Path constrained spectrophotometer and method for determination of spatial distribution of light or other radiation scattering and absorbing substances in a radiation scattering medium

A spectrophotometer for providing an image of a radiation scattering medium having one or more radiation attenuating constituents, comprising:

• means for illuminating said medium with electromagnetic radiation of at least one wavelength, and for modulating intensity of said electromagnetic energy in accordance with a phase-modulation waveform;
• means for detecting portions of said electromagnetic radiation propagating through a region of said medium;
• means for determining a phase shift Of said phase-modulation waveform associated with each of said detected portions of said electromagnetic radiation, each of said phase shifts corresponding to a function of the distribution of radiation path lengths through said region of said medium;
• means for measuring intensity of each of said detected portions of electromagnetic radiation wherein each of said measured intensities corresponds to attenuation of said region;
• and
• means for generating said image in accordance with said measured intensities and phase shifts.

A method for providing an image of a radiation scattering medium having one or more radiation attenuating constituents, comprising the steps of:

• illuminating said medium with electromagnetic radiation of at least one wavelength from a source location at a time t.sub.0, said electromagnetic radiation propagating through a region of said medium over a plurality of paths;
• detecting, during a set of detection windows commencing at selected times relative to time t.sub.0, portions of said electromagnetic radiation emerging from said medium at a first detection location after having propagated through said medium from said source location to said first detection location over a corresponding set of paths of selected length;
• measuring intensity of each of said detected portions of electromagnetic radiation wherein said measured intensities are a function of attenuation of said region;
• and
• generating said image based upon said intensities measured during each of said detection windows at said first detection location and upon corresponding ones of said paths of selected length.

A method for providing an image of a radiation scattering medium having one or more radiation attenuating constituents, comprising the steps of:

• illuminating said medium with electromagnetic radiation of at least one wavelength, and modulating intensity of said electromagnetic energy in accordance with a phase-modulation waveform;
• detecting portions of said electromagnetic radiation propagating through a region of said medium;
• determining a phase shift of said phase-modulation waveform associated with each of said detected portions of said electromagnetic radiation, each of said phase shifts corresponding to a function of the distribution of radiation path lengths through said region of said medium;
• measuring intensity of each of said detected portions of electromagnetic radiation wherein each of said measured intensities corresponds to attenuation of said region;
• and
• generating said image in accordance with said measured intensities and phase shifts.

A spectrophotometer for providing an image of a radiation scattering medium having one or more radiation attenuating constituents, comprising:

• light source means for illuminating said medium with electromagnetic radiation characterized by a first time-intensity relationship, said electromagnetic radiation propagating through said medium over a plurality of paths:
• detection means for detecting said electromagnetic radiation having propagated through said medium over at least one path of one or more selected lengths, said detection means including means for identifying a second-tine intensity relationship characterizing said detected electromagnetic energy having propagated over said at least one path of said one or more selected lengths;
• and
• means for generating an image based on said one or more selected lengths and said second time-intensity relationship.

A spectrophotometer for providing a measurement of a radiation scattering medium having one or more radiation attenuating constituents, comprising:

• light source means for illuminating said medium from a source location at a time t.sub.0 with electromagnetic radiation of at least one wavelength, said electromagnetic radiation propagating through said medium over a plurality of paths;
• means for detecting, during a set of detection windows commencing at selected times relative to time t.sub.0, portions of said electromagnetic radiation emerging from said medium at a first detection location after having propagated through said medium from said source location to said first detection location over a corresponding set of paths of selected length;
• intensity measuring means for measuring intensity of each of said detected portions of electromagnetic radiation during said detection windows wherein said measured intensities are a function of attenuation of said region;
• and
• means for generating a result representative of said measurement based upon said intensities measured during each of said detection windows and upon corresponding ones of said paths of selected length.

A spectrophotometer for providing a measurement of a radiation scattering medium having one or more radiation attenuating constituents, comprising:

• means for illuminating said medium with electromagnetic radiation of at least one wavelength, and for modulating intensity of said electromagnetic energy in accordance with a phase-modulation waveform;
• means for detecting portions of said electromagnetic radiation propagating through a region of said medium;
• means for determining a phase shift of said phase-modulation waveform associated with each of said detected portions of said electromagnetic radiation, each of said phase shifts corresponding to a function of the distribution of radiation path lengths through said region of said medium;
• means for measuring intensity of each of said detected portions of electromagnetic radiation wherein each of said measured intensities corresponds to attenuation of said region;
• and
• means for generating a result representative of said measurement in accordance with said measured intensities and phase shifts.

A method for providing a measurement of a radiation scattering medium having one or more radiation attenuating constituents, comprising the steps of:

• illuminating said medium with electromagnetic radiation of at least one wavelength from a source location at a time t.sub.0, said electromagnetic radiation propagating through a region of said medium over a plurality of paths;
• detecting, during a set of detection windows commencing at selected times relative to time t.sub.0, portions of said electromagnetic radiation emerging from said medium at a first detection location after having propagated through said medium from said source location to said first detection location over a corresponding set of paths of selected length;
• measuring intensity of each of said detected portions of electromagnetic radiation wherein said measured intensities are a function of attenuation of said region;
• and
• generating a result representative of said measurement based upon said intensities measured during each of said detection windows and upon corresponding ones of said paths of selected length.

A method for providing a measurement of a radiation scattering medium having one or more radiation attenuating constituents, comprising the steps of:

• illuminating said medium with electromagnetic radiation of at least one wavelength, and modulating intensity of said electromagnetic energy in accordance with a phase-modulation waveform;
• detecting portions of said electromagnetic radiation propagating through a region of said medium;
• determining a phase shift of said phase-modulation waveform associated with each of said detected portions of said electromagnetic radiation, each of said phase shifts corresponding to a function of the distribution of radiation path lengths through said region of said medium;
• measuring intensity of each of said detected portions of electromagnetic radiation wherein
• each of said measured intensities corresponds to attenuation of said region, and generating a result representative of said measurement in accordance with said measured intensities and phase shifts.

A spectrophotometer for providing a measurement of a radiation scattering medium having one or more radiation attenuating constituents, comprising:

• light source means for illuminating said medium with electromagnetic radiation characterized by a first time-intensity relationship, said electromagnetic radiation propagating through said medium over a plurality of paths;
• detection means for detecting said electromagnetic radiation having propagated through said medium over at least one path of one or more selected lengths, said detection means including means for identifying a second time-intensity relationship characterizing said detected electromagnetic energy having propagated over said at least one path of said one or more selected lengths;
• and
• means for generating a result representative of said measurement based on said one or more selected lengths and said second time-intensity relationship.