Three-view matching algorithm for multipolyhedron reconstruction using genetic algorithm

AbstractIn this paper, a novel stereo matching algorithm based on genetic algorithm (GA) is proposed to find the correspondences among multipolyhedron objects in a three-view system. Optimal camera configuration in the approach is used to reduce the feature searching area on the image plane, and GA is then used to refine the matching results. Due to optimal camera configuration, we can achieve a smaller searching area, less ambiguity, and a faster matching process. The features on the second image near the intersection of the two epipolar lines derived from the first and the third images considered as possible triplets are refined using GA. The fitness function for every corresponding triplet is assigned according to the corresponding distance between the feature location and the intersection of two epipolar lines. The consistent connection relationship is then enforced in the evolution process to resolve the ambiguous correspondence triplets. Experimental results show that the 3-D multiple polyhedra in a complex scene can be successfully reconstructed in a three-view system

A Multi-Stage Classifier for Face Recognition Undertaken by Coarse-to-fine Strategy

Face recognition has been a very active research area for past two decades due to its widely applications such as identity authentication, airport security and access control, surveillance, and video retrieval systems, etc. Numerous approaches have been proposed for face recognition and considerable successes have been reported [1]. A successful face recognitio

Reversible Data Hiding Scheme with High Embedding Capacity Using Semi-Indicator-Free Strategy

A novel reversible data-hiding scheme is proposed to embed secret data into a side-matched-vector-quantization- (SMVQ-) compressed image and achieve lossless reconstruction of a vector-quantization- (VQ-) compressed image. The rather random distributed histogram of a VQ-compressed image can be relocated to locations close to zero by SMVQ prediction. With this strategy, fewer bits can be utilized to encode SMVQ indices with very small values. Moreover, no indicator is required to encode these indices, which yields extrahiding space to hide secret data. Hence, high embedding capacity and low bit rate scenarios are deposited. More specifically, in terms of the embedding rate, the bit rate, and the embedding capacity, experimental results show that the performance of the proposed scheme is superior to those of the former data hiding schemes for VQ-based, VQ/SMVQ-based, and search-order-coding- (SOC-) based compressed images

Markerless Augmented Reality via Stereo Video See-Through Head-Mounted Display Device

Conventionally, the camera localization for augmented reality (AR) relies on detecting a known pattern within the captured images. In this study, a markerless AR scheme has been designed based on a Stereo Video See-Through Head-Mounted Display (HMD) device. The proposed markerless AR scheme can be utilized for medical applications such as training, telementoring, or preoperative explanation. Firstly, a virtual model for AR visualization is aligned to the target in physical space by an improved Iterative Closest Point (ICP) based surface registration algorithm, with the target surface structure reconstructed by a stereo camera pair; then, a markerless AR camera localization method is designed based on the Kanade-Lucas-Tomasi (KLT) feature tracking algorithm and the Random Sample Consensus (RANSAC) correction algorithm. Our AR camera localization method is shown to be better than the traditional marker-based and sensor-based AR environment. The demonstration system was evaluated with a plastic dummy head and the display result is satisfactory for a multiple-view observation

A Two-Stage Classifier Using SVM and RANSAC for Face Recognition

Abstract-A novel face recognition scheme based on twostage classifier, which includes methods of support vector machine (SVM), and random sample consensus (RANSAC), is proposed in this paper. The whole decision process is undertaken by cascade stages. The first stage with OAO-SVM (one-against-one) method picks out two classes with the least variations to the testing images. From the selected two classes, the second stage with "RANSAC" method is used for a fine match with testing images. A fine class with greatest geometric similarity to testing images is thus produced at second stage. This two-stage face recognition system has been tested on Olivetti Research Laboratory (ORL) databases, and the experimental results give evidence that the proposed approach is superior to the previous approaches based on the single classifier and multi-parallel classifier in recognition accuracy

Is clopidogrel better than aspirin following breakthrough strokes while on aspirin? A retrospective cohort study.

