Python opencv 图像 *** 作的基本示例笔记

图片的读取显示保存

from cv2 import imwrite
import numpy as np
import cv2

img = cv2.imread("lena.jpg",0)
cv2.imshow("lena",img)
k = cv2.waitKey(0)
if k == 27:
    cv2.destroyAllWindows() 
elif k == ord('s'):
    cv2.imwrite("lenagray.jpg",img)
    cv2.destroyAllWindows() 

摄像头数据的读取

import numpy as np
import cv2

cap = cv2.VideoCapture(0)
if cap.isOpened() == True:
    while(True):
        print(cap.get(3),cap.get(4),cap.get(5))
        ret,frame = cap.read()
        gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
        cv2.imshow("lena",gray)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            cv2.destroyAllWindows()
            break

cap.release()

视频数据保存

from cv2 import COLOR_RGB2GRAY
import numpy as np
import cv2

cap = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi',fourcc,20.0,(640,640))
while(cap.isOpened()):
    ret,frame = cap.read()
    if ret == True:
        gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
        frame = cv2.flip(gray,0)
        out.write(frame)
        cv2.imshow("camera",frame)
        if cv2.waitKey(0) & 0XFF == ord('q'):
            break
    else:
        break
cap.release()
out.release()
cv2.destroyAllWindows()

画图图形方法

import numpy as np
import cv2

img = np.zeros((512,512,3),np.uint8)
cv2.line(img,(0,0),(512,512),(255,0,0),5)#画一条蓝线
cv2.rectangle(img,(256,128),(384,256),(0,255,0),10)#方框
cv2.circle(img,(256,256),63,(0,0,255),-1)#圆圈
cv2.ellipse(img,(256,256),(100,50),0,0,180,255,-1)

cv2.putText(img,"Hello world",(10,500),cv2.FONT_HERSHEY_SIMPLEX,2,(255,255,255),2)
cv2.imshow("graph",img)

if cv2.waitKey() == True:
    cv2.destroyAllWindows()

持续更新…