Reducing field distortion for galvanometer scanning system using a vision system

• Innovative and cost-effective method using a novel coaxially coupled vision system for reducing field distortions for galvanometer scanning systems.
• The required marking and measuring procedures of conventional methods is avoided and the possibility of introducing angular or orthogonal errors during the measuring procedures is reduced.
• The tasks for coupling conventional coordinate's tables and conventional scanning systems are simplified and possible angular and orthogonality deviations are reduced.
• The vision system is a powerful tool, not only for measuring target coordinates and calculating new correction tables, but also for other recognition tasks.
• The overall precision of the calibration process depends on the precision of the calibration plate and the resolution of the vision system.

Laser galvanometer scanning systems are well-established devices for material processing, medical imaging and laser projection. Besides all the advantages of these devices like high resolution, repeatability and processing velocity, they are always affected by field distortions. Different pre-compensating techniques using iterative marking and measuring methods are applied in order to reduce such field distortions and increase in some extends the accuracy of the scanning systems. High-tech devices, temperature control systems and self-adjusting galvanometers are some expensive possibilities for reducing these deviations. This contribution presents a method for reducing field distortions using a coaxially coupled vision device and a self-designed calibration plate; this avoids, among others, the necessity of repetitive marking and measuring phases.