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角膜曲率测量中自动识别的对焦评价

Focus evaluation for automatic recognition in corneal curvature measurement

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摘要

角膜曲率测量一般是采用视标成像的方法得到角膜的反射像后, 通过对反射像的再成像间接得到角膜的曲率半径。为了实现对角膜曲率测量图像的对焦判断, 在简化角膜曲率测量系统的基础上, 对获取的图像对焦算法进行研究。对角膜曲率测量图像的六个测试光标分别进行像素统计, 初步判别过度离焦的状态。对角膜曲率测量图像进行四方向Sobel算子的卷积运算, 对得到的边缘增强图像进行对数灰度级像素统计, 得到对焦评价值。将该算法与Tenengrad函数、方差函数和单一对数灰度级像素统计评价函数算法做对比实验, 评价该算法的可行性。实验结果表明, 该对焦评价函数具有良好的精确度、单峰性、灵敏度和无偏性, 对细节信息较少、结构简单的图像的对焦评价方面有应用前景。

Abstract

The corneal curvature measurement is generally obtained by using the method of visual imaging to obtain the reflection image of the cornea. The corneal curvature radius is indirectly obtained by re-imaging the reflected image. In order to achieve the focus judgment of the corneal curvature measurement image, the acquired image-focusing algorithm is researched based on the simplified corneal curvature measurement system. The six test cursors of the corneal curvature measurement image were separately counted in pixels, and excessive defocusing state was judged and eliminated initially. Gradient image was constructed by using four-direction Sobel operator with corneal curvature measurement image. The acquired edge enhanced image was used pixel statistical based on different gray level. In addition, focus evaluation value was obtained. The algorithm was compared with the Tenengrad function, the variance function and the single logarithmic gray level pixel statistical evaluation function algorithm to prove the feasibility of the algorithm. The experimental results show that the proposed focus evaluation function has good accuracy unimodality, sensitivity and unbiasedness. Therefore, the proposed method has a potential application for image focusing evaluation with less detail and simple structure.

Newport宣传-MKS新实验室计划
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中图分类号:TP391

所属栏目:光信息处理

基金项目:国家自然科学基金(61378060)

收稿日期:2018-09-25

修改稿日期:2018-12-25

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作者单位    点击查看

方丽萍:上海理工大学 医疗器械与食品学院 生物医学光学与视光学研究所, 上海 200093
陈兆学:上海理工大学 医疗器械与食品学院 生物医学光学与视光学研究所, 上海 200093
陈鹏:上海理工大学 医疗器械与食品学院 生物医学光学与视光学研究所, 上海 200093
王成:上海理工大学 医疗器械与食品学院 生物医学光学与视光学研究所, 上海 200093
张大伟:上海理工大学 光电信息与计算机工程学院 上海市现代光学系统重点实验室 教育部光学仪器与系统工程研究中心, 上海 200093

联系人作者:方丽萍(18818261978@163.com)

备注:方丽萍(1993-), 女 , 硕士研究生, 从事生物医学光学图像处理研究。

【1】Tyan J. The optimal measure for passive auto-focusing and depth-from-focus[C]∥ Symposium on Videometrics IV. Philadelphia,USA:EI,1995:2598(8):89-99.

【2】Yu S, Duthaler S, Nelson B J. Autofocusing algorithm selection in computer microscopy[C]∥IEEE/RSJ International Conference on Intelligent Robots & Systems.Edmonton,Canada:EI,2005:70-76.

【3】Redondo R, Bueno G, Valdiviezo J C, et al. Autofocus evaluation for brightfield microscopy pathology[J]. Journal of Biomedical Optics,2012,17(3):036008.

【4】Yao Y , Abidi B , Doggaz N , et al. Evaluation of sharpness measures and search algorithms for the auto focusing of high-magnification images[C]∥ SPIE/Visual Information Processing XV. Kissimmee,USA:EI,2006,6246:62460G.

【5】翟永平, 周东翔, 刘云辉, 等. 聚焦函数性能评价指标设计及最优函数选取[J]. 光学学报,2011,31(4):234-244.
Zhai Yongping, Zhou Dongxiang, Liu Yunhui, et al. Design of evaluation index for auto-focusing and optimal function selection [J]. Acta Optica Sinica,2011,31(4):234-244.

【6】钱青, 臧冬菊. 一种改进的Sobel算子图像清晰度评价函数[J]. 计算机与数字工程,2015,43(10):1865-1870.
Qian Qing, Zang Dongju. A modified sharpness-evaluation function of image based on sobel [J]. Computer & Digital Engineering,2015,43(10):1865-1870.

