6 research outputs found
Implicit Language Model in LSTM for OCR
Neural networks have become the technique of choice for OCR, but many aspects
of how and why they deliver superior performance are still unknown. One key
difference between current neural network techniques using LSTMs and the
previous state-of-the-art HMM systems is that HMM systems have a strong
independence assumption. In comparison LSTMs have no explicit constraints on
the amount of context that can be considered during decoding. In this paper we
show that they learn an implicit LM and attempt to characterize the strength of
the LM in terms of equivalent n-gram context. We show that this implicitly
learned language model provides a 2.4\% CER improvement on our synthetic test
set when compared against a test set of random characters (i.e. not naturally
occurring sequences), and that the LSTM learns to use up to 5 characters of
context (which is roughly 88 frames in our configuration). We believe that this
is the first ever attempt at characterizing the strength of the implicit LM in
LSTM based OCR systems
Deep Multimodal Image-Repurposing Detection
Nefarious actors on social media and other platforms often spread rumors and
falsehoods through images whose metadata (e.g., captions) have been modified to
provide visual substantiation of the rumor/falsehood. This type of modification
is referred to as image repurposing, in which often an unmanipulated image is
published along with incorrect or manipulated metadata to serve the actor's
ulterior motives. We present the Multimodal Entity Image Repurposing (MEIR)
dataset, a substantially challenging dataset over that which has been
previously available to support research into image repurposing detection. The
new dataset includes location, person, and organization manipulations on
real-world data sourced from Flickr. We also present a novel, end-to-end, deep
multimodal learning model for assessing the integrity of an image by combining
information extracted from the image with related information from a knowledge
base. The proposed method is compared against state-of-the-art techniques on
existing datasets as well as MEIR, where it outperforms existing methods across
the board, with AUC improvement up to 0.23.Comment: To be published at ACM Multimeda 2018 (orals
MONet: Multi-scale Overlap Network for Duplication Detection in Biomedical Images
Manipulation of biomedical images to misrepresent experimental results has
plagued the biomedical community for a while. Recent interest in the problem
led to the curation of a dataset and associated tasks to promote the
development of biomedical forensic methods. Of these, the largest manipulation
detection task focuses on the detection of duplicated regions between images.
Traditional computer-vision based forensic models trained on natural images are
not designed to overcome the challenges presented by biomedical images. We
propose a multi-scale overlap detection model to detect duplicated image
regions. Our model is structured to find duplication hierarchically, so as to
reduce the number of patch operations. It achieves state-of-the-art performance
overall and on multiple biomedical image categories.Comment: To appear at ICIP 202