Senzorski sustav za lokalizaciju izvora akustičkih emisija u biljnim tkivima za prijenos vode analizom vremena dolaska ultrazvučnih valova

master's thesis

• Title (english): Sensor System for Localization of Acoustic Emission Sources in Plant's Water Transport Tissues by Time-of-arrival Analysis of Ultrasonic Waves
• Author: Anamarija Jelić
• Mentor: Dinko Oletić (mentor)
• Committee member: Dinko Oletić (predsjednik povjerenstva)
• Committee member: Darko Vasić (član povjerenstva)
• Committee member: Davorin Ambruš (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2022-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Biljke tijekom procesa sušenja proizvode akustične emisije čijom se analizom može vršiti neinvazivni udaljeni nadzor stanja biljke. U ovom radu, istražena su fizikalna načela rasprostiranja ultrazvučnih mehaničkih valova. Korištenjem piezoelektričnog senzora i laboratorijske opreme određene su vremensko-frekvencijske značajke signala za lokalizaciju izvora ultrazvučnih emisija. Osmišljen je i ispitan algoritam lokalizacije korištenjem laboratorijske opreme i prototipnog senzorskog sustava. Lokalizacija je izvedena analizom vremensko-frekvencijskih značajki simetričnog i asimetričnog moda vala u cilindru pomoću kontinuirane Wavelet transformacije. Za određivanje udaljenosti koristila se analiza vremena dolaska moda, a za određivanje dubine izvora koristila se analiza omjera maksimalnih amplituda A0 i S0 moda. Na laboratorijskom modelu stabljike od PVC materijala, točnost određivanja udaljenosti je 85.33%, a dubina se klasificira u četiri područja. Točnost određivanja dubine iznosi 63.89%.

Abstract (english)

Plants produce acoustic emissions during the drying process which can be used for non-invasive remote monitoring of plant condition. In this thesis, the physical principles of propagation of ultrasonic mechanical waves are investigated. Using a piezoelectric sensor and laboratory equipment, the time-frequency characteristics of the signal for localization of ultrasonic emission sources were determined. A localization algorithm was designed and tested using laboratory equipment and a prototype sensor system. Localization was performed by analyzing the time-frequency characteristics of symmetrical and asymmetrical wave modes in cylinder using continuous wavelet transformation. The analysis of the time of arrival of the mode was used to determine the distance, and the analysis of the ratio of the maximum amplitudes of A0 and S0 mode was used to determine the source depth. The accuracy of the localization algorithm, on PVC rod as a model for branches, for determining the source distance is 85.33%, and for determining the depth, which is classified into four areas is 63.89%.

• Keywords: ultrazvučni valovi; STM32; ugradbeni računalni sustavi; MATLAB
• Keywords (english): ultrasonic waves; STM32; embedded systems; MATLAB
• Language: croatian
• URN:NBN: urn:nbn:hr:168:114047
• Study programme: Title: Electrical Engineering and Information Technology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije (magistar/magistra inženjer/inženjerka elektrotehnike i informacijske tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-01-14 08:59:52