*3.1. A Framework of the Methodology*

The developed original MCDM methodology for the qualitative rating (selection) of lossy compression algorithms for aerial images includes seven essential stages:


The generalized framework for the implementation of the methodology is presented in Figure 1.

**Figure 1.** The framework for rating the lossy compression algorithms and their compression ratios by their qualitative suitability for the aerial images. Different colors present stages related to the data selection, lossy compression (alternatives), lossy compression evaluation by the qualitative parameters (criteria) and data processing for qualitative ranking of lossy compression.

> The transform-based lossy compression algorithms—JPEG2000, ECW, and JPEG were selected to implement our methodology. The algorithms were ranked by the amount of the distortions introduced to the aerial image, estimated using: (a) the supervised objective image quality measures; (b) subjective evaluation; (c) the change in the appropriate firstorder statistical measures; (d) the change in the second-order statistical measures. The novelty of the approach is the use of a weighted combination of different qualitative parameters for lossy compression estimation compared to the estimation using only single objective image quality metrics. Thus, the effect of lossy compression on the image content can be evaluated more precisely. This also allows targeting different subtasks, either altering the weights or the set of aspects: the same approach can be used to assess the texture or color quality after the compression.
