Fast and precision image mosaic based on grating

In order to improve the speed and precision of image mosaic for IC vision inspection, a fast and accurate image mosaic technique based on precision grating measurement system was presented. The self-calibration method can solve the problem of conventional calibration affected by the manufacturing precision of standard unit and light intensity, and can increase the calibration accuracy and decrease the cost. After accurate calibration, the image mosaic model based on grating precision location was established. The experiments demonstrate that this system has high image mosaic precision, average error within 0.4 μm, and 0.872 μm in 2σ, which is up to sub-pixel precision; also the system has high mosaic speed, the time of two image mosaic is about 10 ms.