特征点检测算法
特征点检测算法
Harris角点检测
cv2.cornerHarris(gray,blockSize=4,ksize=5,k=0.04)
import cv2
import matplotlib.pyplot as plt
import numpy as np
def cv_show(name,image):
"""图像显示函数
name：字符串，窗口名称
img：numpy.ndarray，图像
"""
cv2.namedWindow(name,cv2.WINDOW_NORMAL)
cv2.imshow(name,image)
cv2.waitKey(0)
cv2.destroyAllWindows()
if __name__=="__main__":
img = cv2.imread('.\data\Box.jpg')
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
gray = np.float32(gray)
# 角点检测
dst = cv2.cornerHarris(gray,blockSize=4,ksize=5,k=0.04)
# 对角点进行膨胀操作
dst = cv2.dilate(dst,None)
img[dst>0.01*dst.max()] = [0,0,255]
# 显示图像
cv_show('Harris Corners',img)
SIFT特征检测
import cv2
import numpy as np
def cv_show(name,image):
"""图像显示函数
name：字符串，窗口名称
img：numpy.ndarray，图像
"""
cv2.namedWindow(name,cv2.WINDOW_NORMAL)
cv2.imshow(name,image)
cv2.waitKey(0)
cv2.destroyAllWindows()
if __name__=="__main__":
img = cv2.imread('.\data\975-1.jpg')
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
sift = cv2.xfeatures2d.SIFT_create()
keypoints,descriptor = sift.detectAndCompute(gray,None)
# 在图上绘制关键点
img = cv2.drawKeypoints(image=img,outImage=img,keypoints=keypoints,flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS,color=(255,255,0))
cv_show('sift_keypoints',img)
cv2.imwrite('.\opencv_python\SIFT.jpg',img)
SURF特征检测
import cv2
import numpy as np
def cv_show(name,image):
"""图像显示函数
name：字符串，窗口名称
img：numpy.ndarray，图像
"""
cv2.namedWindow(name,cv2.WINDOW_NORMAL)
cv2.imshow(name,image)
cv2.waitKey(0)
cv2.destroyAllWindows()
if __name__=="__main__":
img = cv2.imread('.\data\975-1.jpg')
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
surf = cv2.xfeatures2d.SURF_create(8000)
keypoints,descriptor = surf.detectAndCompute(gray,None)
img = cv2.drawKeypoints(image=img,outImage=img,keypoints=keypoints,flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS,color=(255,255,0))
cv_show('surf_keypoints',img)
cv2.imwrite('.\opencv_python\SURF.jpg',img)
ORB特征检测
def img_show(name,image):
"""matplotlib图像显示函数
name：字符串，图像标题
img：numpy.ndarray，图像
"""
if len(image.shape) == 3:
image = cv2.cvtColor(image,cv2.COLOR_BGR2RGB)
plt.imshow(image,'gray')
plt.xticks([])
plt.yticks([])
plt.xlabel(name,fontproperties='FangSong',fontsize=12)
if __name__=="__main__":
img1 = cv2.imread('.\data\974-1.jpg')
img2 = cv2.imread('.\data\975-1.jpg')
gray1 = cv2.cvtColor(img1,cv2.COLOR_BGR2GRAY)
gray2 = cv2.cvtColor(img2,cv2.COLOR_BGR2GRAY)
orb = cv2.ORB_create()
kp1,des1 = orb.detectAndCompute(gray1,None)
kp2,des2 = orb.detectAndCompute(gray2,None)
bf = cv2.BFMatcher(cv2.NORM_HAMMING,crossCheck=True)
matches = bf.match(des1,des2)
matches = sorted(matches,key=lambda x:x.distance)
img3 = cv2.drawMatches(img1,kp1,img2,kp2,matches[:80],img2,flags=2)
plt.figure(figsize=(60,80),dpi=80)
img_show('',img3)
作者：陨星落云
