Posterior Mean Super-Resolution with a Compound Gaussian Markov Random Field Prior

This manuscript proposes a posterior mean (PM) super-resolution (SR) method with a compound Gaussian Markov random field (MRF) prior. SR is a technique to estimate a spatially high-resolution image from observed multiple low-resolution images. A compound Gaussian MRF model provides a preferable prior for natural images that preserves edges. PM is the optimal estimator for the objective function of peak signal-to-noise ratio (PSNR). This estimator is numerically determined by using variational Bayes (VB). We then solve the conjugate prior problem on VB and the exponential-order calculation cost problem of a compound Gaussian MRF prior with simple Taylor approximations. In experiments, the proposed method roughly overcomes existing methods.Comment: 5 pages, 20 figures, 1 tables, accepted to ICASSP2012 (corrected 2012/3/23

An LDPCC decoding algorithm based on Bowman-Levin approximation --Comparison with BP and CCCP--

Belief propagation (BP) and the concave convex procedure (CCCP) are both methods that utilize the Bethe free energy as a cost function and solve information processing tasks. We have developed a new algorithm that also uses the Bethe free energy, but changes the roles of the master variables and the slave variables. This is called the Bowman-Levin (BL) approximation in the domain of statistical physics. When we applied the BL algorithm to decode the Gallager ensemble of short-length regular low-density parity check codes (LDPCC) over an additive white Gaussian noise (AWGN) channel, its average performance was somewhat better than that of either BP or CCCP. This implies that the BL algorithm can also be successfully applied to other problems to which BP or CCCP has already been applied.Comment: 2005 IEEE International Symposium on Information Theor

Adaptive intermittent control: A computational model explaining motor intermittency observed in human behavior

It is a fundamental question how our brain performs a given motor task in a real-time fashion with the slow sensorimotor system. Computational theory proposed an influential idea of feed-forward control, but it has mainly treated the case that the movement is ballistic (such as reaching) because the motor commands should be calculated in advance of movement execution. As a possible mechanism for operating feed-forward control in continuous motor tasks (such as target tracking), we propose a control model called "adaptive intermittent control" or "segmented control," that brain adaptively divides the continuous time axis into discrete segments and executes feed-forward control in each segment. The idea of intermittent control has been proposed in the fields of control theory, biological modeling and nonlinear dynamical system. Compared with these previous models, the key of the proposed model is that the system speculatively determines the segmentation based on the future prediction and its uncertainty. The result of computer simulation showed that the proposed model realized faithful visuo-manual tracking with realistic sensorimotor delays and with less computational costs (i.e., with fewer number of segments). Furthermore, it replicated "motor intermittency", that is, intermittent discontinuities commonly observed in human movement trajectories. We discuss that the temporally segmented control is an inevitable strategy for brain which has to achieve a given task with small computational (or cognitive) cost, using a slow control system in an uncertain variable environment, and the motor intermittency is the side-effect of this strategy

Divergence insufficiency associated with high myopia

Hiromi Kohmoto, Kenji Inoue, Masato WakakuraInouye Eye Hospital, Chiyoda-ku, Tokyo, JapanPurpose: Divergence insufficiency is generally regarded as a neurological event. While high myopia is not a well-known cause of divergence insufficiency, we frequently encounter divergence insufficiency in high-myopia patients. Thus, the purpose of this study was to report detailed information on such cases and examine mechanisms that might potentially be responsible for this disorder.Methods: We investigated 20 cases of high myopia (>-6 D) with divergence insufficiency, 20 cases of high myopia without double vision, and 10 normal cases as controls. Using magnetic resonance imaging (MRI), a coronal image 6 mm anterior to the eyeball–optic nerve junction was measured and used to examine the extraocular muscle (EOM) path shift and angle of the eye. Higher angles in each patient were used for statistical comparison.Results: In high-myopia patients with divergence insufficiency, ocular axis measurements ranged from 24.8 to 31.0 (mean ± SD: 27.6 ± 1.6) mm. In high-myopia patients without double vision, the ocular axis length was 27.6 ± 1.3 mm. In normal cases, the ocular axis length was 23.5 ± 1.0 mm. The EOM angles in these patients ranged from 100 to 140 (112.9 ± 9.7) degrees, which was significantly higher (P < 0.05) than that seen in the high-myopia patients without double vision (average EOM angle, 99.2 ± 2.8 degrees) and normal cases (average EOM angle, 97.9 ± 3.8 degrees). However, orbital lengths in the patients were 41.0 to 48.9 (44.6 ± 2.3) mm, which also differed from the high-myopia patients without double vision (average orbital length, 49.9 ± 2.0 mm) significantly (P < 0.05). In normal cases, average orbital length was 45.5 ± 1.6 mm.Conclusion: In high-myopia patients with divergence insufficiency, nasal shift of the superior rectus and an inferior shift of the lateral rectus were observed, but the orbital lengths were normal. Divergence insufficiency may be caused mechanically by shifts of the EOM due to the presence of a long axis. Therefore, high myopia with a long axis can be considered to be a risk factor for the occurrence of divergence insufficiency.Keywords: divergence insufficiency, high myopia, MRI, extraocular muscl

Ocular hypotensive effect, preservation of visual fields, and safety of adding dorzolamide to prostaglandin therapy for twelve months

Kenji Inoue1,3, Mieko Masumoto1,3, Masato Wakakura1, Goji Tomita2, On behalf of the Ochanomizu Ophthalmology Study Group31Inouye Eye Hospital, Tokyo, Japan; 2Department of Ophthalmology, Toho University School of Medicine, Tokyo, Japan; 3Ochanomizu Ophthalmology, Tokyo, JapanPurpose: To prospectively evaluate the safety, hypotensive effect, and preservation of visual fields of dorzolamide when added to latanoprost.Subjects and methods: This study included 46 patients (46 eyes) with primary open-angle glaucoma who had been treated with latanoprost. Dorzolamide (1%) was added to latanoprost, and the intraocular pressure (IOP) was monitored before and after 3, 6, and 12 months. The mean deviation shown by Humphrey perimetry was compared before and after twelve months of treatment. Adverse reactions were monitored over the 12-month study period.Results: The mean baseline IOP was 17.2 ± 3.0 mmHg while those after 3, 6 and 12 months of treatment were 14.9 ± 3.0 mmHg, 14.5 ± 3.2 mmHg, and 14.6 ± 2.6 mmHg respectively (P < 0.0001, 1-ß(power) = 0.9999571). The absolute reduction of IOP and the percent reduction were similar after 3, 6, and 12 months of treatment. The mean deviation on Humphrey perimetry was similar before and after twelve months of treatment. Three patients discontinued dorzolamide therapy due to elevation of IOP and one patient discontinued it because of adverse reactions.Conclusion: Dorzolamide is safe and effective when used for twelve months as add-on therapy to latanoprost for open-angle glaucoma.Keywords: dorzolamide, primary open-angle glaucoma, latanoprost&nbsp