37,085 research outputs found
The Parameter-Less Self-Organizing Map algorithm
The Parameter-Less Self-Organizing Map (PLSOM) is a new neural network
algorithm based on the Self-Organizing Map (SOM). It eliminates the need for a
learning rate and annealing schemes for learning rate and neighbourhood size.
We discuss the relative performance of the PLSOM and the SOM and demonstrate
some tasks in which the SOM fails but the PLSOM performs satisfactory. Finally
we discuss some example applications of the PLSOM and present a proof of
ordering under certain limited conditions.Comment: 29 pages, 27 figures. Based on publication in IEEE Trans. on Neural
Network
Hybrid LSTM and Encoder-Decoder Architecture for Detection of Image Forgeries
With advanced image journaling tools, one can easily alter the semantic
meaning of an image by exploiting certain manipulation techniques such as
copy-clone, object splicing, and removal, which mislead the viewers. In
contrast, the identification of these manipulations becomes a very challenging
task as manipulated regions are not visually apparent. This paper proposes a
high-confidence manipulation localization architecture which utilizes
resampling features, Long-Short Term Memory (LSTM) cells, and encoder-decoder
network to segment out manipulated regions from non-manipulated ones.
Resampling features are used to capture artifacts like JPEG quality loss,
upsampling, downsampling, rotation, and shearing. The proposed network exploits
larger receptive fields (spatial maps) and frequency domain correlation to
analyze the discriminative characteristics between manipulated and
non-manipulated regions by incorporating encoder and LSTM network. Finally,
decoder network learns the mapping from low-resolution feature maps to
pixel-wise predictions for image tamper localization. With predicted mask
provided by final layer (softmax) of the proposed architecture, end-to-end
training is performed to learn the network parameters through back-propagation
using ground-truth masks. Furthermore, a large image splicing dataset is
introduced to guide the training process. The proposed method is capable of
localizing image manipulations at pixel level with high precision, which is
demonstrated through rigorous experimentation on three diverse datasets
Learning to Extract a Video Sequence from a Single Motion-Blurred Image
We present a method to extract a video sequence from a single motion-blurred
image. Motion-blurred images are the result of an averaging process, where
instant frames are accumulated over time during the exposure of the sensor.
Unfortunately, reversing this process is nontrivial. Firstly, averaging
destroys the temporal ordering of the frames. Secondly, the recovery of a
single frame is a blind deconvolution task, which is highly ill-posed. We
present a deep learning scheme that gradually reconstructs a temporal ordering
by sequentially extracting pairs of frames. Our main contribution is to
introduce loss functions invariant to the temporal order. This lets a neural
network choose during training what frame to output among the possible
combinations. We also address the ill-posedness of deblurring by designing a
network with a large receptive field and implemented via resampling to achieve
a higher computational efficiency. Our proposed method can successfully
retrieve sharp image sequences from a single motion blurred image and can
generalize well on synthetic and real datasets captured with different cameras
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