*4.7. Overall Comments*

When the numerical values from the seven spectral metrics for three different test sites (Tables A1, A3 and A5) were evaluated, the proposed CIELab had a consistent behavior for different metrics and for different land categories, and ranked as the first among all methods. On the other hand, for the other Pan sharpening methods, different metrics provided various accuracies and did not show a consistent manner for different metrics and even, for different images, the same metric. As an example, the GS method generally had the second ranking for the ERGAS metric for different test sites. However, in the case of the RASE metric, the GS method had second ranking just for some images, while the GIHS method took the second rank for the remaining images. This phenomenon is similar for the worse results; there is no one method that can be mentioned as the worst for all test sites and all metrics. All facts about the consistent manner of the proposed method can also be asserted for the spatial metrics. The CIELab method had the best spatial performance for the all ten test sites, while second through seventh rankings were variable across different metrics and different images. As an outcome, it is evident that the proposed method presents the best results considering spectral and spatial quality metrics and visual interpretation for ten different sites having different landscape characteristics. Moreover, it provided efficient spectral conservation performance according to comparative evaluation performed with binary classification of VARI index. An overall ranking

is provided in Table 5, according to expert judgement by considering the quantitative, metric-based results and visual interpretation results together for different landscapes across spectral and spatial domains. Lastly, in order to check the consistency of spectral quality indices through each band of the images, these indices were calculated band-by-band for the test site F3 (Table A7). According to this evaluation, the averaged values for each index are in accordance with the band-based calculations and indices, providing consistent characteristics across image bands in most of the cases.

**Figure 4.** Comparison of visible atmospherically resistant index (VARI) index results extracted from multispectral (MS) and CIELab pansharpened images of test site F3. (**a**) Original MS, (**b**) threshold applied VARI of MS, (**c**) zoomed region from VARI of MS, (**d**) original CIELab, (**e**) threshold applied VARI of CIELab and (**f**) zoomed region from VARI of CIELab.


**Table 5.** The overall relative ranking of the methods evaluated.
