We aim at verifying whether the use of high-resolution coherency functionals could improve the signal-to-noise ratio (S/N) of Ground-Penetrating Radar data by introducing a variable and precisely picked velocity field in the migration process. After carrying out tests on synthetic data to schematically simulate the problem, assessing the types of functionals most suitable for GPR data analysis, we estimated a varying velocity field relative to a real dataset. This dataset was acquired in an archaeological area where an excavation after a GPR survey made it possible to define the position, type, and composition of the detected targets. Two functionals, the Complex Matched Coherency Measure and the Complex Matched Analysis, turned out to be effective in computing coherency maps characterized by high-resolution and strong noise rejection, where velocity picking can be done with high precision. By using the 2D velocity field thus obtained, migration algorithms performed better than in the case of constant or 1D velocity field, with satisfactory collapsing of the diffracted events and moving of the reflected energy in the correct position. The varying velocity field was estimated on different lines and used to migrate all the GPR profiles composing the survey covering the entire archaeological area. The time slices built with the migrated profiles resulted in a higher S/N than those obtained from non-migrated or migrated at constant velocity GPR profiles. The improvements are inherent to the resolution, continuity, and energy content of linear reflective areas. On the basis of our experience, we can state that the use of high-resolution coherency functionals leads to migrated GPR profiles with a high-grade of hyperbolas focusing. These profiles favor better imaging of the targets of interest, thereby allowing for a more reliable interpretation.

中文翻译：

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高分辨率相干函数可改善探地雷达数据的速度分析

我们的目标是通过在迁移过程中引入可变且精确挑选的速度场，来验证高分辨率相干函数的使用是否可以提高探地雷达数据的信噪比（S / N）。在对合成数据进行测试以示意性地模拟问题之后，评估了最适合GPR数据分析的功能类型之后，我们估算了相对于真实数据集的变化速度场。该数据集是在考古地区采集的，该地区在进行GPR调查后的挖掘工作中可以定义所检测目标的位置，类型和组成。事实证明，两种功能（复杂匹配相干度量和复杂匹配分析）可有效地计算以高分辨率和强噪声抑制为特征的相干图，可以高精度进行速度拾取。通过使用由此获得的2D速度场，迁移算法的性能要比恒定或1D速度场的情况更好，衍射事件令人满意地崩溃，并且反射能量在正确的位置移动。在不同的直线上估计了变化的速度场，并将其用于迁移构成整个调查区域的所有GPR剖面。与从非迁移或以恒速GPR迁移得到的时间片相比，使用迁移得到的时间片产生的信噪比更高。改进是线性反射区域的分辨率，连续性和能量含量所固有的。根据我们的经验，我们可以指出，高分辨率相干函数的使用会导致迁移的GPR配置文件具有高度的双曲线聚焦。这些配置文件有利于对感兴趣的目标进行更好的成像，从而可以进行更可靠的解释。