Multispectral Content

Group 8 Technology, Inc. (G8T) coats and fabricates ground calibration panels that have spectral structure content that differs across the visible, NIR and SWIR domains.

Multispectral targets have wide band spectral content in the visible, NIR and SWIR regions. These include legacy colors consisting of the additive primaries (Red, Green, Blue) and the subtractive primaries (Cyan, Magenta, Yellow). The colorimetric properties of these specific color panels are designed to be complimentary pairs under irradiance of 6500̊K color temperature, as shown in the CIE diagram below. The pigmentation of these coatings is selected to also modulate the spectral profile across the NIR and SWIR regions. This spectral modulation provides differing wavelength dependent signal levels to multispectral and hyperspectral sensors that are sensitive in these spectral regions. The Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) values for the primary (RGB) and complimentary color (CMY) target panels have been calculated and are inidicated along with the spectral reflectivity data plotted below.  

G8T fabricates multispectral panels the same size range as gray scale panels as well as custom combinations of neutral gray scale and color subpanels forming a single target. An example is a 3%, 33%, 56%, Red, Green and Blue combination target with each subpanel element being 1.2 x 1.2 meters to form a single target 2.4 x 3.6 meters in size. Combination targets may also be custom fabricated to be extended linear arrays of colors and gray scale panels. The required dimension for each gray or color panel is defined by the GSD of the imaging system and the pixel sampling statistics needed to provide sufficient confidence in the calibration. G8T does not price list spectral content panels. The spectral structure is usually specified by the user based upon the bandpass sensitivity domains of the multispectral system to be calibrated or tested and the remote sensing goals (crops, soil mapping, mineral exploration). Each panel set is fabricated to these requirements and is priced as a custom product. Please contact G8T for a quotation based upon your specific multispectral calibration or test requirement.

Color Band Average Diffuse Hemispherical Reflectance Colormetric Data relative to 6500°K
420-700nm 450-1000nm 750-1000nm 900-1700nm Dom λ, nm Purity Luminosity
Red (612) 25.4% 49.8% 72.3% 65.2% 612 0.75 10.6%
Green (518) 13.1% 31.7% 55.3% 30.9% 518 0.22 17.5%
Blue (476) 7.9% 6.3% 5.0% 42.4% 476 0.22 17.5%
Cyan (490) 24.0% 44.7% 68.5% 33.9% 489 0.45 24.8%
Magenta (-522) 28.2% 49.4% 69.0% 62.8% -503 0.27 12.9%
Yellow (575) 54.5% 68.4% 75.2% 70.2% 575 0.800 63.8%
White 80% 83.1% 81.1% 79.4% 72.2% 549 0.021 81.7%
Gray 50% 48.7% 49.1% 49.3% 49.2% 572 0.033 48.0%