skewing or shearing an image in python

Question

I need to shear and skew some images using python. I've come across this skimage module but I don't seem able to understand exactly how I'm supposed to use this.

I've tried a few things, which obviously gave me errors, because as I suddenly realized later, I'm not passing in my image to the function. I then noticed that the function doesn't take my image as an input parameter in the first place. So how should the transformation be applied? Or is this even the right function to be looking at in order to skew or shear an image?

Answer 1

If you want to use the skimage module the order of operations are:

• Load image or define data to work with
• Create the transformation you want
• Apply the transformatioin

A work flow might look like the following:

from skimage import io
from skimage import transform as tf

# Load the image as a matrix
image = io.imread("/path/to/your/image.jpg")

# Create Afine transform
afine_tf = tf.AffineTransform(shear=0.2)

# Apply transform to image data
modified = tf.warp(image, inverse_map=afine_tf)

# Display the result
io.imshow(modified)
io.show()

The AffineTransform class from the skimage module accepts a transformation matrix as its first parameter (which the class constructs if you instead use the other parameters).