Multispectral Imaging

Multispectral imaging captures reflected sunlight in multiple discrete wavelength bands — typically 4–12 bands spanning visible light (blue, green, red), near-infrared (NIR), and shortwave infrared (SWIR). Each band reveals different surface properties invisible to normal photography. The near-infrared band, for example, strongly reflects from healthy vegetation but is absorbed by water — enabling computation of the Normalised Difference Vegetation Index (NDVI) for crop monitoring and deforestation detection. Landsat (NASA/USGS) pioneered multispectral Earth observation in 1972 and remains the longest continuous satellite imagery record. Sentinel-2 (ESA) provides 13-band multispectral imaging at 10–60 m resolution with a 5-day revisit. Hyperspectral imaging extends this to 100–300+ narrow bands for even finer spectral analysis.