Liqua-Telecentric Autofocusing System

The project requires the team to design and test a telecentric optical system with autofocus capabilities for machine vision. The design integrates a liquid lens into an existing telecentric lens system, and incorporates both optical components with a control algorithm. The liquid lens provides the autofocus function without the use of mechanics to adjust the focus. The team had to solve problems such as camera selection, thermal stability, autofocus, maintaining object space telecentricity, and minimizing magnification change with focus. The algorithms accurately report to the user a view of the current focus and provide metrics for the user to decide how much to adjust the focus. The system was tested to meet optical specifications in a mounted environment with the test objective back-illuminated by a sodium source. Images captured of the test objective are processed against the magnification and modulation transfer function requirements and an adjustment to the focus of the system is patched to the liquid lens driver. Automating the focusing of this system allows for more efficient monitoring of any manufacturing process in which machine vision is a tool for qualitative analysis.