525 research outputs found
ST-GAN: Spatial Transformer Generative Adversarial Networks for Image Compositing
We address the problem of finding realistic geometric corrections to a
foreground object such that it appears natural when composited into a
background image. To achieve this, we propose a novel Generative Adversarial
Network (GAN) architecture that utilizes Spatial Transformer Networks (STNs) as
the generator, which we call Spatial Transformer GANs (ST-GANs). ST-GANs seek
image realism by operating in the geometric warp parameter space. In
particular, we exploit an iterative STN warping scheme and propose a sequential
training strategy that achieves better results compared to naive training of a
single generator. One of the key advantages of ST-GAN is its applicability to
high-resolution images indirectly since the predicted warp parameters are
transferable between reference frames. We demonstrate our approach in two
applications: (1) visualizing how indoor furniture (e.g. from product images)
might be perceived in a room, (2) hallucinating how accessories like glasses
would look when matched with real portraits.Comment: Accepted to CVPR 2018 (website & code:
https://chenhsuanlin.bitbucket.io/spatial-transformer-GAN/
Adversarial training with cycle consistency for unsupervised super-resolution in endomicroscopy
In recent years, endomicroscopy has become increasingly used for diagnostic
purposes and interventional guidance. It can provide intraoperative aids for
real-time tissue characterization and can help to perform visual investigations
aimed for example to discover epithelial cancers. Due to physical constraints
on the acquisition process, endomicroscopy images, still today have a low
number of informative pixels which hampers their quality. Post-processing
techniques, such as Super-Resolution (SR), are a potential solution to increase
the quality of these images. SR techniques are often supervised, requiring
aligned pairs of low-resolution (LR) and high-resolution (HR) images patches to
train a model. However, in our domain, the lack of HR images hinders the
collection of such pairs and makes supervised training unsuitable. For this
reason, we propose an unsupervised SR framework based on an adversarial deep
neural network with a physically-inspired cycle consistency, designed to impose
some acquisition properties on the super-resolved images. Our framework can
exploit HR images, regardless of the domain where they are coming from, to
transfer the quality of the HR images to the initial LR images. This property
can be particularly useful in all situations where pairs of LR/HR are not
available during the training. Our quantitative analysis, validated using a
database of 238 endomicroscopy video sequences from 143 patients, shows the
ability of the pipeline to produce convincing super-resolved images. A Mean
Opinion Score (MOS) study also confirms this quantitative image quality
assessment.Comment: Accepted for publication on Medical Image Analysis journa
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