Localization of an object in tissue with phase modulation spectroscopy: reduction of the effects of the relative amplitude and phase on amplitude cancellation

摘要

In this paper, we discuss the effects of various factors on the localization of an object with amplitude cancellation phase modulation spectroscopy (PMS) by an analytical method. The factors include the relative modulation phase and the amplitude between two sources, the absorption coefficient and the size of the localized absorber. A localization method that can reduce the effects of the relative modulation amplitude and phase between two sources on measurement is presented. In the new method, two measurements are carried out, where modulation signals of two sources in the second measurement are exchanged relative to those in the first measurement. The principle and the feasibility of the method are shown theoretically. Primary experimental results are presented.