437 research outputs found

    Oriented Response Networks

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    Deep Convolution Neural Networks (DCNNs) are capable of learning unprecedentedly effective image representations. However, their ability in handling significant local and global image rotations remains limited. In this paper, we propose Active Rotating Filters (ARFs) that actively rotate during convolution and produce feature maps with location and orientation explicitly encoded. An ARF acts as a virtual filter bank containing the filter itself and its multiple unmaterialised rotated versions. During back-propagation, an ARF is collectively updated using errors from all its rotated versions. DCNNs using ARFs, referred to as Oriented Response Networks (ORNs), can produce within-class rotation-invariant deep features while maintaining inter-class discrimination for classification tasks. The oriented response produced by ORNs can also be used for image and object orientation estimation tasks. Over multiple state-of-the-art DCNN architectures, such as VGG, ResNet, and STN, we consistently observe that replacing regular filters with the proposed ARFs leads to significant reduction in the number of network parameters and improvement in classification performance. We report the best results on several commonly used benchmarks.Comment: Accepted in CVPR 2017. Source code available at http://yzhou.work/OR

    Observation of Anticorrelation with Classical Light in a Linear Optical System

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    Two-photon anticorrelation is observed when laser and pseudothermal light beams are incident to the two input ports of a Hong-Ou-Mandel interferometer, respectively. The spatial second-order interference pattern of laser and pseudothermal light beams is reported. Temporal Hong-Ou-Mandel dip is also observed when these two detectors are at the symmetrical positions. These results are helpful to understand the physics behind the second-order interference of light.Comment: 5 pages, 4 figures. Comments are welcom
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