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arXiv 2404.16571cs.CV

MonoPCC:用于内窥镜图像单目深度估计的光度不变循环约束

MonoPCC: Photometric-invariant Cycle Constraint for Monocular Depth Estimation of Endoscopic Images

Huazhong University of Science and Technology(华中科技大学);Wuhan United Imaging Healthcare Surgical Technology Co., Ltd.(武汉联影外科技术有限公司);Tongji Hospital(同济医院);Tongji Medical College(同济医学院);Britton Chance Center for Biomedical Photonics(布里顿·钱斯生物光子学中心);Wuhan National Laboratory for Optoelectronics(武汉光电国家实验室)

Zhiwei Wang, Ying Zhou, Shiquan He, Ting Li, Fan Huang, Qiang Ding, Xinxia Feng, Mei Liu, Qiang Li

AI总结:

提出MonoPCC方法,通过将光度约束重塑为闭环循环形式解决内窥镜图像亮度不一致问题,结合相位频率移植与EMA策略提升自监督单目深度估计的鲁棒性与精度。

摘要:

光度约束对于自监督单目深度估计是不可或缺的。它涉及使用估计的深度和位姿将源图像扭曲到目标视图,然后最小化扭曲图像与目标图像之间的差异。然而,内窥镜内置光源会导致显著的亮度波动,从而使光度约束变得不可靠。以往的努力仅依靠额外模型校准图像亮度来缓解此问题。在本文中,我们提出MonoPCC,通过将光度约束重塑为循环形式,从根本上解决亮度不一致问题。MonoPCC不再仅扭曲源图像,而是构建一个由两条相反的前向-后向扭曲路径组成的闭环:从目标到源,再回到目标。因此,目标图像最终接收到一个由自身循环扭曲的图像,这自然使该约束对亮度变化保持不变。此外,MonoPCC将源图像的相位频率移植到中间扭曲图像中以避免结构丢失,并通过指数移动平均(EMA)策略稳定训练,以避免前向扭曲的频繁变化。在四个内窥镜数据集上的全面广泛实验结果表明,我们提出的MonoPCC对亮度不一致表现出极大的鲁棒性,并分别将绝对相对误差至少降低了7.27%、9.38%、9.90%和3.17%,超越了其他最先进方法。

英文摘要:

Photometric constraint is indispensable for self-supervised monocular depth estimation. It involves warping a source image onto a target view using estimated depth&pose, and then minimizing the difference between the warped and target images. However, the endoscopic built-in light causes significant brightness fluctuations, and thus makes the photometric constraint unreliable. Previous efforts only mitigate this relying on extra models to calibrate image brightness. In this paper, we propose MonoPCC to address the brightness inconsistency radically by reshaping the photometric constraint into a cycle form. Instead of only warping the source image, MonoPCC constructs a closed loop consisting of two opposite forward-backward warping paths: from target to source and then back to target. Thus, the target image finally receives an image cycle-warped from itself, which naturally makes the constraint invariant to brightness changes. Moreover, MonoPCC transplants the source image's phase-frequency into the intermediate warped image to avoid structure lost, and also stabilizes the training via an exponential moving average (EMA) strategy to avoid frequent changes in the forward warping. The comprehensive and extensive experimental results on four endoscopic datasets demonstrate that our proposed MonoPCC shows a great robustness to the brightness inconsistency, and exceeds other state-of-the-arts by reducing the absolute relative error by at least 7.27%, 9.38%, 9.90% and 3.17%, respectively.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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