Hypercolumns for object segmentation and fine-grained localization

B Hariharan, P Arbeláez, R Girshick… - Proceedings of the IEEE …, 2015 - cv-foundation.org
Proceedings of the IEEE conference on computer vision and pattern …, 2015cv-foundation.org
Recognition algorithms based on convolutional networks (CNNs) typically use the output of
the last layer as feature representation. However, the information in this layer may be too
coarse to allow precise localization. On the contrary, earlier layers may be precise in
localization but will not capture semantics. To get the best of both worlds, we define the
hypercolumn at a pixel as the vector of activations of all CNN units above that pixel. Using
hypercolumns as pixel descriptors, we show results on three fine-grained localization tasks …
Abstract
Recognition algorithms based on convolutional networks (CNNs) typically use the output of the last layer as feature representation. However, the information in this layer may be too coarse to allow precise localization. On the contrary, earlier layers may be precise in localization but will not capture semantics. To get the best of both worlds, we define the hypercolumn at a pixel as the vector of activations of all CNN units above that pixel. Using hypercolumns as pixel descriptors, we show results on three fine-grained localization tasks: simultaneous detection and segmentation [20], where we improve state-of-the-art from 49.7 mean AP^ r [20] to 59.0, keypoint localization, where we get a 3.3 point boost over [19] and part labeling, where we show a 6.6 point gain over a strong baseline.
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