Spectral Resolution

we would require a sensor with higher spectral resolution. Spectral resolution describes the ability of a sensor to define fine wavelength intervals. The finer the spectral resolution, the narrower the wavelength range for a particular channel or band. Black and white film records wavelengths extending over much, or all of the visible portion of the electromagnetic spectrum. Its spectral resolution is fairly coarse, as the various wavelengths of the visible spectrum are not individually distinguished and the overall reflectance in the entire visible portion is recorded.

 Colour film is also sensitive to the reflected energy over the visible portion of the spectrum, but has higher spectral resolution, as it is individually sensitive to the reflected energy at the blue, green, and red wavelengths of the spectrum. Thus, it can represent features of various colours based on their reflectance in each of these distinct wavelength ranges.

Many remote sensing systems record energy over several separate wavelength ranges at
various spectral resolutions. These are referred to as multi-spectral sensors and will be
described in some detail in following sections. Advanced multi-spectral sensors called
hyperspectral sensors, detect hundreds of very narrow spectral bands throughout the visible,
near-infrared, and mid-infrared portions of the electromagnetic spectrum. Their very high
spectral resolution facilitates fine discrimination between different targets based on their
spectral response in each of the narrow bands.