34 research outputs found
ESVIO: Event-based Stereo Visual Inertial Odometry
Event cameras that asynchronously output low-latency event streams provide
great opportunities for state estimation under challenging situations. Despite
event-based visual odometry having been extensively studied in recent years,
most of them are based on monocular and few research on stereo event vision. In
this paper, we present ESVIO, the first event-based stereo visual-inertial
odometry, which leverages the complementary advantages of event streams,
standard images and inertial measurements. Our proposed pipeline achieves
temporal tracking and instantaneous matching between consecutive stereo event
streams, thereby obtaining robust state estimation. In addition, the motion
compensation method is designed to emphasize the edge of scenes by warping each
event to reference moments with IMU and ESVIO back-end. We validate that both
ESIO (purely event-based) and ESVIO (event with image-aided) have superior
performance compared with other image-based and event-based baseline methods on
public and self-collected datasets. Furthermore, we use our pipeline to perform
onboard quadrotor flights under low-light environments. A real-world
large-scale experiment is also conducted to demonstrate long-term
effectiveness. We highlight that this work is a real-time, accurate system that
is aimed at robust state estimation under challenging environments
Multi-Mobile Robot Localization and Navigation based on Visible Light Positioning
We demonstrated multi-mobile robot navigation based on Visible Light
Positioning(VLP) localization. From our experiment, the VLP can accurately
locate robots' positions in navigation
PL-EVIO: Robust Monocular Event-based Visual Inertial Odometry with Point and Line Features
Event cameras are motion-activated sensors that capture pixel-level
illumination changes instead of the intensity image with a fixed frame rate.
Compared with the standard cameras, it can provide reliable visual perception
during high-speed motions and in high dynamic range scenarios. However, event
cameras output only a little information or even noise when the relative motion
between the camera and the scene is limited, such as in a still state. While
standard cameras can provide rich perception information in most scenarios,
especially in good lighting conditions. These two cameras are exactly
complementary. In this paper, we proposed a robust, high-accurate, and
real-time optimization-based monocular event-based visual-inertial odometry
(VIO) method with event-corner features, line-based event features, and
point-based image features. The proposed method offers to leverage the
point-based features in the nature scene and line-based features in the
human-made scene to provide more additional structure or constraints
information through well-design feature management. Experiments in the public
benchmark datasets show that our method can achieve superior performance
compared with the state-of-the-art image-based or event-based VIO. Finally, we
used our method to demonstrate an onboard closed-loop autonomous quadrotor
flight and large-scale outdoor experiments. Videos of the evaluations are
presented on our project website: https://b23.tv/OE3QM6
Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease
BACKGROUND:
Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes.
METHODS:
We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization.
RESULTS:
During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events.
CONCLUSIONS:
Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)
Channel-Attention-Enhanced LSTM Neural Network Decoder and Equalizer for RSE-Based Optical Camera Communications
In an RGB-LED-based optical camera communication system, it is an essential goal to have better performance in the data rate and BER. However, in a higher symbol rate, due to the conventional sampling algorithm, the deterioration of transmission performance brought by the inter-symbol interference and inter-channel interference is significant. Innovatively, in this paper, the sub-image obtained by a captured frame of received video is encoded by a channel-attention-Net-based encoder to generate a descriptor without existing sampling methods. Moreover, we propose an LSTM-based equalizer to decode the descriptor and mitigate transmission performance deterioration. Utilizing the long-short-term memory of an LSTM unit, an equalizer not only can reduce bit error rates but also increase the data rate. The experimental results show that at a symbol rate of 46 kbaud/s, a record-high data rate at 44.03 kbit/s is achieved under random data transmission while still meeting the pre-forward error correction requirement