248 research outputs found
Sunspot shearing and sudden retraction motion associated with the 2013 August 17 M3.3 Flare
In this Letter, we give a detailed analysis to the M3.3 class flare that
occurred on August 17, 2013 (SOL2013-08-17T18:16). It presents a clear picture
of mutual magnetic interaction initially from the photosphere to the corona via
the abrupt rapid shearing motion of a small sunspot before the flare, and then
suddenly from the corona back to the photosphere via the sudden retraction
motion of the same sunspot during the flare impulsive phase. About 10 hours
before the flare, a small sunspot in the active region NOAA 11818 started to
move northeast along a magnetic polarity inversion line (PIL), creating a
shearing motion that changed the quasi-static state of the active region. A
filament right above the PIL was activated following the movement of the
sunspot and then got partially erupted. The eruption eventually led to the M3.3
flare. The sunspot was then suddenly pulled back to the opposite direction upon
the flare onset. During the backward motion, the Lorentz force underwent a
simultaneous impulsive change both in magnitude and direction. Its directional
change is found to be conformable with the retraction motion. The observation
provides direct evidence for the role of the shearing motion of the sunspot in
powering and triggering the flare. It especially confirms that the abrupt
motion of a sunspot during a solar flare is the result of a back reaction
caused by the reconfiguration of the coronal magnetic field
RetouchingFFHQ: A Large-scale Dataset for Fine-grained Face Retouching Detection
The widespread use of face retouching filters on short-video platforms has
raised concerns about the authenticity of digital appearances and the impact of
deceptive advertising. To address these issues, there is a pressing need to
develop advanced face retouching techniques. However, the lack of large-scale
and fine-grained face retouching datasets has been a major obstacle to progress
in this field. In this paper, we introduce RetouchingFFHQ, a large-scale and
fine-grained face retouching dataset that contains over half a million
conditionally-retouched images. RetouchingFFHQ stands out from previous
datasets due to its large scale, high quality, fine-grainedness, and
customization. By including four typical types of face retouching operations
and different retouching levels, we extend the binary face retouching detection
into a fine-grained, multi-retouching type, and multi-retouching level
estimation problem. Additionally, we propose a Multi-granularity Attention
Module (MAM) as a plugin for CNN backbones for enhanced cross-scale
representation learning. Extensive experiments using different baselines as
well as our proposed method on RetouchingFFHQ show decent performance on face
retouching detection. With the proposed new dataset, we believe there is great
potential for future work to tackle the challenging problem of real-world
fine-grained face retouching detection.Comment: Under revie
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