Color coding of radiographic changes over time by means of image addition

Ulf Welander, Inger Eklund, Gunilla Tronje, William D. McDavid, S. Brent Dove, Roger Mähler, C. Donald Wilcox, Ann Catherine Mörner, Afsoun Uddhammar

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Differences between sequential radiographs may be displayed in color if the individual radiographs are transformed into monochromatic images and then added. Information in regions where the radiographs are identical is retained whereas differences are emphasized by the color coding that comes about in a quantitative manner from the gray level values in the sequence of radiographs. By using the three additive primary colors, red, blue, and green, two or three radiographs from a sequence may be added. Every possible state of a bone disease, progression, regression, or any combination, will produce a different and specific color code. Different development cycles are described, and the color coding that appears when color image addition is performed is analyzed. The color addition technique should constitute a useful substitute or alternative to subtraction.

Original languageEnglish (US)
Pages (from-to)531-538
Number of pages8
JournalOral Surgery, Oral Medicine, Oral Pathology
Issue number4
StatePublished - Oct 1994

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Dentistry(all)


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