Graphics and Archaeology: Interpreting the Past
Snowbird, Utah
20-23 May 2000
Presentation:
- CAMEO-SIM: A Physically Accurate Scene Generation System
Presenters:
- Kevin Mitchell
Presentation Resources:
Summary:
Kevin's presentation covered a CAMEO-SIM overview, Image Fidelity work, and a project with the National Gallery (SALI 99).
CAMEO-SIM is a physics-based synthetic scene simulation facility. It simulates a section of the Salisbury Plain for use as a synthetic proving ground for work performed by DERA. It is radiometrically accurate and can be used to evaluate both broadband or spectral calculations. Data in the form of geometric wireframe, material properties, atmospheric properties, etc., is input into the simulator. It can then evaluate a number of energy spectrums.
In terms of visible band output, synthetic versus real can be examined. He showed a simulation of an attack helicopter in a forest of trees with examples of:
- all surfaces diffuse - no shadows
- hard shadows (clear day)
- soft shadows (cloudy day)
- BRDF applied to airframe
- everything applied at once
The Image Fidelity project is currently "fit for purpose", meaning it is constrained to specific applications. The aim of the programme is to find a metric or combination of metrics to quantify the fidelity of synthetic imagery. Using the metrics, it might be possible to identify the optimum method of creating fit for purpose imagery for different applications.
The National Gallery project was a 3 week feasibility approach to render images of a Renaissance painting under an artificial illuminant and candlelight. Artwork displayed in the National Gallery is currently viewed under a diffuse daylight type illumination. This is not representative of the original creator's environment. When viewed under original beeswax candlelight, gold stands out and ultramarine blues appear much deeper.
Work with the University of Bristol has performed rendering experiments to understand eye movement patterns across this work in an attempt to understand possible illumination scenarios and design of the art for specific viewing contexts.
Conclusions / Issues:
- CAMEO-SIM is a sophisticated broad-band, high fidelity simulation system that can be used to evaluate various illumination theories of interest to archaeologists interested in testing various color and illuminant properties.
- Future work (from the feasibility study) might include:
- using more spectral samples
- using more illuminants including measured beeswax candlelight
- use of a calibrated monitor and investigation of different display systems
- including gold BRDFs and surface topology into the simulation
- producing animations of a flickering candle
- comparing images quantitatively and perceptually