ObjectiveThere is insufficient evidence on which to base a recommendation for optimal antiplatelet therapy following a stroke while on aspirin. The objective was to compare clopidogrel initiation vs aspirin reinitiation for vascular risk reduction among patients with ischaemic stroke on aspirin at the time of their index stroke.DesignRetrospective.SettingWe conducted a nationwide cohort study by retrieving all hospitalised patients (≥18 years) with a primary diagnosis of ischaemic stroke between 2003 and 2009 from Taiwan National Health Insurance Research Database.ParticipantsAmong 3862 patients receiving aspirin before the index ischaemic stroke and receiving either aspirin or clopidogrel after index stroke during follow-up period, 1623 were excluded due to a medication possession ratio <80%. Also, 355 were excluded due to history of atrial fibrillation, valvular heart disease or coagulopathy. Therefore, 1884 patients were included in our final analysis.InterventionsPatients were categorised into two groups based on whether clopidogrel or aspirin was prescribed during the follow-up period. Follow-up was from time of the index stroke to admission for recurrent stroke or myocardial infarction, death or the end of 2010.Primary and secondary outcome measuresThe primary end point was hospitalisation due to a new-onset major adverse cardiovascular event (MACE: composite of any stroke or myocardial infarction). The leading secondary end point was any recurrent stroke.ResultsCompared to aspirin, clopidogrel was associated with a lower occurrence of future MACE (HR=0.54, 95% CI 0.43 to 0.68, p<0.001, number needed to treat: 8) and recurrent stroke (HR=0.54, 95% CI 0.42 to 0.69, p<0.001, number needed to treat: 9) after adjustment of relevant covariates.ConclusionsAmong patients with an ischaemic stroke while taking aspirin, clopidogrel initiation was associated with fewer recurrent vascular events than aspirin reinitiation

A Downlink and Uplink Alignment Scheme for Power Saving in IEEE 802.16 Protocol

This study shows the problem of power saving mechanism (PSM) that sleep intervals of uplink (UL) connections do not synchronize with sleep intervals of downlink (DL) connections. That is, the energy of a mobile station (MS) is not really saved if the DL connections are in the sleep mode while the UL connections are in normal mode, and vice versa. To avoid the asynchronism of power saving (PS) between UL and DL connections, we invent a mechanism of DL connections regulating UL connections, called DL and UL Alignment (DUAL) scheme, to improve the energy efficiency for PS. Considering that the buffer size of MS is limited, DUAL uses the mean packet arrival rate of UL λu and a relatively safe threshold of buffer size QT as the parameters to estimate the maximum allowable waiting time to align the UL with the DL connections. To analyze the performance of DUAL, a system model of PS is proposed to evaluate the performance of DUAL under different conditions. The correctness of performance analysis of DUAL is validated by using simulation with realistic parameters. Numerical experiments show that DUAL improves the energy conservation significantly when UL traffic is greater than DL traffic

Measuring center of pressure signals to quantify human balance using multivariate multiscale entropy by designing a force platform

Copyright @ 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).To assess the improvement of human body balance, a low cost and portable measuring device of center of pressure (COP), known as center of pressure and complexity monitoring system (CPCMS), has been developed for data logging and analysis. In order to prove that the system can estimate the different magnitude of different sways in comparison with the commercial Advanced Mechanical Technology Incorporation (AMTI) system, four sway tests have been developed (i.e., eyes open, eyes closed, eyes open with water pad, and eyes closed with water pad) to produce different sway displacements. Firstly, static and dynamic tests were conducted to investigate the feasibility of the system. Then, correlation tests of the CPCMS and AMTI systems have been compared with four sway tests. The results are within the acceptable range. Furthermore, multivariate empirical mode decomposition (MEMD) and enhanced multivariate multiscale entropy (MMSE) analysis methods have been used to analyze COP data reported by the CPCMS and compare it with the AMTI system. The improvements of the CPCMS are 35% to 70% (open eyes test) and 60% to 70% (eyes closed test) with and without water pad. The AMTI system has shown an improvement of 40% to 80% (open eyes test) and 65% to 75% (closed eyes test). The results indicate that the CPCMS system can achieve similar results to the commercial product so it can determine the balance.National Science Council (NSC) of Taiwan and the Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan (which is sponsored by the NSC)

Low-dose versus standard-dose alteplase in acute ischemic stroke in Asian stroke registries: an individual patient data pooling study

10.1177/1747493019858777INTERNATIONAL JOURNAL OF STROKE147670-67

Association between Oral Frailty and Physical Frailty among Rural Middle-Old Community-Dwelling People with Cognitive Decline in Taiwan: A Cross-Sectional Study

This cross-sectional study was conducted to clarify the association between oral frailty (OF) and physical frailty (PF). In total, 308 Taiwanese middle-old (75–84 years) community-dwelling people with cognitive decline were recruited from random rural community health care centers. Eight items were considered for the evaluation of their OF status. The Study of Osteoporotic Fracture index was used for frailty assessment, which revealed that 22% of the participants had PF. In an adjusted model, PF was significantly associated with the OF subdomains of difficult to eat hard food (p = 0.009), choking (p = 0.008), denture use (p = 0.008), and inability to chew hard food (p = 0.001); and high risk of OF (OR = 3.03; p = 0.002). After eight steps with elimination of the least significant independent variable, age (p= 0.008), self-reported health status of fair (p = 0.000) and poor (p = 0.000), mild cognitive impairment (p < 0.001) and denture use (p = 0.011) were found to be the indispensable predictors for PF. The logistic regression model with 5 indispensable variables had a predictive value of 78.2%. Longitudinal analyses are needed to examine whether OF is a risk factor for PF onset