Active Proximal Sensing: Review of Waveband Selection, Vegetation Indices, Scientific Trump Cards, Etc.

Active proximal sensors have become a popular precision agriculture tool for both production agriculture and agricultural research. Consideration of the various factors that influence measurements produced by active proximal sensors is essential to optimizing their effectiveness as a sensing tool.  The goal of this presentation is to provide an overview of the technology in light of the fields of remote sensing, precision agriculture and electro-optics with an emphasis on choosing the appropriate wavelengths, vegetation indices, and/or sensing protocol for a given application. An overview regarding the electromagnetic interaction of plant tissue with light will also be presented along with practical questions the researcher/practitioner should consider when applying active proximal sensing technology to their research. Other topics to be discussed include: basic mathematical rules-of-thumb for sensor data usage, multi-wavelength background correction, region-specific algorithm versus general algorithm development, conversion of height-variant reflectance measurements to absolute reflectance measurements, plant height measurements and practical implement control using active proximal sensors.