3 research outputs found
Streaming Aerial Video Textures
We present a streaming compression algorithm for huge time-varying aerial imagery. New airborne optical sensors are capable of collecting billion-pixel images at multiple frames per second. These images must be transmitted through a low-bandwidth pipe requiring aggressive compression techniques. We achieve such compression by treating foreground portions of the imagery separately from background portions. Foreground information consists of moving objects, which form a tiny fraction of the total pixels. Background areas are compressed effectively over time using streaming wavelet analysis to compute a compact video texture map that represents several frames of raw input images. This map can be rendered efficiently using an algorithm amenable to GPU implementation. The core algorithmic contributions of this work are methods for fast, low-memory streaming wavelet compression and efficient display of wavelet video textures resulting from such compression
Towards Data-Driven Large Scale Scientific Visualization and Exploration
Technological advances have enabled us to acquire extremely large
datasets but it remains a challenge to store, process, and extract
information from them. This dissertation builds upon recent advances
in machine learning, visualization, and user interactions to
facilitate exploration of large-scale scientific datasets. First, we
use data-driven approaches to computationally identify regions of
interest in the datasets. Second, we use visual presentation for
effective user comprehension. Third, we provide interactions for
human users to integrate domain knowledge and semantic information
into this exploration process.
Our research shows how to extract, visualize, and explore informative
regions on very large 2D landscape images, 3D volumetric datasets,
high-dimensional volumetric mouse brain datasets with thousands of
spatially-mapped gene expression profiles, and geospatial trajectories
that evolve over time. The contribution of this dissertation include:
(1) We introduce a sliding-window saliency model that discovers
regions of user interest in very large images; (2) We develop visual
segmentation of intensity-gradient histograms to identify meaningful
components from volumetric datasets; (3) We extract boundary surfaces
from a wealth of volumetric gene expression mouse brain profiles to
personalize the reference brain atlas; (4) We show how to efficiently
cluster geospatial trajectories by mapping each sequence of locations
to a high-dimensional point with the kernel distance framework.
We aim to discover patterns, relationships, and anomalies that would
lead to new scientific, engineering, and medical advances. This work
represents one of the first steps toward better visual understanding
of large-scale scientific data by combining machine learning and human
intelligence
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Streaming Aerial Video Textures
We present a streaming compression algorithm for huge time-varying aerial imagery. New airborne optical sensors are capable of collecting billion-pixel images at multiple frames per second. These images must be transmitted through a low-bandwidth pipe requiring aggressive compression techniques. We achieve such compression by treating foreground portions of the imagery separately from background portions. Foreground information consists of moving objects, which form a tiny fraction of the total pixels. Background areas are compressed effectively over time using streaming wavelet analysis to compute a compact video texture map that represents several frames of raw input images. This map can be rendered efficiently using an algorithm amenable to GPU implementation. The core algorithmic contributions of this work are methods for fast, low-memory streaming wavelet compression and efficient display of wavelet video textures resulting from such compression