Geometric transformation of images is a class of operations that alter the spatial relationships between the pixels. It generally includes resizing, rotating, flipping, trimming, cropping, shearing of the images and image offset.
These operations can be used to improve the appearance of the images:
The resize tool helps to change the aspect ratio, reduce the size of the image or amplify the details.
Rotation and shearing can be useful preprocessing routines for applications where directional operators (such as directional edge detecting) are applied.
Trimming and cropping removes unwanted areas from the image.
Image offset helps to align two images so as to facilitate operations like background subtraction.