Visual linearization of the display of digital radiographs
| Autor: | P. Sällström, Kazunori Yoshiura, Ulf Welander, William D. McDavid, Gang Li |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Brightness
Visual perception Light media_common.quotation_subject Image processing Square (algebra) Linearization Linear regression Image Processing Computer-Assisted Humans Contrast (vision) Radiology Nuclear Medicine and imaging Computer vision General Dentistry Mathematics media_common Observer Variation business.industry Linear model Radiography Dental Digital General Medicine Models Theoretical Radiographic Image Enhancement Otorhinolaryngology Computer Terminals Data Display Linear Models Visual Perception Artificial intelligence business Algorithms |
| Zdroj: | Dentomaxillofacial Radiology. 31:131-136 |
| ISSN: | 1476-542X 0250-832X |
| DOI: | 10.1038/sj.dmfr.4600663 |
| Popis: | Objectives: To derive and test a method to linearize the visual response of the display of digital radiographs so that equal steps in gray levels will be perceived as equal steps in brightness. Method: A mathematical analysis was performed and expressions for visual linearization were derived. Twenty-four test images were computer generated to confirm that visual linearization may be achieved. Each image had three groups of square areas of diAerent size placed in three rows. The left and right squares in each row were given diAerent gray levels to simulate various contrast levels. The middle squares were initially given the same gray level value as one of the outer squares. The images were examined by ten observers who could change the gray levels of the middle squares so that the step in brightness between the middle square and the outer squares become subjectively equal. The test was performed three times employing two diAerent monitors. Results: The experimental test confirmd that visual linearization could be achieved. Linear regression analyses gave determination coeAcients of 0.9926 amd 0.9942 for monitors with gvalues of 1.93 and 2.50, respectively. The mean data from the ten observers perfectly fitted those theoretically calculated. Conclusion: Visual linearization of gray levels can be achieved but further clinical research is needed to determine if this improves diagnosis. Dentomaxillofacial Radiology (2002) 31, 131‐136. DOI: 10.1038/sj/dmfr/4600663 |
| Databáze: | OpenAIRE |
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