Abstract: Because of the limitation of measurement methods in traditional visual detective systems, the measured objects are always confined to those parts with small size, and the measurement systems are also lacking in versatility. When the targets are buildings or tanks having bulky size and fixed location, it is very difficult to measure their size with traditional visual detective systems. A vision measurement system proposed in this paper avoids the limitations of light source and standard parts on the measurement distance in traditional measurement methods. It utilizes two laser spots emitted by two laser range finders to determine the proportion relationship between the pixel and the actual geometric size and then calculate the measured dimensions. The experiment results show that the measurement accuracy of the system is better than 0.15 mm within distances of 200 m. Since this measurement method has no limits for the placement and distance of measured objects, it can be widely used in the dimension measurements of random objects. It can also be extended to the size measurement of dynamic targets.

Key words: test measurement technology and instrument, dimension measurement, machine vision, CCD