一种基于椭圆拟合的内窥镜畸变率检测方法

摘要

为提高医用内窥镜畸变率的检测效率,文中提出了一种基于椭圆拟合的内窥镜畸变率检测方法.对采集到的测标板上的图像进行自动阈值预处理并进行模板匹配,运用投影和反投影技术,去除多余边缘,通过直接最小二乘法进行拟合椭圆,进而求取其畸变率.文中以QM423T 型号医用内窥镜为对象进行畸变率检测,选取畸变板上 5 个椭圆,经过 20 次测量,不同位置的椭圆和平均畸变率测量结果为:左上(0.897 4)、右上(0.876 5)、中心(0.934 8)、左下(0.893 0)、右下(0.907 9),测量结果均符合该型号内窥镜畸变率的测量范围,满足QM42 3 T 型号医用内窥镜的相关标准的测试要求.文中方法检测效率稳定,可重复操作,可减少人工检测的误差,对实际应用具有参考价值.%A method based on ellipse fitting for detecting optical performance parameters of the endoscope distortion rate is proposed in this paper.For the image captured on the test plate,automatic threshold preprocessing and template matching were done.The excess edges were removed by the proj ection and back proj ection technology,and then the distortion rate of the fitted ellipse was calculated by the direct least square method.In this paper,the distortion rate of the QM423T model medical endoscope is detected.5 ellipses selected on the distorted board were measured 20 times.The results of the ellipse at different locations and average distortion rate are:upper left (0.897 4),upper right(0.876 5),center (0.934 8),lower left (0.893 0)and lower right(0.9079).The results are within the measurement range of the endoscope distortion rate of this model,which satisfies the standards of the QM423T medical endoscope.The proposed method is stable and repeatable and is able to reduce errors in manual detection.The study is referential to its practical application.