基本思想
1、选择图像上任何方向的固定窗口滑动。如果灰度变化很大,则认为窗口内部有一个角。
2、步骤,阅读并将其转换为灰度图。估计响应函数。根据响应值选择角度。绘制原始图表上的检测角度。
实例
frompylabimport* fromnumpyimport* fromscipy.ndimageimportfilters defcompute_harris_response(im,sigma=3): """ComputetheHarriscornerdetectorresponsefunction foreachpixelinagraylevelimage.""" #derivatives imx=zeros(im.shape) filters.gaussian_filter(im,(sigma,sigma),(0,1),imx) imy=zeros(im.shape) filters.gaussian_filter(im,(sigma,sigma),(1,0),imy) #computecomponentsoftheHarrismatrix Wxx=filters.gaussian_filter(imx*imx,sigma) Wxy=filters.gaussian_filter(imx*imy,sigma) Wyy=filters.gaussian_filter(imy*imy,sigma) #determinantandtrace Wdet=Wxx*Wyy-Wxy**2 Wtr=Wxx+Wyy returnWdet/Wtr defget_harris_points(harrisim,min_dist=10,threshold=0.1): """ReturncornersfromaHarrisresponseimage min_dististheminimumnumberofpixelsseparating cornersandimageboundary.""" #findtopcornercandidatesaboveathreshold corner_threshold=harrisim.max()*threshold harrisim_t=(harrisim>corner_threshold)*1 #getcoordinatesofcandidates coords=array(harrisim_t.nonzero()).T #...andtheirvalues candidate_values=[harrisim[c[0],c[1]]forcincoords] #sortcandidates(reversetogetdescendingorder) index=argsort(candidate_values)[::-1] #storeallowedpointlocationsinarray allowed_locations=zeros(harrisim.shape) allowed_locations[min_dist:-min_dist,min_dist:-min_dist]=1 #selectthebestpointstakingmin_distanceintoaccount filtered_coords=[] foriinindex: ifallowed_locations[coords[i,0],coords[i,1]]==1: filtered_coords.append(coords[i]) allowed_locations[(coords[i,0]-min_dist):(coords[i,0]+min_dist), (coords[i,1]-min_dist):(coords[i,1]+min_dist)]=0 returnfiltered_coords defplot_harris_points(image,filtered_coords): """Plotscornersfoundinimage.""" figure() gray() imshow(image) plot([p[1]forpinfiltered_coords], [p[0]forpinfiltered_coords],'*') axis('off') show()
fromPILimportImage fromnumpyimport* #这就是为什么上面要新建一个,因为import现在可以了 importHarris_Detector frompylabimport* fromscipy.ndimageimportfilters #filename im=array(Image.open(r"").convert('L')) harrisim=Harris_Detector.compute_harris_response(im) filtered_coords=Harris_Detector.get_harris_points(harrisim) Harris_Detector.plot_harris_points(im,filtered_coords)
以上就是python中Harris角点的检测方法,希望对大家有所帮助。更多Python学习指导:python基础教程
本文教程操作环境:windows7系统Python 3.9.1,DELL G3电脑。