Patent ID: 8708907

Claim:
A method for obtaining physiological information from a subject in accordance with a light field whose intensity varies according to location, the method comprising: a) applying partially or entirely coherent light to a target region of the subject to induce a light response signal from the illuminated target region which contributes to a location-dependent light field LF(x, y, z); b) detecting the light field LF(x 1 , y 1 , z 1 ) prevailing at a first location (x 1 , y 1 , z 1 ) to generate a first analog electrical signal A 1 (t), the first analog electrical signal A 1 (t) including a dynamic light scattering (DLS) component DLS(A 1 (t)) that is indicative of a first DLS measurement; c) detecting the light field signal LF(x 2 , y 2 , z 2 ) prevailing at a second location (x 2 , y 2 , z 2 ) to generate a second analog electrical signal A 2 (t), the second analog electrical signal A 2 (t) including a DLS component DLS(A 2 (t)) that is indicative of a second DLS measurement and that is uncorrelated with the DLS component of the first analog signal A 1 (t); d) processing, by analog electrical circuitry, the first and second analog electrical signals to generate a processed analog electrical signal processed(t) from a difference between the first and second analog electrical signals, wherein: (i) a first DLS contribution ratio  DLS ⁡ ( A 1 ⁡ ( t ) )   A 1 ⁡ ( t )  is defined as the ratio between a magnitude |DLS(A 1 (t))| of the DLS component of the first analog electrical signal and a magnitude |A 1 (t)| of the first electrical analog signal; (ii) a second DLS contribution ratio  DLS ⁡ ( A 2 ⁡ ( t ) )   A 2 ⁡ ( t )  is defined as the ratio between a magnitude |DLS(A 2 (t))| of the DLS component of the second analog electrical signal and a magnitude |A 2 (t)| of the second analog electrical signal; (iii) processed analog electrical signal processed(t) includes a DLS component that is indicative of a combination of the first and second dynamic scattering measurements; (iv) a processed signal DLS contribution ratio  DLS ⁡ ( processed ⁡ ( t ) )   processed ⁡ ( t )  is defined as a ratio between a (i) magnitude |DLS(processed(t))| of the DLS component of the processed analog electrical signal and (ii) a magnitude |processed(t)| of the processed analog signal; and (v) the detecting and the processing are performed so that a ratio between: i) the processed signal DLS contribution ratio  DLS ⁡ ( processed ⁡ ( t ) )   processed ⁡ ( t )  ; ii) at least one of the first DLS contribution ratio  DLS ⁡ ( A 1 ⁡ ( t ) )   A 1 ⁡ ( t )  and the second DLS contribution ratio  DLS ⁡ ( A 2 ⁡ ( t ) )   A 2 ⁡ ( t )  is at least 10.