What is the difference between active target and passive target used in zoom visual displacement monitor for structural health monitoring based on machine vision?

The most direct difference must be that one needs electricity to shine and the other doesn't. Therefore, the active target needs power supply and wiring, and the passive target does not need power supply and wiring, which saves the trouble of on-site wiring and is more efficient and convenient to install. Very suitable for slopes, geological disasters, mines and other scenes without commercial power. But at present, most of the machine vision measuring instruments on the market are active targets, and there are still many unsolved problems in the intelligent identification and accuracy of passive targets. However, we have recently seen the latest data released by Anrui Measurement and Control official website, which has overcome this series of problems. The latest series of machine vision measurement not only introduces passive targets, but also comes with codes and self-defined targets, which can automatically identify the spatial position information of targets, thus better measuring displacement changes with high accuracy.