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Author Topic: Resizing distortion  (Read 935 times)

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Frolin Marek

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Resizing distortion
« on: 2016-11-27 22:18:47 »
Anyone else still finding (and getting tired) of the 'resizing' feature in ThumpsPlus, over the recent versions?

This is when you say, take a higher resolution photo like 4000x3000 pixels, and resize it down to say 1100x825.  The result is some distortion and fuzzy edges.  Does not seem as bad if using a default size like  1024x768  but looking for a little bigger size.  And at times smaller like say, 500x375.

This has been a problem for years now with ThumbsPlus in the last couple versions, up to and including Version 10.  It was presented again in January of this year by Michael in this thread...
   http://forums.cerious.com/forum/index.php?id=5039
I also presented this question in June of 2015 with similar results...
   http://forums.cerious.com/forum/index.php?id=4468

There are a couple others that mentioned it also.  Maybe Cerious has no interest in this problem or fixes to it, as I reported a couple times  (at least by me)  and in this forum.


Anyone found a major selection in TP that fixes this, where you do not have to do any tricks, simply open a large format picture, select Resize, can key in a custom size and it reduces the size and does not distort the quality?

Been using TP also, like Michael, for many years over the many upgrades, but this bug or design flaw (call it what makes your happy), has been an issue for some time and really makes TP less-good for the daily photo crop and resize, of modern larger format pictures...

Frolin

Daan van Rooijen

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Resizing distortion
« Reply #1 on: 2016-11-27 23:56:41 »
It would help if you post some examples where TP's resizing quality is below par, preferably with an example of the same image resized better using different software. Please also show the TP settings used. Without such examples I don't see how we can make a case to Cerious.
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Frolin Marek

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Resizing distortion
« Reply #2 on: 2016-11-28 00:18:47 »
Here is a picture taken with a Canon Rebel XS camera...

The original photo is  3888x2592-24
 -- can not upload because it's over 2meg in size
 -- so here is the photo file on my site to view 'online'...
 --  http://www.frolin.net/test/FM-Osier_3888x2592-24.jpg

Here is the photop reduced to  1200x800-24
 

And here (the original) is reduced to  600x400-24
 

These were reduced using the default settings in the  'Resize'  option.

Look at the letters and numbers on the side of the railroad cars, and notice they get distorted with reduction.


Frolin

Daan van Rooijen

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Resizing distortion
« Reply #3 on: 2016-11-28 01:46:30 »
> Look at the letters and numbers on the side of the railroad cars, and notice they get distorted with reduction.

Yes. The more you reduce an image, the more distorted its small details become. At some point, it is no longer possible to render details correctly because you're cramming them into too little space. Resizing algorithms have to compromise between detail and distortion and between what is technically correct and what is visually correct.

In your previous topic on this subject, you said that MS-Paint did a better job. So, let's compare MS-Paint to TP10:



    [*]The first image shows MS Paint
    [*]The second image shows TP10 (algorithm: resample)
    [*]The third image is the second image with Unsharp Mark, Strength 5 applied.[/list]

    The second image is the technically correct version. It looks fuzzier than the MS Paint image, because MS Paint is secretly applying Unsharp Mask to bring out details. So, I applied UM too, and that resulted in image 3 which is very similar to what MS Paint does.

    (note: MS Paint only allows reduction to a fixed percentage. I chose 15% which results in a 584x389 image, from which I took a crop. Note also that reducing to 15% happened to result in less distortion than the (600/3888=)15.43% from your example)

    My conclusion is that TP does a fine job reducing the image. It doesn't produce more distortion than MS Paint. And it does not artificially enhance detail like MS Paint does, but you can do so yourself if you prefer it. Once you have applied Unsharp Mask to an image, you only have to press Ctrl-F to apply it to the next image (Ctrl-F remembers the last used filter).
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    Frolin Marek

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    Resizing distortion
    « Reply #4 on: 2016-11-28 10:51:39 »
    OK, I have been using the Filter to  'Sharpen'  the image with some results, but felt was still not as crisp and clean, as the original picture.  

    You used the 'UnSharp Mask'  option in the 'Sharpen' filter area  (vs my 'Sharpen/Sharpen') to clean up the edges.
    And this was done after the resize reduction.

    When I 'zoom in' after I still have blurry lettering on the sides of the rail cars though.


    Frolin

    Daan van Rooijen

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    Resizing distortion
    « Reply #5 on: 2016-11-28 18:45:10 »
    It's hard to beat physics.. if you find a program or algorithm that does a better job, please let me know.
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    mschnell

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    Resizing distortion
    « Reply #6 on: 2016-12-10 13:08:31 »
    I tried Lanzcos that in many cases does a good job with resolution reducing, e.g. preventing aliazing with sloped lines better than the algorithms provided by TP, but with this picture it does not help.

    -Michael

    Frolin Marek

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    « Reply #7 on: 2016-12-10 17:25:49 »
    Daan,

    A program that seems to resize larger images to common or semi custom sizes, without extra steps by the User...  MS Paint,  seems to do a better job out of the box than Thumbsplus. If it is auto doing stuff, as your post seems to say, then why isn't TP auto doing stuff.  

