基于改进均值漂移算法的绿色作物图像分割方法  

Image segmentation method for green crops using improved mean shift

作　　者：伍艳莲[1,2] 赵力[1] 姜海燕[1,2] 郭小清[1] 黄芬[1,2] 

机构地区：[1]南京农业大学信息科学与技术学院,南京210095 [2]南京农业大学国家信息农业工程技术中心,南京210095

出　　处：《农业工程学报》2014年第24期161-167,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(30971697);国家863计划(2013AA100404);国家科技支撑计划(2011BAD21B03)

摘　　要：针对绿色农作物图像背景复杂且分割难的问题,提出一种基于改进均值漂移算法的分割方法。采用均值漂移算法对图像进行平滑和分割时,带宽的选择直接影响平滑和分割的结果。传统的均值漂移分割方法需要人为地设定空域带宽和值域带宽这2个参数。该文首先根据绿色作物图像的颜色特点,提取图像的颜色指数;然后采用均值漂移算法,将图像的颜色信息与空间信息结合起来,根据作物图像颜色分布的丰富程度定义自适应空域带宽,采用渐近积分均方差来获得自适应值域带宽,对图像进行平滑滤波;最后采用Otsu方法将平滑后的图像分成两部分:绿色部分和背景部分。试验结果表明,该方法能够有效地分割出绿色作物,并在分割性能上明显优于常规的颜色指数方法,作物图像的错分率均小于6.5%。Digital image processing technology has received considerable attention in many aspects of agriculture, some typical examples including estimation physiological status of crops, disease and insect pest identification, vegetation-cover estimation, and quality detection for agricultural products. One of the most important and essential tasks is the crop image segmentation which separates the green crop material or region of interest from the background. In recent years, green crop image segmentation has been an important research topic and several methods have been proposed. However, green crop image segmentation is still a difficult problem since the green crop images usually involve complicated backgrounds. To deal with this problem, we propose in this paper a novel segmentation method based on Mean shift and color index. Mean shift is an iterative procedure that shifts each data point to the average of data points in its neighborhood. The performance of Mean shift depends heavily on the size of bandwidth which means that bandwidth selection is a key issue in mean shift-based image smoothing and segmentation. Classical Mean shift segmentation method needs spatial bandwidth and range bandwidth to be initialized, which usually leads to lower segmentation precision. We present an improved Mean shift algorithm by using adaptive spatial and range bandwidth. Firstly, color index was extracted according to the color feature of the green crop image in the RGB color space. Secondly, with the extracted color index, images were smoothed and segmented by Mean shift algorithm. The proposed improved Mean shift algorithm employs an adaptive bandwidth strategy where the adaptive spatial bandwidth is determined according to the color distribution of the images by combining color information and spatial information. It means that a small spatial bandwidth is suitable for images containing much more detailed information, while images containing large flat areas require a larger bandwidth. This approach smoothed the images without t

关 键 词：图像分割 带宽 算法 作物 颜色指数 均值漂移 

分 类 号：S126[农业科学—农业基础科学] TP391.41[自动化与计算机技术—计算机应用技术]