This dissertation presents work on Geometric Super-resolution (GSR) and discloses three techniques addressing non-zero pixel size issue of Charged Coupled Devices (CCD). Digital imagers employ a CCD (an array of sensors) at its image plane instead of conventional films. CCDs have lower resolution than camera films. It is due to two geometrical characteristics of CCD: non-zero pixel size and pitch greater than pixel size. The pixels lose all the subpixel details falling over it yielding a single value whereas the pitch provides the sampling interval for the information falling on it and allows lower image frequency to be recorded. Manufacturers prefer large pixel size for higher signal to noise ratio (SNR). Pixel size and pitch are thus the resolution limiting factors and needs to be addressed. GSR techniques try to recover the original inherent details of the object which otherwise are integrated by the pixels or under-sampled by the CCD. The GSR techniques in spatial domain resolve the pixel into an array or matrix of subpixels. This corresponds to GSR in 1D and 2D. In this way, the issue of non-zero pixel size is resolved whereas the GSR techniques in spectral domain extend the spectrum beyond CCD-spatial cut-off frequencies in the x and y directions. In this way, the under sampled spatial frequencies are recovered. This thesis addresses the resolution limiting issues due to finite pixel sizes and presents three GSR techniques in spatial domain. These are based on active optical coding of image followed by computational decoding of the recorded low resolution coded images. Three GSR techniques work at the image plane by scanning a (a) negative rect mask, (b) tri-level grey mask, (c) dual bi-level rect mask. A trivial mask is also described – which provides a base line to compare its results against those obtained through other masks. The GSR of one dimensional (1D) and two dimensional (2D) CCDs have been presented and verified through simulation. The 1D and the 2D GSR of isolated pixels as well as array of pixels (CCDs) have been presented and verified through simulation. These theoretical and simulation results are promising. The three techniques presented in the thesis indicate that subpixelling to any desired level is theoretically possible and any limit will be dictated by the experimental parameters.