Design and evaluation of an imaging spectrophotometer incorporating a uniform light source

S D Noble; R B Brown; T G Crowe

doi:10.1063/1.3697858

Design and evaluation of an imaging spectrophotometer incorporating a uniform light source

Rev Sci Instrum. 2012 Mar;83(3):033112. doi: 10.1063/1.3697858.

Authors

S D Noble¹, R B Brown, T G Crowe

Affiliation

¹ Department of Chemical and Biological Engineering, University of Saskatchewan, College of Engineering, 57 Campus Drive, Saskatoon, Saskatchewan S7N 5A9, Canada.

PMID: 22462911
DOI: 10.1063/1.3697858

Abstract

Accounting for light that is diffusely scattered from a surface is one of the practical challenges in reflectance measurement. Integrating spheres are commonly used for this purpose in point measurements of reflectance and transmittance. This solution is not directly applicable to a spectral imaging application for which diffuse reflectance measurements are desired. In this paper, an imaging spectrophotometer design is presented that employs a uniform light source to provide diffuse illumination. This creates the inverse measurement geometry to the directional illumination/diffuse reflectance mode typically used for point measurements. The final system had a spectral range between 400 and 1000 nm with a 5.2 nm resolution, a field of view of approximately 0.5 m by 0.5 m, and millimeter spatial resolution. Testing results indicate illumination uniformity typically exceeding 95% and reflectance precision better than 1.7%.