19,301 research outputs found
Action Recognition in Videos: from Motion Capture Labs to the Web
This paper presents a survey of human action recognition approaches based on
visual data recorded from a single video camera. We propose an organizing
framework which puts in evidence the evolution of the area, with techniques
moving from heavily constrained motion capture scenarios towards more
challenging, realistic, "in the wild" videos. The proposed organization is
based on the representation used as input for the recognition task, emphasizing
the hypothesis assumed and thus, the constraints imposed on the type of video
that each technique is able to address. Expliciting the hypothesis and
constraints makes the framework particularly useful to select a method, given
an application. Another advantage of the proposed organization is that it
allows categorizing newest approaches seamlessly with traditional ones, while
providing an insightful perspective of the evolution of the action recognition
task up to now. That perspective is the basis for the discussion in the end of
the paper, where we also present the main open issues in the area.Comment: Preprint submitted to CVIU, survey paper, 46 pages, 2 figures, 4
table
Survey of Object Detection Methods in Camouflaged Image
Camouflage is an attempt to conceal the signature of a target object into the background image. Camouflage detection
methods or Decamouflaging method is basically used to detect foreground object hidden in the background image. In this
research paper authors presented survey of camouflage detection methods for different applications and areas
Gait recognition and understanding based on hierarchical temporal memory using 3D gait semantic folding
Gait recognition and understanding systems have shown a wide-ranging application prospect. However, their use of unstructured data from image and video has affected their performance, e.g., they are easily influenced by multi-views, occlusion, clothes, and object carrying conditions. This paper addresses these problems using a realistic 3-dimensional (3D) human structural data and sequential pattern learning framework with top-down attention modulating mechanism based on Hierarchical Temporal Memory (HTM). First, an accurate 2-dimensional (2D) to 3D human body pose and shape semantic parameters estimation method is proposed, which exploits the advantages of an instance-level body parsing model and a virtual dressing method. Second, by using gait semantic folding, the estimated body parameters are encoded using a sparse 2D matrix to construct the structural gait semantic image. In order to achieve time-based gait recognition, an HTM Network is constructed to obtain the sequence-level gait sparse distribution representations (SL-GSDRs). A top-down attention mechanism is introduced to deal with various conditions including multi-views by refining the SL-GSDRs, according to prior knowledge. The proposed gait learning model not only aids gait recognition tasks to overcome the difficulties in real application scenarios but also provides the structured gait semantic images for visual cognition. Experimental analyses on CMU MoBo, CASIA B, TUM-IITKGP, and KY4D datasets show a significant performance gain in terms of accuracy and robustness
Unoriented 3d TFTs
This paper generalizes two facts about oriented 3d TFTs to the unoriented
case. On one hand, it is known that oriented 3d TFTs having a topological
boundary condition admit a state-sum construction known as the Turaev-Viro
construction. This is related to the string-net construction of fermionic
phases of matter. We show how Turaev-Viro construction can be generalized to
unoriented 3d TFTs. On the other hand, it is known that the "fermionic"
versions of oriented TFTs, known as Spin-TFTs, can be constructed in terms of
"shadow" TFTs which are ordinary oriented TFTs with an anomalous
1-form symmetry. We generalize this correspondence to Pin-TFTs by showing
that they can be constructed in terms of ordinary unoriented TFTs with
anomalous 1-form symmetry having a mixed anomaly with
time-reversal symmetry. The corresponding Pin-TFT does not have any anomaly
for time-reversal symmetry however and hence it can be unambiguously defined on
a non-orientable manifold. In case a Pin-TFT admits a topological boundary
condition, one can combine the above two statements to obtain a
Turaev-Viro-like construction of Pin-TFTs. As an application of these
ideas, we construct a large class of Pin-SPT phases.Comment: 41 pages, 31 figures, v2: additional references, v3: minor revisio
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