**5. Image enhancement**

Image enhancement methods can be applied to biomedical image data to more effectually render the data for subsequent analysis and interpretation. The selected algorithm may manipulate: the contrast of a single image; the data of multiple images at the same time; or the spatial features in an original or derived image [25]. The output image data tends to have intensified visual distinctions that are useful for both digital and visual analyses. As already mentioned, applying image enhancement operations in Excel requires a new output worksheet for resampling, in which the appropriate formula is applied to one cell and then copied to additional cells within the dimension of the original data. The original source data worksheets are retained and referenced in entering the formulas. The procedures used to implement these enhancements have been exemplified in [16, 17].
