發(fā)布時間：2018-01-09 22:11

  本文關(guān)鍵詞：基于激光激發(fā)聲表面波光譜技術(shù)檢測人體皮膚病變的研究　出處：《天津大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 聲表面波 有限元仿真 皮膚檢測

【摘要】：在醫(yī)學界，皮膚疾病的檢測和治療在很大程度上依靠皮膚科醫(yī)生的視覺判斷。一個皮膚科醫(yī)生的培養(yǎng)需要多年的培訓和臨床經(jīng)驗，然而即使如此，有些情況下視覺判斷仍無法給出準確定量的信息。因此，通過一種能夠準確的檢測皮膚疾病的方法來避免模棱兩可的判斷顯得尤為重要。 本課題的主要研究目的是開發(fā)一種應(yīng)用激光聲表面波的新型非破壞式檢測系統(tǒng)以實現(xiàn)對皮膚病變的快速檢測，通過應(yīng)用激光激發(fā)聲表面波的傳播特性來檢測皮膚各層的特性以及探測皮膚各層發(fā)生的機械和幾何變化以判斷皮膚病變。 與傳統(tǒng)超聲檢測方式不同，激光超聲檢測法采用脈沖激光光束作為非接觸式激發(fā)光源在皮膚表面產(chǎn)生聲表面波。當一個樣品表面被一個高頻的激光脈沖照射，由于吸收激光輻射，在局部產(chǎn)生熱膨脹，進而產(chǎn)生了聲表面波并沿樣品表面?zhèn)鞑�。激光激發(fā)聲表面波的特性很大程度上取決于激光光束的光學穿透和產(chǎn)生的熱擴散、待測材料的彈性參數(shù)和幾何特征。激光激發(fā)聲表面波檢測方法最大的優(yōu)勢在于無損激發(fā)，與檢測材料不發(fā)生物理接觸。 本課題通過應(yīng)用有限元仿真技術(shù)來理解和分析激光源與皮膚組織之間相互作用，產(chǎn)生聲表面波的原理以及波傳播過程中受到的影響和產(chǎn)生的變化，同時深入分析了皮膚病變尺寸不同和網(wǎng)格大小劃分不同對仿真結(jié)果的影響。 本課題的主要研究工作有：介紹了人體皮膚以及皮膚各組成結(jié)構(gòu)的特性，，分析了一些皮膚病變給皮膚機械和幾何參數(shù)帶來的變化。簡要介紹了激光激發(fā)聲表面波理論和聲表面波在樣品上傳播的原理，討論如何模擬激光激發(fā)聲表面波及其傳播過程。概述有限元建模原理和用于模擬激光激發(fā)聲表面波以及在表面?zhèn)鞑ミ^程的仿真步驟。介紹了理想人體皮膚的模型的建模，并利用激光激發(fā)聲表面波去檢測人體皮膚模型各層機械和幾何變化以判斷皮膚疾病。用Matlab程序?qū)τ邢拊M得到的結(jié)果進行數(shù)字信號處理，計算出聲表面波色散曲線。通過對比色散曲線的變化判斷出該檢測方法能檢測到的最小的皮膚腫瘤尺寸為0.03mm，以及劃分網(wǎng)格尺寸對仿真結(jié)果的影響。最后提出了應(yīng)用激光激發(fā)聲表面波檢測皮膚疾病的總結(jié)與展望。
[Abstract]:In medicine, the detection and treatment of skin diseases depend largely on the visual judgment of dermatologists. The cultivation of a dermatologist requires years of training and clinical experience, but even so. In some cases, visual judgment still can not give accurate quantitative information. Therefore, it is very important to avoid ambiguity through a method that can accurately detect skin diseases. The main purpose of this paper is to develop a new type of non-destructive detection system using laser surface acoustic wave (LSAW) to detect skin lesions quickly. The characteristics of each layer of skin and the mechanical and geometric changes of each layer of skin were detected by using the propagation characteristics of surface acoustic wave (saw) excited by laser to judge the skin lesions. Different from the traditional ultrasonic detection method, the laser ultrasonic detection method uses pulsed laser beam as a non-contact excitation light source to produce saw on the skin surface, when a sample surface is irradiated by a high-frequency laser pulse. Because of the absorption of laser radiation, local thermal expansion is produced. Then the surface acoustic wave is produced and propagated along the surface of the sample. The characteristics of the surface acoustic wave excited by the laser depend to a great extent on the optical penetration of the laser beam and the thermal diffusion produced by the laser beam. The biggest advantage of the laser-excited saw detection method lies in the nondestructive excitation, and there is no physical contact with the tested material. In this paper, finite element simulation technology is used to understand and analyze the interaction between laser source and skin tissue, the principle of surface acoustic wave (saw) generation, and the influence and change of wave propagation. At the same time, the effects of different skin lesion size and mesh size on the simulation results are analyzed. The main research work of this thesis is as follows: the characteristics of human skin and the structure of skin are introduced. The changes of skin mechanical and geometric parameters caused by some skin lesions are analyzed. The theory of surface acoustic wave excited by laser and the principle of surface acoustic wave propagating on the sample are briefly introduced. This paper discusses how to simulate laser-induced saw and its propagation process. The principle of finite element modeling and the simulation steps used to simulate laser-induced saw and its propagation on the surface are summarized. The model of ideal human skin is introduced. Modeling. The surface acoustic wave (saw) was used to detect the mechanical and geometric changes of human skin model in order to judge the skin disease. The results of finite element simulation were processed by Matlab program. The surface acoustic wave dispersion curve was calculated and the smallest skin tumor size detected by this method was 0.03mm by comparing the dispersion curve. The effect of mesh size on the simulation results is also discussed. Finally, the application of laser-excited saw to detect skin diseases is summarized and prospected.
【學位授予單位】：天津大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：R318.51;TN249

【參考文獻】

相關(guān)博士學位論文 前1條

1 白茂森;激光聲表面波法測量薄膜楊氏模量的理論與系統(tǒng)研究[D];天津大學;2012年

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