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In Nagy and O'Leary (2003a), regularization is used to make the least-squares deblurring problem less sensitive to the noise. Figures and show the result of using the identity operator for regularization. This is comparable to the results presented in Nagy and O'Leary (2003b). We go a step further by using
regularization to impose *a priori* information on the solution of the problem. We exploit the fact that letters should be homogeneous for intervals (piecewise constant) with abrupt discontinuities between them.

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Figure 2 A) Original image, B) Deblurred image using LS with damped regularization.

**comp_damp_graph
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Figure 3 Comparison between Figures A and B; A) Slice *y*=229 and B) Slice *x*=229.