http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
저화질 흑백 이미지의 복원을 위한 영상채색 및 초해상화의 상호 분리적 학습 모델
권순용,서기성 대한전기학회 2023 전기학회논문지 Vol.72 No.3
Restoring low-resolution gray images to high-resolution color images is a challenging task known as the ill-posed problem with no fixed answer. In addition to the traditional image processing techniques, deep learning methods have recently been attempted, but it is still very difficult to restore images naturally. Various and effective approaches have been developed for each colorization and enhancing resolution of images, but simply combining the two techniques results in accumulation of errors. To solve the above problem, we propose a network that separates the loss function between colorization and super-resolution with adding a super-resolution model in parallel to maintain the performance of super-resolution. The performance of the proposed method on the DIV2K, ImageNet-1k validation dataset was compared to others via PSNR, SSIM, and FID metrics. Experimental results show that our method outperforms existing methods.
고속스핀에코 기법을 이용한 MRI 검사 시 영상 변수가 전자파 흡수율과 온도 증가에 미치는 영향 평가 : 재위상화 RF의 FA과 ETL 증가에 따른 영향
권순용,이정우 대한자기공명기술학회 2022 대한자기공명기술학회지 Vol.32 No.1
The purpose of this study was to evaluate the effect of imaging parameters on SAR and temperature rise in MRIs using the fast spin echo (FSE) technique. To evaluate the effect of imaging parameters, a human equivalent tissue phantom was created and MRI was performed with increasing refocusing FA and ETL under the same conditions. The head SAR value calculated from the device was used, and the temperature rise of the phantom was calculated using the proton resonance frequency. When the FA was increased from 60° to 180°, the SAR increased by approximately 8 times and the temperature rise of the phantom increased by approximately 2.8 times (0.21°-0.599°). In a multiple regression analysis, FA had a high correlation with the β of 0.935 and 0.741 in the relationship between SAR and temperature rise. When the ETL was increased from 15 to 30, the SAR increased by approximately 2 times. However, the temperature rise of the phantom decreased by 39.2% (0.53°-0.303°). In the multiple regression analysis results, ETL had a positive correlation with the β of 0.741 in the relation of SAR but a β of −0.482 for temperature rise, exhibiting a negative correlation. This may be attributable to the decrease in the exposure time to electromagnetic waves; the scan time was shortened by approximately 43% as the ETL was increased from 15 to 30. Ultimately, MRI using the FSE technique is expected to improve patient safety by minimizing refocusing FA and maximizing ETL within the reference SAR range to minimize temperature rise due to electromagnetic waves
자기공명영상 장치의 보어 내 무릎 위치에 따른 무릎 연골의 T2 값의 변화 평가
권순용,김상우,정해원,강충환,김성호,한상현 대한자기공명기술학회 2022 대한자기공명기술학회지 Vol.32 No.1
This study evaluated how T2 values of the knee cartilage change as the knee is moved from the center of the bore in a knee MRI study. Ten volunteers without knee disease were recruited for this study; their T2 values were measured at locations of 0, 10, and 20 cm from the center of the bore. A spin echo technique was used to acquire multiple images of the knee by selecting several echo times at 13.8, 27.6, 41.4, 55.2, and 69 ms, which were applied to calculate quantitative T2 values. Additionally, signal intensity in the femoral and tibial cartilages was measured in all knee images for each TE and location to validate the relationship between the change in T2 values and the signal of knee positions. The T2 value and signal intensity decreased as the knee was moved away from the bore center (p<0.00). The T2 value was reduced by increasing knee position from the bore center (0 cm: 39.16 ms; 10 cm: 32.59 ms; 20 cm: 26 ms). The signal intensity of the corresponding knee position was reduced by approximately 46.2% in the TE 69 ms. The correlation analysis revealed a negative correlation between the knee position and the T2 value (r = −0.736, p<0.00). The knee position provided the decreased T2 value of the knee cartilage, indicating that the accuracy or the reproducibility of T2 values can be reduced. It can protect that new corrected techniques are introduced for any variation with knee positions, or the knee during the MRI scan approaches the bore center.