File Exchange

image thumbnail

Keystone Corrector

version (1.3 MB) by JKMSMKJ

JKMSMKJ (view profile)

Corrects perspective in an image.


Updated 29 Apr 2016

View License

This app 'keystone corrects' a given image. Basically, it straightens merging lines to correct perspective as expected in photos of tall buildings, snapshots of display boards shot at an angle, etc. A discussion of the algorithm behind this app is given here: .
[For "draggable quadrilateral corners", see this post on Mike's blog: ]
Any feature suggestions or comments are welcome. Thanks for trying the app (if you did, that is) and enjoy (the life, in general)!

Comments and Ratings (5)


JKMSMKJ (view profile)

Thanks Nikolay. I don't use the image processing toolbox so can't help you with the built-in functions.
I can share my basic code if you send me an email.

Very nice app, but I need to correct for distortion series of images, so I will have to write my own code for this purpose. Could you tell me, what function do you use to warp the image after the parameters of transformation are determined? I tried to calibrate the camera, then using projective2d to determine transformation, invert and imwarp to correct the distortion, but this seems the wrong way, since imwarp produces downsampled image.


JKMSMKJ (view profile)

Chun-Jen Hsueh: Could you please let me know the error you get when trying to load an image? Thanks.

This app doesn't work. I can not even read an image.

Kin Sung Chan


Revamped GUI (Draggable quadrilateral corners to select the region to be corrected, Border extent selector, Previews of selected & corrected regions, etc.); Updated algorithm to take care of non-convex regions; Custom crop option.

Cropping algorithm updated; More options for saving an image; Minor GUI & bug fixes.

MATLAB Release Compatibility
Created with R2016a
Compatible with any release
Platform Compatibility
Windows macOS Linux

Inspired by: GUI Layout Toolbox

Discover Live Editor

Create scripts with code, output, and formatted text in a single executable document.

Learn About Live Editor