... Thenoise is assumed to be additive. This is a rather realistic assumption, standard infactor analysis and signal processing, and allows for a simple formulation of the noisymodel. Thus, the noisy ... as:sign(15.26)where ,and is set to zero in case the square root in (15.26)is imaginary. This is a shrinkage function that has a stronger thresholding flavor, asdepicted in Fig. 15.1.Part III EXTENSIONS AND RELATED ... observations . Denotingby a nongaussian random variable, and by a gaussian noise variable of variance, we should be able to express the relation between and in simple algebraic terms. In general,...