According to the speckle feature in Optical coherence tomography(OCT),images with speckleindicate not only noise but also signals,an improved wavelet hierarchical threshold filter(IWHTF)method is proposed.At first,a m...According to the speckle feature in Optical coherence tomography(OCT),images with speckleindicate not only noise but also signals,an improved wavelet hierarchical threshold filter(IWHTF)method is proposed.At first,a modified hierarchical threshold-selected algorithm isused to prevent signals from being removed by asssing suitable thresholds for different noiselevels,Then,an improved wavelet threshold function based on two traditional threshold fumnc.tions is proposed to trade-ff betwen speckle removing and sharpness degradation.The de-noising results of an OCT finger skin image shows that the IWHTF method obtains betterobjective evaluation metrics and visual image quality improvement,Whenαa=0.2,β=5.0 andK=1.2,the improved method can achieve 9.58 dB improvement in signal-to-noise ratio,withsharpnesdegraded by 3.81%.展开更多
基金supported by National Nature Science Foundation of China(Nos.61378090,61421002,61505036,61327004,61435003 and 61675226)the Sichuan Province International Cooperative Project(No.2015HH0056)+3 种基金the National Key R&D Program of China(Nos.2016YFF0102000,2016YFF0102003)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB02060000)the Frontier Science Research Project of the Chinese Academy of Sciences(No.QYZDB-SSW-JSC03)the Jiangsu Province Science Fund for Distinguished Young Scholars(No.BK20060010).
文摘According to the speckle feature in Optical coherence tomography(OCT),images with speckleindicate not only noise but also signals,an improved wavelet hierarchical threshold filter(IWHTF)method is proposed.At first,a modified hierarchical threshold-selected algorithm isused to prevent signals from being removed by asssing suitable thresholds for different noiselevels,Then,an improved wavelet threshold function based on two traditional threshold fumnc.tions is proposed to trade-ff betwen speckle removing and sharpness degradation.The de-noising results of an OCT finger skin image shows that the IWHTF method obtains betterobjective evaluation metrics and visual image quality improvement,Whenαa=0.2,β=5.0 andK=1.2,the improved method can achieve 9.58 dB improvement in signal-to-noise ratio,withsharpnesdegraded by 3.81%.
