Research On The Extraction Of Target Detection Signals From Rhinolophus Bats

After a long period of natural selection,most bats have evolved a set of biological sonar systems with high sensitivity and accuracy.The bat biosonar system is mainly composed of an ultrasound signal emitting organ(mouth or nose),a signal receiving organ(ear),and a signal processing organ(brain).Anatomical studies have shown that bats(mouth or nose)and(ears)with ultrasound localization function are usually covered with complex fold structures.Current studies have shown that the presence of fold structures(nasal lobes)on the organ of sonar signal transmission is In order to reflect its complex acoustic functions.Due to the variability and diversification existing in the process of auto-regulation of organisms,and limitations in current research in bionics,the relevant e xperimental studies are rather immature,but the simple observation and measurement of related phenomena is limited to only a few of them.The results were qualitatively analyzed and discussed.However,there are many kinds of bats in nature,and there are still quite a few bats that we have not contacted,let alone study.So far,the research work on the Chinese chinook bat has been limited to its acoustic spectrum analysis,and there has been no research on the relationship between its biological acoustic signal transmission and its reception and its related organizational structure.Therefore,in this thesis,the acoustical functions of the auricle structure of the outer ears of Chinese chinooks were studied.In this paper,Fourier signal theory is used to analyze the echo signal processing process.For the first time,the bat's bionic structure model is used to measure and process the echoes of different target materials at different azimuth angles.The acoustical function of the auricle structure is performed the study.A physical model of the ear of a Chinese chinook bat has been proposed and produced as a bionic sensor on a customized rotating test platform.Through the collection of echo signals,the corresponding spectral energy is analyzed to identify the signal and material properties and the biomimetic sensor orientation.Research.For the first time,the directional characteristics of the bat bionic ear-sensor are revealed,and the relationship between the echo signal strength,power spectrum and frequency of target objects with different materials is revealed.The production process of the physical model of the auricle structure of the outer ear is as follows: First,X-ray tomography scan of the auricle sample of the Chinese chrysanthemum bat is performed to obtain the original digital projection image of the auricle.Secondly,the cone-beam reconstruction algorithm is used to obtain the cross-sectional images of the auricle structure.Then the images of air and tissue structure can be clearly resolved by Gaussian filter and binarization processing.Finally,the three-dimensional digital reconstruction is used to obtain the Chinese chrysanthemums.A three-dimensional digital image of the auricle and a 3D printing technique were used to create a realistic model of the auricle of the Chinese chrysanthemum head bat.The next step is the detection of echo signals.The physical model of the ear-shaped bats of the Chinese chrysanthemum is used as a bionic sensor on a customized rotating test platform.The sinusoidal modulation with a frequency of 40 kHz is provided by the AFG-2225 signal generator(Taiwan).Signals,collecting echo signals of different material targets under different receiving azimuth angles,and analyzing the corresponding spectral energy using Fourier transform and wave superposition theory,and performing signal and material characteristic recognition and research on direction of bionic sensors,revealing The detection characteristics of the bat's bionic auricle sensor and the relationship between echo signal strength,power spectrum,and frequency of target objects of different materials.For the following analysis of the acoustic function of the pinna.The result shows that the bionic sensor has directionality and can realize the recognition of the target material.