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医用硬性内窥镜是一种常用的医疗器械,成像质量的好坏直接影响着内窥镜的检测效果,因此内窥镜光学传递函数测量是一个亟待解决的课题。设计了基于刀口法的内窥镜调制传递函数测量系统,利用CMOS相机分别对刀口移动时刀口像的灰度值进行连续采样和刀口静止时刀口像的灰度值进行单步采样,电子计算机将所得到的数据进行微分、傅里叶变换和滤波,就可以快速地得到内窥镜的调制传递函数。以0°鼻窦镜为测量模型,实验表明,在中心视场空间频率5lp/mm处,刀口扫描法测得的MTF值比仿真值低0.03,空间频率10lp/mm处,刀口扫描法测得的MTF值比仿真值低0.01,且刀口扫描法和刀口目标成像法都可以测量出稳定的MTF曲线。
Medical rigid endoscope is a commonly used medical device, the quality of the imaging directly affects the endoscopic detection, so the measurement of endoscopic optical transfer function is an urgent problem to be solved. A measurement system of endoscopic modulation transfer function based on blade edge was designed. By using the CMOS camera to continuously sample the gray value of the edge image when the edge was moving and the gray value of the edge image when the edge was still, single-step sampling The resulting data are differentiated, Fourier transformed, and filtered to quickly obtain the modulation transfer function of the endoscope. Taking the 0 ° sinusoscope as the measurement model, the experimental results show that the MTF value measured by the knife-edge scanning method is lower than the simulation value at the spatial frequency of 5 lp / mm at the central field of view by 0.03 and the spatial frequency is 10 lp / mm. The MTF value is lower than the simulation value of 0.01, and both the knife-edge scanning method and the knife-edge target imaging method can measure the stable MTF curve.