Le mercredi 27 janvier 2016, Matteo Niccoli a écrit : > Can something like this (which by the way I can't get to work): > http://stackoverflow.com/questions/3114925/pil-convert-rgb-image-to-a > -specific-8-bit-palette > > What I would like to do is this: > 1) Import an RGB image, which would have its own colormap - say this > one for example: > https://upload.wikimedia.org/wikipedia/commons/b/b3/Jupiter_new_hubble_view_above_pole.png
> 2) convert it to intensity, display the intensity color-mapped to the > same colours the original RGB had. According to the PNG header, this image does not have a palette (i.e. a list of colors). The data chunks define the image as an array of NxMx3 values (N rows, M cols, 3 channels=no alpha), each value being defined using 8 bits. I may however badly understand what you call the "own colormap"... You still can convert it to a grayscale img representing the intensity (NxM values), but you then lose some information and you cannot display it back with the same colors as originally. Because some different RGB tuple are converted into the same intensity level, you can then not discriminate them using the intensity image only. Maybe there is some trick to convert to a grayscale image where those RGB values are converted to almost-equal-but-different intensity levels that would enable the later reconstruction, but I am not aware of... Fabrice ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
