More than Meets the Eye - A Study in Seismic Visualization
Steven Lynch
This thesis is primarily concerned with examining the properties of SeisScape displays, which render seismic data as a three-dimensional surface. SeisScape displays are fundamentally different from conventional seismic displays in that they fully engage the visual system and produce sensations of perception. These perceptions are the goal of scientific visualization. Visualization itself is placed into context with respect to seismic data by discussing how the display acts as a filter upon seismic resolution. There are two levels of seismic resolution; absolute resolution, which is a product of spatial and temporal resolution; and apparent resolution, which is a product of the display. It is established that the apparent resolution of conventional displays is significantly lower than the absolute resolution of the data.
The primate visual system is the second, immutable, stage of the seismic display filter. It is not, however, a general purpose tool. To learn how to use it appropriately, the evolution and properties of the primate visual system are discussed in the context of determining how primates establish their perceptions of form and color.
Two terms that describe the structure of a seismic section are introduced. The first is macrostructure, which is the collection of strong amplitude events that are visible on any seismic section. The second is the microstructure, which is the collection of weak amplitude events that are often only observed as perturbations upon the macrostructure. Several techniques for tessellating the seismic surface are developed. Examples are presented to illustrate the effect that tessellation has on the ability to perceive both macrostructure and microstructure. Various techniques are developed to calculate the reflectance of the seismic surface and examples show how reflectance is primarily responsible for our ability to perceive microstructure.
The use of color on seismic data is examined from the perspective of the evolution of primate trichromacy. Conventional color palettes, which were developed for use in a perception free environment, are shown to be inappropriate for use on SeisScape displays. Two new color palettes, HA1 and HA2, are developed and examples show that they are more appropriate for use in a perceptive environment.