Diffuse Reflectance Calibration Target, Mapir T3-R50 for Multispectral Cameras

Caution: The material used for the targets is similar to felt and thus must be kept debris-free to perform correctly.  It is recommended to hold your drone over the target or taking off away from it and then hovering overhead in order to reduce the amount of debris that could potentially land on the target.  The best working distance to capture the image depends on the angle of view.  The target material’s diffuse properties means that you do not need to worry about camera orientation to get good results.  The detection pattern (fiducial) is also much lower in resolution making detecting in our post processing software much easier, even with images having high noise (typically near-infrared wavelengths).  Reflective measurements were made using multiple Shimadzu spectrophotometers incorporating an integrating sphere.

By using Mapir’s Mapir Camera Control (MCC) software you can select the photo of this target taken before your survey, the fiducial pattern 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.  You can also calibrate the entire ortho, or groups of orthos.  Using the Viewer tab in MCC you can calculate the rastor/index images (for example NDVI) and then apply your color map (lut).