Hi! Some of you may now that I am working on a raw denoising algorithm. One of the hard thing was that prior to demosaic, the algorithms are computed on unscaled data, while after demosaic the algorithms can compute a preview on a downscaled image, which is easier in terms of speed.
So I tried to downscale the raw data, to be able to use that for preview. There was 2 existing algorithm in darktable to do that (thank you Johannes for showing me these algorithms!): dt_iop_clip_and_zoom_mosaic_half_size_f for bayer files and dt_iop_clip_and_zoom_mosaic_third_size_xtrans_f for xtrans files My problem was that they only allow to downscale the images by a fixed factor (2 in the case of bayer, and 3 in the case of xtrans). So I designed an algorithm, that work on both bayer and xtrans, and that can be used whatever the scale factor. The source code is available here: https://github.com/rawfiner/darktable/tree/rawfiner-fix-downscale-algo (commit 9992cf66fc8510f637e5e5f8ae26c49c2cba2eaa) The graphic interface in raw denoise module is just here to be able to see the effect of the algorithm in "fit to screen" zoom mode, and to activate or desactivate the algorithm. It allows to compare what we get by downscaling the picture before demosaic to what we would obtain without this downscaling. The first slider controls the downscaling factor (0.25 means that width is multiplied by 0.25, thus divided by 4) The second slider is useless for now. I made a quick video to compare the algorithm with the existing ones, and to explain how the algorithm work: https://youtu.be/oE38w1YOhNQ Sorry for the slow speed of speech, I am not used yet to do videos in english ;-) You can also find some examples here: https://drive.google.com/open?id=19xveG0EeF2RUjlRjDTs1AA9f-TnFZe2W cheers, rawfiner ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
