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時(shí)空域脈搏信號(hào)檢測(cè)方法研究

發(fā)布時(shí)間:2019-03-16 13:39
【摘要】:脈搏是人體重要的生理運(yùn)動(dòng),它源自心臟,影響范圍波及全身。脈搏包含豐富的生理信息,是評(píng)價(jià)健康狀況和診斷疾病的重要依據(jù),具有其它生理信號(hào)無(wú)法替代的價(jià)值。橈動(dòng)脈脈搏易于檢測(cè),歷來(lái)是研究的熱點(diǎn)。傳統(tǒng)檢測(cè)方法主要關(guān)注單點(diǎn)脈搏信號(hào),獲取信息十分有限。時(shí)空域脈搏信號(hào)是傳統(tǒng)脈搏信號(hào)的擴(kuò)展和創(chuàng)新,除了具有傳統(tǒng)脈搏信號(hào)的內(nèi)涵,還可反映動(dòng)脈血管彈性、順應(yīng)性和血流狀態(tài)等生理信息,可為傳統(tǒng)中醫(yī)對(duì)脈象的模糊性描述找到相應(yīng)的量化指標(biāo)和依據(jù)?傊,時(shí)空域脈搏信號(hào)具有廣闊的研究前景和應(yīng)用價(jià)值。本文研究工作圍繞時(shí)空域脈搏信號(hào)從下列四個(gè)方面展開(kāi):(1)研制了采用雙目視覺(jué)測(cè)量、具有氣囊式仿指柔性探頭的時(shí)空域脈搏信號(hào)檢測(cè)系統(tǒng)。檢測(cè)系統(tǒng)總體上為氣動(dòng)調(diào)節(jié)平衡狀態(tài)的杠桿式結(jié)構(gòu),通過(guò)改變小型氣缸內(nèi)壓調(diào)節(jié)探頭與手腕的接觸壓力。探頭的接觸膜由丁腈材料制成,在探頭內(nèi)壓作用下接觸膜膨脹,其力學(xué)性能和觸感類似手指的指腹,具有仿生性。工作狀態(tài)下,接觸膜隨脈搏發(fā)生周期性變形,變形幅度和范圍與脈搏密切相關(guān)。利用雙目立體視覺(jué)測(cè)量接觸膜變形狀態(tài)即可獲得時(shí)空域脈搏信號(hào)。(2)研究基于雙目立體視覺(jué)的接觸膜時(shí)空域形變測(cè)量方法。測(cè)量方法基于Marr視覺(jué)理論框架,主要分為四個(gè)步驟:相機(jī)系統(tǒng)標(biāo)定、圖像特征提取、特征匹配和空間三維坐標(biāo)計(jì)算。采用張正友標(biāo)定法對(duì)雙相機(jī)系統(tǒng)進(jìn)行標(biāo)定。將接觸膜上印制的網(wǎng)格狀結(jié)構(gòu)線交點(diǎn)作為特征點(diǎn)。傳統(tǒng)基于灰度偏微分的特征點(diǎn)檢測(cè)方法效果不理想,提出基于全局結(jié)構(gòu)參數(shù)的圖像分割方法和基于脊線的廣義交點(diǎn)檢測(cè)方法。實(shí)驗(yàn)證明該方法準(zhǔn)確率高、所得交點(diǎn)全部位于網(wǎng)格線相交區(qū)域中心。建立交點(diǎn)矩陣數(shù)據(jù)結(jié)構(gòu),將交點(diǎn)坐標(biāo)根據(jù)位置關(guān)系存儲(chǔ)在矩陣當(dāng)中,利用矩陣下標(biāo)實(shí)現(xiàn)左右圖像交點(diǎn)快速匹配。交點(diǎn)的位置關(guān)系則根據(jù)網(wǎng)格變形程度利用基于正交網(wǎng)格的預(yù)測(cè)算法和基于骨架線的漫延搜索算法確定。根據(jù)透鏡成像原理和雙目視差原理計(jì)算交點(diǎn)實(shí)際三維坐標(biāo),進(jìn)而重構(gòu)接觸膜三維曲面,并從中提取時(shí)空域脈搏信號(hào)。(3)研究建立探頭作用下的橈動(dòng)脈脈搏有限元模型。有限元建模包括幾何模型、材料模型、邊界條件、載荷、分析步和單元?jiǎng)澐值葍?nèi)容。根據(jù)醫(yī)學(xué)影像資料和標(biāo)本,對(duì)手腕解剖結(jié)構(gòu)進(jìn)行合理簡(jiǎn)化,建立手腕組織幾何模型,探頭三維幾何模型與實(shí)物相同。將幾何模型離散化為結(jié)構(gòu)化的三維線性六面體單元。血管壁和皮膚軟組織的材料模型分別采用Holzapfel和Haut等人的研究成果。對(duì)接觸膜進(jìn)行拉伸試驗(yàn),確定二階Mooney-Rivlin超彈性材料模型的材料常數(shù)。根據(jù)對(duì)實(shí)際系統(tǒng)關(guān)鍵因素的合理抽象設(shè)定邊界條件,模型執(zhí)行步驟與實(shí)際檢測(cè)步驟相同。載荷包括血壓、接觸壓力和探頭內(nèi)壓,研究接觸膜在三種載荷協(xié)同作用下的時(shí)空域變形規(guī)律。利用高精度激光位移傳感器對(duì)模型進(jìn)行驗(yàn)證和優(yōu)化,仿真結(jié)果與雙目立體視覺(jué)測(cè)量結(jié)果吻合。(4)基于有限元仿真結(jié)果分析時(shí)空域脈搏信號(hào)特征,發(fā)現(xiàn)接觸膜底部總體平坦,中間有微小丘狀凸起,凸起范圍近似橢圓,稱凸起部分為關(guān)鍵區(qū)域。脈搏強(qiáng)度越大在宏觀上導(dǎo)致關(guān)鍵區(qū)域長(zhǎng)寬比越大,在微觀上導(dǎo)致區(qū)域中心點(diǎn)主曲率中的較大分量迅速變大,而較小分量變化較緩。表明中心點(diǎn)局部幾何特征在一定程度上可替代關(guān)鍵區(qū)域總體幾何特征描述時(shí)空域脈搏信號(hào)。建立接觸膜中心點(diǎn)振幅與血壓、接觸壓力和探頭內(nèi)壓關(guān)系的非線性模型,利用多元回歸分析和遺傳算法獲得模型參數(shù),最終得到連續(xù)血壓測(cè)量的數(shù)學(xué)模型。此外,時(shí)空域脈搏信號(hào)與中醫(yī)觸診的脈搏指感原理類似,基于時(shí)空域脈搏信號(hào)提出7種中醫(yī)脈象因素的量化指標(biāo),這些指標(biāo)可作為脈診客觀化的工具和橋梁。
[Abstract]:The pulse is an important physiological movement of the human body, which is derived from the heart, which affects the whole body. The pulse contains abundant physiological information, is an important basis for evaluating the health status and the diagnosis of the disease, and has the value that other physiological signals can not be replaced. The pulse of the arterial artery is easy to detect, and has always been the hot spot of the study. The traditional detection method is mainly concerned with the