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Digikam: Share your tips / Ask a question

Discussion in 'Image Processing' started by mushmorok, Apr 15, 2011.

  1. mushmorok

    mushmorok Mu-43 Regular

    27
    Jan 5, 2011
    I wanted to start a discussion that would collect all kind of tips and tricks that can be done with Digikam, similar to the "Share your Lightroom tips - LR3" thread.
    Digikam IMHO is great at least for a novice, semi-pro photographers and as it is native linux app, it was my natural choice of photo editing software.
    And being quite a novice (at photo editing, not linux :) I cannot share any useful tips at this point, so instead I will start with asking you to help me with one task.
    I'm sure that there are members here, that know the answer already :biggrin:

    So what I'm trying to accomplish is to "rotate" this image on the Y axis so the left part of it to move "forward" and the right side to move "backward" a little bit.

    3253764_small.

    I've tried using the tools Transform->Shear and Transform->Perspective Adjust, but was not able to make the bench to look like it was right in from of the camera. I suspect the right tool is "Shear", but I'm not quite sure.
     
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  2. mauve

    mauve Mu-43 Top Veteran

    892
    Mar 9, 2010
    Paris, France
    1st, with perspective (I mistakenly labeled the picture "shear", but it IS the perspective tool) :

    <table style="width:auto;"><tr><td><a href="https://picasaweb.google.com/lh/photo/0RSb2lt-0BHOim2Yrnv2zg?feat=embedwebsite">https://lh3.googleusercontent.com/_ze5jr2vpAvc/TahW35BfyLI/AAAAAAAACOY/y6Rwjg41r24/s800/digikam-shear.jpeg" height="450" width="800" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">De <a href="https://picasaweb.google.com/manuel.viet0/Test?feat=embedwebsite">test</a></td></tr></table>

    Then a crop to remove Imageless areas :

    <table style="width:auto;"><tr><td><a href="https://picasaweb.google.com/lh/photo/b6NmKxewnnf9RQvC3hlZCQ?feat=embedwebsite">[img]https://lh6.googleusercontent.com/_ze5jr2vpAvc/TahW40by-2I/AAAAAAAACOc/NQQffSU-vP4/s800/digikam-shear2.jpeg" height="450" width="800" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">De <a href="https://picasaweb.google.com/manuel.viet0/Test?feat=embedwebsite">test</a></td></tr></table>

    final result (after a quick sharpening because your image was slightly out of focus) :

    <table style="width:auto;"><tr><td><a href="https://picasaweb.google.com/lh/photo/74PmxibrClGpHDmaHXh1Sw?feat=embedwebsite">[ATTACH=full]162273[/ATTACH]"600" width="800" /></a></td></tr><tr><td style="font-family:arial,sans-serif; font-size:11px; text-align:right">De <a href="https://picasaweb.google.com/manuel.viet0/Test?feat=embedwebsite">test</a></td></tr></table>

    It will always look a bit awkward when fully corrected because you still can see the side of the bench foot while you shouldn't had the picture been taken straight from the front. That's why I didn't straightened the top of the bench, to ease the composition into a painter side perspective with top and bottom lines as defined by the seat and back of the bench joining at some imaginary point to the left of the image.

    Perspective is powerful, it can straighten a bit some unavoidable geometry defects, but it doesn't replace a carefully composed picture.

    Cheers,
     
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  3. mushmorok

    mushmorok Mu-43 Regular

    27
    Jan 5, 2011

    Thank you for the lightning fast reply :eek: And now that you mentioned it - this made me realize that the photo is really out of focus (this really shows how novice I am :rofl:).

    What is the best way to sharpen a picture?
    I've used Enhance->Sharpen->Simple Sharp and set the Sharp value to 15 as I didn't want to push it too much.

    After reproducing your steps, I've realized that I was trying to use "Perspective Adjustment" with "Inverse transformation" turned on.
    So this is what I ended up (yes, I've tried to cut the bench foot ;-):
    3253764_modsmall.
     
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