Access to SPIE eBooks is limited to subscribing institutions. Access is not available as part of an individual subscription. However, books can be purchased on SPIE.Org
Chapter 8:
Flat Fielding
Fixed pattern noise is removed from images by a technique called flat fielding, where a computer adjusts pixel sensitivities to be equal. Fixed pattern noise severely limits S/N performance for CCD and CMOS imagers, which will be discussed in Chapter 10. Fortunately, simple computer algorithms can remove FPN and achieve the shot noise limit, thereby significantly improving S/N performance. The flat-fielding technique demonstrated in Fig. 8.1 shows two raw sinusoidal video traces that are FPN limited (labeled as S RAW ). Also presented is a flat-field trace used to remove FPN (labeled as S FF ). The solid dark curves shown are the corrected traces after the raw traces are divided (pixel-by-pixel) by the flat-field level and the result multiplied by μ FF according to Eq. (8.1). Note that S/N performance improves significantly after flat fielding. Figure 8.2 presents images for the lowest-contrast sinusoidal shown in Fig. 8.1 before and after flat fielding is performed. The improvement in image quality is obvious.
Online access to SPIE eBooks is limited to subscribing institutions.

Back to Top