Method and apparatus for providing high contrast imaging

A spectral imaging apparatus for non-invasive, in vivo analysis of a subject's tissue and blood, comprising:

• a light source for illuminating a region of interest, wherein a light path is formed between said light source and said region of interest;
• means for transforming light emanating from said light source into a illuminating pattern having a low intensity region and a high intensity region;
• means for projecting said low intensity region of said illumination pattern onto an object within said region of interest and beneath a surface of said region of interest and for projecting said high intensity region of said illumination pattern onto the object substantially outside said region of interest;
• and
• image capturing means for capturing an image of said region of interest formed by scattered illumination from said high intensity illumination pattern that is transmitted through the object and said region of interest and propagates along an image path, formed between the object and said image capturing means, to said image capturing device.

A method for creating a source of illumination in a sub-surface tissue region that contains an object of interest, wherein the object is illuminated from all directions about an object plane wherein the object is located, wherein an image of said object is detected by an image capturing device, comprising the steps of:

• (a) providing a light source;
• (b) transforming light from said light source into an illumination pattern having a high intensity portion and a low intensity portion;
• (c) directing said illumination pattern onto a surface of the tissue region such that said high intensity portion of said illumination pattern is incident upon said object plane outside a field of view of the image capturing device and said low intensity portion is incident upon said object plane within the field of view of the image capturing device;
• and
• (d) detecting scattered light that interacts with the object with the image capturing device, wherein said high intensity portion of said illumination pattern undergoes one or more scattering events in the sub-surface tissue region.

An apparatus for optically penetrating an object and detecting subsurface optical characteristics of an object, comprising:

• a light source for illuminating the object at a wavelength such that the multiple scattering depth is small compared to the penetration depth of the illuminating light;
• a first polarizer for polarizing light from said light source;
• means for transforming said illuminating light source into a high contrast illumination pattern which is projected onto the object substantially outside and surrounding a desired portion of the object to be imaged;
• imaging means for detecting an image emanating from beneath the surface of the desired portion of the illuminated object, said image being formed by scattered illumination from said high contrast illumination pattern that is transmitted through the subsurface of the object and propagates along an image path to said imaging means;
• and
• a second polarizer disposed in said image path between the object and said imaging means through which the scattered light passes, wherein a plane of polarization of said second polarize is substantially orthogonal relative to a plane of polarization of said first polarizer.

An apparatus for quantitatively measuring absorption properties of an imaged object, comprising:

• a light source for illuminating an object to be imaged;
• a first polarizer for polarizing light from said light source;
• an illumination system for transforming said illuminating light source into a high contrast illumination pattern which is projected onto the object substantially outside and surrounding a desired portion of the object to be imaged;
• imaging means for detecting an image emanating from beneath a surface of the desired portion of the illuminated object, said image being formed by scattered illumination from said high contrast illumination pattern that is transmitted through the subsurface of the object and propagates along an image path to said imaging means;
• a second polarizer disposed in said image path, wherein a plane of polarization of said second polarizer is substantially orthogonal relative to a plane of polarization of said first polarizer;
• and
• measuring means coupled to said imaging means for quantitatively measuring differences in absorption properties between imaged structures using said image.