9 research outputs found
A novel robust reversible watermarking scheme for protecting authenticity and integrity of medical images
It is of great importance in telemedicine to protect authenticity and
integrity of medical images. They are mainly addressed by two technologies, which
are region of interest (ROI) lossless watermarking and reversible watermarking.
However, the former causes biases on diagnosis by distorting region of none interest
(RONI) and introduces security risks by segmenting image spatially for watermark
embedding. The latter fails to provide reliable recovery function for the tampered
areas when protecting image integrity. To address these issues, a novel robust
reversible watermarking scheme is proposed in this paper. In our scheme, a reversible
watermarking method is designed based on recursive dither modulation (RDM) to
avoid biases on diagnosis. In addition, RDM is combined with Slantlet transform and
singular value decomposition to provide a reliable solution for protecting image
authenticity. Moreover, ROI and RONI are divided for watermark generation to
design an effective recovery function under limited embedding capacity. Finally,
watermarks are embedded into whole medical images to avoid the risks caused by
segmenting image spatially. Experimental results demonstrate that our proposed
lossless scheme not only has remarkable imperceptibility and sufficient robustness,
but also provides reliable authentication, tamper detection, localization and recovery
functions, which outperforms existing schemes for protecting medical image
Bilateral impending macular holes after a high-voltage electrical shock injury and its surgical outcome: a case report
The Comparison of Regional RNFL and Fundus Vasculature by OCTA in Chinese Myopia Population
Purpose. To determine the correlations between peripapillary vessel density, retinal nerve fibre layer (RNFL) thickness, and myopic indices at retina quadrants with optical coherence tomography angiography (OCTA) in Chinese. Methods. Fifty-six subjects with a mean spherical equivalent (MSE) of −3.63 ± 0.29 D were included. Peripapillary RNFL thickness and retinal vessel density in four sectors (superior, nasal, inferior, and temporal quadrants) were determined by OCTA, and correlations of the main outcomes were analyzed. Results. Negative correlations were found between the peripapillary RNFL thickness and axial length (AL) at superior (r=−0.335, P=0.001) and inferior (r=−0.551, P<0.001) quadrants. There was a significant positive correlation with spherical equivalent (SE) at the corresponding quadrants as well as at the nasal quadrant (r=0.339, P=0.001; r=0.379, P<0.001; and r=0.209, P=0.039, resp.). Peripapillary retinal vessel density was also negatively correlated with AL at the nasal quadrant (r=−0.392, P<0.001), and only at the nasal quadrant, there was a positive correlation between the peripapillary vessel density and SE (r=0.319, P=0.001). Conclusions. The degree of myopia and elongation of AL were negatively correlated with peripapillary RNFL thickness at superior and inferior quadrants and with peripapillary retinal vessel density at the nasal quadrant