| Popis: |
It has been observed that image intensifier contrast ratio measurements taken on clinically installed systems always produce lower values than reported by the manufacturer. One common method of measuring the contrast ratio in the field uses the film recording camera which comes with the system, while the manufacturers always measure the image intensifier isolated from other system components. Evidence is presented showing that the difference between the two measurements is attributable to contrast losses in the optics. Also, evidence is presented suggesting that there is no observable difference in contrast presentation for image tubes with contrast ratios larger than 15. Contrast ratio measurement on clinically installed systems are recommended for performance monitoring purposes only.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
