9,500 research outputs found
Shadow Optimization from Structured Deep Edge Detection
Local structures of shadow boundaries as well as complex interactions of
image regions remain largely unexploited by previous shadow detection
approaches. In this paper, we present a novel learning-based framework for
shadow region recovery from a single image. We exploit the local structures of
shadow edges by using a structured CNN learning framework. We show that using
the structured label information in the classification can improve the local
consistency of the results and avoid spurious labelling. We further propose and
formulate a shadow/bright measure to model the complex interactions among image
regions. The shadow and bright measures of each patch are computed from the
shadow edges detected in the image. Using the global interaction constraints on
patches, we formulate a least-square optimization problem for shadow recovery
that can be solved efficiently. Our shadow recovery method achieves
state-of-the-art results on the major shadow benchmark databases collected
under various conditions.Comment: 8 pages. CVPR 201
Fast Shadow Detection from a Single Image Using a Patched Convolutional Neural Network
In recent years, various shadow detection methods from a single image have
been proposed and used in vision systems; however, most of them are not
appropriate for the robotic applications due to the expensive time complexity.
This paper introduces a fast shadow detection method using a deep learning
framework, with a time cost that is appropriate for robotic applications. In
our solution, we first obtain a shadow prior map with the help of multi-class
support vector machine using statistical features. Then, we use a semantic-
aware patch-level Convolutional Neural Network that efficiently trains on
shadow examples by combining the original image and the shadow prior map.
Experiments on benchmark datasets demonstrate the proposed method significantly
decreases the time complexity of shadow detection, by one or two orders of
magnitude compared with state-of-the-art methods, without losing accuracy.Comment: 6 pages, 5 figures, Submitted to IROS 201
Direction-aware Spatial Context Features for Shadow Detection
Shadow detection is a fundamental and challenging task, since it requires an
understanding of global image semantics and there are various backgrounds
around shadows. This paper presents a novel network for shadow detection by
analyzing image context in a direction-aware manner. To achieve this, we first
formulate the direction-aware attention mechanism in a spatial recurrent neural
network (RNN) by introducing attention weights when aggregating spatial context
features in the RNN. By learning these weights through training, we can recover
direction-aware spatial context (DSC) for detecting shadows. This design is
developed into the DSC module and embedded in a CNN to learn DSC features at
different levels. Moreover, a weighted cross entropy loss is designed to make
the training more effective. We employ two common shadow detection benchmark
datasets and perform various experiments to evaluate our network. Experimental
results show that our network outperforms state-of-the-art methods and achieves
97% accuracy and 38% reduction on balance error rate.Comment: Accepted for oral presentation in CVPR 2018. The journal version of
this paper is arXiv:1805.0463
Advances in deep learning methods for pavement surface crack detection and identification with visible light visual images
Compared to NDT and health monitoring method for cracks in engineering
structures, surface crack detection or identification based on visible light
images is non-contact, with the advantages of fast speed, low cost and high
precision. Firstly, typical pavement (concrete also) crack public data sets
were collected, and the characteristics of sample images as well as the random
variable factors, including environmental, noise and interference etc., were
summarized. Subsequently, the advantages and disadvantages of three main crack
identification methods (i.e., hand-crafted feature engineering, machine
learning, deep learning) were compared. Finally, from the aspects of model
architecture, testing performance and predicting effectiveness, the development
and progress of typical deep learning models, including self-built CNN,
transfer learning(TL) and encoder-decoder(ED), which can be easily deployed on
embedded platform, were reviewed. The benchmark test shows that: 1) It has been
able to realize real-time pixel-level crack identification on embedded
platform: the entire crack detection average time cost of an image sample is
less than 100ms, either using the ED method (i.e., FPCNet) or the TL method
based on InceptionV3. It can be reduced to less than 10ms with TL method based
on MobileNet (a lightweight backbone base network). 2) In terms of accuracy, it
can reach over 99.8% on CCIC which is easily identified by human eyes. On
SDNET2018, some samples of which are difficult to be identified, FPCNet can
reach 97.5%, while TL method is close to 96.1%.
To the best of our knowledge, this paper for the first time comprehensively
summarizes the pavement crack public data sets, and the performance and
effectiveness of surface crack detection and identification deep learning
methods for embedded platform, are reviewed and evaluated.Comment: 15 pages, 14 figures, 11 table
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