Characterization, detection, and supression of stationary grids in digital projection radiography imagery

Antiscatter grids are commonly used in projection radiography to reduce scattered x-rays and improve image contrast and signal-to noise ratio. In digital radiography, because of spatial sampling, stationary girds usually cause aliasing and sometimes result in moire patterns. We investigated the impact of stationary grids in computed radiography (CR) for images viewed both on film and soft- copy display devices. First, the relationship of various grid factors as they relate to the problem of aliasing and moire artifacts is presented, as well as recommendations of grid usage with CR systems. Next, because ultimately one would like the freedom to use nay grid configuration with their digital imaging system, we present an automated image processing method to detect and adaptively suppress the grid to reduce aliasing artifacts.