This document discusses a proposed approach for multi-focus image fusion using a discrete cosine wavelet sharpness criterion. Multi-focus image fusion combines information from multiple images of the same scene to produce an "all-in-focus" image. The proposed approach uses a discrete cosine transform to calculate sharpness values for sub-blocks of the input images and selects the sharpest sub-blocks to include in the fused image. Experimental results on images of a clock, bottle, and book show the discrete cosine wavelet criterion produces fused images with higher quality than a bilateral gradient-based sharpness criterion, as measured by mutual information metrics.