Midwest Optical DB550/850 Dual Bandpass Green + 850nm NIR, 535-565nm, 830-870nm Range

The DB550/850 compliments the DB660/850 and DB475/850 filters. When modifying a single color camera by removing its IR blocking filter, incorporation of this filter in its place allows reflected near-infrared light (850nm) to be captured in the camera sensor’s red channel and reflected green light (550nm) to be captured in the sensor’s green channel (the blue channel is not used). Healthy vegetation will absorb (not reflect) green light and strongly reflect near-infrared light. Thus this information can then be used to apply a false color gradient to images to better highlight the contrast between regions of healthy vegetation vs. areas with stressed, diseased or no vegetation.

There are a range of vegetation indices used by the remote sensing and precision agriculture community, and while NDVI is probably the most common, each have their advantages. Any of the indices listed below can be considered when employing a single color sensor camera that has been converted using a DB550/850 filter. Information gathered can then be overlaid on vegetation maps to provide information used to make better crop management decisions.

Green Chlorophyll Index
CIg = (NIR / Green) – 1

Green Difference Vegetation Index
GDVI = NIR – Green

Green Normalised Difference Vegetation Index
GNDVI = (NIR – Green) / (NIR + Green)

Green Ratio Vegetation Index
GRVI = NIR / Green

Green Soil Adjusted Vegetation Index
GSAVI = [(NIR – Green) / (NIR + Green + 0.5)] * (1 + 0.5)