Digital radiography

Concerning a digital radiography system: An early step in image acquisition is conversion of data from an analogue to digital format The size of the image detector is not important, as the final image may be manipulated electronically Detector sensitivity must be high Pixel size influences image resolution Noise is less significant than with film-screen radiography The requirements of a digital radiography system are: Good X-ray sensitivity A small field size A digital-to-analogue converter (DAC) A narrow dynamic range A locally based archive Concerning the digital radiographic image: It is represented numerically in digital form The image is divided into a matrix consisting of multiple pixels The greater the sampling frequency, the greater the spatial resolution Decreasing the detector sampling frequency may reduce detector sensitivity The image may be read out directly from the detector electronically Concerning the digital radiographic image: Signal digitization expresses the image as continuous grey-scale values The function of the analogue-to-digital converter (ADC) is to digitize the input while maintaining resolution of the information A binary system is used for signal digitization Eight bits is typically sufficient for most images Data compression for storage may lead to loss of data The number of bytes of a digital image is dependent upon: The number of pixels within the image Pixel size, assuming matrix size is constant […]