Special Coverage


2D/3D Visual Tracker for Rover Mast

A visual-tracker computer program controls an articulated mast on a Mars rover to keep a designated feature (a target) in view while the rover drives toward the target, avoiding obstacles. Several prior visual tracker programs have been tested on rover platforms; most require very small and well-estimated motion between consecutive image frames — a requirement that is not realistic for a rover on rough terrain. The present visual-tracker program is designed to handle large image motions that lead to significant changes in feature geometry and photometry between frames. When a point is selected in one of the images acquired from stereoscopic cameras on the mast, a stereo triangulation algorithm computes a three-dimensional (3D) location for the target. As the rover moves, its body-mounted cameras feed images to a visual-odometry algorithm, which tracks two-dimensional (2D) corner features and computes their old and new 3D locations. The algorithm rejects points, the 3D motions of which are inconsistent with a rigid-world constraint, and then computes the apparent change in the rover pose (i.e., translation and rotation). The mast pan and tilt angles needed to keep the target centered in the field-ofview of the cameras (thereby minimizing the area over which the 2D-tracking algorithm must operate) are computed from the estimated change in the rover pose, the 3D position of the target feature, and a model of kinematics of the mast. If the motion between the consecutive frames is still large (i.e., 3D tracking was unsuccessful), an adaptive view-based matching technique is applied to the new image. This technique uses correlation-based template matching, in which a feature template is scaled by the ratio between the depth in the original template and the depth of pixels in the new image. This is repeated over the entire search window and the best correlation results indicate the appropriate match. The program could be a core for building application programs for systems that require coordination of vision and robotic motion.

Posted in: Briefs


Measurement and Controls Data Acquisition System

Measurement and Controls Data Acquisition System (MCDAS) is an application program that integrates the functions of two stand-alone programs: one for acquisition of data, the other for controls.

Posted in: Briefs, TSP


Adding Hierarchical Objects to Relational Database General-Purpose XML-Based Information Managements

NETMARK is a flexible, high-throughput software system for managing, storing, and rapid searching of unstructured and semi-structured documents. NETMARK transforms such documents from their original highly complex, constantly changing, heterogeneous data formats into well structured, common data formats in using Hypertext Markup Language (HTML) and/or Extensible Markup Language (XML). The software implements an object-relational database system that combines the best practices of the relational model utilizing Structured Query Language (SQL) with those of the object oriented, semantic database model for creating complex data. In particular, NETMARK takes advantage of the Oracle 8i object-relational database model using physical-address data types for very efficient keyword searches of records across both context and content. NETMARK also supports multiple international standards such as WEBDAV for drag-and-drop file management and SOAP for integrated information management using Web services. The document-organization and -searching capabilities afforded by NETMARK are likely to make this software attractive for use in disciplines as diverse as science, auditing, and law enforcement.

Posted in: Briefs, TSP


Dr. Murzy Jhabvala, Chief Engineer of the Instrument Systems and Technology Division

Goddard Space Flight Center, Greenbelt, MD Dr. Murzy JhabvalaVisible light is only one narrow band of the electromagnetic spectrum, and doesn't always tell scientists what they need to know. Infrared, which is outside the range of human eyesight, has for years been used to delve out mysteries of distant stars or to allow users to see in the dark. NASA scientists have now improved the Quantum Well Infrared Photodetector (QWIP) array infrared technology to gain more detail than ever before. NASA engineer Dr. Murzy Jhabvala led the project.

Posted in: Who's Who


30 Years of Test & Measurement

In celebration of the 30th Anniversary of NASA Tech Briefs, our features in 2006 highlight a different technology category each month, tracing the past 30 years of the technology, and continuing with a glimpse into the future of where the technology is headed. Along the way, we include insights from industry leaders on the past, present, and future of each technology. This month, we take a look at the past 30 years of Test & Measurement.

Posted in: Articles


NASA Imaging Technology Used to Fight Diabetes

This photomicrograph of a sliced rat beta cell has been processed with the modified NASA imaging technology. Insulin granules are the dark black spots surrounded by the white halo area. The colored borders around the granules are labels added to identify and classify them. (NASA/Tim McClanahan)NASA image processing technology used to explore orbital images of Earth is being modified for use in diabetes research. A team from George Washington University (Washington, DC) and Cornell University (Ithaca, NY) modified the technology, which has increased the speed of the research.

Posted in: UpFront


Technique Measures Material Properties

Applied Materials Developed for quality control and wafer metrology in the semiconductor manufacturing market, this non-destructive technology may be highly adaptable to measuring material properties such as a coating’s thickness, thermal and electrical conductivity, and material imperfections. The technology uses two overlapping lasers to measure the thickness of metal on a substrate using the metal’s known heat conductivity and reflectivity. Depending on the metal, thicknesses from 5 μm down to 100 Angstroms can be measured. The technology is sensitive to residues and extremely fine contaminants. Voids, breaks, bridges, or connections between fine metal lines can be detected. If there is a known differential in thermal conductivity between the surface metal deposition and its substrate, metal thickness can be deduced. The nominal laser spot size is 3 μm; measurements may be made to within approximately 20 μm from the edge of a work piece.

Posted in: Techs for License