I'm just curious to know what determines the output spectra you get from an equipment. Is it the imaging light source mode or the sensor signal default of the equipment? Im thinking its the latter but i have seen some reports seemingly talking of reflectance spectra because their light source was in reflectance mode and talking of transmittance spectra because the light source was in transmittance mode. Is the light source really the determining factor for spectra output signal? or is it what the inbuilt sensor was built to measure? Will i have a transmittance spectra just because i position my light source at the bottom shining perpendicularly to my sample and have a reflectance spectral just because i incline my light sources at angle 45 degrees to each other to reflect information out of my sample. No matter the position of my light source(s), should the output signal not be what the inbuilt sensor is designed to measure? I need clarity please!
Without the use of 'active' optical materials, there is no way to add something to the spectrum of the light source. You may 'subtract' some components by filtering.
Thus the output spectrum firstly depends on the output spectrum of the light source. Reflectance resp. transmittance spectra of the same light source can differ in the way, that some components could be filtered off differently - depending on the path of light.
Adeyemi,
Your question is a basic question and concerns the optical properties of materials. Generally, the properties of materials are determined by their response to specific stimuli. The stimuli can be a force or energy. The response of the materials to photons of light is called optical properties of materials. These properties are the reflectance, the absorbance and the transmittance.This stems from that when a light beam is incident on a material part of it will be reflected, part of it will be absorbed by the material and the remaining part will go out of the material and called transmitted,
part. The three parts equal to the total input photons.
The incident photons are characterized by photon energy and consequently a wavelength. So, they have certain wavelength distribution called the frequency spectrum of the light. The photons are generated by light sources. Every light source has its spectral emittance. On the other side every material has is specific spectral response characteristics in the sense that the refelectance, the absorption and the transmittance depends on the wavelength of the incident light.
In order to measure these responses one uses a optical spectrometer.
wish you success
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