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Perkins, David Nikolaus

Publications and source records attributed to Perkins, David Nikolaus.

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Apparatus, system and method for highlighting activity-induced change in multi-pass synthetic aperture radar imagery

Described herein are various technologies relating to constructing a differenced change product (DCP) image. A plurality of synthetic aperture radar (SAR) images of a scene are generated based upon radar signals directed towards and reflected off of the scene, and a plurality of coherence change detection (CCD) images of the scene are generated based upon the SAR images. The CCD images are registered with one another, and their pixel values re-scaled according to a monotonic mapping function. The DCP image is generated based upon a computed pixel-wise difference between a pair of the re-scaled CCD images. The DCP image identifies locations in the scene where human activity-induced change is likely to have occurred between a pair of SAR passes of the scene.

42 ENGINEERING↗
DOE OSTI2019

Small mover target detection in synthetic aperture radar imagery

The various technologies presented herein relate to detecting small moving entities or targets in radar imagery. Two SAR images can be captured for a common scene, wherein the scene is imaged twice from the same flight path. The first image is captured at a first instance and the second image is captured at a second instance, and differences between the two images are determined using a complex SAR change measure, excess coherency factor or DeltaC, based in part upon quantification of incoherent (or magnitude) change between the two images. A plurality of operations are performed to enable extraction of coherent change measures relating to the small moving entities from measures relating to large objects, stationary reflective structures, radar focusing artifacts, etc.

Simonson, Katherine M.↗
DOE OSTI2018

Superpixels for improved structure and terrain classification using multiple synthetic aperture radar image products

Various embodiments presented herein relate to assigning labels to segments of a synthetic aperture radar (SAR) image, where the segments are based upon a speckle-reduced SAR image product. A plurality of SAR images of a scene are co-registered to form a registered stack of SAR images. A speckle-reduced SAR image product is generated based upon at least one registered SAR image in the registered stack of SAR images. The speckle-reduced SAR image product is segmented into a plurality of superpixels, and boundaries of the superpixels are applied to the at least one registered SAR image to form a segmented SAR image. A segment of the SAR image is then labeled as including or not including a feature, wherein the label is assigned based upon values of pixels in the segment.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Searches over graphs representing geospatial-temporal remote sensing data

Various technologies pertaining to identifying objects of interest in remote sensing images by searching over geospatial-temporal graph representations are described herein. Graphs are constructed by representing objects in remote sensing images as nodes, and connecting nodes with undirected edges representing either distance or adjacency relationships between objects and directed edges representing changes in time. Geospatial-temporal graph searches are made computationally efficient by taking advantage of characteristics of geospatial-temporal data in remote sensing images through the application of various graph search techniques.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

Geospatial-temporal semantic graph representations of trajectories from remote sensing and geolocation data

Various technologies for facilitating analysis of large remote sensing and geolocation datasets to identify features of interest are described herein. A search query can be submitted to a computing system that executes searches over a geospatial temporal semantic (GTS) graph to identify features of interest. The GTS graph comprises nodes corresponding to objects described in the remote sensing and geolocation datasets, and edges that indicate geospatial or temporal relationships between pairs of nodes in the nodes. Trajectory information is encoded in the GTS graph by the inclusion of movable nodes to facilitate searches for features of interest in the datasets relative to moving objects such as vehicles.

58 GEOSCIENCES↗
DOE OSTI2015

Creating Fantastic PI Workshops

The goal of this SAND report is to provide guidance for other groups hosting workshops and peerto-peer learning events at Sandia. Thus this SAND report provides detail about our team structure, how we brainstormed workshop topics and developed the workshop structure. A Workshop “Nuts and Bolts” section provides our timeline and check-list for workshop activities. The survey section provides examples of the questions we asked and how we adapted the workshop in response to the feedback.

Biedermann, Laura B.↗
DOE OSTI2015

The PANTHER User Experience

This document describes the PANTHER R&D Application, a proof-of-concept user interface application developed under the PANTHER Grand Challenge LDRD. The purpose of the application is to explore interaction models for graph analytics, drive algorithmic improvements from an end-user point of view, and support demonstration of PANTHER technologies to potential customers. The R&D Application implements a graph-centric interaction model that exposes analysts to the algorithms contained within the GeoGraphy graph analytics library. Users define geospatial-temporal semantic graph queries by constructing search templates based on nodes, edges, and the constraints among them. Users then analyze the results of the queries using both geo-spatial and temporal visualizations. Development of this application has made user experience an explicit driver for project and algorithmic level decisions that will affect how analysts one day make use of PANTHER technologies.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

Registering coherent change detection products associated with large image sets and long capture intervals

A set of co-registered coherent change detection (CCD) products is produced from a set of temporally separated synthetic aperture radar (SAR) images of a target scene. A plurality of transformations are determined, which transformations are respectively for transforming a plurality of the SAR images to a predetermined image coordinate system. The transformations are used to create, from a set of CCD products produced from the set of SAR images, a corresponding set of co-registered CCD products.

97 MATHEMATICS AND COMPUTING↗