Computer-Generated Holography (CGH)

PHYS4412 (Computational Science II)
Department of Physics & Astronomy
Louisiana State University

The concept of computer-generated-holography (CGH) has been of interest to me for a number of years because my astrophysics research group relies heavily upon animation sequences of complicated volume-rendered images to interpret the results of our large-scale fluid simulations and I am always looking for more effective ways to display/examine these complex three-dimensional structures. In the early 1990s I had the general impression that researchers knew quite well how to create holograms digitally from "virtual" computer-generated 3D surfaces but that it had not yet become practical to implement CGH techniques to make, for example, holographic movies because high-resolution digital images would require many many many (!) 2D FFTs. But it also seemed clear to me that with the advent of massively parallel computers (my group was effectively utilizing an 8K-node MasPar at the time), particularly ones that might utilize digital-signal-processing (DSP) hardware, the community might just be crossing a threshold that would make CGH techniques practical.

In 1994, I mentioned to W.O. Hamilton (LSU Department of Physics & Astronomy) my interest in CGH and he pointed me to the American Journal of Physics article by A.E. Macgregor's (1992) --- an article that I now consider to be a superb (perhaps the best!) introduction to the subject of CGH, at least from the perspective of a computational scientist who has relatively little background in Fourier optics. However, my commitment of time to other projects and duties prevented me from looking seriously into CGH techniques and their accompanying computational challenges until this year (1999). And I am quite sure that I would not have found the time even this year to study CGH techniques except for the fact that several students from my PHYS 2411 class requested that I teach a second semester of Computational Science. Because a number of students in that class had impressed me with their native computational skills, I agreed to add PHYS 4412 (Computational Science II) on top of my normal instructional load if students interested in such a class were willing to work with me in a fairly unstructured environment toward a goal of learning together how to do CGH.

Well...they agreed, and here we are! Two-thirds of the way through the semester and I think we've figured out how to do it! With this experience behind us, I am convinced more than ever that this field is just about to take off. Virtual reality, here we come!

Joel E. Tohline
tohline@physics.lsu.edu
April 10, 1999