4 Results

The $F_{\rm En}(j, k)$ images obtained through the relation (2) are shown in Fig. 5. It is possible to see how the images showing more spatial details are those obtained by using the second and the third principal component (Figs. 5b and 5c). Figure 5a does not contain any spatial detail; this fact was quite expected because the PC1 image is not sensible to the spectral content of the data. In order to quantitatively evaluate the performances of the enhancement technique in terms of spatial details, in Fig. 6 horizontal profiles across Bessel and Dawes craters taken, respectively, on the $F_{\rm R}$ and $F_{\rm En}$ images are shown. Here, we have used $F_{\rm En}$ obtained by means of the PC2 and PC3 images. Note the great increase of spatial contrast. The two peaks visible in the center-right plots correspond to the western and eastern rim of the two craters. The technique has spatially resolved the rims of the Bessel and Dawes craters, not visible in the raw image. The effect of the technique has been to remove the surrounding mare contribution from the compositional different craters rim.

  

Figure 5: Enhanced images obtained by means of relation (2). b-c) show more spatial details respect to the raw image shown in Fig. 2

  

Figure 6: Profiles across the Bessel and Dawes craters taken on the 0.7 $\mu$m raw images (left panels) and the PC3 images (center and right panels). Note how the spatial contrast has been improved