  Estimating and rectifying the orientation angle of any image is a pretty
challenging task. Initial work used the hand engineering features for this
purpose, where after the invention of deep learning using convolution-based
neural network showed significant improvement in this problem. However, this
paper shows that the combination of CNN and a custom loss function specially
designed for angles lead to a state-of-the-art results. This includes the
estimation of the orientation angle of any image or document at any degree (0
to 360 degree),

Computer Vision and Pattern Recognition;Machine Learning;Image and Video Processing