Homography mapping calculation (Labview code)

[Klemen]

Hello,

I am posting Labview code to calculate the perspective projective mapping between two planes (homography), assuming that locations of at least 4 corresponding points are known. This can be used for pixel-to-real world mapping by eliminating perspective distortion, after which the measurements of a real world object can be performed. For example, the previous post describes the practical application of this (https://decibel.ni.com/content/blogs/kl3m3n/2015/03/13/optical-water-level-measurements-with-automat...).

Or you can just do some cool stuff like this :

base image

images of koala and penguins (obviously ).

final image (koala and penguins subjected to perspective distortion and inserted into both base image frames).

I am attaching the Labview program to calculate the homography and perform a simple check of the result. The calculated homography can then be used for example to map the pixel-to-real world or pixel-to-pixel coordinates.

Best regards,

K

[Ale914]

Hello Klemen, good work as usual.

One question: is it possible to adapt your example to 3D points (adding Z coordinate)?

Thanks.

Alessandro.

[Klemen]

Hello,

what are you trying to achieve? You can extract the rotation and translation parameters (object pose) based on the camera matrix and homography. Homography is basically a plane to plane mapping (perspective transformation), considering the pinhole camera model.

Best regards,

K

[alexderjuengere]

Thanks for sharing! May I ask you, how did you visualize the cube?

I plan to figure out the difference of your approach towards this approach shown here, using LV 3d picture control:

http://forums.ni.com/t5/LabVIEW/3D-Picture-Applying-Different-Textures-to-Faces-of-a-Cube/m-p/150050...

[Klemen]

Hello,

this is actually not 3d visualization, but a 2d image - I used IMAQ display indicator.

Best regards,K

[FilipeFontana]

Hello, K

could you please post the koala-penguins code?

I could not found a way to implement Homography matrix in my images.

Best regards,

Filipe

[Spalabuser]

Hello everyone, after seeing the related transformation made by klemen, I wanted to know if someone had made a transformation of this type ...
any portion you see, especially those on the left, must be brought to a rectangle (dx-dy)
the final goal is to bring each portion from the most distorted to the least distorted ones all on each rectangle (dx-dy)