E.T. Aksenov, D.V. Mokrova, G.A. Kafidova
It is known that pulse wave makes it possible to obtain a lot of information. That is why sensor capable to measure its shape accurately may increase diagnostic information and be applied in medicine.
The aim of the paper is to elaborate and investigate practical model of non contact laser optical electronic speckle sensor for pulse wave shape, and pulse sequences as well.
The amplitude model of the sensor has been considered lately. But it demonstrated high sensitivity to external vibrations and noisy flare. Optical differential scheme for registration of pulse wave makes it possible to overcome these disadvantages.
Optical scheme of differential sensor may be different. The basic principal is separation light beam in several coherent rays, that interacting with the object under investigation travel different optical paths, then they combine and interfere. In connection with the fact that the object under investigation is moving, path difference between light beams is changing too which results in interference fringe shift. By registration of intensity change, caused fringe movement in some point of speckle it is possible to detect surface vibration of the object.
Having in mind development of the best differential scheme for pulse wave registration and creation of practical model of sensor, several variants of differential scheme were considered and investigated in the paper.
The results of investigation are provided. They confirmed possibility of schemes developed for making measurements. Approach to solution of the problem on whole is shown.