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The large size and multiple bands of todays satellite data require increasingly powerful tools in
order to display and interpret the acquired imagery in a timely fashion. Pixar has developed two major
tools for use in this data interpretation. These tools are the Electronic Light Table (ELT), and an
extensive image processing package, ChapiP. These tools operate on images limited only by disk
volume size, currently 3 Gbytes.
The Electronic Light Table package provides a fully windowed interface to these large 12 bit
monochrome and multiband images, passing images through a software defined image interpretation
pipeline in real time during an interactive roam. A virtual image software framework allows interactive
modification of the visible image. The roam software pipeline consists of a seventh order polynomial
warp, bicubic resampling, a user registration affine, histogram drop sampling, a 5x5 unsharp mask, and
per window contrast controls. It is important to note that these functions are done in software, and
various performance tradeoffs can be made for different applications within a family of hardware
configurations. Special high spped zoom, rotate, sharpness, and contrast operators provide interactive
region of interest manipulation. Double window operators provide for flicker, fade, shade, and
difference of two parent windows in a chained fashion. Overlay graphics capability is provided in a
PostScfipt* windowed environment (NeWS**).
The image is stored on disk as a multi resolution image pyramid. This allows resampling and
other image operations independent of the zoom level. A set of tools layered upon ChapIP allow
manipulation of the entire pyramid file. Arbitrary combinations of bands can be computed for arbitrary
sized images, as well as other image processing operations. ChapIP can also be used in conjunction
with ELT to dynamically operate on the current roaming window to append the image processing
function onto the roam pipeline. Multiple ChapiP operations can be thus chained.
A videotape showing the use of ELT and ChapIP with multispectral data will be presented.
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