At present, most of the bands or spectral indices used in the high temperature target remote sensing recognition researches only involve qualitative analysis, with the lack of quantitative evaluation indicators and screening methods. In order to establish a universal band screening principle and screening method for judging indicators so as to achieve effective identification of high temperature targets, the authors, according to the idea of variance analysis, constructed a separability metric to screen characteristic bands between high temperature targets and various types of normal temperature objects respectively, determined some effective bands for high temperature targets identification, constructed identification indices with the spectral characteristics of the ground objects, and screened the optimal one. The result shows that the optimal spectral index determined by quantitative screening can effectively distinguish high temperature targets from most normal temperature objects. On such a basis, by using the other optimal identification index between high temperature targets and their confusing color steel objects to identify once again, the recognition accuracy could be improved further, and recognition accuracy of high temperature targets reached 95.4% and 97.6% , respectively.
Qin ZHENG,Jun PAN,Lijun JIANG, et al. A study of high temperature targets identification method based on spectral index[J]. Remote Sensing for Land & Resources,
2019, 31(3): 51-58.
Fig.1 Radiation flux density of blackbody at different temperatures
T/K
M/(W·cm-2·μm-1)
T/K
M/(W·cm-2·μm-1)
300
2.40×10-7
700
6.28×10-2
400
5.64×10-5
800
2.02×10-1
500
1.49×10-3
900
5.03×10-1
600
1.32×10-2
1 000
1.04
Tab.1 Shortwave infrared emission radiation flux density at different temperatures(λ=2.201 μm)
地物类别
反射辐射通 量密度均值/ (W·cm-2·μm-1)
地物类别
反射辐射通 量密度均值/ (W·cm-2·μm-1)
水体
1.84×10-4
林地(阳坡)
5.04×10-4
裸地
1.65×10-3
林地(阴坡)
3.20×10-4
居民地
1.47×10-3
高温目标
5.75×10-3
火烧迹地
8.84×10-4
Tab.2 Shortwave infrared reflectance radiation flux density of different surface features(λ=2.201μm)
Fig.2 Spectral curves of normal temperature objects
Fig.3 Spectral curves of high temperature targets with different area percentage at the same temperature
Fig.4 Spectral curves of different types of high temperature targets and typical normal temperature objects
Fig.5 Principle of separability measure
Fig.6 Research area OLI remote sensing image composed with B7(R),B5(G),B3(B)
Fig.7 Feature bands screening for distinguish high temperature targets and all kinds of normal temperature objects
Fig.8 Two-dimensional scatter diagram of every two effective bands
Fig.9 Separability measurement of spectral indices for distinguish high temperature targets and all kinds of normal temperature objects respectively
区分类别
最优光谱指数
火点—水体
(B7-B5-B4)/(B7+B5+B4)
火点—裸地
(B7-B4)/(B7+B4)
火点—居民地
(B7-B4)/(B7+B4)
火点—火烧迹地
(B7-B5-B4)/(B7+B5+B4)
火点—林地(阳坡)
(B7-B5)/(B7+B5)
火点—林地(阴坡)
(B7-B5)/(B7+B5)
火点—彩钢地物
B7-2B5+B4
火点—所有常温地物
(B7-B5-B4)/(B7+B5+B4)
Tab.3 Optimal spectral indices between high temperature targets and all kinds of normal temperature objects
Fig.10 Distribution histogram for (B7-B5-B4)/(B7+B5+B4) value of various kinds of ground objects
Fig.11 High temperature targets recognition results
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