## 3 Results and Discussion
### Spectral Consistency  
The results for the spectral consistency evaluation are outlined in Tables 2-8 below. The CC results are indicative of spectral similarity between the fused image and original multispectral image. The values range from \(-1\) to \(+1\) and the ideal value is considered to be close to \(1\). While this metric is quite popular, one of its disadvantages is that it is insensitive to a constant gain and bias between two images and is not able to distinguish subtle fusion artifacts. The results indicate that the IMVM method produced the best results followed by the RCS method. The worst results were produced by the Brovey method. The ERGAS results are indicative of the spectral distortions in the fused image. This gives an indication of the general quality of the fused image at a global level. Lower values are considered more ideal and the domain values range from zero to infinity. The best results were produced by the IMVM pansharpening method while RCS was second. The Brovey method performed poorly. The UIQI results show the spectral and spatial distortions in the fused image. Results of this similarity index point to correlation losses as well as distortions in luminance and contrast. The domain values range from \(-1\) to \(1\) and values close to \(1\) are considered ideal. The ideal value for UIQI is \(1\). The IMVM pansharpening algorithm produced the best results while the RCS method took second place. The worst results were produced by the Brovey method. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**BAND \#** & **BAY** & **BRO** & **CNS** & **EHLERS** & **GRS** & **IMVM** & **MIHS** & **PANSHARP** & **PCA** & **RCS** & **WAVELET** \\ \hline
1 & 0.610 & 0.008 & 0.049 & 0.719 & 0.569 & 0.973 & 0.721 & 0.614 & 0.307 & 0.921 & 0.548 \\
2 & 0.524 & 0.004 & 0.046 & 0.532 & 0.472 & 0.972 & 0.569 & 0.539 & 0.278 & 0.869 & 0.786 \\
3 & 0.473 & 0.009 & 0.046 & 0.345 & 0.475 & 0.972 & 0.375 & 0.491 & 0.308 & 0.776 & 0.866 \\ \hline AVERAGE & 0.536 & 0.007 & 0.047 & 0.532 & 0.505 & **0.972** & 0.555 & 0.548 & 0.298 & 0.856 & 0.733 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Spectral consistency: universal image quality index (UIQI). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**BAND \#** & **BAY** & **BRO** & **CNS** & **EHLERS** & **GRS** & **IMVM** & **MIHS** & **PANSHARP** & **PCA** & **RCS** & **WAVELET** \\ \hline
1 & 0.655 & 0.499 & 0.690 & 0.714 & 0.586 & 0.970 & 0.721 & 0.620 & 0.579 & 0.913 & 0.645 \\
2 & 0.587 & 0.407 & 0.560 & 0.584 & 0.498 & 0.969 & 0.585 & 0.556 & 0.533 & 0.866 & 0.870 \\
3 & 0.540 & 0.546 & 0.452 & 0.410 & 0.509 & 0.968 & 0.415 & 0.512 & 0.543 & 0.786 & 0.907 \\ \hline AVERAGE & 0.594 & 0.484 & 0.567 & 0.570 & 0.531 & **0.969** & 0.574 & 0.562 & 0.552 & 0.855 & 0.808 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Spectral consistency: correlation coefficient (CC). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**BAND \#** & **BAY** & **BRO** & **CNS** & **EHLERS** & **GRS** & **IMVM** & **MIHS** & **PANSHARP** & **PCA** & **RCS** & **WAVELET** \\ \hline
1 & 0.655 & 0.499 & 0.690 & 0.714 & 0.586 & 0.970 & 0.721 & 0.620 & 0.579 & 0.913 & 0.645 \\
2 & 0.587 & 0.407 & 0.560 & 0.584 & 0.498 & 0.969 & 0.585 & 0.556 & 0.533 & 0.866 & 0.870 \\
3 & 0.540 & 0.546 & 0.452 & 0.410 & 0.509 & 0.968 & 0.415 & 0.512 & 0.543 & 0.786 & 0.907 \\ \hline AVERAGE & 0.594 & 0.484 & 0.567 & 0.570 & 0.531 & **0.969** & 0.574 & 0.562 & 0.552 & 0.855 & 0.808 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Spectral consistency: correlation coefficient (CC).