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Brost, Randolph

Publications and source records attributed to Brost, Randolph.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Dual-Image Color Normalization to Enable High-Performance Concentrating Solar Optical Metrology

Concentrating Solar Power (CSP) requires precision mirrors, and these in turn require metrology systems to measure their optical slope. In this project we studied a color-based approach to the correspondence problem, which is the association of points on an optical target with their corresponding points seen in a reflection. This is a core problem in deflectometry-based metrology, and a color solution would enable important new capabilities. We modeled color as a vector in the [R,G,B] space measured by a digital camera, and explored a dual-image approach to compensate for inevitable changes in illumination color. Through a series of experiments including color target design and dual-image setups both indoors and outdoors, we collected reference/measurement image pairs for a variety of configurations and light conditions. We then analyzed the resulting image pairs by selecting example [R,G,B] pixels in the reference image, and seeking matching [R,G,B] pixels in the measurement image. Modulating a tolerance threshold enabled us to assess both match reliability and match ambiguity, and for some configurations, orthorectification enabled us to assess match accuracy. Using direct-direct imaging, we demonstrated color correspondence achieving average match accuracy values of 0.004 h, where h is the height of the color pattern. We found that wide-area two-dimensional and linear one-dimensional color targets outperformed hybrid linear/lateral gradient targets in the cases studied. Introducing a mirror degraded performance under our current techniques, and we did not have time to evaluate whether matches could be reliably achieved despite varying light conditions. Nonetheless, our results thus far are promising.

14 SOLAR ENERGY↗
DOE OSTI2024

Scene Reconstruction User Guide

These instructions show how to use the OpenCSP Scene Reconstruction application. Scene Reconstruction calculates the three-dimensional positions of Aruco markers placed around a scene using photogrammetry. This has multiple applications within OpenCSP; this document is referenced by multiple other OpenCSP documents.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

SOFAST 2.0 User Guide and Technical Description, Document Version 1.0

This report accompanies Sandia’s deflectometry tool, SOFAST 2.0, providing both a user guide and a basic technical description. SOFAST is a deflectometry tool used to measure surface slope maps of concentrating solar power (CSP) mirrors and collectors. The original SOFAST performed high-resolution measurement of a variety of CSP mirror types. SOFAST 2.0 is a completely new version, re-implemented in Python and including many extensions and improvements.

14 SOLAR ENERGY↗
DOE OSTI2024

Preliminary Results of the 3D-shape Round-Robin

In the framework of SFERA-III WP10 Task3, ENEA has organized the 3D-shape round-robin (RR); the purpose is to compare the main geometrical parameters of 3D shape measurement of parabolic-trough (PT) reflective panels evaluated with the instruments adopted by each participant among: ENEA, DLR, F-ISE, NREL, and SANDIA. The last two institutions are outside of the EU, but benefited from the Transnational Access institute to visit several European laboratories, including the ENEA Casaccia research center where they accomplished some measurements with a portable experimental set-up. RR is based on the inter-laboratory circulation of 3 inner plus 3 outer PT panels. The start of the RR was delayed by the covid pandemic, then the circulation of the specimen-set and their measurement took more than one year. At the time of drafting this deliverable at the end of SFERA-III project, NREL has not yet completed the analysis of the measurements, making available only the deviations of the slopes. Therefore here will be reported only the preliminary results. The full comparison will be published as soon as possible, maybe in the open access venue Open Research Europe.

14 SOLAR ENERGY↗
DOE OSTI2023

Toward Autonomous Field Inspection of CSP Collectors With a Polarimetric Imaging Drone

We developed a polarimetric imaging drone to perform field inspections of heliostats and carried out field tests at Sandia’s National Solar Thermal Test Facility (NSTTF). The preliminary results show that Degree of Linear Polarization (DOLP) and Angle of Polarization (AOP) images greatly enhanced the edge detection results compared with the conventional visible images, supporting fast and accurate detection of heliostat mirror edges and cracks. The system holds the promise to enable future automated detection of heliostats optical errors and mirror defects.

14 SOLAR ENERGY↗
DOE OSTI2023

OpenCSP v.1.0

SAND2024-08987O OpenCSP analyzes and improves the performance of optical mirrors that reflect sunlight and concentrate it onto a receiver. The algorithms in this library analyze the flow of light from an original source—such as the sun—reflecting off one or more mirrors, and onto a receiver, optical screen, or camera. OpenCSP also analyzes optical systems using other techniques, such as shape or slope comparison. The software calculates aggregate properties of the optical system, such as its efficiency, manufacturing error, pointing control error, expected performance, and other useful parameters. OpenCSP also includes high-level tools, such as Open SOFAST, a program that obtains high-resolution measurement of CSP mirrors, full heliostats, and other CSP collectors. OpenCSP supports producing meaningful output data to help CSP designers and field operators improve the performance of their systems. OpenCSP also includes classes and functions that support these calculations, including input utilities, analysis output libraries, geometric constraint analysis for drone flight planning, and more. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Brost, Randolph↗