Speckle modulation in the laser beam projection scenarios such as adaptive optics, remote sensing, and active imaging has been a long-standing challenge that causes intensity fluctuation and further degrades the performance of the system. Speckle statistical characteristics coupled with the feature of the laser beam intensity distribution can be obtained by analyzing the speckle variation through a single point detector or an image sensor. A single point detector has the advantage in high sampling rate but may lose speckle spatial information, while the image sensor has a high spatial resolution but slow sampling rate. In this paper, we defined a dynamic speckle metric based on a linear array detector to estimate the encircled energy of the far-field spot on the diffuse target, which well balanced the trade-off between sampling rate and spatial resolution. The potential of the metric is analyzed using a physics-based speckle simulation and experimental verification. Both results agree with each other, showing that the metrics based on the speckle-field spatiotemporal spectrum analysis are monotonically dependent on the target focused-spot size.

自适应光学、遥感和主动成像等激光束投影场景中的散斑调制一直是一个长期存在的挑战，会导致强度波动并进一步降低系统性能。通过单点检测器或图像传感器分析散斑变化，可以获得散斑统计特征与激光束强度分布特征相结合的特征。单点探测器的优点是采样率高，但可能会丢失散斑空间信息，而图像传感器的空间分辨率高，但采样率低。在本文中，我们定义了一种基于线阵检测器的动态散斑度量来估计漫射目标上远场光斑的环绕能量，这很好地平衡了采样率和空间分辨率之间的权衡。使用基于物理的散斑模拟和实验验证来分析度量的潜力。两个结果相互一致，表明基于散斑场时空谱分析的指标单调依赖于目标聚焦光斑大小。