放射量の種類

FranciscoCáceresClavero

私はMicasense Rededge-Pカメラを持っており、Downwelling Light Sensor (DSL2)が装備されています。このセンサーはカメラの5つのバンドそれぞれの環境光と太陽角度を測定し、その情報をカメラで撮影されたTIFF画像のメタデータに記録します。また、キャリブレーションパネルも持っており、各飛行ミッションで写真を撮影しています。<\/P>

1) 画像メタデータに記録されたDSL2による照度値を考慮したい場合、どの放射量の種類を使用すべきでしょうか？
2) DSL2データとキャリブレーションパネルデータを一緒に使用できる放射量の種類はありますか？<\/P>

CodyBinkelheim

Francisco

for Radiometric Quantity Type you should use Reflectance.  See help here: 

https://doc.arcgis.com/en/drone2map/latest/help/radiometric-calibration.htm

At this time we have not implemented support for the DLS inside Drone2Map.  What I would recommend is to capture images of the reflectance panel before and after your flight, and look at the DLS values for those calibration images and also for the images captured over your project site.  If the "before" and "after" calibration images have DLS values that are very similar (within a few %) and your flight images show consistent DLS values, your results should still be valid.  

If the DLS data indicates significant changes during the flight (perhaps more than ~15%, but this is just an estimate) then you would need to consider how changes in your multispectral values from early vs. late in the flight may appear in your data.  e.g. if your flightlines run north/south and proceed from west to east, and illumination drops by 15% from first image to last, your spectral values MAY show a bias from west to east.

However, if you're using NDVI, this concern is largely reduced, since the normalization of the NDVI compensates for variable illumination.  Further, your drone will most likely change the exposure parameters to compensate for the change in illumination.