2015-05-13, 08:52 PM
De-logo Patch Technique™
What is the De-logo Patch Technique™?
It's a method to get ridden of a logo (usually TV) using a second source to obtan a "patch" that will cover it.
How does it work?
It's quite simple: you need two sources aligned (spatially and temporally); then, take a portion of the source without logo, to make a "transplant" to cover the source with logo; you could do a simple geometrical shape patch - to be the shape of the logo, make elaborated, multi shaped patch - like several simple geometrical shapes put together, to cover for example a logo composed by letters, numbers, symbols etc. or make a mask that cover perfectly the logo.
Why use it, if you have a source without logo?
Good question! Usually, you want to de-logo an high quality source - like a 1080i/p HDTV broadcast, which is the only one available, while lower quality sources are available - 720p HDTV, WEB download, DVD etc.
Using this technique, you have the best quality for the whole image, except for the patch which covers the logo.
What if there is not another source?
Then this technique couldn't be used; you must use another de-logo method, that usually cover the logo interpolating the surrounded details.
Some examples
Here you are the original frame (left), the mask (center) used for a classic de-logo method, and the overlaid mask (right) before the de-logo - (click for 2x zoom):
[Image: original_mask_overlay.jpg]
Now, the original frame (left), a classic de-logo method (center), and the De-logo Patch™ (right) - (click for 2x zoom):
[Image: original_classic_patch_116266.jpg]
The classic De-logo method seems to work well... right? Yes, but only in some shots, usually the most static... see the next examples - two consequential frames:
[Image: original_classic_patch_43828.jpg]
[Image: original_classic_patch_43829.jpg]
Pretty neat, right? WARNING: I haven't tested enough the classic De-logo filter; with carefully chosen settings, it certainly could work better, but it will always produce some artifacts.
The quality of the final result varies, of course, depending on the quality of both sources; near perfect solution is to find two 1080i/p HDTV versions, both with a logo in a different part, and use one as the patch for the other, and vice versa!
Advanced method (updated 2017-11-30)
In some cases, the sources used for this technique have different color grading and/or contrast; it would not be possible to use the De-logo Patch Technique™ "as is"; you first have to regrade one source using the other as a reference, to get a patch as much similar as the source that should be delogo'ed.
Sometimes, the regrade could not be perfect, and the eyes (well, the brain attached to them) are very good to notice some imperfections, in particular straight lines, so to fool them, you could use a variation of the simple logo mask, covering the straight lines and making them less noticeable - I suggest to do a loop of various masks, so every subsequent frame would get a different mask. Also, very important, add a grain plate to the patch, to disguise even more the eventual logo remains.
From top left: untouched HDTV, untouched WEB-DL, simple overlay using untouched sources and a simple logo mask, advanced overlay using colormatched source for the patch, different variation masks, grainplate for the patch and for the final result (and also a color correction, that is beyond this technique)
Variations of the logo mask:
What is the De-logo Patch Technique™?
It's a method to get ridden of a logo (usually TV) using a second source to obtan a "patch" that will cover it.
How does it work?
It's quite simple: you need two sources aligned (spatially and temporally); then, take a portion of the source without logo, to make a "transplant" to cover the source with logo; you could do a simple geometrical shape patch - to be the shape of the logo, make elaborated, multi shaped patch - like several simple geometrical shapes put together, to cover for example a logo composed by letters, numbers, symbols etc. or make a mask that cover perfectly the logo.
Why use it, if you have a source without logo?
Good question! Usually, you want to de-logo an high quality source - like a 1080i/p HDTV broadcast, which is the only one available, while lower quality sources are available - 720p HDTV, WEB download, DVD etc.
Using this technique, you have the best quality for the whole image, except for the patch which covers the logo.
What if there is not another source?
Then this technique couldn't be used; you must use another de-logo method, that usually cover the logo interpolating the surrounded details.
Some examples
Here you are the original frame (left), the mask (center) used for a classic de-logo method, and the overlaid mask (right) before the de-logo - (click for 2x zoom):
[Image: original_mask_overlay.jpg]
Now, the original frame (left), a classic de-logo method (center), and the De-logo Patch™ (right) - (click for 2x zoom):
[Image: original_classic_patch_116266.jpg]
The classic De-logo method seems to work well... right? Yes, but only in some shots, usually the most static... see the next examples - two consequential frames:
[Image: original_classic_patch_43828.jpg]
[Image: original_classic_patch_43829.jpg]
Pretty neat, right? WARNING: I haven't tested enough the classic De-logo filter; with carefully chosen settings, it certainly could work better, but it will always produce some artifacts.
The quality of the final result varies, of course, depending on the quality of both sources; near perfect solution is to find two 1080i/p HDTV versions, both with a logo in a different part, and use one as the patch for the other, and vice versa!
Advanced method (updated 2017-11-30)
In some cases, the sources used for this technique have different color grading and/or contrast; it would not be possible to use the De-logo Patch Technique™ "as is"; you first have to regrade one source using the other as a reference, to get a patch as much similar as the source that should be delogo'ed.
Sometimes, the regrade could not be perfect, and the eyes (well, the brain attached to them) are very good to notice some imperfections, in particular straight lines, so to fool them, you could use a variation of the simple logo mask, covering the straight lines and making them less noticeable - I suggest to do a loop of various masks, so every subsequent frame would get a different mask. Also, very important, add a grain plate to the patch, to disguise even more the eventual logo remains.
From top left: untouched HDTV, untouched WEB-DL, simple overlay using untouched sources and a simple logo mask, advanced overlay using colormatched source for the patch, different variation masks, grainplate for the patch and for the final result (and also a color correction, that is beyond this technique)
Variations of the logo mask: