854 research outputs found
Diffusion Models for Medical Image Analysis: A Comprehensive Survey
Denoising diffusion models, a class of generative models, have garnered
immense interest lately in various deep-learning problems. A diffusion
probabilistic model defines a forward diffusion stage where the input data is
gradually perturbed over several steps by adding Gaussian noise and then learns
to reverse the diffusion process to retrieve the desired noise-free data from
noisy data samples. Diffusion models are widely appreciated for their strong
mode coverage and quality of the generated samples despite their known
computational burdens. Capitalizing on the advances in computer vision, the
field of medical imaging has also observed a growing interest in diffusion
models. To help the researcher navigate this profusion, this survey intends to
provide a comprehensive overview of diffusion models in the discipline of
medical image analysis. Specifically, we introduce the solid theoretical
foundation and fundamental concepts behind diffusion models and the three
generic diffusion modelling frameworks: diffusion probabilistic models,
noise-conditioned score networks, and stochastic differential equations. Then,
we provide a systematic taxonomy of diffusion models in the medical domain and
propose a multi-perspective categorization based on their application, imaging
modality, organ of interest, and algorithms. To this end, we cover extensive
applications of diffusion models in the medical domain. Furthermore, we
emphasize the practical use case of some selected approaches, and then we
discuss the limitations of the diffusion models in the medical domain and
propose several directions to fulfill the demands of this field. Finally, we
gather the overviewed studies with their available open-source implementations
at
https://github.com/amirhossein-kz/Awesome-Diffusion-Models-in-Medical-Imaging.Comment: Second revision: including more papers and further discussion
Knowledge-driven deep learning for fast MR imaging: undersampled MR image reconstruction from supervised to un-supervised learning
Deep learning (DL) has emerged as a leading approach in accelerating MR
imaging. It employs deep neural networks to extract knowledge from available
datasets and then applies the trained networks to reconstruct accurate images
from limited measurements. Unlike natural image restoration problems, MR
imaging involves physics-based imaging processes, unique data properties, and
diverse imaging tasks. This domain knowledge needs to be integrated with
data-driven approaches. Our review will introduce the significant challenges
faced by such knowledge-driven DL approaches in the context of fast MR imaging
along with several notable solutions, which include learning neural networks
and addressing different imaging application scenarios. The traits and trends
of these techniques have also been given which have shifted from supervised
learning to semi-supervised learning, and finally, to unsupervised learning
methods. In addition, MR vendors' choices of DL reconstruction have been
provided along with some discussions on open questions and future directions,
which are critical for the reliable imaging systems.Comment: 46 pages, 5figures, 1 tabl
A Survey on Generative Diffusion Model
Deep learning shows excellent potential in generation tasks thanks to deep
latent representation. Generative models are classes of models that can
generate observations randomly concerning certain implied parameters. Recently,
the diffusion Model has become a rising class of generative models by its
power-generating ability. Nowadays, great achievements have been reached. More
applications except for computer vision, speech generation, bioinformatics, and
natural language processing are to be explored in this field. However, the
diffusion model has its genuine drawback of a slow generation process, single
data types, low likelihood, and the inability for dimension reduction. They are
leading to many enhanced works. This survey makes a summary of the field of the
diffusion model. We first state the main problem with two landmark works --
DDPM and DSM, and a unified landmark work -- Score SDE. Then, we present
improved techniques for existing problems in the diffusion-based model field,
including speed-up improvement For model speed-up improvement, data structure
diversification, likelihood optimization, and dimension reduction. Regarding
existing models, we also provide a benchmark of FID score, IS, and NLL
according to specific NFE. Moreover, applications with diffusion models are
introduced including computer vision, sequence modeling, audio, and AI for
science. Finally, there is a summarization of this field together with
limitations \& further directions. The summation of existing well-classified
methods is in our
Github:https://github.com/chq1155/A-Survey-on-Generative-Diffusion-Model
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