Grant, All we are trying to say is that -normalize may lose data. As you are on a rather old system. I would suggest, you simply try using -contract-stretch 0 rather than -normalize and see what happens.
Each image is different. Thus it may need custom tuning. You may not be able to use one technique across the boards. You can try -contrast-stretch with various percentages until you find something you like. You may even need to try other techniques as there is no one best way to process every image. You can use -level as another approach to try, but again you may have to tune the values it uses to your image to get the best results. I know nothing about how to do this in perlmagick, but there is User Group for that on the discourse server at http://www.imagemagick.org/discourse-server/. You can inquire there. Good luck Fred > > With regard to my suggestion for using -contrast-stretch, I would >> note that it also uses a histogram to stretch the image. >> >> The other way to do this is to feed the min and max image values to >> -level. Anthony Thyssen has recently greatly improved this function. >> So in unix with a shell, you could do (in IM 6.3.9-1 or higher) >> >> min=`identify -format "%[min]"` >> max=`identify -format "%[max]"` >> convert <inputimage> -level ${min},${max} <outputimage> >> >> That would be the most exact method for stretching the image so that >> it just exactly spans the range from 0 to QuantumRange, i.e. from >> full black to full white. >> >> >> See notes about -level (and +level) at >> http://www.imagemagick.org/Usage/color/#contrast > >Thanks for the help guys. Anthony points to Fred's work and Fred >points to Anthony's work. I'm a little confused on the best way to do >this. Is it the above? I'm using imagemagick-6.3.8.3-r1 with >perlmagick. > >- Grant _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
