Optical coherence tomography(OCT)provides significant advantages of high resolution(approaching the histopathology level)realtime imaging of tsess without use of contrast agents.Based on these advantages,the microstru...Optical coherence tomography(OCT)provides significant advantages of high resolution(approaching the histopathology level)realtime imaging of tsess without use of contrast agents.Based on these advantages,the microstructural features of tumors can be visualized and detected intra-operatively.However,it is still not clinically accepted for tumor margin delin-eation due to poor specificity and accuracy.In contrast,Raman spectroscopy(RS)can obtain tissue information at the molecular level,but does not provide real-time inaging capability.Therefore,combining OCT and RS could provide synergy.To this end,we present a tissue analysis and dassification method using both the slope of OCT intensity signal Vs depth and the principle components from the RS spectrum as the indicators for tissuse characterization.The goal of this study was to understand prediction accuracy of OCT and combined OCT/RS method for dassification of optically similar tisues and organs.Our pilot experiments were performed on mouse kidneys,livers,and small intestines(SIs).The prediction accuracy with five-fold cross validation of the method has been evaluated by the support vector machine(SVM)method.The results demonstrate that tissue characterization based on the OCT/RS method was superior compared to using OCT structural information alone.This combined OCT/RS method is potentially useful as a noninvasive optical biopsy technique for rapid and automatic tissue characterization during surgery.展开更多
文摘从传统的接收机环路多径抑制方法出发,通过纠正码环相关曲线畸变和自适应载波信号更新机制跟踪弱动态载波信号两个层次,并行减缓多径效应对接收机跟踪捕获带来的延迟影响。首先,针对码环内部函数畸变带来的自相关迭代误差问题,利用机器学习领域中的随机霍夫变换(RHT)斜率检测法辅助减小窄相关器的误差;其次,设计了一种自适应阈值载波跟踪信号状态模型,用于解决高遮挡低载噪比(CNR)条件下的信号跟踪受限问题。从不同的角度将该方法与现有方法做了对比和分析,结果表明:应用RHT斜率抑制法辅助自适应增强载波信号跟踪的定位模型性能相较于传统的高分辨率技术(HRC)和卡尔曼滤波(KF)载波跟踪方法均有明显的提升,其中本文提出的方法可以在1.8 s左右的信号延迟时及时恢复载波信号失锁。此外,从最终的定位结果可知,实验场景中多径(MP)效应较强的D区域,定位误差的均方根误差(RMSE)降低了6.3 m.
基金supported in part by the grants to Kirill Larin from NIH 1R01EY022362,1R01HL120140,U54HG006348,and DOD PRJ71Tsupported by grants to Wei-Chuan Shih from NSF CAREER Award (CBET-1151154)+1 种基金NASA Early Career Faculty Grant (NNX12AQ44G)Gulf of Mexico Research Initiative (GoMRI-030).
文摘Optical coherence tomography(OCT)provides significant advantages of high resolution(approaching the histopathology level)realtime imaging of tsess without use of contrast agents.Based on these advantages,the microstructural features of tumors can be visualized and detected intra-operatively.However,it is still not clinically accepted for tumor margin delin-eation due to poor specificity and accuracy.In contrast,Raman spectroscopy(RS)can obtain tissue information at the molecular level,but does not provide real-time inaging capability.Therefore,combining OCT and RS could provide synergy.To this end,we present a tissue analysis and dassification method using both the slope of OCT intensity signal Vs depth and the principle components from the RS spectrum as the indicators for tissuse characterization.The goal of this study was to understand prediction accuracy of OCT and combined OCT/RS method for dassification of optically similar tisues and organs.Our pilot experiments were performed on mouse kidneys,livers,and small intestines(SIs).The prediction accuracy with five-fold cross validation of the method has been evaluated by the support vector machine(SVM)method.The results demonstrate that tissue characterization based on the OCT/RS method was superior compared to using OCT structural information alone.This combined OCT/RS method is potentially useful as a noninvasive optical biopsy technique for rapid and automatic tissue characterization during surgery.
