# Sea Clutter Suppression and Target Detection Algorithm of Marine Radar Image Sequence Based on Spatio-Temporal Domain Joint Filtering

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## Abstract

**:**

## 1. Introduction

## 2. Sea Clutter Model of Marine Radar Image Sequence

## 3. Sea Clutter Suppression and Target Detection Algorithm

#### 3.1. Spatio-Temporal Domain Joint Sea Clutter Suppressor

#### 3.2. Sea Clutter Suppressed Image Sequence Target Detection

## 4. Experimental Result

#### 4.1. Marine Radar Parameters and Experimental Data

#### 4.2. Emd Sea Clutter Suppression Method for Marine Radar

#### 4.3. Performance Evaluation Index

#### 4.4. Experimental Result

## 5. Conclusions

- A sea clutter suppression link is added before the detecting target. The leading wavelength dispersion relation is introduced into the target detection of marine radar for the first time, and a sea clutter suppression and target detection algorithm of marine radar image sequence based on spatio-temporal joint filtering was proposed;
- Compared with the traditional EMD sea clutter suppression method, the spatio-temporal combined sea clutter suppressor proposed in this paper can effectively suppress the sea spikes in the image and can increase SNR by 15.3 db at most, which is more than 8.6 db of the EMD method;
- Compared with the WL-CFAR without sea clutter suppression method, the detection algorithm under sea clutter suppression proposed in this paper can excellently improve the detection probability of weak targets in complex sea conditions, and the probability can be up to 37% at most.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## References

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**Figure 3.**Radar image containing target and 2D cross section of 3D image spectrum ${I}_{\omega ,\mathrm{k}}$ along $\left|K\right|$ direction. (

**a**) radar image containing target. (

**b**) 2D cross section of 3D image spectrum ${I}_{\omega ,\mathrm{k}}$ along $\left|K\right|$ direction.

**Figure 7.**Low sea condition: (

**a**) the 10th original image in radar image sequence; (

**b**) the 10th sea clutter suppression image in radar image sequence; (

**c**) 2D cross section of the 3D image spectrum of the original radar image sequence along $\left|K\right|$; (

**d**) 2D cross section of the 3D image spectrum of the sea clutter suppressed radar image sequence along $\left|K\right|$.

**Figure 8.**Medium sea condition: (

**a**) the 3rd original image in radar image sequence; (

**b**) the 3rd sea clutter suppression image in radar image sequence; (

**c**) 2D cross section of the 3D image spectrum of the original radar image sequence along $\left|K\right|$; (

**d**) 2D cross section of the 3D image spectrum of the sea clutter suppressed radar image sequence along $\left|K\right|$.

**Figure 9.**High sea condition: (

**a**) The 10th original image in radar image sequence (

**b**) The 10th sea clutter suppression image in radar image sequence (

**c**) 2D cross section of the 3D image spectrum of the original radar image sequence along the $\left|K\right|$ (

**d**) 2D cross section of the 3D image spectrum of the sea clutter suppressed radar image sequence along the $\left|K\right|$.

**Figure 10.**The 10th original image and corresponding suppression image in radar image sequence under low sea conditions.

**Figure 11.**The 3rd original image and corresponding suppression image in radar image sequence under medium sea conditions.

**Figure 12.**The 10th original image and corresponding suppression image in radar image sequence under high sea conditions.

**Figure 13.**The suppression effect of EMD and the proposed method on sea clutter in three sea conditions of different SNR.

Radar Parameters | The Performance |
---|---|

Electromagnetic Wave Frequency | 9.4 Ghz |

Antenna Angular Speed | 26 r.p.m |

Antenna Height | 25 m |

Polarization | HH |

Range Resolution | 7.5 m |

Horizontal Beam Width | 1.3° |

Vertical Beam Width | 23° |

Pulse Repetiton Frequency | 1300 Hz |

Pulse Width | 0.7° |

Proposed Algorithm | EMD | ||||
---|---|---|---|---|---|

Processing Coefficient α | Original Image SNR (db) | Suppressed Image SNR (db) | SNR Improvement (db) | Suppressed Image SNR (db) | SNR Improvement (db) |

