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How can i remove this watermark...

Posted: 2009-08-10T16:05:58-07:00
by vanhoa
Hello, I have an image like this:

Image

I want to remove the center text (VuiLen.com) since sometimes it makes the comic page harder to read...
With photoshop I can do this by:
1. Hue Composite the original image with an same-size image filled with ED8EEB (237,142,235)
2. Use the Color Dodge Composition for the result image with an same-size image filled with 127114 (18,133,20)
3. Saturation the result image with black (000000)
4. Multiply the result image with itself about 2-5 times
and the result is like this:

Image

How can I do this with imagemagick?
And can you find a better solution? (This method is not good... It remove not only the text but also the light parts of the image...)

Thank you very much,
vanhoa

Re: How can i remove this watermark...

Posted: 2009-08-10T17:38:06-07:00
by fmw42
try this:

convert Untitled3.jpg -colorspace HSB -channel B -separate -channel rgb -white-threshold 75% Untitled3_b_wt75.png

Image

Re: How can i remove this watermark...

Posted: 2009-08-10T20:18:42-07:00
by anthony
What you really want is to somehow remove just the color parts.

The colors are however added to all three color channels, which makes it much more difficult.

However your steps do not define what 'Hue Composite' does!!! and how it composes with the specific color you describe. Where did you get these steps from?

I look forward to other peoples responses to this problem!



NOTE: once you have the technique down, apply the exact same operators to a HALT: image. You can than very quickly re-apply ALL the color modifications to ANY image using that modified HALT image!
http://www.imagemagick.org/Usage/color/#hald-clut

Re: How can i remove this watermark...

Posted: 2009-08-10T22:29:06-07:00
by vanhoa
Thank you fmw42, works very well :)

To anthony, I use the word 'Hue Composition' from Photoshop. About the steps... I dont know why I can find it, I opened Photoshop, think about the result, and try the steps I can think up and see the result... But I really dont know how can I obtain them :? Sorry for my bad English

Re: How can i remove this watermark...

Posted: 2009-08-11T00:21:49-07:00
by vanhoa
fmw42, your solution has a little prblem with this image

Image

Re: How can i remove this watermark...

Posted: 2009-08-11T01:53:15-07:00
by anthony
I think the best steps would be to first isolate the pixels that are 'colorful'.
then figure out how type of color should be removed.

If the exact same watermark is being used on the exact same sized image, over and over, then on step would be to recover the watermark that was used, in terms of color and transparency.

What that the difference between the water mark and the specific color should be able to be extracted, especially once the 'transparency' is known, so you know how much a specific color is watermark and how much original image.

That is it should be posible to recover a near perfect replica of the original image!!!

Re: How can i remove this watermark...

Posted: 2009-08-11T02:36:26-07:00
by vanhoa
The wartermark position is not the same in each image...
About the transparency, we can get the level easily by comparing the color at the pink-wartermarked blackest pixel and the pink-wartermarked whitest pixel.
...

Here is the detailed steps in my solutions:

Here is the original (croped) image:
Image Image

Adding a upper layer filled with pink (ED8EEB:237,142,235) and compositing by Hue composition:
Image Image Image

Adding a upper layer filled with green (127114: 18,133,20) and compositing by Color dogle composition:
Image Image Image

Saturation with a upper level black-filled image:

Image Image Image

Flatten the layers, multiply the result image by itself:
Image Image

And it's the final image. Compare it (right) with the original (left):
ImageImage

Re: How can i remove this watermark...

Posted: 2009-08-11T03:07:15-07:00
by vanhoa
I've found 2 other solutions:


First:
Image
Layer 1 is the original image with only the blue chanel (subtracted the red chanel and the green chanel).
Layer 2 is the original image, compositing with the layer1 by "Soft Light".
____________________________
Second:
Image
Layer 1 is the original image, applied the "Sharpen edge" filter.
Layer 2 is filled with ED8EEB, compositing method is "Hue".
Layer 3 is filled with 127114, compositing method is "Color dodge".
Layer 4 is filled with 127114, compositing method is "Overlay".
Layer 5 is filled with ED8EEB, compositing method is "Overlay".
Layer 6 is filled with 000000, compositing method is "Saturation".

Re: How can i remove this watermark...

Posted: 2009-08-11T08:06:56-07:00
by fmw42
try post processing your result with my approach (and vary the threshold value if needed)

Re: How can i remove this watermark...

Posted: 2009-08-11T11:02:59-07:00
by vanhoa
Hello fmw42, I really new to imagemagick and it seems that I can not write the code myself... Please help me :(

Re: How can i remove this watermark...

Posted: 2009-08-11T11:57:14-07:00
by vanhoa
well this works:

Code: Select all

\( +clone -colorspace HSB -channel B -separate -channel rgb -white-threshold 80% \) +swap -channel rgb -compose overlay -composite -colorspace Gray
Image

Re: How can i remove this watermark...

Posted: 2009-08-11T18:42:30-07:00
by vanhoa
I've tried to remove the wartermark with php, just recolor the color pixel and here is the result:

Image

8)