508 research outputs found
Contrastive Image Synthesis and Self-supervised Feature Adaptation for Cross-Modality Biomedical Image Segmentation
This work presents a novel framework CISFA (Contrastive Image synthesis and
Self-supervised Feature Adaptation)that builds on image domain translation and
unsupervised feature adaptation for cross-modality biomedical image
segmentation. Different from existing works, we use a one-sided generative
model and add a weighted patch-wise contrastive loss between sampled patches of
the input image and the corresponding synthetic image, which serves as shape
constraints. Moreover, we notice that the generated images and input images
share similar structural information but are in different modalities. As such,
we enforce contrastive losses on the generated images and the input images to
train the encoder of a segmentation model to minimize the discrepancy between
paired images in the learned embedding space. Compared with existing works that
rely on adversarial learning for feature adaptation, such a method enables the
encoder to learn domain-independent features in a more explicit way. We
extensively evaluate our methods on segmentation tasks containing CT and MRI
images for abdominal cavities and whole hearts. Experimental results show that
the proposed framework not only outputs synthetic images with less distortion
of organ shapes, but also outperforms state-of-the-art domain adaptation
methods by a large margin
Some q-Identities derived by the ordinary derivative operator
In this paper, we investigate applications of the ordinary derivative
operator, instead of the -derivative operator, to the theory of -series.
As main results, many new summation and transformation formulas are established
which are closely related to some well-known formulas such as the -binomial
theorem, Ramanujan's formula, the quintuple product identity,
Gasper's -Clausen product formula, and Rogers' formula, etc.
Among these results is a finite form of the Rogers-Ramanujan identity and a
short way to Eisenstein's theorem on Lambert series.Comment: 22 page
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