Apparatus and method for measuring optical characteristics of an object

A method for determining spectral characteristics of an object comprising the steps of:

• positioning a probe and/or the object such that the probe is in proximity relative to the object, wherein the probe provides light to a surface of the object via one or more light sources and receives light from the object via one or more light receivers, wherein the one or more light sources and the one or more light receivers define a plurality of light source/light receiver pairs, wherein a first light source/light receiver pair defines a first critical height from the surface below which no specularly reflected light from the light source of the first light source/light receiver pair is received and propagated by the light receiver of the first light source/light receiver pair, and a second light source/light receiver pair defines a second critical height from the surface below which no specularly reflected light from the light source of the second light source/light receiver pair is received and propagated by the light receiver of the second light source/light receiver pair, wherein the first critical height is different from the second critical height;
• prior to positioning the probe and/or the object such that the probe is in proximity relative to the object, taking a plurality of position-sensitive calibration/normalization measurements, wherein the probe is controllably moved relative to a calibration/normalization reference, wherein a plurality of calibration/normalization measurements are taken with the probe at a plurality of predetermined positions with respect to the calibration/normalization reference;
• when the probe is positioned in proximity relative to the object determining the intensity of light received by the one or more light receivers in a plurality of spectral bands with one or more measurements;
• determining the spectral characteristics of the object based on the one or more measurements and based on data taken from one or more of the calibration/normalization measurements.

A method for determining spectral characteristics of an object comprising the steps of:

• positioning a probe and/or the object such that the probe is in proximity relative to the object, wherein the probe provides light to a surface of the object via at least a first light source and receives light from the object via at least a first light receiver, wherein the first light source and the first light receiver define a first critical height from the surface below which no specularly reflected light from the first light source is received and propagated by the first light receiver;
• prior to positioning the probe and/or the object such that the probe is in proximity relative to the object, taking a plurality of position-sensitive calibration/normalization measurements, wherein the probe is controllably moved relative to a calibration/normalization reference, wherein a plurality of calibration/normalization measurements are taken with the probe at a plurality of predetermined positions with respect to the calibration/normalization reference;
• when the probe is positioned in proximity relative to the object determining the intensity of light received by the first light receiver in a plurality of spectral bands with one or more measurements;
• determining the spectral characteristics of the object based on the one or more measurements and based on data taken from one or more of the calibration/normalization measurements.