Patent ID: 7242480

Claim:
A method for diagnosing a human condition from a characteristic of tissue in a biological sample, the method comprising: directing broadband light by means of a sensing light path at the biological sample at a first depth defined by effective light path lengths of said sensing light path and a reference light path; receiving said broadband light reflected from the biological sample by means of said sensing light path; directing said broadband light by means of said reference light path at a reflecting device; receiving said broadband light reflected from said reflecting device by means of said reference light path; modulating at about a distance of a center wavelength said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said first depth; detecting said broadband light resulting from said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, to generate a first signal indicative of an interference of said broadband light reflected from said first depth in the biological sample and said broadband light reflected from said reflecting device, wherein said first signal is a product of a cosine function; determining a first phase component that is an argument of the cosine function of the first signal; changing said effective light path lengths of at least one of said reference light path and said sensing light path to define a second depth; modulating at about a distance of said center wavelength of said broadband light an effective light path length of at least one of said reference light path and said sensing light path with respect to said second depth; detecting said broadband light resulting from said broadband light reflected from said second depth in the biological sample and said broadband light reflected front said reflecting device, to generate a second signal indicative of an interference of said broadband light reflected from said second depth in the biological sample and said broadband light reflected from said reflecting device, wherein said second signal is a product cosine function; determining a second phase component that is an argument of the cosine function of the second signal; determining a characteristic of the biological sample from said first phase component and said second phase component; and diagnosing a human condition from the characteristic.