Imaging systems and methods.

摘要

A computed tomography (CT) scanner (10) non-invasively examines a region of interest of a patient to create an image representation that is stored in an image memory (14). Each pixel of the image representation has a relatively large number of bits of radiation intensity resolution, e.g. 14 bits or 16k levels, which is larger than the gray scale resolution of a conventional video monitor (24), e.g. 8 bits or 256 levels. A look-up table (38) digitally filters each plxel value with digital filter values to reduce the number of levels of each pixel value to the number of gray scale levels displayable by the video monitor. While the image is being displayed, the operator selectively adjusts the digital filtering to optimize the displayed image for the intended diagnostic purpose. During the vertical flyback or other non-display periods of the video monitor, a central processor (30) generates most significant bits of addresses that read digital filter longwords from a filter memory (44). A multiplexer (54) breaks each word into a plurality of filter values or bytes which are serially conveyed to the digital filter look-up table. A least significant bit address generator (62) generates the least significant bits of the address for each filter value concurrently with its conveyance to the look-up table. The multiplexer and least significant bit address generator are clocked at a faster rate than the central processor such that within one read clock pulse of the central processor, a plurality of digital filter values are loaded into the digital filter look-up table. In this manner, image filtering via look-up table in real time is enhanced through an improved, faster loading method.