Small Target Detection in Sea Clutter Background Based on Tsallis Entropy of Doppler Spectrum
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摘要: 根据海杂波和目标多普勒谱的聚集性差异,可以用熵特征来检测海杂波背景下的小目标,然而常用的香农熵仅仅是统计学角度的宏观量值,并不能反映出海杂波的非线性特性。非广延熵是香农熵的推广,可以描述海杂波已被证实的多重分形特性。该文首先给出了非广延熵与分形维数的关系,然后结合有目标单元回波的多普勒谱较纯杂波单元回波的多普勒谱聚集性更强以及海杂波回波具有多重分形特性的特点,提出了基于多普勒谱非广延熵的海杂波背景下的小目标检测方法,最后通过实测数据进行实验比较,验证了该文算法的有效性,在观测时间较短的情况下,与现有的多重分形频域Hurst指数方法和基于香农熵的方法相比,该文算法具有更好的检测性能。Abstract: According to the different concentration levels of Doppler spectrum between sea clutter and target, small target in sea clutter background can be detected using Shannon entropy. However, Shannon entropy is merely a special case of Tsallis entropy and cannot reflect the multifractality of sea clutter. In this paper, the relation between Tsallis entropy and the generalized fractal dimension is first presented, and then the Doppler spectrum’s concentrative level and multifractality of sea clutter are combined; finally an algorithm for detecting small target in sea clutter background based on Tsallis entropy of Doppler spectrum rather than of Shannon entropy is proposed. By comparison via IPIX dataset, the detection’s performance of Tsallis entropy is better than that of Shannon entropy and Hurst exponent as per short observations.
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Key words:
- Sea clutter /
- Target detection /
- Doppler spectrum /
- Tsallis entropy /
- Multifractality
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表 1 1993年IPIX雷达数据主要参数说明
Table 1. Description of the data sets of IPIX radar database in 1993
数据编号 目标所在单元 受目标影响单元 风速(km/h) 浪高(m) #17 9 8:11 9 2.2 #26 7 6:8 9 1.1 #30 7 6:8 19 0.9 #31 7 6:9 19 0.9 #40 7 5:8 9 1.0 #54 8 7:10 20 0.7 #280 8 7:10 10 1.6 #310 7 6:9 33 0.9 #311 7 6:9 33 0.9 #320 7 6:9 28 0.9 表 2 全部单元多普勒谱非广延熵值
Table 2. Tsallis entropy of Doppler spectrum of all the cells
距离单元号 $q = 0.5$ $q = 1.0$ $q = 2.0$ $q = 3.0$ $q = 4.0$ $q = 5.0$ 1 0.7992 0.8919 0.9387 0.9564 0.9674 0.9748 2 0.7966 0.8851 0.9355 0.9553 0.9672 0.9751 3 0.7994 0.8768 0.9311 0.9533 0.9662 0.9744 4 0.8147 0.8757 0.9228 0.9449 0.9591 0.9687 5 0.8216 0.8727 0.9167 0.9392 0.9542 0.9647 6 0.8177 0.8707 0.9180 0.9418 0.9571 0.9674 7 0.6705 0.6834 0.7165 0.7511 0.7805 0.8045 8 0.6025 0.6017 0.6330 0.6725 0.7064 0.7343 9 0.6429 0.6522 0.6827 0.7191 0.7505 0.7760 10 0.7458 0.7839 0.8224 0.8526 0.8760 0.8939 11 0.8080 0.8668 0.9123 0.9368 0.9530 0.9642 12 0.8152 0.8717 0.9153 0.9372 0.9519 0.9623 13 0.8081 0.8635 0.9131 0.9382 0.9541 0.9647 14 0.8043 0.8671 0.9177 0.9419 0.9570 0.9672 表 3 不同FFT点数下最佳q值
