Two-dimensional discrete sine transform scheme for image mirroring and rotation
Do Nyeon Kim, K. R. Rao · Journal of Electronic Imaging · 2008
Mirroring an image (horizontally or vertically) and rotation by 90, 180, and 270 deg in the spatial domain is implemented by changing the signs of the 2-D discrete cosine transform (DCT) coefficients of the original image appropriately. This approach leads to an efficient compressed domain-based image mirroring and rotation. This method is now extended to a 2-D discrete sine transform (DST), i.e., a 2-D DST possesses properties similar to 2-D DCT and it can be applied to image mirroring (horizontally or vertically) and also rotation by angles of 90, 180, and 270 deg. We illustrate these methods in a video-editing application.