航空学报 > 2024, Vol. 45 Issue (10): 329162-329162   doi: 10.7527/S1000-6893.2023.29162

基于MatchNet和多点匹配约束的可见光-SAR图像匹配

叶熠彬, 滕锡超, 于起峰, 李璋()   

  1. 国防科技大学 空天科学学院,长沙 410073
  • 收稿日期:2023-06-13 修回日期:2023-07-17 接受日期:2023-08-11 出版日期:2024-05-25 发布日期:2023-09-01
  • 通讯作者: 李璋 E-mail:zhangli_nudt@163.com
  • 基金资助:
    国家自然科学基金(61801491)

Optical⁃SAR image matching based on MatchNet and multi⁃point matching constraint

Yibin YE, Xichao TENG, Qifeng YU, Zhang LI()   

  1. College of Aerospace Science and Engineering,National University of Defence Technology,Changsha 410073,China
  • Received:2023-06-13 Revised:2023-07-17 Accepted:2023-08-11 Online:2024-05-25 Published:2023-09-01
  • Contact: Zhang LI E-mail:zhangli_nudt@163.com
  • Supported by:
    National Natural Science Foundation of China(61801491)

摘要:

基于可见光和SAR成像的异源图像匹配是实现复杂场景下飞行器视觉导航的关键。由于成像机理的差异,可见光-SAR图像匹配需要面对成像几何特性差异、非线性辐射失真以及噪声干扰等挑战。近年来,基于深度学习的图像匹配方法表现出比传统方法更优的场景适应性,但现有深度学习方法仍未完全解决上述几个挑战,还无法完全满足视觉导航中的高精度匹配需求。基于经典的MatchNet匹配框架,针对其单个模板匹配精度不足的问题,提出一种多点匹配约束的匹配方法(MMC-MatchNet)。方法主要分为2步:第1步生成子模板并利用MatchNet进行匹配,第2步基于多点几何约束剔除误匹配子模板并优化匹配结果。该方法在保持MatchNet输入尺寸不变的同时提升了网络对多尺寸可见光-SAR图像的匹配精度。此外,还提出了一种多级数据集构建方法来训练MatchNet。与随机采样构建负样本的方式相比,所提方法更关注于匹配任务中的困难样本,是一种适用于图像匹配的数据增强手段。对MMC-MatchNet在2种可见光-SAR图像匹配数据上进行了测试,取得了比NCC、NMI、HOPC以及单模板MatchNet方法更好的匹配结果,在与HOPC匹配精度相似的前提下,MMC-MatchNet可大幅提高匹配正确率(CMR)。同时,多点匹配约束和多级数据构建方法还适用于其他基于Patch的图像匹配模型。

关键词: 图像匹配, 模板匹配, 可见光图像, SAR图像, MatchNet

Abstract:

Multimodal image matching between optical and SAR images is critical for visual navigation of the aircraft flying over complex areas. Due to different imaging mechanisms, accurate optical-SAR image matching faces several challenges, such as imaging geometry differences between optical and SAR, nonlinear radiation distortion of SAR, and noise interference. Although deep learning-based image matching methods have shown better adaptability than traditional methods, they still cannot fully solve the above-mentioned challenges and their matching accuracy may be not enough for visual navigation tasks. This paper proposes a new image matching method called Multi-point Matching Constraint MatchNet (MMC-MatchNet) based on the typical MatchNet framework, so as to improve the matching accuracy of the single template matching using MatchNet. The method consists of two main steps: sub-templates sampling and matching using MatchNet, and mismatched sub-templates removal based on multi-point geometric constraint. The original input image size of the MatchNet is maintained, while the matching accuracy for optical-SAR image matching is improved. This paper also proposes a multi-level training dataset generation method to train the MMC-MatchNet. Compared to the random sampling method, our method focuses on the difficult samples in image matching, and can be seen as a special data augmentation method for image matching. MMC-MatchNet is tested on two multi-modal image matching datasets, outperforming NCC, NMI, HOPC and the single-template MatchNet. With similar matching accuracy to that of HOPC, MMC-MatchNet can improve the Correctly Matching Rate (CMR). The method based on multi-point matching constraint and multi-level dataset generation can be easily extend to other patch-based image matching models.

Key words: image matching, template matching, optical image, SAR image, MatchNet

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