Chen S K, Hollender L
Department of Oral Medicine, School of Dentistry, University of Washington, Seattle.
Oral Surg Oral Med Oral Pathol. 1994 Mar;77(3):308-13. doi: 10.1016/0030-4220(94)90305-0.
An impulse train method to control aliasing was used to measure the modulation transfer function of a digital dental x-ray system (RVG 32000 ZHR, Trophy Radiologie, Vincennes, France). The detector of this system is composed of an intensifying screen, a fiber optics taper, and a charged couple device chip. The modulation transfer function could not be measured by impulse method such as the line spread function or edge response function because of aliasing from undersampling of the digital system. The system modulation transfer function was difficult to recover at the spatial frequencies smaller than the Nyquist frequency. The modulation transfer function beyond the Nyquist frequencies was impossible to recover in this study.
采用脉冲序列法控制混叠，以测量数字化牙科X射线系统（RVG 32000 ZHR，法国万森纳特罗菲放射学公司）的调制传递函数。该系统的探测器由一个增感屏、一个光纤锥和一个电荷耦合器件芯片组成。由于数字系统欠采样导致的混叠，无法通过诸如线扩展函数或边缘响应函数等脉冲法来测量调制传递函数。在小于奈奎斯特频率的空间频率下，系统调制传递函数难以恢复。在本研究中，不可能恢复超过奈奎斯特频率的调制传递函数。