【7】韩西达, 王敏, 黄强, 等. 用于多孔板细胞分析的自动显微成像系统[J]. 光学精密工程,2013,21(10):2543-2548.
Han Xida, Wang Min, Huang Qiang, et al. Auto-microimaging system for cell analysis with multiple well plates[J]. Optics and Precision Engineering,2013,21(10):2543-2548.

【8】周丽平, 孙志峻, 张泉. 显微视觉系统的自动聚焦及控制[J]. 光学精密工程,2013,21(3):807-812.
Zhou Liping, Sun Zhijun, Zhang Quan. Auto-focusing and control of micro-vision system[J]. Optics and Precision Engineering,2013,21(3):807-812.

【9】郑英娟, 张有会, 王志巍, 等. 基于八方向Sobel算子的边缘检测算法[J]. 计算机科学,2013,40(11a):354-356.
Zheng Yingjuan, Zhang Youhui, Wang Zhiwei, et al. Edge detection algorithm based on the eight directions Sobel operator[J]. Computer Science,2013,40(11a):354-356.

【10】王铨, 黄战华, 蔡怀宇, 等. 高精度分划板自动对焦评价函数研究[J]. 传感技术学报,2013,26(1):49-52.
Wang Quan, Huang Zhanhua, Cai Huaiyu, et al. Research on high precision evaluation function for auto-focus of reticule[J]. Chinese Journal of Sensors and Actuators,2013,26(1):49-52.

【11】Li H, Fu C. An improved focusing algorithm based on image definition evaluation[C]∥ International Conference on Artificial Intelligence, Management Science and Electronic Commerce. IEEE,Dengfeng,China:EI,2011:3743-3746.

【12】Castillo-Secilla J M, Saval-Calvo M, Medina-Valdès L, et al. Autofocus method for automated microscopy using embedded GPUs[J]. Biomedical Optics Express,2017,8(16):1731-1740.

【13】薛万勋, 卞春江, 陈红珍. 基于点锐度和平方梯度的图像清晰度评价方法[J]. 电子设计工程,2017,25(8):163-167.
Xue Wanxun, Bian Chunjiang, Chen Hongzhen. Image clarity evaluation based on point sharpness and square gradient [J]. Electronic Design Engineering,2017,25(8):163-167.

【14】李洪宇, 杨帆, 谭文斌, 等. 基于HVS算子的自适应清晰度自动调焦评价函数[J]. 红外技术,2017,39(7):632-637.
Li Hongyu, Yang Fan, Tan Wenbin, et al. A self-adaptive clarity auto focus evaluation function based on HVS operator [J]. Infrared Technology,2017,39(7):632-637.

【15】王烨茹, 冯华君, 徐之海, 等. 基于饱和像素剔除的自动对焦评价函数[J]. 光学学报,2016,36(12):81-88.
Wang Yeru, Feng Huajun, Xu Zhihai, et al. Autofocus evaluation function based on saturate pixels removing [J]. Acta Optica Sinica,2016,36(12):81-88.

【16】何炳阳, 张智诠, 杨秋实,等. 热成像系统自适应自动对焦算法[J]. 激光与红外,2017,47(10):1259-1263.
He Bingyang, Zhang Zhiquan, Yang Qiushi, et al. Adaptive auto-focusing algorithm of thermal imaging system [J]. Laser & Infrared,2017,47(10):1259-1263.

【17】邹昌帆, 刘秉琦, 黄富瑜, 等. 基于多向最大梯度阈值的自动调焦评价函数[J]. 激光与红外,2016,46(1):115-118.
Zou Changfan, Liu Bingqi, Huang Fuyu, et al. Automatic focusing evaluation function based on multi-directional maximal gradient threshold method [J]. Laser & Infrared,2016,46(1):115-118.

【18】何远清, 刘永基, 翟奕. 成像角膜曲率计的光学设计[J]. 中国光学,2014,7(6):956-961.
He Yuanqing, Liu Yongji, Zhai Yi. Optical design of imaging keratometer [J]. Chinese Optics,2014,7(6):956-961.

引用该论文

FANG Liping,CHEN Zhaoxue,CHEN Peng,WANG Cheng,ZHANG Dawei. Focus evaluation for automatic recognition in corneal curvature measurement[J]. Optical Technique, 2019, 45(2): 218-223

方丽萍,陈兆学,陈鹏,王成,张大伟. 角膜曲率测量中自动识别的对焦评价[J]. 光学技术, 2019, 45(2): 218-223

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