single-point pulse signal, and the information is very limited. The time-space pulse signal is the extension and innovation of the traditional pulse signal, in addition to the connotation of the traditional pulse signal, the physiological information such as the elasticity, the compliance and the blood flow state of the arterial blood tube can be reflected, and the corresponding quantitative index and the basis can be found for the fuzzy description of the pulse image by the traditional Chinese medicine. In conclusion, the time-space pulse signal has a wide prospect and application value. In this paper, the time-domain pulse signal is expanded from the following four aspects: (1) It has developed a time-space pulse signal detection system with a binocular vision measurement and an air-bag type finger-like flexible probe. The detection system is generally a lever-type structure in which the balance state of the pneumatic regulation is adjusted, and the contact pressure between the probe and the wrist is adjusted by changing the internal pressure of the small cylinder. The contact film of the probe is made of a nitrile material, the contact film is expanded under the action of the internal pressure of the probe, and the mechanical property and the touch feel of the contact film are similar to that of a finger, and have the bionic property. In the working state, the contact film is periodically deformed with the pulse, and the amplitude and range of the deformation are closely related to the pulse. And the time-domain pulse signal can be obtained by using the binocular stereo vision to measure the deformation state of the contact film. (2) The method for measuring the spatial deformation of the contact film based on the binocular stereo vision is studied. The measurement method is based on the Marr vision theory frame, which is mainly divided into four steps: camera system calibration, image feature extraction, feature matching and spatial three-dimensional coordinate calculation. The two-camera system is calibrated by the method of Zhang Zhengyou calibration. The grid-like structure line intersection point printed on the contact film is taken as a feature point. The traditional feature point detection method based on the gray-scale partial differential is not ideal, and the image segmentation method based on the global structure parameter and the generalized intersection point detection method based on the ridge line are proposed. The experimental results show that the accuracy of the method is high, and the intersection of the obtained intersection points is located at the intersection of the grid lines. And the intersection point matrix data structure is established, and the intersection coordinates are stored in the matrix according to the position relation, and the intersection point of the left and right images is quickly matched with the matrix index. The position relation of the intersection point is determined by using the orthogonal grid-based prediction algorithm and the extension search algorithm based on the skeleton line according to the degree of the mesh deformation. According to the lens imaging principle and the