Design of Coded Targets and Automated Measurement Procedures in Industrial Vision Metrology

In industrial photogrammetric measurement with CCD cameras, the number of target images may amount to several hundred when large and complex objects are involved. It is therefore impractical to use solely manual means to identify these image points. This paper reports on a further design for coded targets, which can be automatically located and identified, and it also discusses special arrangements of reference targets called exterior orientation devices. These can be employed in conjunction with new computational schemes for sensor orientation to facilitate automated data processing. Procedures adopted to ensure sufficient speed and reliability in automated off-line digital photogrammetric measurements employing these developments, which have been found in practise to reduce data processing time by as much as 93%, are discussed and experimental results are reported.