| Co-Investigator(Kenkyū-buntansha) |
OHTA Mitsuo Kinki Univ. Faculty of Eng. Professor, 工学部, 教授 (90020164)
IKUTA Akira Hiroshima Univ. Faculty of Eng. Research Associate, 工学部, 助手 (30145164)
ITOH Katsuhide Hiroshima Univ. Sch. of Medicine Professor, 医学部, 教授 (20034035)
FUJITA Minoru Hiroshima Univ. Dental Hospital Assist. Professor, 歯学部附属病院, 講師 (90116658)
WADA Takuro Hiroshima Univ. Sch. of Dentistry Professor, 歯学部, 教授 (10028756)
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| Research Abstract |
In this study, some restoration methods for the x-ray images with optical blurs and quantum mottles were developed by considering each physical mechanism of the medical x-ray image formation. More specifically, the optical blurs were first deterministically cleared away by using the transfer characteristic of the laser scanner, the characteristic curve of the film, the logarithmic transformation of the optical density and a pseudo-inverse filter based on the point spread function. Next, two restoration methods for remaining quantum mottles were derived from the basis of a Bayes' theorem. One was a wide sense digital filter of a stochastic type using the statistical properties of quantum mottles. Another was a new extended regression model that might have a little information lack and a simple experimental regression model. Thus, the quantum mottles were statistically removed. The results were presented as iA new restoration method for medical x-ray images with optical blurs and quantum
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mottles j (Trans. of IEICE, Vol. E73, No. 5, pp. 670-678 (1990) ) and as iA restoration method of medical x-ray images based on an extended regression analysis method j (Denshi Joho Tsushin Gakkai Ronbunshi D-II, Vol. J74-D-II, No. 3, pp. 442-452 (1991) ), respectively. Moreover, by expanding the multi-variate Bayes' theorem into the hierarchical form matched to the actual complexity of various wave forms, a dynamical method of restoring the degraded images under the random measurement noises was newly established. This result was presented as iA dynamical method of adaptive restoration for the medical x-ray images with optical blurs and quantum mottles by use of wide sense digital filter j in The International Conference on Noise in Physical Systems and 1/f Fluctuations in Kyoto in Oct. 1991.
Finally, the restoration method of x-ray images proposed in this study was applied to those of the actual dental images, and dentists visually evaluated and confirmed the effectiveness of these processed images. Less
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