Target Echo Detection Based on the Signal Conditional Random Field Model for Full-Waveform Airborne Laser Bathymetry
Target Echo Detection Based on the Signal Conditional Random Field Model for Full-Waveform Airborne Laser Bathymetry
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DOI：
10.1109/tgrs.2022.3223401
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发表时间：
2022
影响因子：
8.2
通讯作者：
Kai Guo;Qingquan Li;Chisheng Wang;Qingzhou Mao;Yanxiong Liu;Yongzhong Ouyang;Yikai Feng;Jiasong Zhu;Anlei Wu
中科院分区：
文献类型：
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作者：
Kai Guo;Qingquan Li;Chisheng Wang;Qingzhou Mao;Yanxiong Liu;Yongzhong Ouyang;Yikai Feng;Jiasong Zhu;Anlei Wu
数字化全波形信号采集机载激光测深系统通过激光照射，从多个后向散射面获得相应的时间位置。这些信息有助于描述目标的多高度结构，并探索激光传输过程中不同非均匀介质中回波信号的衰减响应。因此，全波形回波信号在水陆综合探测中具有很强的实用性。然而，ALB系统中使用的波长一般在470-580 nm的可见光范围内，接收信号经常受到许多非目标因素的干扰，如接收信道的缺陷或传输介质的强散射。传统的处理方法将非目标干扰转化为噪声点云滤波或分类提取，从而能够检测出单一表面或规则几何形状。由于噪声信号强度较大，多高度目标表面回波信号的识别和提取精度往往较低。通过构造回波信号特征函数和基于全波形分解的条件随机场(CRF)模型，提出了一种信号分量检测方法。对实际测量数据的处理结果验证了CRF策略能有效降低目标表面检测的不确定性。与单波束测深仪相比，两个不同实验区水下高程偏差的均方根误差分别减小了3.2和4.9 cm。
Airborne laser bathymetry (ALB) systems with digital full-waveform signal collection can obtain the corresponding temporal positions from several backscattering surfaces by laser beam irradiation. This information can help describe the multielevation structures of the target and explore the echo signal attenuation response in different nonuniform mediums during laser propagation. Therefore, a full-waveform echo signal is quite practical for integrated water–land detection. However, the wavelength used in the ALB system is generally in the visible band range of 470–580 nm, and the received signal is constantly interfered with by many nontarget factors, such as imperfections in the receiving channel or the strong scattering from the transmission medium. The conventional processing method transforms nontarget interference into noise point cloud filtering or classification extraction, enabling the detection of a single surface or regular geometry. The accuracy of the identification and extraction for multielevation target surfaces echo signal is always reduced due to the significant noise signal intensity. We proposed a signal component detection method by constructing the echo signal feature functions and the conditional random field (CRF) model based on the full-waveform decomposition. The processing result for actual measurement data verified that the CRF strategy can effectively reduce the uncertainty of target surface detection. Compared with the single-beam echo sounder, the root-mean-squared errors of the elevation deviation underwater were reduced by 3.2 and 4.9 cm in the two different experimental areas.