Introduction to Digital Image Processing

102 IMAGE SAMPLING AND RECONSTRUCTION

Figure 4.2-6 shows a model for the quantitative analysis of aliasing effects. In

this model, the ideal image is assumed to be a sample of a two-dimensional

random process with known power-spectral density . The ideal image is

linearly filtered by a presampling spatial filter with a transfer function .

This filter is assumed to be a low-pass type of filter with a smooth attenuation of

high spatial frequencies (i.e., not a zonal low-pass filter with a sharp cutoff). The fil-

tered image is then spatially sampled by an ideal Dirac delta function sampler at a

resolution . Next, a reconstruction filter interpolates ...