Speaker: Scott Daly, Research Fellow, Sharp Laboratories of America, Camas, WA
Title: Bit-Depth-Extension: Overcoming LCD-Driver Limitations by Using Models of the Equivalent Input Noise of the Visual System
Abstract: Continuous tone, or “contone”, imagery usually has 24 bits/pixel as a minimum, with eight bits each for the three primaries in typical displays. However, lower-cost displays constrain this number because of various system limitations. Conversely, higher quality displays seek to achieve 9-10 bits/pixel/color, though there may be system bottlenecks limited at 8. The two main artifacts from reduced bit-depth are contouring and loss of amplitude detail; these can be prevented by dithering the image prior to these bit-depth losses. Our technique builds on Roberts’ noise modulation idea and the subsequently influenced work in halftoning for hardcopy and dithering for displays. However, most halftoning/dithering work was primarily directed to displays at the lower end of bits/pixel (e.g., 1 bit as in halftoning) and higher ppi. We approach the problem from the higher end of bits/pixel/color, say 6 to 8, and lower spatial resolution (<100 ppi), which changes the game substantially from halftoning experience.
Instead of spatial dither, it is better to use an amplitude dither. In addition, dynamic displays allow for the use of a temporal dithering component. This paper will report on techniques and observations made in achieving contone quality on ~100 or less ppi LCD displays starting with from 4 to 8 bits driver limits, and resulting with no visible dither patterns, noise, contours, or loss of amplitude detail at viewing distances as close as the near focus limit (~ 120 mm).
Speaker Background: Scott Daly has degrees in electrical engineering and bioengineering from North Carolina State University and University of Utah, respectively. The bioengineering thesis was in retinal neurophysiology, specifically the temporal information processing of cone photoreceptors. He has worked for RCA in the 70’s doing proto-digital video, for Photo Electronic Corporation in West Palm Beach in the early 80’s with early high-resolution laser scanning systems and WYSIWYG simulators, and for Eastman Kodak in the 80’s and 90’s in the arenas of image compression, image fidelity models, and data image embedding. He shares a technical Emmy with several Kodak co-workers for a video transceiver used in the Tianamen Square news coverage of 1989. He has also taught courses on Applied Perception at Siggraph in 2000 and 2001 in New Orleans and Los Angeles. Currently a research fellow and leader of the Center for Displayed Appearance at Sharp Laboratories of America, he is now applying visual models towards improving digital video and displays. He has 20 patents ranging from tonescale to steganography and is currently a member of IEEE, SPIE, and SID.
Location:
Apple Computer, Inc.
Singapore at Gate One
1 Infinite Loop
Cupertino California 95014
How to get to Apple’s Singapore Conference Room. From Interstate 280, take De Anza Blvd. south to Mariani Avenue (the first stoplight).
Post-Seminar Dinner: The seminar is free. Please join our speaker for dinner ($10-20) afterwards. Directions to the restaurant will be given at the seminar.