The DB475/850 filter has been primarily designed for NDVI imaging applications. When using a single camera, incorporation of this filter allows reflected near-infrared light (850 nm) to be captured in the camera sensor’s red channel and reflected blue light (475 nm) to be captured in the sensor’s blue channel (the green channel is not used). Even when using an inexpensive consumer camera (that has first had its IR blocking filter removed), this easy separation than makes it possible to post-process the red and blue channels for NDVI by performing the calculation: NDVI = (red – blue) / (blue red). Healthy vegetation will absorb (not reflect) blue 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.
- Useful Range: 460 to 490 nm, 830 to 870 nm
- FWHM: 45 nm, 55 nm
- Tolerance: +/- 5 nm
- Minimum Peak Transmission: >90%
- Surface Quality: 40/20