37,136 research outputs found
VNect: Real-time 3D Human Pose Estimation with a Single RGB Camera
We present the first real-time method to capture the full global 3D skeletal
pose of a human in a stable, temporally consistent manner using a single RGB
camera. Our method combines a new convolutional neural network (CNN) based pose
regressor with kinematic skeleton fitting. Our novel fully-convolutional pose
formulation regresses 2D and 3D joint positions jointly in real time and does
not require tightly cropped input frames. A real-time kinematic skeleton
fitting method uses the CNN output to yield temporally stable 3D global pose
reconstructions on the basis of a coherent kinematic skeleton. This makes our
approach the first monocular RGB method usable in real-time applications such
as 3D character control---thus far, the only monocular methods for such
applications employed specialized RGB-D cameras. Our method's accuracy is
quantitatively on par with the best offline 3D monocular RGB pose estimation
methods. Our results are qualitatively comparable to, and sometimes better
than, results from monocular RGB-D approaches, such as the Kinect. However, we
show that our approach is more broadly applicable than RGB-D solutions, i.e. it
works for outdoor scenes, community videos, and low quality commodity RGB
cameras.Comment: Accepted to SIGGRAPH 201
Ultrasensitive Label-Free Nanosensing and High-Speed Tracking of Single Proteins
: Label-free detection, analysis, and rapid tracking
of nanoparticles is crucial for future ultrasensitive sensing
applications, ranging from understanding of biological
interactions to the study of size-dependent classical-quantum
transitions. Yet optical techniques to distinguish nanoparticles
directly among their background remain challenging. Here we
present amplified interferometric scattering microscopy (aiSCAT)
as a new all-optical method capable of detecting
individual nanoparticles as small as 15 kDa proteins that is
equivalent to half a GFP. By balancing scattering and reflection
amplitudes the interference contrast of the nanoparticle signal
is amplified 1 to 2 orders of magnitude. Beyond high
sensitivity, a-iSCAT allows high-speed image acquisition exceeding several hundreds of frames-per-second. We showcase the
performance of our approach by detecting single Streptavidin binding events and by tracking single Ferritin proteins at 400
frames-per-second with 12 nm localization precision over seconds. Moreover, due to its extremely simple experimental
realization, this advancement finally enables a cheap and routine implementation of label-free all-optical single nanoparticle
detection platforms with sensitivity operating at the single protein level.Peer ReviewedPostprint (author's final draft
Single NanoParticle Photothermal Tracking (SNaPT) of 5 nm gold beads in live cells
Tracking individual nano-objets in live cells during arbitrary long times is
an ubiquitous need in modern biology. We present here a method for tracking
individual 5 nm gold nanoparticles on live cells. It relies on the photothermal
effect and the detection of the Laser Induced Scattering around a NanoAbsorber
(LISNA). The key point for recording trajectories at video rate is the use of a
triangulation procedure. The effectiveness of the method is tested against
Single fluorescent Molecule Tracking in live COS7 cells on subsecond time
scales. We further demonstrate recordings for several minutes of AMPA receptors
trajectories on the plasma membrane of live neurons. SNaPT has the unique
potential to record arbitrary long trajectory of membrane proteins using
non-fluorescent nanometer sized labels
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