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Yanhua Han

Publications and source records attributed to Yanhua Han.

2 recordsLinked to original sources

Does Attention-Guided Masking Really Help Object Discovery in Object-Centric Learning?

Object-Centric Learning (OCL) aims to decompose images into objects without human annotations. A major family of mainstream methods uses Slot Attention to aggregate image features into object-level representations and then from them reconstructs masked image content, i.e., Random Masking (RM), to provide self-supervision. The recent method DIAS simply masks image patches at uniform randomness yet achieves competitive object discovery accuracy. Since attention during aggregation already possesses object discovery ability, we explore using it to develop a better image patch masking strategy, i.e., Attention Guided Masking (AGM), thereby providing better self-supervision. Results on six recognized datasets show that AGM does not always outperform RM. Under unconditional slot initialization, AGM substantially improves background segmentation on datasets with realistic textures (COCO and VOC); Regardless of conditional or unconditional slot initialization and across datasets, foreground object discovery remains comparable or decreases. We suggest peer researchers in the OCL community that attempts to exploit internal attention semantics to improve OCL with masked decoding are risky. Our source code, model checkpoints and evaluation logs is available on https://github.com/und-entropy/Does-Attention-Guided-Masking-Really-Help-Object-Discovery-in-Object-Centric-Learning-.

cs.CV

D-shaped photonic crystal fiber plasmonic refractive index sensor based on gold grating

In this work, we proposed a high resolution D-shaped photonic crystal fiber (PCF) surface plasmon resonance (SPR) sensor based on gold grating. Gold grating is introduced to modulate the resonance wavelength and enhance the refractive index (RI) sensitivity. Structure parameters of PCF and gold grating are analyzed by finite element method (FEM) for optimizing the SPR sensor. The simulation results indicate that air hole pitch, air hole diameter and gold thickness and grating constant have little influence on the sensitivity of refractive index, which reduces the requirement of precise processing. For improving the resolution of RI sensing, two-feature (2F) interrogation method which combines wavelength interrogation and amplitude interrogation is used and the maximum theoretical resolution of SPR sensor reaches to 5.98*10-6 RIU in range of 1.36-1.38 and the wavelength sensitivity reaches to 3340nm/RIU. The proposed SPR sensor shows potential applications on developing a high-sensitivity, real time and fast-response SPR-RI sensor.

physics.optics