계수공제영상의 비선형 대조도 증강효과에 관한 연구 = NONLINEAR CONTRAST ENHANCEMENT ON SUBTRACTION IMAGES

다국어 초록 (Multilingual Abstract)

This study was performed to demonstrate the effect of linear or nonlinear contrast enhancement on subtraction images. Three different textures were radiograped on dental film. The first radiograph was taken without the presence of and object. the second, which showed trabucular bone, was taken of the molar area of a human. the third radiograph was taken of the coronal part of molars. Each film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-3510AF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh LC Ⅲ computer(Apple Computer, Charlotte, N.C.). This resulted in three pairs of images, including different textures-plain, bone and enamel. Digital regular, linearly and nonlinearly enhanced subtraction was performed. Computer software was used to simulate lesions in the shape of a 2D-Gaussian curve on each of a pair of images. The each subtraction images were presented in a random sequence to two groups of 10 observers(students and dentists). ROC analysis was used to compare observer performance.
The following results were obtained;
1. All of LCE subtraction, equalized subtraction and regular subtraction images of plain texture were diagnosed the best by far.
2. The data revealed a significant LCE effect in both the student group and the expert group.
3. Clinical expertise was a helphul factor for the observers in this study.

목차 (Table of Contents)

• Ⅰ. 서 론
• Ⅱ. 연구재료 및 방법
• Ⅲ. 연구성적
• Ⅳ. 총괄 및 고안
• Ⅳ. 결 론
• 참고문헌
• 영문초록