182 research outputs found
Harvesting Information from Captions for Weakly Supervised Semantic Segmentation
Since acquiring pixel-wise annotations for training convolutional neural
networks for semantic image segmentation is time-consuming, weakly supervised
approaches that only require class tags have been proposed. In this work, we
propose another form of supervision, namely image captions as they can be found
on the Internet. These captions have two advantages. They do not require
additional curation as it is the case for the clean class tags used by current
weakly supervised approaches and they provide textual context for the classes
present in an image. To leverage such textual context, we deploy a multi-modal
network that learns a joint embedding of the visual representation of the image
and the textual representation of the caption. The network estimates text
activation maps (TAMs) for class names as well as compound concepts, i.e.
combinations of nouns and their attributes. The TAMs of compound concepts
describing classes of interest substantially improve the quality of the
estimated class activation maps which are then used to train a network for
semantic segmentation. We evaluate our method on the COCO dataset where it
achieves state of the art results for weakly supervised image segmentation
A convolutional autoencoder approach for mining features in cellular electron cryo-tomograms and weakly supervised coarse segmentation
Cellular electron cryo-tomography enables the 3D visualization of cellular
organization in the near-native state and at submolecular resolution. However,
the contents of cellular tomograms are often complex, making it difficult to
automatically isolate different in situ cellular components. In this paper, we
propose a convolutional autoencoder-based unsupervised approach to provide a
coarse grouping of 3D small subvolumes extracted from tomograms. We demonstrate
that the autoencoder can be used for efficient and coarse characterization of
features of macromolecular complexes and surfaces, such as membranes. In
addition, the autoencoder can be used to detect non-cellular features related
to sample preparation and data collection, such as carbon edges from the grid
and tomogram boundaries. The autoencoder is also able to detect patterns that
may indicate spatial interactions between cellular components. Furthermore, we
demonstrate that our autoencoder can be used for weakly supervised semantic
segmentation of cellular components, requiring a very small amount of manual
annotation.Comment: Accepted by Journal of Structural Biolog
Weakly supervised underwater fish segmentation using affinity LCFCN
Estimating fish body measurements like length, width, and mass has received considerable research due to its potential in boosting productivity in marine and aquaculture applications. Some methods are based on manual collection of these measurements using tools like a ruler which is time consuming and labour intensive. Others rely on fully-supervised segmentation models to automatically acquire these measurements but require collecting per-pixel labels which are also time consuming. It can take up to 2 minutes per fish to acquire accurate segmentation labels. To address this problem, we propose a segmentation model that can efficiently train on images labeled with point-level supervision, where each fish is annotated with a single click. This labeling scheme takes an average of only 1 second per fish. Our model uses a fully convolutional neural network with one branch that outputs per-pixel scores and another that outputs an affinity matrix. These two outputs are aggregated using a random walk to get the final, refined per-pixel output. The whole model is trained end-to-end using the localization-based counting fully convolutional neural network (LCFCN) loss and thus we call our method Affinity-LCFCN (A-LCFCN). We conduct experiments on the DeepFish dataset, which contains several fish habitats from north-eastern Australia. The results show that A-LCFCN outperforms a fully-supervised segmentation model when the annotation budget is fixed. They also show that A-LCFCN achieves better segmentation results than LCFCN and a standard baseline
Conditional Diffusion Models for Weakly Supervised Medical Image Segmentation
Recent advances in denoising diffusion probabilistic models have shown great
success in image synthesis tasks. While there are already works exploring the
potential of this powerful tool in image semantic segmentation, its application
in weakly supervised semantic segmentation (WSSS) remains relatively
under-explored. Observing that conditional diffusion models (CDM) is capable of
generating images subject to specific distributions, in this work, we utilize
category-aware semantic information underlied in CDM to get the prediction mask
of the target object with only image-level annotations. More specifically, we
locate the desired class by approximating the derivative of the output of CDM
w.r.t the input condition. Our method is different from previous diffusion
model methods with guidance from an external classifier, which accumulates
noises in the background during the reconstruction process. Our method
outperforms state-of-the-art CAM and diffusion model methods on two public
medical image segmentation datasets, which demonstrates that CDM is a promising
tool in WSSS. Also, experiment shows our method is more time-efficient than
existing diffusion model methods, making it practical for wider applications
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