Image Fusion Combining Frequency Domain Techniques Based on Focus

Image focus is a property closely related to image quality. In some images it is not possible to obtain a clear focus in all regions simultaneously, so an alternative is to use image fusion to combine pictures with different focus into one with all the best-focused regions. This paper describes two image fusion algorithms in the frequency domain that are based on focus: Contrast in DCT domain and Spatial Frequency. The algorithms divide the images in fixed size blocks to decide which image should be selected to constitute the final result. Improvements are made to both techniques to decide when to choose an entire block or pixels individually. The proposed approach combines the different techniques (or different settings of a single technique), by comparing evaluation metrics (PSNR) values obtained for each block independently and selecting the technique that performs better for the analyzed block. The final image quality, evaluated using PSNR and RMSE, is superior compared to the results of the individual techniques.