Image warping using transform.PolynomialTransform: crazy results
Hi, I found very few examples for transform.PolynomialTransform on the internet so I hope someone in this group can help me understand what I am doing wrong. If it's not the right place to ask for help, please forgive me! Here is my problem. I have a greyscale image with some curved lines. I want to transform it so the lines become straight. https://lh3.googleusercontent.com/l7PVL6ZCek/VGsf6aKWYpI/AAAAAAAABSk/Pae2V... So I measure the position of the lines at regular intervals (in the attached file source_test2.csv) And compute the desired positions after transformation (in the attached file destination_test2.csv) So i have a nice set of input points and their correspondences as in the figure below (red = input points, and blue = desired positions after transformation): https://lh4.googleusercontent.com/2SjXbAQwJHU/VGsibqv8OI/AAAAAAAABSw/JsniN... Next I compute the transformation using skimage.transform.PolynomialTransform and a polynomial of order 2, and apply the transformation to get the warped image using skimage.transform.warp But the warped image is completely crazy! See below: https://lh3.googleusercontent.com/VZmvMqQjNTo/VGsjdSpuklI/AAAAAAAABS4/OsAHo... It seems the transformation found by PolynomialTransform is completely wrong... *Note that I managed to get a good transformation in some cases for subimages (e.g using the first 400 columns only).* What am I doing wrong? Are PolynomialTransform too unstable? Do I need a regular grid? I attach the code I use (warp.py) Thanks for your help! Hervé
Hi Hervé
On 20141118 13:21:34, Herve Bouy
Here is my problem. I have a greyscale image with some curved lines. I want to transform it so the lines become straight.
https://lh3.googleusercontent.com/l7PVL6ZCek/VGsf6aKWYpI/AAAAAAAABSk/Pae2V...
So I measure the position of the lines at regular intervals (in the attached file source_test2.csv)
And compute the desired positions after transformation (in the attached file destination_test2.csv)
I had a look at your input CSV files, but I cannot quite match the coordinates given there to what is happening in the image. Can you provide some insight? Regards Stéfan
participants (2)

Herve Bouy

Stefan van der Walt