Spectral filtering approach to the skin blood flow imaging in limbs via infrared thermography: its scope and limits

Abstract

We develop the new technique for skin blood flow imaging in limbs by means of infrared thermography. In contrast to the lock-in and pulsed phase thermography the proposed method does not use an external heater. Instead, we consider variation of blood volume within the vessels of limbs as a source of thermal waves, travelling through the biotissue. Thus, the blood flow dynamics serves as a non-periodical heater of biological tissue. To reconstruct the blood flow variation from dynamic thermograms we used the spectral filtering approach (SFA), which transforms the temperature signal into the blood flow signal. Reaction of lower limbs on the thermal impact is illustrated by examples of dynamics blood flow maps that are extracted from dynamic thermograms. Limitations and advantages of the blood flow exploration via infrared thermography within each of the frequency range have been discussed.