Stiles–Crawford effect (SCE) is exclusively observed in cone photoreceptors, but why the SCE is absent in rod photoreceptors is still a mystery. In this study, we employed dynamic near infrared light imaging to monitor photoreceptor kinetics in freshly isolated frog and mouse retinas stimulated by oblique visible light flashes. It was observed that retinal rods could rapidly (onset: ∼10 ms for frog and 5 ms for mouse; time-to-peak: ∼200 ms for frog and 30 ms for mouse) shift toward the direction of the visible light, which might quickly compensate for the loss of luminous efficiency due to oblique illumination. In contrast, such directional movement was negligible in retinal cones. Moreover, transient rod phototropism could contribute to characteristic intrinsic optical signal (IOS). We anticipate that further study of the transient rod phototropism may not only provide insight into better understanding of the nature of vision but also promise an IOS biomarker for functional mapping of rod physiology at high resolution.
This study is to test anatomic correlates, including connecting cilium (CC) and inner segment (IS) ellipsoid, to the hyper-reflective band visualized by optical coherence tomography (OCT) and commonly attributed to the photoreceptor inner/outer segment (IS/OS) junction. A line-scan OCT (LS-OCT) was constructed to achieve sub-cellular resolution (lateral: ∼ 2 μm; axial: ∼ 4 μm) of excised living frog retinas. An electro-optic phase modulator was employed for rapid and vibration-free phase modulation. Comparison of normalized distance measurements between LS-OCT images and histological images revealed that the dominant source of the signal reported as the IS/OS OCT band actually originates from the IS.
Based on double random phase encoding method (DRPE), watermarking technology may provide a
stable and robust method to protect the copyright of the printing. However, due to its linear character,
DRPE exist the serious safety risk when it is attacked. In this paper, a complex coding method,
which means adding the chaotic encryption based on logistic mapping before the DRPE coding, is
provided and simulated. The results testify the complex method will provide better security
protection for the watermarking. Furthermore, a low-noise multiple watermarking is studied, which
means embedding multiple watermarks into one host printing and decrypt them with corresponding
phase keys individually. The Digital simulation and mathematic analysis show that with the same
total embedding weight factor, multiply watermarking will improve signal noise ratio (SNR) of the
output printing image significantly. The complex multiply watermark method may provide a robust,
stability, reliability copyright protection with higher quality printing image.