ABSTRACT
This chapter describes methods and tools for the assessment of image quality in digital radiography and digital mammography, including detector characterization. It deals with the various steps involved in the physical evaluation of factors that influence image quality using transfer function methods. The chapter discusses the link between the noise equivalent quanta and signal detection theory methods, with the simple detection task used in the contrast-detail (CD) test object methods. Threshold CD test objects provide a summary measure of X-ray detector or system low contrast detectability and provide the quality control (QC) physicist with useful information regarding the absolute value of the quality score and whether there have been changes in system performance since the previous QC visit. One of the fundamental parameters relating to the quality of the images produced by a detector is image sharpness, which describes the ability of a system to transfer detail present in the input image through to the output image.
