Sensing Optical remote sensing makes use of visible, near infrared and short-wave infrared sensors to form images of the earth's surface by detecting the solar radiation reflected from targets on the ground.
Different materials reflect and absorb differently at different wavelengths.
Thus, the targets can be differentiated by their spectral reflectance signatures in the remotely sensed images. The sensor is a single channel detector sensitive to radiation within a broad wavelength range. The physical quantity being measured is the apparent brightness of the targets. Each channel is sensitive to radiation within a narrow wavelength band. Solar Irradiation Optical remote sensing depends on the sun as the sole source of illumination.