A large variety of autofocus functions used for assessing image sharpness is evaluated for the application in a passive autofocus system in the context of microindentation-based Vickers hardness testing. The functions are evaluated on a significant dataset of microindentation images with respect to the accuracy of sharpness assessment, their robustness to downsampling the image data, and their computational demand. Experiments suggest that the simple Brenner autofocus function is the best compromise between accuracy and computational effort in the considered application context.
展开▼
