TomographicVolume ImagesUtilizing a Varifocal Mirror

Described isasystem forthemultidimensional display and analysis oftomographic images utilizing theprinciple ofvariable focal (varifocal) length optics. Thedisplay system usesavibrating mirror in theformofanaluminized membranestretched overaloudspeaker, coupled withacathode raytube(CRT)display monitor suspended face downoverthemirror, plus theassociated digital hardware togenerate aspace filling display. Themirror ismadetovibrate backandforth, asaspherical cap,byexciting theloudspeaker witha30Hzsinewave. "Stacks" of2-Dtomographic images aredisplayed, oneimage ata time, ontheCRTinsynchrony withthemirrormotion. Because ofthe changing focal length ofthemirrorandtheintegrating natureofthe humaneye-brain combination, thetimesequence of2-Dimages, dis- played ontheCRTface, appears asa3-Dimage inthemirror. The system simplifies procedures suchas:reviewing large amountsof3-D image information, exploring volume images inthree dimensions, and gaining anappreciation orunderstanding ofthree-dimensional shapes andspatial relationships. Thedisplay system facilitates operator inter- activity, e.g., theusercanpoint atstructures within thevolume image, removeselected imageregions tomoreclearly visualize underlying structure, andcontrol theorientation ofbrightened oblique planes through thevolume.