1 | 16.8 | 25.2 | 8.4 | 23.3 | 8.0 |

1.2 | 13.5 | 21.0 | 7.5 | 18.4 | 7.2 |

1.4 | 10.6 | 17.0 | 6.4 | 15.1 | 6.1 |

1.6 | 8.0 | 13.7 | 5.7 | 12.7 | 5.3 |

1.8 | 5.7 | 10.5 | 4.8 | 9.9 | 4.4 |

2 | 3.6 | 7.4 | 3.8 | 7.9 | 3.3 |

Proposed Algorithm | EMD | ||||
---|---|---|---|---|---|

Processing Coefficient α | Original Image SNR (db) | Suppressed Image SNR (db) | SNR Improvement (db) | Suppressed Image SNR (db) | SNR Improvement (db) |

1 | 16.6 | 28.8 | 12.2 | 24.9 | 7.3 |

1.2 | 13.0 | 24.4 | 11.3 | 20.2 | 6.2 |

1.4 | 10.0 | 20.0 | 10 | 16.3 | 5.3 |

1.6 | 7.4 | 15.7 | 8.3 | 12.9 | 4.5 |

1.8 | 5.0 | 12.3 | 7.3 | 9.7 | 3.7 |

2 | 2.9 | 7.5 | 4.6 | 6.8 | 2.9 |

Proposed Algorithm | EMD | ||||
---|---|---|---|---|---|

Processing Coefficient α | Original Image SNR (db) | Suppressed Image SNR (db) | SNR Improvement (db) | Suppressed Image SNR (db) | SNR Improvement (db) |

1 | 15.5 | 30.3 | 14.8 | 24.1 | 8.6 |

1.2 | 11.9 | 25.6 | 13.7 | 19.8 | 7.9 |

1.4 | 8.8 | 21.3 | 12.5 | 15.8 | 7.0 |

1.6 | 6.2 | 17.4 | 11.2 | 12.4 | 6.2 |

1.8 | 3.8 | 13.7 | 9.9 | 9.2 | 5.4 |

2 | 1.7 | 10.2 | 8.5 | 6.1 | 4.4 |

PD(%) | ||||||
---|---|---|---|---|---|---|

original image $SNR$ | 3.6 (db) | 5.7 (db) | 8.0 (db) | 10.6 (db) | 13.5 (db) | 16.8 (db) |

proposed method | 37.2 | 58.3 | 71.1 | 83.3 | 90.0 | 97.8 |

original image | 29.3 | 52.2 | 63.9 | 75.0 | 81.1 | 88.3 |

PD(%) | ||||||
---|---|---|---|---|---|---|

original image $SNR$ | 2.9 (db) | 5.0 (db) | 7.4 (db) | 10.0 (db) | 13.0 (db) | 16.6 (db) |

proposed method | 23.4 | 40.9 | 62.8 | 77.6 | 86.1 | 97.1 |

original image | 0.0 | 10.2 | 21.0 | 40.2 | 77.3 | 80.6 |

PD(%) | ||||||
---|---|---|---|---|---|---|

original image $SNR$ | 1.7 (db) | 3.8 (db) | 6.2 (db) | 8.8 (db) | 11.9 (db) | 15.5 (db) |

proposed method | 25.3 | 36.0 | 52.0 | 64.0 | 90.7 | 97.3 |

original image | 0.0 | 0.0 | 0.0 | 18.7 | 48.0 | 77.3 |

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**MDPI and ACS Style**

Wen, B.; Wei, Y.; Lu, Z.
Sea Clutter Suppression and Target Detection Algorithm of Marine Radar Image Sequence Based on Spatio-Temporal Domain Joint Filtering. *Entropy* **2022**, *24*, 250.
https://doi.org/10.3390/e24020250

**AMA Style**

Wen B, Wei Y, Lu Z.
Sea Clutter Suppression and Target Detection Algorithm of Marine Radar Image Sequence Based on Spatio-Temporal Domain Joint Filtering. *Entropy*. 2022; 24(2):250.
https://doi.org/10.3390/e24020250

**Chicago/Turabian Style**

Wen, Baotian, Yanbo Wei, and Zhizhong Lu.
2022. "Sea Clutter Suppression and Target Detection Algorithm of Marine Radar Image Sequence Based on Spatio-Temporal Domain Joint Filtering" *Entropy* 24, no. 2: 250.
https://doi.org/10.3390/e24020250