Optical measuring systems

摘要

An optical system for measuring the reflectance of an object comprising: an extended source (44) of light with approximately uniform radiance over some range of angles; a telecentric illuminating system (46) comprising an aperture stop chosen such that the range of ray angles passed by the stop is within the range where the source (44) is approximately uniform in radiance; and one or more lenses used to image the source onto the object (48) to be measured; and a telecentric receiving system (50) arranged to collect the light spectrally reflected from the object, the telecentric receiving system (50) comprising two or more lenses and positioned relative to the object and illuminating system such that an image of the stop of the illuminating system is formed in such a manner as to make the receiving system telecentric, and such that the image of the source (44) reflected from the object and re-imaged on the detector (52) is relayed such that the image of the source (44) at the detector (52) is larger than the detector (52). <IMAGE>