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Author Topic: DxO Optics distortion correction and cropping  (Read 8825 times)

igvk

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DxO Optics distortion correction and cropping
« on: June 03, 2016, 07:44:20 pm »
I suggest the following to the DxO Optics:
When you have distortion correction, especially common case of barrel distortion, and you correct it in DxO - the resulting picture is cropped to be rectangular.
But when you also need to correct some rotation, you end up with even more cropped picture - where at the same time you could use some of the information that was lost after distortion correction during the first auto-crop.
So, it would be better to not crop the picture after distortion correction to allow for more freedom in cropping it manually after rotation.

platypus

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Re: DxO Optics distortion correction and cropping
« Reply #1 on: June 04, 2016, 11:44:08 am »
If you disengage auto-cropping, you can crop to whatever you want. Switch off the crop tool, then open it's palette and set it to manual and ratio to unconstrained.

The default setting is "original ratio" and you can switch to unconstrained and modify your presets to include it.

A while ago, OP's default setting has been set to unconstrained, but they changed it back.

Cheerio
Platypus
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igvk

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Re: DxO Optics distortion correction and cropping
« Reply #2 on: June 04, 2016, 11:55:24 am »
The problem that I describe is also present in unconstrained manual cropping.
Somehow DOP always crops picture to rectangular form, when you manually (or auto) correct the barrel distortion ("Keep aspect ratio" is also off). And when you rotate it, there is no way to recover the lost areas, even with manual crop settings.

You may try for yourself by correcting barrel distortion (just for example) on any picture - the corners will be lost (rotated picture won't show them also). I may also send my sample picture to understand what I am trying to describe here.
« Last Edit: June 04, 2016, 12:48:04 pm by igvk »

igvk

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Re: DxO Optics distortion correction and cropping
« Reply #3 on: June 04, 2016, 12:46:55 pm »
Here is a sample raw file with dop settings to illustrate what I was trying to tell:
http://www.mediafire.com/download/wkl3k5wkn0rc4gl/DOP_CropSample.zip

The information from corners is lost in distortion correction, though it could actually be used to fill in the black areas and not to crop even more.

Pieloe

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Re: DxO Optics distortion correction and cropping
« Reply #4 on: June 04, 2016, 01:21:26 pm »
The problem that I describe is also present in unconstrained manual cropping.
Somehow DOP always crops picture to rectangular form, when you manually (or auto) correct the barrel distortion ("Keep aspect ratio" is also off). And when you rotate it, there is no way to recover the lost areas, even with manual crop settings.

You may try for yourself by correcting barrel distortion (just for example) on any picture - the corners will be lost (rotated picture won't show them also). I may also send my sample picture to understand what I am trying to describe here.

I don't see anything missing on your photo.
Have you unchecked "Keep aspect ratio" ?

igvk

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Re: DxO Optics distortion correction and cropping
« Reply #5 on: June 04, 2016, 01:38:10 pm »
Please compare the original image with processed one.
For example, take a look at the lower left corner of the image: the stake there is cropped, and all that we have is an ugly black triangle in the corner. The picture needs to be cropped more, when at the same time the information was available in the raw file.

platypus

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Re: DxO Optics distortion correction and cropping
« Reply #6 on: June 04, 2016, 02:06:53 pm »
Yes, you are right. OP keeps the image rectangular. Lightroom shows curved edges under certain circumstances, but OP does not.

Therefore, I fully support your proposition.

Cheerio
Platypus

PS: Screenshot from Lr
« Last Edit: June 04, 2016, 02:29:13 pm by platypus »
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igvk

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Re: DxO Optics distortion correction and cropping
« Reply #7 on: June 04, 2016, 02:09:51 pm »
For comparison: the same raw image processed in another editor.

Bencsi

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Re: DxO Optics distortion correction and cropping
« Reply #8 on: June 04, 2016, 09:32:24 pm »
What about this version ?

If you are interesting how to do it, please advice.

Endre
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igvk

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Re: DxO Optics distortion correction and cropping
« Reply #9 on: June 04, 2016, 09:58:17 pm »
Sorry, but left side looks ugly and doesn't coincide with reality.
I know that you can try to "fix" black parts in Photoshop if they don't carry much information, but this particular image was an example.
What if you are really interested in what happens in that parts of the image?

Bencsi

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Re: DxO Optics distortion correction and cropping
« Reply #10 on: June 04, 2016, 10:03:34 pm »
You are right, the left is not corrected perfectly. I made the correction in one shot only.
If I'm interested what should be on the left side, I make an image include that part. Without information, DoP is unable to expand the reality.
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igvk

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Re: DxO Optics distortion correction and cropping
« Reply #11 on: June 04, 2016, 10:20:19 pm »
This is not a request for DOP to expand the reality, only to keep what's already present.
And the author of the photo can decide later what to crop.
Sometimes we are limited in our technical means or simply don't make the best possible shot.

In this particular case - it would be better to hold the camera horizontally and increase exposure, possibly shoot another scene, etc.
But it doesn't mean that software shouldn't have tools to correct angle or exposure (because you should have shot it right if you want the image to be correct!).

Please, take a look at the original raw file to understand that there was information from the
corners that should be kept when correcting distortion.

Nick_

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Re: DxO Optics distortion correction and cropping
« Reply #12 on: June 04, 2016, 10:51:56 pm »
So, it would be better to not crop the picture after distortion correction to allow for more freedom in cropping it manually after rotation.
That's a pretty good idea and I am sure it would be very simple to implement.
This feature should apply to all the geometry tools, such a perspective correction, as well.
It should be automatic: when using the horizon tool for example it would retrieve the hidden parts if there are any.
Pretty simple!
Nick

Bencsi

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Re: DxO Optics distortion correction and cropping
« Reply #13 on: June 04, 2016, 10:52:42 pm »
OK, I downloaded the original RAW file.

Here are the EXIF details of the SONY RX-100 image ( Distortion EXIF.jpg ). It include the image size in pixels 5472x3648. It is a 2:3 image rate This is the - DoP call it - Preserve aspect ratio.

The RAW images generally are bigger, than it is visible on the final image. The RAW file includes 5934x3648 px image. You can control by selecting the Crop tool. The crop borders designate the 2:3 image area. However you can expand it horizontally by hand. This feature works after the Horizon, Perspective and Distortion tool applied too.
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igvk

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Re: DxO Optics distortion correction and cropping
« Reply #14 on: June 04, 2016, 11:08:48 pm »

So, please compare the original image with the one you see corrected in DxO - and take a look at the lower left corner.
You will see that there are some pixels that are stretched out after applying corrections (particularly barrel distortion correction) and that are cropped no matter how you try to tune the picture manually. You may take a look at the intersection of wooden stake with ground/border to notice what's lost.

 

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