Development of a Field-Portable Omnidirectional Video System to Quantify Three-Dimensional Motion

为了研究自然环境中的运动，特别是户外运动，开发了一种电池供电的防风雨双摄像机视频系统和计算机分析系统。在数据收集系统中，每个摄像机都由操作员进行定向和聚焦。相机将能够平移和缩放，以便可以轻松地跟踪主题。设计用于研究生物运动的其它系统要求固定摄像机的方向，但是这里由两个光轴编码器（分辨率为0.036度）测量的摇摄和倾斜角度以及缩放因子（由线性轴编码器测量）以视频帧速率（30 Hz）存储在条形码中的图像上。通过同步锁相摄像机并将相同的SMPTE时间码与每个视频信号混合，两个视频图像在时间上同步。 图像处理系统由一个RISC工作站组成，该工作站运行软件来解码摄像机的平移和倾斜角度以及时间代码。此外，该软件可以计算每个视频帧中多个对象的质心的像素坐标。物体识别软件由SVS公司的Jack Sanders-Reed博士设计。最初用于武器试验场。它具有像素处理，背景杂波抑制，目标检测和描述，帧到帧跟踪模块。 来自两个摄像机的对象的质心的摄像机角度和像素坐标用于计算作为时间的函数的对象在三维空间中的位置。根据这些基本信息，可以计算其他重要的性能特征，例如速度、加速度和转弯半径以及不同物体之间的距离。新的图像分析技术将有助于自动处理视频图像，如果手动完成，这是一项时间密集型活动。 与其他15位科学家进行了一系列合作实验，旨在测试该系统在野外条件下研究若虫运动、动物行为和保护生物学的实用性和多功能性。这种仪器大大提高了我们量化户外运动和行为的能力。它将提供数据收集的灵活性和图像分析的能力，这是任何商业运动分析系统都无法比拟的。

To study motion in natural settings, especially out of doors, a battery-powered weather proof two-camera video system and computer analysis system are developed. In the data collection system each camera is oriented and focused by a human operator. The cameras will be able to pan and zoom so that a subject can be easily followed. Other systems designed to study biological motion require that the orientation of the cameras be fixed, but here the pan and tilt angles measured by two optical shaft encoders (resolution 0.036 degrees) and zoom factor (measured by a linear shaft encoder) are stored at video frame rates (30 Hz) on the image in bar code. The two video images are synchronized in time by genlocking the cameras and mixing the same SMPTE time code with each video signal. The image processing system is consists of a RISC workstation that runs software to decode the pan and tilt angles of the cameras and the time code. In addition, the software can compute the pixel coordinates of the center of mass of multiple objects in each video frame. The object recognition software was designed by Dr. Jack Sanders-Reed of SVS Inc. and was originally used at weapons test ranges. It features modules for pixel processing, background clutter suppression, object detect and description, and frame to frame tracking. The camera angles and pixel coordinates of the center of mass of the objects from both cameras are used to compute the position of the objects in three-dimensional space as a function of time. From this basic information other important performance characteristics such as velocity, acceleration and turning radius and the distance between different objects can be computed. The new image analysis techniques will help automate the processing of video images, which if done manually is a time intensive activity. A series of collaborative experiments with 15 other scientists is designed to test the usefulness and versatility of the system for the study of a nimal locomotion, animal behavior and conservation biology under field conditions. This instrumentation greatly increases our ability to quantify motion and behavior outdoors. It will provide flexibility in data gathering and power for image analysis that no commercial motion analysis system can match.