Radiographic equalization using computer-controlled filter wheels

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Equalization is advantageous in some radiographic applications in order to reduce the dynamic range of the x-ray signal incident on the detector. A technique is discussed which employs several filter wheels, which are radio-transparent wheels mounted near the x-ray tube which can be rotated under computer control. The wheels are designed to contain complex patterns of attenuator material on the annular region of each wheel which intersects the x-ray beam. Rotation of the wheels changes the attenuator pattern presented to the x-ray beam, and therefore this system is capable of regional exposure compensation. The use of multiple filter wheels provides a large selection of compensation patterns, for example, an 8 wheel system with 30 patterns per wheel would allow 1011 patterns. Two different design strategies are discussed, one aimed at digital subtraction angiography, and another at chest equalization. Clinical data bases of 191 DSA images and 250 chest radiographs were employed with computer simulation to evaluate the potential of the filter wheel equalization technique.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Place of PublicationBellingham, WA, United States
PublisherPubl by Int Soc for Optical Engineering
Number of pages10
ISBN (Print)0819408050
StatePublished - 1992
Externally publishedYes
EventMedical Imaging VI: Image Capture, Formatting, and Display - Newport Beach, CA, USA
Duration: Feb 23 1992Feb 24 1992


OtherMedical Imaging VI: Image Capture, Formatting, and Display
CityNewport Beach, CA, USA

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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