Abstract: A trackball (10) is rotatably mounted on rollers (12, 14). The rollers are connected with rotational encoders (16, 18) for producing a series of pulses. Up/down counters (20, 22) convert the pulses into an indication of translation along two axes. Downward, non-rotational pressure on the trackball causes a transducer (B) to output an electrical signal which is recognizable as a selection signal. In some embodiments, the transducer is a strain gauge or other transducer (50) which provides an output whose magnitude varies with the amount of force. A comparitor (54) compares the output of the transducer with a selectable threshold to indicate whether a selection signal is to be issued. In other embodiments, the transducer has two states, e.g. a mechanical switch (70). The transducer changes states in response to the force on the trackball exceeding a preselected minimum.

Abstract: A system for three-dimensional diagnostic imaging generates a plurality of slice images of a specimen. A region of interest is selected from within a slice and is extrapolated to subsequent slices. A boundary indicative of a surface of interest is selected from within the region of interest to facilitate generation of an image representative of a three-dimensional surface of interest to be assembled from subsequent slices of the plurality. A viewing surface is defined in relation to a generated surface image which was selected from the boundary. A scaling means assigns a scaled gray level to the three-dimensional image to facilitate three-dimensional viewing of the object when it is projected on the viewing surface. Image information is selectably modified by data from the original slice images to add surface density visualization. Means is also provided to facilitate selective segmentation of a three-dimensional image along a plane or planes of interest.

Abstract: A system is provided for a display of CT cine images stored in a hybridized memory including both dynamic random access memory (14) and video random access memory frame buffer (16). The system includes memory address space which is allocated between the VRAM and DRAM. Non-linear, chained direct memory access control (22) provides a system to write a series of 640.times.512 pixel images directly from the frame buffer at 60 frames per second. The chaining provides a means for skipping over unused addresses at the end of a display line, thus maximizing utilization of expensive VRAM memory.

Abstract: A system for three-dimensional diagnostic imaging generates a plurality of slice images of a specimen. A region of interest is selected from within a slice and is extrapolated to subsequent slices. A boundary of indicative of a surface of interest is selected from within the region of interest to facilitate generation of an image representation of a three-dimensional surface of interest to be assembled from subsequent slices of the plurality. A viewing surface is defined in relation to a generated surface image which was selected from the boundary. A scaling means assigns a scaled gray level to the three-dimensional image to facilitate three-dimensional viewing of the object when it is projected on the viewing surface. Image information is selectably modified by data from the original slice images to add surface density visualization. Means is also provided to facilitate selective segmentation of a three-dimensional image along a plane or planes of interest.