Spatial noise suppression for LCD displays: Noise contrast

LCD monitors used for radiologic diagnosis exhibit a random spatial gain-fluctuation pattern that can be characterized as multiplicative fixed-pattern noise. Our goal is to use a monitor-particular map of this noise to pre-process mammograms for display. This noise map is obtained by processing a captured image of the monitor screen. In previous work we have demonstrated a method that produces a measurable reduction in the noise level. In this paper we describe the results of our first observer studies and of computer analysis using visual a discrimination model. The result proved to be negative, i.e. the pre-processing provided an insufficient degree of improvement to be judged diagnostically effective. In light of these first results, we have been examining our assumptions and processing methods. We begin with a brief introduction then describe the construction of the noise map and its use in pre-processing. The two key advances follow: the observer-study and the computer-modeling results. Finally, we describe our efforts to understand the relation of our measurement, modeling, and observer results.