Straightening/squaring an image.

Forums › Digital Imaging › Straightening/squaring an image.

Moahunter

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#289056 9-Aug-2021 22:07

If people don't have a scanner they usually copy an existing image like a photo or postcard using their camera/smartphone. This often results in an off-square copy like this.

I'm told that iphone photo editor can correct the distortion but I can't find anything similar in my Samsung photo editor. I would be grateful if someone can enlighten me or, alternatively, suggest a freeware editor that can do it.

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#2757630 10-Aug-2021 01:39

Onedrive can be really good for this

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andrewNZ

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#2757635 10-Aug-2021 04:47

Office lens will do the same as onedrive without having to save it to onedrive. It can autocrop when you take the photo if you scan it as a document, just chose to save it as a photo.

I use office lens to scan receipts and documents to pdf all the time.

jonathan18

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#2757636 10-Aug-2021 06:15

I also can’t see any similar feature in the editing tools of the Samsung photo app, but it is available in Google Photos, if you use that.

As for the original app to take photos of pictures, photos etc as per the OP, I’ve recently discovered Google PhotoScan, which takes multiple images from slightly different perspectives and stitches them together to avoid glare, and also manages the issue above. We’re needing to ‘scan’ thousands of photos belonging to my parents, who threw out all the negatives, and this produces a totally acceptable result.

https://www.google.com/photos/scan/

frankv

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#2757650 10-Aug-2021 07:32

GIMP has a tool for adjusting perspective, which will do what you need.

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#2757699 10-Aug-2021 09:01

Depending on the subject matter etc, you could get away with just a crop.

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chevrolux

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#2757703 10-Aug-2021 09:10

Samsung does that I'm pretty sure? It does it for documents anyway.

Otherwise, look at CamScanner. That had a bezel correction kind of thing that adjust the photo out.

Technofreak

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#2757716 10-Aug-2021 09:35

As a starting point take the photo as square on to the object as possible. Cropping may be necessary but the perspective will be correct. It's much easier to start with something that's closer to what's needed for the finished product.

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Moahunter

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#2757963 10-Aug-2021 13:40

Thanks guys. Sorry if I wasn't clearer with my Q. I don't need advice on using my smartphone for copying, I already have a scanner.

I was looking for ways to remedy other people's inadequate attempts., especially those that result in sloping/off square edges/sides to the originals. I guess Apple have allowed for such results and incorporated some correcting function in their iphone photo editor. Doesn't seem like Samsung have been as clever.

michaelmurfy

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#2757968 10-Aug-2021 13:52

In Photoshop - the perspective crop tool will give you instant results. From here I could work on restoring it with Photoshop also.

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eracode

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#2757991 10-Aug-2021 14:45

The image just above appears to have significantly changed the aspect ratio of the photo - at same width, it’s quite a lot higher - now almost square. People look taller and skinnier.

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Moahunter

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#2758008 10-Aug-2021 15:12

Found what I wanted in GIMP, used the Perspective tool on the 2 bottom corners and moved them horizontally until the sides of the original postcard are vertical.

This is the most common fault/distortion when photos/postcards have been copied using a smartphone.

frankv

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#2758027 10-Aug-2021 15:17

eracode:

The image just above appears to have significantly changed the aspect ratio of the photo - at same width, it’s quite a lot higher - now almost square. People look taller and skinnier.

Maybe they were tall skinny subjects. ;)

But that's kind of inevitable for this image... you're broadening the bottom and narrowing the top, so objects near the top will get skinnier. I guess there are centres of rotation for each side which need to be the right distance apart. If the side centres are too close together, you get elongation of objects. To be truly accurate, I think you need to know the focal length of the camera used to take the photograph of the photo, and/or the actual width and height of the original photo.

Moahunter

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#2758105 10-Aug-2021 17:47

I think postcards tend to be in a 3:2 ratio, the corrected image above being commented on was a bit squarer than that.

malamute5

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#2762545 18-Aug-2021 15:46

You could try Snapseed.

It's an app that is available on the apple app store however not sure if it is available for android. It's great for not only changing the perspective of photos but editing them and better yet, it's free 😃

Bung

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#2762638 18-Aug-2021 17:14

Strangely enough it does seem to be available for Android.

"Snapseed is a photo-editing application for iOS and Android that enables users to enhance photos and apply digital filters. It was created by Nik Software, and is now owned by Google."

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