Study on improvement of signal detectability considering noise characteristics in medical X-ray images

The purpose of this study is to develop method for improvement of low-contrast signal detectability of general X-ray images used for observing overviews, included noise reduction technique and signal amplification technique, that are difficult to detect in the observing overview. The proposal method consists signal amplification part and noise reduction part. The noise reduction part first identifies and mathematizes the characteristics of the noise attributed to the X-ray imaging system before the subject is imaged. The noise information derived from mathematization is used to remove the noise representing the system noise from the subject image. After noise reduction, all the signals on the subject image with sufficiently reduced noise are amplified by multiplication with an arbitrary coefficient. The feasibility of the proposed method was indicated by three evaluations that were performed vision assessment using the image including the virtual low-contrast signals by four radiological technologists. That of the proposed method was confirmed from results of the evaluations. That of the proposed method was confirmed from results of the evaluations.