利用聲波檢測鴨蛋外殼裂痕之研究

• Main Authors: Shih-Yu Pai, 白世煜
• Other Authors: Ching-Wei Cheng
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/31011127715543710398

碩士 === 國立中興大學 === 農業機械工程學系 === 88 === Abstract The purpose of this study is to offer a method for examining eggshells' fissures in order to make an effective application to the development of the future eggshells' fissures examining automatic system. This experiment uses the sound-gathering tube to knock at the duck eggshells and by the means of the oscillograph, receives the sound-wave messages to undertake a swift FFT transformation, and then analyzes the change of the frequencies, the declining of the amplitudes, the forms of the wave-crests, and the resonant frequencies. By comparing the temporal waveforms of the perfect eggs to the ones of the fissured eggs, between the first and second crest of the perfect part's waveforms, the amplitude declines 10% to 30%. But between the first and second crest of the ssured par's waveforms, the amplitude declines 40% to 50%, and because the waveforms of the part beside the fissures could be affected, between the first and second crest, the amplitude here declines 30% to 40%. By the means of the swift FFT, the waveforms above could be transformed into numeral waveforms, whose first resonant frequencies are all discovered to be 1.21KHz, but the amplitudes among them are obviously different. The amplitude of the fissured part's first resonant frequency is under-30dB,the one of the perfect part is between —27.1dB and —28.7dB, and the one of the part beside the fissures is between —28.7dB and —30dB. The result will be identified as the base of the judgement on the perfect eggs and fissured eggs by the perfect egg automatic examining system.