Polyphase Antialiasing in Enlargements

Changing resolution of images is a common operation. It is also common to use simple, i.e., small interpolation kernels satisfying some ”smoothness” qualities that are determined in the spatial domain. Typical applications use linear interpolation or piecewise cubic interpolation. These are popular since the interpolation kernels are small and the results are acceptable. However, since the interpolation kernel, i.e., the impulse response, has a finite, and small length, the frequency domain characteristics are not good. Therefore, when we enlarge the image by a rational factor of  ¢¡¤£¦¥¨§ , aliasing effects usually appear and cause a noticeable degradation in quality of the image. One such effect is jagged edges. Another effect is low frequency modulation of high frequency components such as sampling noise. Enlarging an image by a factor of  ¢¡©£¥¨§ , is represented by first interpolating the image on a grid ¡ times finer than the original sampling grid, and...

• Type: Conference
• Year: 2003
• Where: SIP
• Authors: Daniel Seidner
• Keywords: Interpolation, Interpolation Kernel, SIP 2003, SIP 2007, Small Interpolation Kernels