3D Motion Analysis based on Optical Doppler Imaging

今年的研究重点是外差模式飞行时间相机的原理。外差模式飞行时间相机将目标径向速度编码到测量值中，与传统的飞行时间传感相比具有独特的优势，在高速速度传感中具有广阔的应用前景。该方法对传统方法进行了极大的扩展，使其精度更高、鲁棒性更强、易于获取。在这项研究中，建立了一个新的框架，可以同时解码距离和速度从四个测量。通过一种新颖的理论讨论，我提出了一种最适合速度传感的外差频率。首次明确了目标距离对速度传感精度的巨大影响。最后提出了两种译码方法，一种是基于优化的译码方法，另一种是快速译码方法。该方法在商用设备组成的硬件平台上进行了验证，与传统方法相比，在精度和鲁棒性方面有明显提高。这项工作是第一次深入的理论讨论外差模式飞行时间相机的速度传感。指出了传统工作的局限性和错误，并在理论讨论的基础上提出了一种先进的方法。该方法是目前唯一能够实现速度的瞬时、全场成像的方法，将对传感、机器人等领域产生巨大影响。本研究暂时被相关领域的顶级期刊接受。

This year, the research concentrated on the principles of heterodyne-mode time-of-flight cameras. Heterodyne-mode time-of-flight cameras encode the target radial velocity into the measurement, which is unique compared with conventional time-of-flight sensing, and is promising for high-speed velocity sensing. The proposed method greatly extends the conventional method, making it more accurate, more robust, and more accessible.In this study, a new framework that can simultaneously decode distance and velocity from four measurements is built. With a novel theoretical discussion, I proposed a heterodyne frequency that is optimal for velocity sensing. For the first time, it was made clear that the target distance has a huge influence on the velocity sensing precision. Finally, I proposed two decoding methods, including an optimization-based decoding and a fast decoding method. The proposed method is validated on a hardware platform composed of commercially available devices and has obvious improvement compared with conventional work in terms of accuracy and robustness.This work is the first thorough theoretical discussion on heterodyne-mode time-of-flight cameras for velocity sensing. I pointed out the limitations and mistakes of the conventional work, and proposed an advanced method based on the theoretical discussion. The proposed method is the only method that can make instantaneous, full-field imaging of velocity, which will have a huge impact in the field such as sensing and robotics. This study is provisionally accepted by a top journal in the related field.