3 ms·
In the images in the blog post and the live map? Those aren’t pansharpened at all. If we do add pansharpening in a later version, it’ll likely be naïve, without
by celoyd 12y ago
In the images in the blog post and the live map? Those aren’t pansharpened at all. If we do add pansharpening in a later version, it’ll likely be naïve, without spatially aware modeling of the multispectral data. (Specifically, it’ll probably be a cleaned-up, rasterio-based, null-aware, parallelized descendant of this sketch of the Brovey transform in numpy: https://gist.github.com/celoyd/2e7beed82951d22b9b90 https://gist.github.com/celoyd/2e7beed82951d22b9b90 .)
From what I’ve seen – and I haven’t tested it carefully yet, so I could be wrong – the more elaborate methods are severe overkill on Landsat 8. It has only 4 pan px per multi px (where some commercial data has 9 or 16), and the pan band is almost exactly R+G+B (without NIR). So my gut and some simple experiments suggest that doing PCA-or-whatever is overthinking it.
- sjtrny 12y agoIn the blog post > Pansharpened Malibu, 15 m (50 ft) per pixel. Notice the wave texture in the water. Ugh, Brovey. There's better options available. Like MMP (really low spectral distortion but can be slow): http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6677587 http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6677587) or even affinity/guided filtering (my own paper, more spectral distortion than MMP but a lot faster and you can sharpen hyperspectral with multispectral or RGB): http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7008094 http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7008094.