opencv基本操作学习

'''
图像操作
'''
import numpy as np
import cv2
'''
img = cv2.imread('D:\cvimg.jpg',0)  #参数‘0’将图片以灰度图的形式读出，‘1’彩图读取
cv2.namedWindow('cvimg',cv2.WINDOW_NORMAL)#cv2.WINDOW_NORMAL先创建一个可以手动调整的窗口，cv2.WINDOW_AUTOSIZE自动窗口调整
cv2.imshow('cvimg',img)#显示图片
cv2.imwrite('D:\img.png',img)#保存图片
cv2.waitKey(0)#参数为0，那它将会无限期的等待键盘输入。
cv2.destroyAllwindows()#删除任何我们建立的窗口，括号内输入你想删除的窗口名。
'''
'''
img = cv2.imread('D:\cvimg.jpg',0)
cv2.namedWindow('cvimg',cv2.WINDOW_NORMAL)
cv2.imshow('cvimg',img)
k = cv2.waitKey(0)  #如果是64位的系统，需要加上&&0XFF
if k == 27:  #通过键值ESC退出窗口
    cv2.destroyAllWindows()
elif k== ord('s'):#通过键值s保存图片，并退出窗口
    cv2.imwrite('D:\img.jpg',img)
    cv2.destroyAllWindows()
'''
'''
使用matplotlib绘制图像
'''
'''
from matplotlib import pyplot as plt

img = cv2.imread('D:\cvimg.jpg',0)
plt.imshow(img,cmap='gray',interpolation='bicubic')
plt.xticks([]),plt.yticks([])#隐藏坐标
plt.show()
'''
'''
摄像头操作获得视频
'''
'''
cap = cv2.VideoCapture(0)
print(cap.get(3))
print(cap.get(4))
while(cap.isOpened()):
    ret,frame = cap.read()
    if ret == True:
        gray = cv2.cvtColor(frame,cv2.COLOR_BGR2BGRA)
        cv2.imshow('frame',gray)
        if cv2.waitKey(1) == ord('q'):
            break
    else:
        break
cap.release()
cv2.destroyAllWindows()
'''
'''
保存视频
'''
'''
cap = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*'XVID')#确定编码方式
out = cv2.VideoWriter('output.avi',fourcc,20.0,(640,480))#创建一个视频保存的对象

while (cap.isOpened()):
    ret,frame = cap.read()
    if ret == True:
        frame = cv2.flip(frame,1)#反转，1水平，0垂直，-1两者同时
        out.write(frame)
        cv2.imshow('frame',frame)
        if cv2.waitKey(1)==ord('q'):
            break
    else:
        break
cap.release()
out.release()
cv2.destroyAllWindows()
'''
'''
画线
'''
'''
img = np.zeros((512,512,3),np.uint8)
cv2.line(img,(0,0),(512,512),(255,0,0),5)
'''
#mouse callback function
def draw_circle(event,x,y,flags,param):
    if event==cv2.EVENT_LBUTTONDBLCLK:
        cv2.circle(img,(x,y),100,(255,0,0),-1)


# 创建图像与窗口并将窗口与回调函数绑定
img=np.zeros((512,512,3),np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image',draw_circle)
while(1):
    cv2.imshow('image',img)
    if cv2.waitKey(20)&0xFF==27:
        break
cv2.destroyAllWindows()