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Proceedings Paper

Novel NPS measurement method for medical liquid crystal display using periodic components subtraction technique
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Paper Abstract

A novel noise power spectrum (NPS) measurement method for medical liquid crystal display (LCD) was developed. A uniform image displayed on an LCD was imaged with a high-resolution single-lens reflex type digital camera (D70, Nikon) equipped with a close-up lens. In order to avoid significant errors (frequency leakages) caused by strong periodic components of the pixel structures, noise profile data was processed by periodic components subtraction, and NPS was calculated from the processed profile with fast Fourie transformation (FFT). Horizontal NPS at the center of display area was measured up to the 10 times of Nyquist frequency. Actual measurements were performed with various models of monochrome two million and three million pixel LCDs to investigate difference of conventional method and our proposed method. Resultant NPS obtained from the conventional method with simple FFT included significant errors over the whole frequency ranges. In contrast, our proposed method could compensate most of those errors. Resultant NPS of our method indicated clearly the difference of noise property between three displays we measured, which corresponded to the visual evaluation for them. In conclusion, our method is very useful for evaluation of noise properties of medical LCD due to the good accuracy and reproducibility.

Paper Details

Date Published: 2 March 2006
PDF: 8 pages
Proc. SPIE 6142, Medical Imaging 2006: Physics of Medical Imaging, 61423H (2 March 2006); doi: 10.1117/12.653424
Show Author Affiliations
Katsuhiro Ichikawa, Nagoya Univ. (Japan)
Yoshie Kodera, Nagoya Univ. (Japan)
Akiko Horii, Graduate School of Medicine, Nagoya Univ. (Japan)

Published in SPIE Proceedings Vol. 6142:
Medical Imaging 2006: Physics of Medical Imaging
Michael J. Flynn; Jiang Hsieh, Editor(s)

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