密着不良をパラメータにもちいた総合画像評価の基礎的研究

概要

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As a parameter for factors of image quality, a poor contacting one was used, and the total evaluation of image qualty of screen and film was examined by physical and visual evaluations. It was verified that accompanying the increase in the poor contact, sharpness worsened and graininess improved, and when the nubmer of noise-equivalent quanta(U)[NEQ(U)] was calculated for the screen and film, in the vicinity of 0.5 cycle/mm, image of twice the size was observed. In addition, in the calculation of signal-to-noise ratio(SNR)using the acrylic beads of a 1.0 mm radius as the object signal, improvement in detectability could be increased by about 1.1 times. In the calculation of the detectability of the area under ROC curves(Az)in the case of the acrylic beads of 1.0 mm diameter, maximum value was obtained with a poor contact of about 30 μm, and thereafter, it decreased, and at 150 μm, it became the same as that of the contact state. Similar to the calculation of SNR by a physical evaluation, it was lowered beyond 150 μm, and it was verified that the slightly poor contact had the function of heightening the detectability.
公益社団法人日本放射線技術学会の論文
1995-04-01