Abstract

It is widely appreciated that the faithfulness in estimation of an unknown object depends strongly upon what is known a priori about the object. In particular, the knowledge that any object must be positive, called "positivity,” has been well exploited in both restoration schemes^1-4 and reconstruction schemes.^5-8 Positivity, specifically, produces the benefit of sharper edge gradients where the edge meets the known (or zero) background level,⁹ the extent where the gradient profile contains spatial frequencies that may exceed appreciably the cutoff frequency in the data.^3,4

© 1984 Optical Society of America