    But to doing a stock click button option resize, Paint.  It does not do many many other things TP does, but one would expect Cerious to consider photo size reduction a common and critical feature in photo editing.


    Michael,

    Thanks for the test also. Confirms what I have been finding, all the new large format, hi res photos our cameras take, are not being cleaning resized without loss of some quality, by Thumbsplus.  

    And you can do some clean up / extra steps as Daan listed, but TP impacts quality when it resizes.

    Frolin

    Daan van Rooijen

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    Resizing distortion
    « Reply #8 on: 2016-12-10 21:22:50 »
    > If it is auto doing stuff, as your post seems to say, then why isn't TP auto doing stuff.

    Because bringing out artificial detail is NOT part of resizing and should be left to the user, who can determine for himself if and how strongly he wants to apply it.

    An Unsharp Mask increases the contrast between adjacent pixels. This makes details more visible, but it goes at the expense of tonality and it emphasizes noise in an image. So, what Paint does is not 'better' or even 'correct', but if you want to emulate it in ThumbsPlus, a single key press will do it for you. And if you want to do it with a whole bunch of photos at once, you can add the Unsharp Mask command to your batch command.

    ThumbsPlus does not distort your image when it resizes it. Paint does, but you just happen to like the distortion that it applies. Well, that's fine. Some people think that Instagram takes 'better' photos than their regular camera app does. That doesn't mean that the camera app should make all photos look like aged polaroids.
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    slanoue

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    Resizing distortion
    « Reply #9 on: 2018-07-12 10:52:49 »
    Hi.  I don't understand the technical stuff you guys are saying here. I'm just a home user who's been using the software for years, and I find the same problem occurs. I usually only use Thumbplus to view my photos, crop, and resize (occasionally to lighten it up). So I don't know that other stuff you mentioned or how to use it.  I, too, find that the photos are often grainy when I reduce them, but if I use Paint, they come out fine.

    I don't like having to use Paint to resize files. It's not as good as Thumbsplus for viewing my files. It requires extra steps and doesn't have all the bells and whistles.

    Here is an example for you.

    The first is the original file.  The second is the TP reduced file. The third is the Paint version.






    Daan van Rooijen

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    « Reply #10 on: 2018-07-12 12:46:01 »
    The Resize dialog has an option called 'interpolation'. Set it to 'downsample' for a better result.

    If you want to sharpen the result to bring out more detail, try Image | Filter | Select Filter | Category:Sharpen | Filter:Unsharp Mask.

    Note: once you have used a filter, you can quickly repeat it using the 'Last Filter' (Ctrl-F) command. This shortcut is helpful when you're resizing and sharpening a whole bunch of photos.
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    slanoue

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    Resizing distortion
    « Reply #11 on: 2018-07-12 13:43:32 »
    Thanks! That helps...

    Frolin Marek

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    « Reply #12 on: 2018-07-13 01:17:58 »
    Daan,

    Have been using the 'downsize' setting for a couple years, it helps but does not fully correct the distortion problem that  Thumbsplus  creates when you resize an image.  When you resize large images,  TP  will create grainy results.

    It is unfortunate that for years and several versions,  Cerious  has not addressed this basic issue and function of a photo tool.

    So the problem remains, I ran in to it this weekend again,  working with various photos and needing to resize down about 1/4 the size and it was clearly grainy.  When I switched to MS-Paint, I had no issues resizing.

    Frolin

    Daan van Rooijen

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    Resizing distortion
    « Reply #13 on: 2018-07-13 14:34:12 »
    > It is unfortunate that for years and several versions, Cerious has not addressed this basic issue and function of a photo tool.

    Well, you keep saying that there is an issue, but you never demonstrate it. Each time that you or someone else posts a sample, I show how TP actually does a very good job if only you use it correctly. Then things get quiet for a year or so, and then the complaining starts all over.

    Anyway, your problem used to be that TP created fuzzy results, and today the problem is that they are grainy. I hope you realize that grainy is the opposite of fuzzy.

    > So the problem remains, I ran in to it this weekend again, working with various photos and needing to resize down about 1/4 the size and it was clearly grainy.

    Well, without a sample, I can't offer any useful comments. If the original image is very large, you could just crop out a representative section and post that, along with a resized version that you feel is unsatisfying. Hopefully there is a simple solution to the graininess.

    Again, there is no single resizing process that will yield the best results for all images. In my own use, with regular photographic images targeted for use on the web, the 'Downsample' resize-algorithm followed by the 'Unsharp Mask' filter works very well nearly all the time. With some images, I use the 'Sharpen' or 'Sharpen Less' filter (which use a wider diameter) before I apply Unsharp Mask. When I have to process a lot of images from a single shoot, I make a simple batch process that resizes and sharpens hundreds of images in a few minutes. I have a fairly critical eye when it comes to photos, but in my 25 years of using TP, I've honestly never felt that TP has an issue here.
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