基于Radon变换的时空图像纹理角识别方法  

Method of space-time image velocimetry based on Radon transform

作　　者：李涵 金世俊[1] Li Han;Jin Shijun(School of Instrument Science and Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]东南大学仪器科学与工程学院,南京210096

出　　处：《电子测量技术》2024年第1期178-185,共8页Electronic Measurement Technology

摘　　要：时空图像测速法以河流表面自然特征为分析对象,检测生成的时空图像中的纹理主方向,根据物象变换关系、拍摄所得视频参数和纹理方向倾角的正切值计算出河流表面的一维时均流速。针对实际应用中生成的时空图像受噪声干扰而导致时空图像纹理倾斜角检测精度出现较大误差的问题,本文提出采用改进的同态滤波器来增强河流表面图像的纹理特征,采用融合了自适应直方图均衡化的频域滤波对时空图像去噪,再利用Radon变换检测纹理角方向。通过模拟纹理图像实验,较高、较低流速条件下实地河道实验验证本文改进方法的有效性,实验结果表明,对于标准的模拟纹理图,Radon变换角度检测结果相对误差小于0.03%,对于干扰较多的复杂的实地河道环境,较低和较高流速条件下,基于Radon变换的时空图像纹理角识别结果与人工手动目测值间的相对误差分别小于1.56%和1.80%。实验表明,Radon变换法可行且较其他纹理角检测算法有更高的精度。The space-time image velocimetry technique harnesses the natural features of river surfaces for analysis.By examining the predominant texture direction in the generated space-time images,it calculates the one-dimensional timeaveraged flow velocity of the river surface,factoring in physical transformation relationships,captured video parameters,and the tangent of the texture inclination angle.In view of the problem that the accuracy of the spatiotemporal image texture inclination angle detection is greatly affected by noise interference in practical applications,this paper proposes to use an improved homomorphic filter to enhance the texture features of the river surface image,and adopts a frequency domain filter integrated with adaptive histogram equalization to denoise the spatiotemporal image.Subsequently,the Radon transform is deployed to pinpoint the texture's angular direction.Through simulated texture image experiments and on-site river experiments under high and low flow conditions,the effectiveness of the improved method proposed in this paper is verified.The findings reveal that,for standard simulated texture visuals,the Radon transform's angle detection holds a relative error of less than 0.03%.In on-site river laden with interference,the relative errors between the Radon transform-based spatiotemporal image texture angle detections and manual observations are less than 1.56% and 1.80% under low and high flow conditions,respectively.The experiment indicates that the Radon transform method is feasible and has higher accuracy compared to other texture angle detection algorithms.

关 键 词：河流流速测量 时空图像测速 同态滤波 频域滤波 RADON变换 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]