georgedvore opened this issue on Apr 22, 2004 ยท 6 posts
georgedvore posted Thu, 22 April 2004 at 8:55 PM
Hi there! i was wondering whether the following is possible: say i have a picture of as person or object. the original creator has applied the watercolour filter & saved the image as a .jpg. is there any way i can use a filter on the jpg to reverse the watercolor filter & get back to the original picture. bear in mind only the watercolour filter has been applied. unknown settings. any info on this will be greatly appreciated Thanks:o) GDV
Hoofdcommissaris posted Fri, 23 April 2004 at 2:25 AM
It is impossible (as are those supersharp partial enlargings they do on CSI), to be honest. The pixels of the image are not only shuffled to get the desired effect, their color and lightness has been altered too. Without any memory of their previous live. Actually, they aren't the pixels they were used to be. Theoretically I think it should be possible to analyze the workings of the filter and reverse them, with every possible setting, if you can find someone who is REALLY good at programming and has a lot of time on his hands. The basis would not be the image but the filter, to reverse the process. But then again, the market is probably way to small for an expensive science project like that.
georgedvore posted Fri, 23 April 2004 at 5:30 AM
thats what i thought regarding the way to do it - just remember seeing some stuff related to the mathemathica site about custom filters. thanks for the info m8:o)
RHaseltine posted Fri, 23 April 2004 at 8:50 AM
Not every filter would be reversible, even in theory. If levels or curves have moved two different RGB values into one (as usually happens) then there is no way to undo that, even if you know the exact settings used. Posterise would be another irreversible effect. I strongly suspect that watercolour would be another case where there is just no going back, even in theory.
Hoofdcommissaris posted Fri, 23 April 2004 at 8:58 AM
I have been thinking about it all day. Watercolor is one of those filters in which the result depend on the actual pixelcolors, they get mixed. But different components can result in similar pixel colors, so I guess there is no way to determine how the pixel color was created. So I think RHaseltine is right. Even in theory you are doomed. You will never see that face behind the filter.
georgedvore posted Fri, 23 April 2004 at 2:57 PM
drat!