Table 3. The best q values of different FFT points
数据编号 64 128 256 512 #280HH 6 3 3 2 #280VV 5 3 2 1 #280HV 4 3 2 2 #310HH 3 2 1 2 #310VV 8 3 3 3 #310HV 3 2 2 1 #311HH 3 2 1 1 #311VV 5 3 2 1 #311HV 3 2 1 1 表 4 不同
$\text{q}$ 值下算法的检测概率(%)Table 4. Detection probability of the proposed algorithm of different
$\text{q}$ values (%)数据编号 $q$取值 ${P_f}$ ${10^{ - 3}}$ ${10^{ - 2}}$ ${10^{ - 1}}$ HH VV HV HH VV HV HH VV HV #280 q = 1 82.09 90.14 96.78 85.92 92.56 98.19 92.76 95.37 100 q = 2 90.54 91.95 97.18 93.56 95.77 98.79 95.98 98.79 100 q = 3 92.15 93.56 96.38 94.16 98.19 98.39 96.58 99.40 100 q = 10 82.49 89.94 89.54 89.74 95.77 92.35 96.58 99.40 98.99 #310 q = 1 94.16 13.26 92.15 96.58 30.38 95.37 98.19 62.17 97.79 q = 2 95.98 24.35 94.16 97.99 50.91 97.38 98.79 75.86 98.39 q = 3 92.56 40.44 92.76 97.59 54.53 97.18 98.59 77.06 99.40 q = 10 68.61 42.45 78.27 92.15 55.33 85.51 98.39 72.03 99.20 #311 q = 1 100 98.59 100 100 100 100 100 100 100 q = 2 100 99.20 100 100 100 100 100 100 100 q = 3 100 98.59 100 100 100 100 100 100 100 q = 10 96.78 80.48 97.59 98.79 80.93 100 100 99.60 100 表 5 3种算法的检测概率(%)
Table 5. Detection probability of the three algorithms (%)
序列长度 方法 ${P_{\rm f}}$ ${10^{ - 3}}$ ${10^{ - 2}}$ ${10^{ - 1}}$ 27 频域Hurst指数法 1.00 16.30 46.20 q = 1(香农熵) 58.97 69.57 79.48 q = 3(非广延熵) 72.94 78.49 88.21 28 频域Hurst指数法 8.50 21.30 35.80 q = 1(香农熵) 82.09 85.92 92.76 q = 3(非广延熵) 92.15 94.16 96.58 29 频域Hurst指数法 15.50 32.80 43.10 q = 1(香农熵) 82.16 84.23 90.04 q = 3(非广延熵) 88.38 95.44 97.51 210 频域Hurst指数法 52.90 63.80 78.90 q = 1(香农熵) 61.95 80.53 93.81 q = 3(非广延熵) 89.38 98.23 100 表 6 观测时间为0.064 s所提方法检测概率(%)
Table 6. Detection probability when observation time is 0.064 s (%)
数据编号 ${10^{ - 3}}$ ${10^{ - 2}}$ ${10^{ - 1}}$ #280HH 35.51 46.83 61.53 #280VV 38.07 47.47 59.42 #280HV 54.60 62.12 74.13 #310HH 45.01 52.23 66.99 #310VV 9.64 15.69 30.99 #310HV 45.15 54.06 67.34 #311HH 82.29 89.52 95.52 #311VV 64.24 74.03 86.08 #311HV 85.98 93.31 97.15 表 7 观测时间为0.128 s所提方法检测概率(%)
Table 7. Detection probability when observation time is 0.128 s(%)
数据编号 ${10^{ - 3}}$ ${10^{ - 2}}$ ${10^{ - 1}}$ #280HH 73.64 78.49 88.31 #280VV 72.15 78.10 85.73 #280HV 88.21 92.37 95.24 #310HH 80.57 88.80 95.24 #310VV 31.62 38.75 58.97 #310HV 83.25 91.97 97.42 表 8 观测时间为0.032 s所提方法检测概率(%)
Table 8. Detection probability when observation time is 0.032 s (%)
数据编号 ${10^{ - 3}}$ ${10^{ - 2}}$ ${10^{ - 1}}$ #311HH 32.08 40.55 53.25 #311VV 15.54 23.45 34.94 #311HV 40.36 48.35 59.76 -
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