Thank's all for your answers. I will use the LUT method, cause is the most right for me.
Chaitanya said : "Gamma correction is more related to displaying the data than the data itself". Not in my case. I have to do this correction. But how to do that? Do i embed a VRT with a contrast correction LUT, in another VRT with a gamma correction LUT ? Or there is a method to declare LUTs in order to execute in the same vrt ? Thank's again ! 2012/3/20 Brent Fraser <[email protected]> > I like to use gdal_contrast_stretch from > http://www.gina.alaska.edu/projects/gina-tools/ > > Usage: gdal_contrast_stretch <src.tif> <dst.tif> > { { -linear-stretch <target_avg> <target_stddev> } | > { -percentile-range <from: 0.0-1.0> <to: 0.0-1.0> } | > { -histeq <target_stddev> } } > [ -ndv <no_data_val> ] > Input must be either 8-bit or 16-bit. Output is 8-bit. > > For example: > > gdal_contrast_stretch -percentile-range 0.02 0.98 input16bit.tif > output8bit.tif > > Best Regards, > Brent Fraser > > > On 3/20/2012 9:55 AM, Saâd HESSANE wrote: > > Hi list, > > I use gdal_translate to convert 16bits images to 8bits images. The > gdal_translate have the -scale argument to specify the convertion range > (source->destination). > If I change the destination range (dst_min and dst_max), I can do manually > a brightness correction (also a contrast correction). > > But is there any way to do that with a Photoshop like method? > For example set a brightness to -50, a contrast to +8 and let > gdal_translate do the job ? > > Also can I apply a gamma correction? > > I saw the VRT format and there's a way to apply a LUT. But I don't think a > LUT of 65536 values is the best way to apply the correction. > > Also the VRT have the scale ratio and scale offset elements. I think it > can be useful but I don't understand how use it... > > So simply put, my question : can I do a contrast, brightness or gamma > correction to a raster with gdal? > > Thank you ! > > PS : I apologize for my broken English ! > > > _______________________________________________ > gdal-dev mailing > [email protected]http://lists.osgeo.org/mailman/listinfo/gdal-dev > >
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