Optical signal processing to analyze fluid absorption inside the skin using point by point photon counting

Time-correlated single photon counting (TCSPC) is popular in time resolved techniques due to its prominent performance such as ultra-high time resolution and ultra-high sensitivity. This paper presents advance signal processing tech- niques on the optical TCSPC signals obtained from the series of experiments on fabricated tissue like phantom. A pulsed laser sources at a wavelength of 830 nm transmits the light through the surface of phantom and finally at receiver side, photon counting device generates the histogram of the receiving signal. The noisy data obtained from the photon counter is processed with the splitting based denoising method. The method divide the signal into different subsets based on the transitions. Each subset is then processed individually and final merging of all subsets gives noise free signal. The main objective of this work is to analyze the signal obtained from photon counter in context of skin blood absorption. We had examined the signal obtained by varying the distance between transmitter and receiver to extract the features relevant to the diagnostic problem. Experimental results with our prototype shows more scattering with the increase in the distance at 3dB level and hence less absorption with increase in the distance