10,838 research outputs found
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
High-Resolution Document Shadow Removal via A Large-Scale Real-World Dataset and A Frequency-Aware Shadow Erasing Net
Shadows often occur when we capture the documents with casual equipment,
which influences the visual quality and readability of the digital copies.
Different from the algorithms for natural shadow removal, the algorithms in
document shadow removal need to preserve the details of fonts and figures in
high-resolution input. Previous works ignore this problem and remove the
shadows via approximate attention and small datasets, which might not work in
real-world situations. We handle high-resolution document shadow removal
directly via a larger-scale real-world dataset and a carefully designed
frequency-aware network. As for the dataset, we acquire over 7k couples of
high-resolution (2462 x 3699) images of real-world document pairs with various
samples under different lighting circumstances, which is 10 times larger than
existing datasets. As for the design of the network, we decouple the
high-resolution images in the frequency domain, where the low-frequency details
and high-frequency boundaries can be effectively learned via the carefully
designed network structure. Powered by our network and dataset, the proposed
method clearly shows a better performance than previous methods in terms of
visual quality and numerical results. The code, models, and dataset are
available at: https://github.com/CXH-Research/DocShadow-SD7KComment: Accepted by International Conference on Computer Vision 2023 (ICCV
2023
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