelievable precision and quality or low frequencies for speed or to handle hair and fur. The fringe and binary code processing algorithms are designed to counteract hardware artefacts, projection imperfections, digital and analog system noise and other factors affecting 3D scanning quality.

Mephisto Software

The key part of mephisto 3D scanner is the software solution. It is based on three core components - Calibration, Processing and I0 Interface. Calibration is a very simple solution- geometric system calibration is performed using flat calibration board with checker pattern. It takes just 5 to 6 shots with different calibration board orientation angles to compute system intrinsic and extrinsic parameters. Robust calibration code uses bundle adjustment to optimize solution and produce perfect calibration results.