High-Speed Measurement of Tunnel Front faces with a CCD Camera

1991年上半年主要从事“CCD相机标定中的目标检测”和“地面测量在线CAD的设计与开发”的研究工作。这些原本计划在早些时候完成。下半年是用来做报告的。研究结果如下：(1)目标检测——由于CCD相机的像素尺寸比较大，在标定CCD相机时必须使用特殊的目标。我们使用了球形目标，这样它们就可以在任何方向上被成像。但由于需要非常灵敏的照明来获得真实的圆图像，因此无法获得实际的测量精度。(2) CAD系统的开发——数字盘片的本质是CAD，所有的设备和测量工作都是CAD控制的。我们开发了一个CAD系统来在线绘制测量站点的图形。由于数字绘图仪在实践中还不成熟，我们将其与全站仪联系起来，并将整个系统发布为“基于cad的平面表测量系统”。

The former of the year 1991 was devoted to the research works : "Target Detection for CCD Camera Calibration" and "Design and Development of the ON-line CAD for Ground Surveying". These were originally scheduled to have been done earlier. The latter half of the year was used for making reports. The research results are as follows :(1) Target Detection--- For CCD camera calibration we have to use special targets because the pixel sizes of CCD cameras are relatively large. We employed spherical targets so that they are imaged to circles whatever directions they are sighted in. But since the very sensitive illumination is required to get true circle images, we could not obtain practical measurement precision.(2) Development of the CAD system--- The essence of digital platters is CAD with which all devices and survey works are controls. We developed a CAD system to depict figures on-line at survey sites. Sinice digital plotters are now still immature for practice, we linked this to a total station and published the whole system as "CAD-Based Plane Table Surveying System".