binocular parallax principle, and then the three-dimensional curved surface of the contact film is reconstructed, and the space-space pulse signal is extracted from the three-dimensional surface of the contact film. (3) The finite element model of the arterial pulse under the action of the probe was studied. The finite element modeling includes geometric model, material model, boundary condition, load, analysis step and unit division. According to the medical image data and the specimen, the wrist anatomical structure is reasonably simplified, a wrist tissue geometric model is established, and the three-dimensional geometric model of the probe is the same as the physical object. The geometric model is discretized into a structured three-dimensional linear hexahedron unit. The material models of the blood vessel wall and the soft tissue of the skin were obtained by Holzapfel and Haut et al., respectively. The contact film was subjected to a tensile test to determine the material constant of the second order Mooney-Rivlin super-elastic material model. The model execution step is the same as the actual detection step according to the reasonable abstract set boundary condition for the key factor of the actual system. The load includes blood pressure, contact pressure and internal pressure of the probe. The model is verified and optimized by the high-precision laser displacement sensor, and the simulation results are in good agreement with the binocular stereo vision measurement. (4) Based on the analysis of the simulation results of the finite element, the feature of the spatial pulse signal is found. It is found that the bottom of the contact film is flat and there is a micro-shaped protrusion in the middle. The convex range is approximate to the ellipse, and the convex part is the key area. The larger the pulse intensity, the larger the aspect ratio of the critical region, the larger the larger component in the main curvature of the central point of the region in the micro-scale, and the smaller component changes. It is shown that the local geometric feature of the central point can be used to substitute the spatial pulse signal in some extent to the overall geometric feature of the key region. The nonlinear model of the relationship between the center point amplitude of the contact film and the blood pressure, the contact pressure and the internal pressure of the probe was established. The model parameters were obtained by the multiple regression analysis and the genetic algorithm, and the mathematical model of the continuous blood pressure measurement was obtained. In addition, the pulse signal of the time-domain is similar to that of the palpation of the traditional Chinese medicine, and based on the time-domain pulse signal, seven quantitative indexes of the pulse signal of the traditional Chinese medicine are put forward, and the indexes can be used as a tool and a bridge for the objective of the pulse diagnosis.
【學(xué)位授予單位】:蘭州理工大學(xué)
【學(xué)位級(jí)別】:博士
【學(xué)位授予年份】:2016
【分類號(hào)】:TP391.41;R443
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本文編號(hào):2441478

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