Un apparato per la spettrometria di linea

Righi M., Martinelli M., Benassi A., Chimenti M., Magrini M., Colantonio S., Salvetti O.

Video analysis  Image Processing 

The work describes an apparatus for measuring the spectra of light emitted from a linear array of areas, set on the surface of an object under examination. The light emitted from areas is sent from a target on the entrance slit of a dispersion element, which contains a grid and two prisms, which deflect the light at different angles as a function of wavelength; the light rays emerging from the dispersion device strike the sensor area of a monochrome camera, and is thus obtained a spectral image that can be saved and processed. The dispersion element is aligned with the camera so that each column of the image defines the spectrum of the light emitted from the corresponding captured area. The work shows the procedure of processing that allows you to transform raw data into the camera output (luminance profiles added depending on the line) in values of transmittance or reflectance as a function of wavelength. This apparatus can measure spectra in the range 380-780 nm, with a spectral resolution of about 5 nm; the size of the areas examined, and then the spatial resolution, is fully adjustable.