Training Matting Models without Alpha Labels

Fuente: arXiv
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Main Authors: Liu, Wenze, Ye, Zixuan, Lu, Hao, Cao, Zhiguo, Yue, Xiangyu
Format: Preprint
Published: 2024
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_version_ 1866914917665210368
author Liu, Wenze
Ye, Zixuan
Lu, Hao
Cao, Zhiguo
Yue, Xiangyu
author_facet Liu, Wenze
Ye, Zixuan
Lu, Hao
Cao, Zhiguo
Yue, Xiangyu
contents The labelling difficulty has been a longstanding problem in deep image matting. To escape from fine labels, this work explores using rough annotations such as trimaps coarsely indicating the foreground/background as supervision. We present that the cooperation between learned semantics from indicated known regions and proper assumed matting rules can help infer alpha values at transition areas. Inspired by the nonlocal principle in traditional image matting, we build a directional distance consistency loss (DDC loss) at each pixel neighborhood to constrain the alpha values conditioned on the input image. DDC loss forces the distance of similar pairs on the alpha matte and on its corresponding image to be consistent. In this way, the alpha values can be propagated from learned known regions to unknown transition areas. With only images and trimaps, a matting model can be trained under the supervision of a known loss and the proposed DDC loss. Experiments on AM-2K and P3M-10K dataset show that our paradigm achieves comparable performance with the fine-label-supervised baseline, while sometimes offers even more satisfying results than human-labelled ground truth. Code is available at \url{https://github.com/poppuppy/alpha-free-matting}.
format Preprint
id arxiv_https___arxiv_org_abs_2408_10539
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Training Matting Models without Alpha Labels
Liu, Wenze
Ye, Zixuan
Lu, Hao
Cao, Zhiguo
Yue, Xiangyu
Computer Vision and Pattern Recognition
The labelling difficulty has been a longstanding problem in deep image matting. To escape from fine labels, this work explores using rough annotations such as trimaps coarsely indicating the foreground/background as supervision. We present that the cooperation between learned semantics from indicated known regions and proper assumed matting rules can help infer alpha values at transition areas. Inspired by the nonlocal principle in traditional image matting, we build a directional distance consistency loss (DDC loss) at each pixel neighborhood to constrain the alpha values conditioned on the input image. DDC loss forces the distance of similar pairs on the alpha matte and on its corresponding image to be consistent. In this way, the alpha values can be propagated from learned known regions to unknown transition areas. With only images and trimaps, a matting model can be trained under the supervision of a known loss and the proposed DDC loss. Experiments on AM-2K and P3M-10K dataset show that our paradigm achieves comparable performance with the fine-label-supervised baseline, while sometimes offers even more satisfying results than human-labelled ground truth. Code is available at \url{https://github.com/poppuppy/alpha-free-matting}.
title Training Matting Models without Alpha Labels
topic Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2408.10539