  To defend against manipulation of image content, such as splicing, copy-move,
and removal, we develop a Progressive Spatio-Channel Correlation Network
(PSCC-Net) to detect and localize image manipulations. PSCC-Net processes the
image in a two-path procedure: a top-down path that extracts local and global
features and a bottom-up path that detects whether the input image is
manipulated, and estimates its manipulation masks at multiple scales, where
each mask is conditioned on the previous one. Different from the conventional
encoder-decoder and no-pooling structures, PSCC-Net leverages features at
different scales with dense cross-connections to produce manipulation masks in
a coarse-to-fine fashion. Moreover, a Spatio-Channel Correlation Module (SCCM)
captures both spatial and channel-wise correlations in the bottom-up path,
which endows features with holistic cues, enabling the network to cope with a
wide range of manipulation attacks. Thanks to the light-weight backbone and
progressive mechanism, PSCC-Net can process 1,080P images at 50+ FPS. Extensive
experiments demonstrate the superiority of PSCC-Net over the state-of-the-art
methods on both detection and localization.
