Zoom Recording ID: 94588062088
UUID: VP+BeVBAQY+At0pAOemlXQ==
Meeting Time: 2021-09-13T15:45:12Z
Cornell Institute for Digital Agriculture - Fall 2021 Seminar: Digital Agriculture for Sustainable Farming
Two-dimensional
Normalized Difference metrics: Distinguishing
soil and partial vegetation cover
Bill
Philpot, Professor,
Civil & Environmental Engineering, College of Engineering
Abstract:
Identification of materials based on spectral reflectance is
confounded by variations in reflectance magnitude that are independent of the
spectral shape. In particular, this complicates the quantification of partial
vegetation cover. Local variations such as the viewing/illumination angles,
multiscale soil surface roughness, soil moisture content, even differences in
leaf angle can all drive changes in magnitude that are distinct from the
spectral variations of interest, and complicate detection, identification and
modeling of targets based on spectral features. Normalization metrics that
remove magnitude variations can greatly clarify the nature of spectral
differences, allowing for more effective interpretation of reflectance features
in spectral imagery. The 2-dimensional normalized difference space, described
in this presentation, allows for improved discrimination among bare soils and
emergent vegetation when there are multiple soil types in the scene. Normalized
difference indices are used because of the simplicity of the computation, the
convenient scaling, and the ease with which the normalized difference procedure
can be extended to multiple dimensions.
Bio:
Bill Philpot is a
Professor in Civil & Environmental Engineering at Cornell University with a
focus on spectral remote sensing. His research emphasizes understanding the
interaction of light with materials on the earth's surface and deriving tools
for extracting useful spectral information from the reflected light.