Restoration of high frequency details while constructing the high resolution image
C. V. Rao, J. Malleswara Rao, Anil Kumar, A. S. Manjunath · 2011
Indian Remote Sensing (IRS) Resourcesat satellites have AWiFS, LISS-III, LISS-IV sensors of 56m, 23.2m, 5.8m spatial resolutions respectively and of having identical spectral and temporal (simultaneous acquisition) resolutions but they are different in spatial and radiometric resolutions. In this work, we are trying to create high resolution (HR) image from coarser resolution AWiFS image called as emulated LISS-III like HR image. It will have HR (original LISS-III) image characteristics and minimal Mean Squared Error (MSE), ideally zero difference with LISS-III image as refernce, which inturn processed for identical spatial resolution of LISS - III. Ground sampling distance (GSD) of AWiFS is equivalent to 2.4 pixels of LISS-III. Radiance values are compared for normalization purpose, after weighted averaging of LISS-III to create AWiFS equivalent spatial resolution. Spatial resolution can be enhanced by improving the spatial sampling density of the signal. Nyquist-Shannon sampling theorem directs the sampling rate for exact reconstruction of the signal. The Resourcesat images are pre-processed to match this condition. Papoulis-Gerchberg algorithm is suitably improved for constructing the HR image from AWiFS. The results are compared with the classical interpolation techniques such as nearest neighbor, bilinear, spline, cubic convolution Papoulis-Gerchberg and modified Papoulis-Gerchberg [1].