1.
The Electromagnetic Spectrum
The electromagnetic specturm consists of all the known wavelengths of light.
Above: The electromagnetic spectrum. The approximate scale of wavelength yields a rough idea of the smallest obect that canbe detected using that part of the spectrum
Please note that the part of the spectrum that comprises the visible portion of light is very small with respect to the entire spectrum. And, with respoect to machine vision we typically use that portion of the spectrum from the near infrared to ultraviolet. We describe these wavelengths typically in nanometer scale.
Above: The primary portion of the spectrum used by machine vision CCD or CMOS imaging sensors, expressed in nanometer wavelengths.