基于MTF评价医用硬性内窥镜的分辨率

Research on evaluation of medical rigid endoscope's resolution based on MTF

根据国内外相关检测标准,确定视觉分辨率和调制传递函数模量作为评价指标,设计检测装置和标靶,编写Matlab程序对采集到的标靶图像进行分析,对13支不同品牌、种类的硬性内窥镜进行检测。实现基于机器视觉检测医用硬性内窥镜分辨率的设备和方法,13支内镜的视觉分辨率为5~16 LP/mm,MTF阈值集中于0.2~0.3之间。结果表明:1)硬性内窥镜镜体、中心、边缘的MTF值均呈现随着线对数增大而减小的趋势;2)每支硬性内窥镜均具有合适的亮度使其分辨率最高;3)硬性内窥镜整体的MTF值偏向由中心决定;4)同一区域下,不同亮度所对应的MTF值相关程度较高,说明内窥镜的分辨率由自身决定。

In order to evaluate the resolution of medical rigid endoscopes quantitatively, this article confirmed the visual resolution and modulation transfer function modulus-MTF as the evaluation indexes, designed the testing of target, device and compile Matlab program for automatic analysis and processing of the collected target image to detect 13 different brands,types of rigid endoscopes according to the relevant domestic and international testing standards.The methods and detection equipment based on machine vision were achieved. The visual resolution of 13 endoscopes was ranged from 5 to 16 LP/mm and MTF threshold was between 0.2and 0.3. The results showed: 1)The overall, center, and edge of rigid endoscope's MTF curve showed a trend that MTF values are reducing with logarithmic increasing;2)Rigid endoscope has a appropriate brightness to make the highest resolution; 3)The overall MTF values of rigid endoscope are decided by the center much more;4)in the range of the same region MTF values corresponding to different brightness values have high correlation coefficients. High values of the correlation coefficients reflect the resolution of the endoscope is determined by itself and has little to do with brightness.