Algorithms for improving the performance of conventional tone mapping operators (TMO) by calculating both a contrast waste score and a contrast loss score for a first tone-mapped image produced by the TMO. The two contrast scores can be used to optimize the performance of the TMO by reducing noise and improving contrast. Algorithms for generating an HDR image by converting non-linear color space images into linear color space format, aligning the images to a reference, de-ghosting the aligned images if necessary, and merging the aligned (and potentially de-ghosted) images to create an HDR image. The merging can be performed with exposure fusion, HDR reconstruction, or other suitable techniques.