Patent ID: 8687055
Filing Date: 2014-04-01
Classification: G01J,G01N

Abstract:
1. A spectral imaging system for collecting multi-spectral information of a two dimensional target in motion relative to the imaging system, said system comprising: A) a pulsed light source tunable in wavelength for producing short pulses of wavelength tuned light at a plurality of selected narrow band wavelengths within a spectral range, B) one or more optical components for conveying or directing said short pulses of light to a two dimensional region that is substantially stationary with respect to the imaging system and through which the two dimensional objects are moving relative to the imaging system, and C) a camera synchronized with said tunable pulsed light source and comprising a many pixel array detector, said camera being adapted to: D) a processor adapted to process information from said tunable light source and said camera and to produce multi-spectral image cubes of said target from said information, said image cubes identifying a plurality of optical values for each of said two-dimensional pixels of said target passing through the target region; wherein system parameters are defined as follows: Np=a number of pixels in a the motion direction Nps=a number of pixels in a the strip's width Ns=a number of strips in a the field of view PIX=virtual pixel dimensions PRR=pulse repletion rate of the laser V=target speed (conveyor belt speed) Δλ=a wavelength range #F=number of frames (spectral bands in the spectral data) SR=spectral resolution Ws=strip width, and the system parameters are adjusted such that each strip is exposed only once to each wavelength as it travels across the a target area so the a number of pulses that a strip is exposed to is equal to the number strips in the target area, which is also equal to the number of data points (#F) in the collected spectral data, so: and the spectral resolution is equal to a total wavelength range scanned by the tunable laser divided by the number of the collected data points, i.e. and for a desired number of frames #F the required speed V is the product of the pulse repetition rate and the width of the strip, so: