In conventional 3D Fourier transform (3DFT) MR imaging, signal-to-noise ratio (SNR) is governed by the well-known
relationship of being proportional to the voxel size and square root of the imaging time. Here, we introduce an alternative
3D imaging approach, termed MRT (Magnetic Resonance Tomosynthesis), which can generate a set of tomographic MR
images similar to multiple 2D projection images in x-ray. A multiple-oblique-view (MOV) pulse sequence is designed to
acquire the tomography-like images used in tomosynthesis process and an iterative back-projection (IBP) reconstruction
method is used to reconstruct 3D images. SNR analysis is performed and shows that resolution and SNR tradeoff is not
governed as with typical 3DFT MR imaging case. The proposed method provides a higher SNR than the conventional
3D imaging method with a partial loss of slice-direction resolution. It is expected that this method can be useful for
extremely low SNR cases.
Metallic nanoparticles have drawn much interest due to their distinct plasmonic characteristics especially in imaging and
sensing applications. Surface plasmon resonance (SPR) based biosensors have evolved in many ways, among which
sensitivity enhancement towards molecular sensing capability came up with strategies to overcome the hard limit of the
intrinsic sensitivity of gold thin film. Recently adoption of signal contrast materials has proven successful in biochemical
sensing applications. This study employs gold-SiO2 core-shell nanoparticles (CSNPs) as a strong SPR signal contrast
agents. To reveal the underlying physics for the contrast mechanism, the particle characteristics were analytically
evaluated in terms of light interaction coefficients. We experimentally demonstrate the effect of the CSNPs by applying
them to acquire enhanced signal in DNA hybridization sensing scheme. We also applied gold nanowire grating structure
on conventional gold thin film to further amplify the intrinsic sensitivity, where localized surface plasmon and locally
amplified evanescent fields take parts. The results suggest that CSNPs and the grating structure cooperatively enhance
the sensitivity and the role of nanowire gratings was analyzed with numerical methods to allow optimum sensitivity
enhancement in terms of fill factor variations. The effects of field localization, amplification and enlarged signature of
CSNPs are also discussed.
Visual fatigue is a common problem when viewing stereoscopic images. We propose a depth adjustment method that controls the amount of disparity in stereoscopic images using visual fatigue prediction and conducted subjective preference evaluation based on individual fusional response characteristics. Visual fatigue level is predicted by examining the characteristics of horizontal disparity. Viewers are classified into two groups (those with normal susceptibility to visual fatigue and those with high susceptibility to visual fatigue) according to individual fusional limit and speed of fusion, which are determined using a random dot stereogram test. Subjective preferences for the amount of depth adjustment are investigated based on the degree of fusion ability. Our experimental results support the suitability of the proposed depth adjustment method for reducing visual fatigue.
Multi-view video coding (MVC) is a video coding standard developed by MPEG and VCEG for multi-view video. It
showed average PSNR gain of 1.5dB compared with view-independent coding by H.264/AVC. However, because
resolutions of multi-view video are getting higher for more realistic 3D effect, high performance video codec is needed.
MVC adopted hierarchical B-picture structure and inter-view prediction as core techniques. The hierarchical B-picture
structure removes the temporal redundancy, and the inter-view prediction reduces the inter-view redundancy by
compensated prediction from the reconstructed neighboring views. Nevertheless, MVC has inherent limitation in coding
efficiency, because it is based on H.264/AVC. To overcome the limit, an enhanced video codec for multi-view video
based on Key Technology Area (KTA) is proposed. KTA is a high efficiency video codec by Video Coding Expert
Group (VCEG), and it was carried out for coding efficiency beyond H.264/AVC. The KTA software showed better
coding gain than H.264/AVC by using additional coding techniques. The techniques and the inter-view prediction are
implemented into the proposed codec, which showed high coding gain compared with the view-independent coding
result by KTA. The results presents that the inter-view prediction can achieve higher efficiency in a multi-view video
codec based on a high performance video codec such as HEVC.
In this paper, we proposed a visual fatigue monitoring system based on eye-movement and eye-blink detection. It
analyzes the eye-movement and number of blinks based on the assumption that saccade movement of the eye decreases
and the number of eye blink increases when visual fatigue of viewer is accumulated. The proposed system has an
infrared single camera and an infrared light source. Then, the pupil of the eye can be detected by applying binary
threshold to Purkinje image. The threshold is automatically selected by two constraints which are the eccentricity of
ellipse fitting and the size of the pupil. Finally, total amount of eye movement and the number of eye blinks are
measured by using the positions of the pupil. The results were obtained while watching stereoscopic videos after
personal calibration procedure. The results show that saccade movement of the eye decreases as the visual fatigue of the
viewer is accumulated. However, the number of eye blinks shows large variance along the time axis which implies it is
not proper for visual fatigue monitoring system.
In this paper, we propose a depth map quality metric for three-dimensional videos which include stereoscopic videos and
autostereoscopic videos. Recently, a number of researches have been done to figure out the relationship of perceptual
quality and video impairment caused by various compression methods. However, we consider non-compression issues
which are induced during acquisition and displaying. For instance, using multiple cameras structure may cause
impairment such as misalignment. We demonstrate that the depth map can be a useful tool to find out the implied
impairments. The proposed quality metrics using depth map are depth range, vertical misalignment, temporal
consistency. The depth map is acquired by solving corresponding problems from stereoscopic video, widely known as
disparity estimation. After disparity estimation, the proposed metrics are calculated and integrated into one value which
indicates estimated visual fatigue based on the results of subjective assessment. We measure the correlation between
objective quality metrics and subjective quality results to validate our metrics.