Survey3 Filter Comparison - 10 Grape Leaves of Varying Health
We arranged 10 grape leaves of varying health on a white cotton sheet background. Images captured by Survey3N cameras included our T3-R50 reflectance reference targets. Our DAQ-A-SD light sensor recorded the ambient light spectrum.
Light source was 4x incandescent light bulbs mounted next to the cameras overhead. Incandescent lights have low blue and cyan output so you will notice some noise in those channels below. A spectrometer was used to measure the average reflectance from each leaf, the white target in the T3-R50 package and the ambient light spectrum. Below you can compare the resulting NDVI spectrometer values to the NDVI color lut gradient in the images.
Filter Model |
Spectrum |
Wavelength (FWHM) |
Example (Grape Leaves) |
| RGB |
Red, Green, Blue |
395-638nm |
 |
| RGN |
Red, Green, Near Infrared (NIR) |
653-668nm, 543-558nm, 835-865nm |
 |
| RGN | Red | 653-668nm |
 |
| RGN | Green | 543-558nm |
 |
| RGN | Near Infrared (NIR) | 835-865nm |
 |
| OCN |
Orange, Cyan, Near Infrared (NIR) |
598-640nm, 476-512nm, 798-848nm |
 |
| OCN | Orange | 598-640nm |
 |
| OCN | Cyan | 476-512nm |
 |
| OCN | Near Infrared (NIR) | 798-848nm |
 |
| NGB |
Near Infrared (NIR), Green, Blue |
835-865nm, 543-558nm, 468-483nm |
 |
| NGB | Near Infrared (NIR) |
835-865nm |
 |
| NGB | Green |
543-558nm |
 |
| NGB | Blue |
468-483nm |
 |
| RE | Red-Edge (RE) | 712-735nm |
 |
| NIR | Near Infrared (NIR) | 835-865nm |
 |
Multispectral Index Examples
Filter Model |
Spectrum |
Wavelength (FWHM) |
Example (Grape Leaves) |
| RGB |
Red, Green, Blue |
395-638nm |
|
| RGN |
NDVI (Red vs NIR) |
653-668nm vs 835-865nm |
 |
| OCN |
NDVI (Orange vs NIR) |
598-640nm vs 798-848nm |
 |
| NDRE |
RedEdge (RE) vs Near Infrared (NIR) |
712-735nm vs 835-865nm |
 |
RGB (Visible) |
 |
RGN (NDVI) |
 |
OCN (NDVI) |
 |
RE + NIR (NDRE) |
 |
RGB vs RGN (NDVI) |
 |
Spectrometer Measurements
LEAF NUMBER |
NDVI (RGN FILTER) |
NDVI (OCN FILTER) |
|
LEAF 1 |
0.76 |
0.63 |
|
LEAF 2 |
0.73 |
0.60 |
|
LEAF 3 |
0.72 |
0.55 |
|
LEAF 4 |
0.68 |
0.55 |
|
LEAF 5 |
0.60 |
0.44 |
|
LEAF 6 |
0.50 |
0.36 |
|
LEAF 7 |
0.15 |
0,15 |
|
LEAF 8 |
0.11 |
0.15 |
|
LEAF 9 |
0.12 |
0.17 |
|
LEAF 10 |
0.19 |
0.27 |
