Based on anisotropic total variation regularization(ATVR), a nonnegativity and support constraints recursive inverse filtering(NAS-RIF) blind restoration method is proposed to enhance the quality of optical coherence ...Based on anisotropic total variation regularization(ATVR), a nonnegativity and support constraints recursive inverse filtering(NAS-RIF) blind restoration method is proposed to enhance the quality of optical coherence tomography(OCT) image. First, ATVR is introduced into the cost function of NAS-RIF to improve the noise robustness and retain the details in the image.Since the split Bregman iterative is used to optimize the ATVR based cost function, the ATVR based NAS-RIF blind restoration method is then constructed. Furthermore, combined with the geometric nonlinear diffusion filter and the Poisson-distribution-based minimum error thresholding, the ATVR based NAS-RIF blind restoration method is used to realize the blind OCT image restoration. The experimental results demonstrate that the ATVR based NAS-RIF blind restoration method can successfully retain the details in the OCT images. In addition, the signal-to-noise ratio of the blind restored OCT images can be improved, along with the noise robustness.展开更多
The TEM and HRTEM were utilized to investigate the phase transformation of hydrogenated Ti-6Al-4V alloys （0 wt pct–0.9 wt pct H） treated by annealing and quenching from β field. The results indicate that the ortho...The TEM and HRTEM were utilized to investigate the phase transformation of hydrogenated Ti-6Al-4V alloys （0 wt pct–0.9 wt pct H） treated by annealing and quenching from β field. The results indicate that the orthorhombic α martensite and β phase appear progressively with the increase of hydrogen concentration. On the other hand, hydrides with sizes of 2–5 nm are observed in the specimens containing more than 0.6 wt pct hydrogen. The formation of α and twins can be attributed to the internal stress caused by solid solution of hydrogen and hydrides precipitation.展开更多
基金Supported by National Key Research and Development Program of China(2016YFF0201005)。
文摘Based on anisotropic total variation regularization(ATVR), a nonnegativity and support constraints recursive inverse filtering(NAS-RIF) blind restoration method is proposed to enhance the quality of optical coherence tomography(OCT) image. First, ATVR is introduced into the cost function of NAS-RIF to improve the noise robustness and retain the details in the image.Since the split Bregman iterative is used to optimize the ATVR based cost function, the ATVR based NAS-RIF blind restoration method is then constructed. Furthermore, combined with the geometric nonlinear diffusion filter and the Poisson-distribution-based minimum error thresholding, the ATVR based NAS-RIF blind restoration method is used to realize the blind OCT image restoration. The experimental results demonstrate that the ATVR based NAS-RIF blind restoration method can successfully retain the details in the OCT images. In addition, the signal-to-noise ratio of the blind restored OCT images can be improved, along with the noise robustness.
文摘The TEM and HRTEM were utilized to investigate the phase transformation of hydrogenated Ti-6Al-4V alloys （0 wt pct–0.9 wt pct H） treated by annealing and quenching from β field. The results indicate that the orthorhombic α martensite and β phase appear progressively with the increase of hydrogen concentration. On the other hand, hydrides with sizes of 2–5 nm are observed in the specimens containing more than 0.6 wt pct hydrogen. The formation of α and twins can be attributed to the internal stress caused by solid solution of hydrogen and hydrides precipitation.
