Abstract

Various field portable goniometers have been designed to capture in-situ measurements of a material’s bi-directional reflectance distribution function (BRDF), each with a specific scientific purpose in mind.[1, 2, 3, 4] The Rochester Institute of Technology’s (RIT) Chester F. Carlson Center for Imaging Science recently created a novel instrument incorporating a wide variety of features into one compact apparatus in order to obtain very high accuracy BRDFs of short vegetation and sediments, even in undesirable conditions and austere environments. This next generation system integrates a dual-view design using two VNIR/SWIR spectroradiometers to capture target reflected radiance, as well as incoming radiance, to provide for better optical accuracy when measuring in non-ideal atmospheric conditions or when background illumination effects are non-negligible. The new, fully automated device also features a laser range finder to construct a surface roughness model of the target being measured, which enables the user to include inclination information into BRDF post-processing and further allows for roughness effects to be better studied for radiative transfer modeling. The highly portable design features automatic leveling, a precision-engineered frame, and a variable measurement plane that allow for BRDF measurements on rugged, un-level terrain while still maintaining true angular measurements with respect to the target within 0.2 degrees, all without sacrificing measurement speed. This fully automated design is capable of capturing a full hemispherical scan of 66 points, with 80 spectral samples per point, in just 34 minutes. Despite the expanded capabilities and dual sensor suite, the system weighs less than 75 kg, which allows for excellent mobility and data collection on soft, silty clay or fine sand.

Library of Congress Subject Headings

Angles (Geometry)--Measurement; Reflectance--Measurement; Multispectral imaging

Publication Date

7-29-2016

Document Type

Dissertation

Student Type

Graduate

Degree Name

Imaging Science (Ph.D.)

Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)

Advisor

Charles Bachmann

Advisor/Committee Member

Scott Franklin

Advisor/Committee Member

Carl Salvaggio

Comments

Physical copy available from RIT's Wallace Library at QC103 .H37 2016

Campus

RIT – Main Campus

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