Investigation the frequency characteristics of vibration signals on the human face

Different researches have been made in order to make the interpretation that the tissues of different individuals have different characteristics. These investigations are generally based on vibration signals. In the studies obtained from the literature search, the vibration signals that were generated in the vocal cords were examined. However, no studies on vibration signals recorded by applying any vibration source have been found. However, the examination of the frequency characteristics of the source of vibration with a constant frequency on the tissue softness is of great importance for both the knowledge of the tissue and the investigation of diseases related to it. In this study, it is aimed to investigate the frequency characteristics of the vibration signals received on the human face. For this purpose, a hardware designed to detect vibration at certain points in the first stage of the study is designed. The first part of the equipment consists of a motor and a driver that provides vibration. The other part contains the accelerometer sensors and drivers in the MEMs structure, which enables the detection of vibrations at certain points in the face region. The control of the hardware is carried out by a microcontroller based module. The communication protocol between the computer generated interface and the microcontroller is used to record the vibration signals. With this developed system, a database was established with vibration signals taken from the facial areas of the individuals who were found to be healthy in their clinical examinations. Vibration signals in the database were analyzed by signal processing methods and frequency characteristics of the facial regions of different people were formed. Fast Fourier Transform, median frequency, maximum frequency and Wavelet Packet Transformation were used in the analysis phase. By means of these generated frequency characteristics, a method for mapping the facial region of persons is presented. By means of this mapping, the softness - hardness of the respective facial regions could be made and the frequency ranges of the regions determined on the face were determined. These frequency ranges and the interpretation of the soft and hard regions on the face have resulted in inferences about the conductivity of the tissues in the sinus regions. As a result, low frequency signals are dominant in the hard regions on the face, whereas in the soft regions high frequency signals are dominant. In addition, the hard and soft spots on the face were identified and the vibration frequency ranges of a human face were determined. In wavelet transform analysis, wavelet package transformation was used and analysis was carried out up to level 4. in the DPD analysis performed, when the graphs of the 4th and 11th packages were examined, it was concluded that the frequency range of the data obtained was 109,375 - 131,25 Hz.