Apparatus and methods to assess sub-surface tissue properties

An absorption spectrophotometer, comprising:

• a first spectrophotometer having an optical element operable to collect a diffuse reflected beam of light within a first field-of-view (FOV), and a first pixelated sensor to receive and measure intensity of the diffuse reflected beam of light;
• and
• a second spectrophotometer comprising:
• a shroud positioned to receive diffuse reflected light within a second FOV overlapping the first FOV and surrounding the first FOV, the shroud having an interior surface;
• a center blocking module having an exterior surface, the center blocking module coaxially supported within the shroud and forming a gap between the interior surface of the shroud and the exterior surface of the center blocking module, the center blocking module being sized, shaped, and constructed of an opaque material so as to block first diffuse reflected light within a region of the second FOV overlapping the first FOV, the gap sized and shaped to pass second diffuse reflected light outside of the region overlapping the first FOV and within the second FOV;
• a second pixelated sensor operable to measure intensity of the second diffuse reflected light passing through the gap between the interior surface of the shroud and the exterior surface of the center blocking module;
• and
• an illumination source operable to generate and provide a collimated beam of broadband light to a point-of-illumination (POI) on a surface of a medium within the first FOV and the second FOV.

A method, comprising:

• providing, by an illumination source of an absorption spectrophotometer, a collimated beam of broadband light to a point-of-illumination (POI) on a surface of a medium, the medium having a first layer adjacent to the surface and a second layer beyond the first layer;
• collecting, by an optical element of a first spectrophotometer of the absorption spectrophotometer, first diffuse reflected light passing solely through the first layer and emitted from the surface adjacent to the POI;
• measuring, by a first pixelated sensor of the first spectrophotometer, a first intensity of the first diffuse reflected light;
• receiving, by a shroud of a second spectrophotometer of the absorption spectrophotometer, second diffuse reflected light passing solely through a gap formed between an interior surface of the shroud and an exterior surface of a center blocking module coaxially supported within the shroud, the center blocking module sized, shaped, and constructed of an opaque material so as to block the first diffuse reflected light passing solely through the first layer and emitted from the surface adjacent to the POI, the gap sized and shaped to pass the second diffuse reflected light passing through the second layer at a predetermined range of distances from the POI;
• and
• measuring, by a second pixelated sensor of the second spectrophotometer, a second intensity of the second diffuse reflected light.