Access to eBooks is limited to institutions that have purchased
or currently subscribe to the SPIE eBooks program. eBooks are not
available via an individual subscription. SPIE books (print and
digital) may be purchased individually on
Contact your librarian to recommend SPIE eBooks for your organization.
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 Î¼ 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.