A new gonioreflectometer has been developed at the National Research Council of Canada to measure spectral bidirectional reflectance distribution functions (BRDF). It incorporates a five-axis robot manipulator that holds the sample, and a rotation stage that holds an extended uniform light source of precisely known emitting solid angle. An array spectroradiometer is used to measure the reflected spectral radiance from the sample, which is compared to the spectral radiance of the source itself, allowing the calculation of the BRDF from first principles. The system has been designed in anticipation of a growing demand for traceable spectral BRDF measurements from sectors such as machine vision, remote sensing and color imaging. Capabilities of the system are demonstrated for diffuse reflectance material, vapor-blasted aluminum, and light interference pigments.

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.nrc-cnrc.gc.ca/eng/view/object/?id=d9682c21-38af-4e8e-8896-f53b13c69d2a http://nparc.nrc-cnrc.gc.ca/fra/voir/objet/?id=d9682c21-38af-4e8e-8896-f53b13c69d2a AbstractIn the second part of this two-part series on the development of a versatile reference instrument at the National Research Council of Canada (NRC), we have extended the characterization of t he NRC Reference Goniospectrofluorimeter to high-accuracy fluorescence measurements in a sphere geometry (8:d) that is specified in standard test methods for many practical applications in colorimetry. This builds upon the work reported in part-one of this series which described in detail the design, characterization and validation of this new instrument for realizing a total spectral radiance factor scale in a bidirectional (45a:0) geometry. To extend the measurement capabilities to a sphere geometry, it was configured with a large diameter integrating sphere accessory.Preliminary results using a substitution-mode operating procedure showed large sphere errors that were characterized and corrected for. To improve this traceability, the sphere was modified to operate in comparison-mode and this effectively eliminated many of the sphere-related errors t hat typically limit the accuracy of sphere-based fluorescence 2 measurements. The performance of the instrument configured for a sphere geometry

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