Flat Panel Detectors in Industrial Radiography

Real time imaging in the field of industrial radiography arrived over half a century ago and even before that in medical radiography. All the progress in the field for first 30 – 35 years produced analog images. Digital images have come only recently. Fluorescent screens, proximity focus intensifier and then electromagnetically focused Image Intensifier produced real time images in analog. They were viewed by analog video cameras. It was only in mideighties that the signal from those video camera devices (Vidicon, Isocon, Orthicon) could be digitized using a Frame Grabber cards. Though this may not be called `digital radiography’ in a strict sense, the digital format entered the real time radiography (RTR) field for the first time by this route. It was then possible to modify the image, what we call `Image Processing’ now. These operations were off-line initially as the cards digitized fairly slowly. Bandwidth of 5 MHz and above came later and image processing turned `near Real Time’.