超像素与主动学习相结合的遥感影像变化检测方法
作者简介:王成军(1993-),男,江西萍乡人,硕士生,研究方向为计算机遥感图像处理,地理国情监测技术。E-mail: Wangchengjun_Giser@163.com
收稿日期: 2017-07-22
要求修回日期: 2017-09-24
网络出版日期: 2018-03-02
基金资助
福建省科技厅引导性项目(2017Y01010103)
福建省自然科学基金项目(2017J01464)
福建省中青年教师教育科研项目(JAT160087)
Change Detection Approach for High Resolution Remotely Sensed Images Based on Superpixel and Active Learning
Received date: 2017-07-22
Request revised date: 2017-09-24
Online published: 2018-03-02
Supported by
The Pilot project of Fujian Provincial Science and Technology Department, No.2017Y01010103
The Natural Science Fund Project of Fujian Province, No.2017J01464
The Education Research Project for Young and Middleaged Teachers of Fujian Province, No.JAT160087
Copyright
针对高分辨率遥感影像变化检测结果较破碎,易产生椒盐噪声、监督训练过程中人工标注成本较高、训练样本冗余以及大量未标注样本信息未有效利用等问题,提出一种超像素与主动学习相结合的高分辨率遥感影像变化检测方法。利用超像素分割算法得到超像素对象,提取其光谱和纹理特征;引入并借助主动学习样本选择策略充分利用未标注样本信息,挖掘不确定性最大、最易错分的样本交由用户人工标注;为保证所选样本的多样性,加入基于余弦角距离的样本相似性度量,以减少样本间信息冗余,在减轻人工标注负担的同时获得良好的分类性能。通过对2组不同场景的遥感影像的实验,表明本文提出的2种方法能够在标注少量训练样本的情况下获得较好的变化检测结果,且加入样本相似性度量的变化检测方法在有效减少人工标注成本和训练样本冗余的同时,能够更快地达到收敛、提升检测质量。
王成军 , 毛政元 , 徐伟铭 , 翁谦 . 超像素与主动学习相结合的遥感影像变化检测方法[J]. 地球信息科学学报, 2018 , 20(2) : 235 -245 . DOI: 10.12082/dqxxkx.2018.170336
In terms of change detection with high resolution remote sensing images, there are still some unresolved problems such as scattered plots with ragged boundaries in output, being prone to occurrence of “salt-and-pepper” noise, expensive cost of manual annotation in the process of supervised training, redundancy of training samples, underutilization of information in unlabeled samples and so on. In order to address these problems, this paper proposes a new high resolution remote sensing image change detection method by combining the superpixel segmentation technology and Active Learning (AL) approaches. The proposed method consists of the following steps. Firstly the difference image is derived from two temporal remote sensing images. Subsequently the lattice-like homogenous superpixel are obtained by applying the Simple Linear Iterative Clustering (SLIC) algorithm. Simultaneously, we compare the SLIC algorithm with entropy-rate-based and modified-watershed-based superpixel generating algorithms respectively by means of homogeneity of superpixel and their coherence with image object boundaries. Then we compute the means and standard deviations of three bands of superpixel objects as spectral features and extract the entropy, energy and angular second moment by employing Gray-Level Co-occurrence Matrix (GLCM) as texture features. After that, initial training samples are randomly selected and labeled by introducing and following the Margin Sampling (MS) active learning sample selection strategy which is a kind of SVM based AL algorithm taking advantage of SVM geometrical properties and suitable for bipartition problems. A cosine distance based sample similarity measurement called Angle Based Diversity (ABD) is introduced to relief redundancy and ensure diversity of the selected samples. Lastly change detection is carried out according to the extracted information from trained samples. The proposed algorithms (SLIC-MS, SLIC-MS+ABD) are utilized to process WorldViewⅡmultispectral remote sensing data of urban and suburb scenes and the detection result from proposed sampling is compared with that from random sampling to explain detection accuracy of our methods. To illustrate the efficiency of methods proposed in this article, we investigate the iterative times of three techniques for reaching the same detection accuracy. Experimental results confirm that both SLIC-MS and SLIC-MS+ABD can reduce manual labeling cost and achieve better change detection quality than random sampling methods. They also indicate that the two proposed methods can find out samples with high uncertainty, which can be labeled by user themselves, from the unlabeled sample pool by making full use of and mining unlabeled sample information. Compared with the other two methods, SLIC-MS+ABD is more accurate with respect to identical data sets (the same two mentioned remote sensing images) and the same labeled sample number because the diversity of new selected samples has been considered in the learning process. In addition, SLIC-MS+ABD can obviously reduce iterative times to converge for achieving the same detection accuracy than other two approaches. On the basis of the experiment, it can be concluded that our proposed methods greatly relief the amount of user marking and acquire good change detection performance on high resolution remote sensing data sets as well. Experimental results also indicate that the methods implemented in this article saliently exhibit their advantages of manual cost reduction in sample labeling, avoidance of training sample redundancy to reach the same change detection quality for the same data set.
Fig. 1 Flowchart of the proposed change detection method图1 本文变化检测方法流程 |
Fig. 2 A typical framework of active learning图2 主动学习流程 |
Fig. 3 True color composite(RGB) images of case study area at different times图3 不同时相的研究区真彩色(RGB)影像 |
Tab. 1 Error matrix of change detection表1 变化误差矩阵 |
实际变化像元数 | 实际未变化像元数 | 行像元数之和 | |
---|---|---|---|
检测变化像元数 | TP | FP | P |
检测未变化像元数 | FN | TN | N |
列像元数之和 | P′ | N′ | T |
Fig. 4 Difference images图4 差值影像 |
Fig. 5 The segmentation results of different superpixel segmentation algorithms in Beijing图5 北京地区超像素分割结果 |
Fig. 6 The segmentation results of different superpixel segmentation algorithms in Fuzhou图6 福州地区超像素分割结果 |
Fig. 7 Accuracy comparison of the change detection图7 本文方法与其他方法精度比较 |
Fig. 8 Change detection results of different algorithm图8 变化检测结果 |
Tab. 2 The change detection accuracy of different methods表2 不同方法的检测精度 |
北京 | 福州 | ||||||
---|---|---|---|---|---|---|---|
Kappa系数 | 漏检率 | 误检率 | Kappa系数 | 漏检率 | 误检率 | ||
SLIC-MS+ABD | 0.8306 | 0.1630 | 0.1263 | 0.8763 | 0.0719 | 0.0642 | |
SLIC-MS | 0.8008 | 0.2106 | 0.1439 | 0.8017 | 0.2018 | 0.1153 | |
SLIC-RS | 0.6660 | 0.4106 | 0.1625 | 0.7157 | 0.3098 | 0.1190 |
Tab. 3 The numbers of iteration rounds required by different methods for achieving the same classification accuracy on the two research areas表3 3种方法达到相同精度所需迭代次数 |
研究区迭代次数 | ||
---|---|---|
北京 | 福州 | |
SLIC-MS+ABD | 15 | 13 |
SLIC-MS | 20 | 30 |
SLIC-RS | 90 | 50 |
The authors have declared that no competing interests exist.
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