Computational Displays in 4D, 6D, 8D …
Computational Displays in 4D, 6D, 8D
We have explored how light propagates from thin elements into a volume for viewing for both automultiscopic displays and holograms. In particular, devices that are typically connected with geometric optics, like parallax barriers, differ in treatment from those that obey physical optics, like holograms. However, the two concepts are often used to achieve the same effect of capturing or displaying a combination of spatial and angular information. Our work connects the two approaches under a general framework based in ray space, from which insights into applications and limitations of both parallax-based and holography-based systems are observed.
Both parallax barrier systems and the practical holographic displays are limited in that they only provide horizontal parallax. Mathematically, this is equivalent to saying that they can always be expressed as a rank-1 matrix (i.e, a matrix in which all the columns are linearly related). Knowledge of this mathematical limitation has helped us to explore the space of possibilities and extend the capabilities of current display types. In particular, we have designed a display that uses two LCD panels, and an optimisation algorithm, to produce a content-adaptive automultiscopic display (SIGGRAPH Asia 2010).
(Joint work with R Horstmeyer, Se Baek Oh, George Barbastathis, Doug Lanman, Matt Hirsch and Yunhee Kim) http://cameraculture.media.mit.edu
In other work we have developed a 6D optical system that responds to changes in viewpoint as well as changes in surrounding light. Our lenticular array alignment allows us to achieve such a system as a passive setup, omitting the need for electrical components. Unlike traditional 2D flat displays, our 6D displays discretize the incident light field and modulate 2D patterns in order to produce super-realistic (2D) images. By casting light at variable intensities and angles onto our 6D displays, we can produce multiple images as well as store greater information capacity on a single 2D film (SIGGRAPH 2008).
Ramesh Raskar joined the Media Lab from Mitsubishi Electric Research Laboratories in 2008 as head of the Lab’s Camera Culture research group. His research interests span the fields of computational photography, inverse problems in imaging and human-computer interaction. Recent inventions include transient imaging to look around a corner, next generation CAT-Scan machine, imperceptible markers for motion capture (Prakash), long distance barcodes (Bokode), touch+hover 3D interaction displays (BiDi screen), low-cost eye care devices (Netra) and new theoretical models to augment light fields (ALF) to represent wave phenomena.
In 2004, Raskar received the TR100 Award from Technology Review, which recognizes top young innovators under the age of 35, and in 2003, the Global Indus Technovator Award, instituted at MIT to recognize the top 20 Indian technology innovators worldwide. In 2009, he was awarded a Sloan Research Fellowship. In 2010, he received the Darpa Young Faculty award. He holds over 40 US patents and has received four Mitsubishi Electric Invention Awards. He is currently co-authoring a book on Computational Photography. http://raskar.info