The material we are using for our reflectance targets is brand new to the market and something we designed custom in order to bring superior results at an affordable cost. Our targets are durable, diffuse, easily reproducible (consistent results from batch to batch) and highly lambertian. They will not fade, peel or change over time, and are highly scratch-resistant. The base substrate is durable processed glass with the coating evaporated in high vacuum. Measurements were made using multiple Shimadzu spectrophotometers incorporating an integrating sphere.
Using our MAPIR plugin for the Fiji (ImageJ) software you can select the photo of this target taken before your survey, the QR code will be auto-detected and the reflectance value of each target will be calculated and applied to each of your images. The resulting individual images will then be calibrated and you can generate your ortho-mosaic in the software of your choosing. Using a rastor/index calculator for the desired index (for example NDVI) will properly compute the calibrated indice values.
Note: We use this same package to create the default values in the Calibration step of our Fiji plugin. While the base calibration works well for perfectly clear sunny days, in order to fully normalize your surveys we recommend using this ground target package each flight.