Opencv 学习笔记（一）——Chapter

参考：2020最新-3h精通Opencv

代码

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1.Images-Videos-Webcam

图像、视频、网络摄像头

######################## READ IMAGE ############################
# import cv2
# # LOAD AN IMAGE USING 'IMREAD'
# img = cv2.imread("Resources/lena.png")
# # DISPLAY
# cv2.imshow("Lena Soderberg",img)
# cv2.waitKey(0)

######################### READ VIDEO #############################
# import cv2
# frameWidth = 640
# frameHeight = 480
# cap = cv2.VideoCapture("Resources/test_ video.mp4")
# while True:
#     success, img = cap.read()
#     img = cv2.resize(img, (frameWidth, frameHeight))
#     cv2.imshow("Result", img)
#     if cv2.waitKey(1) & 0xFF == ord('q'):
#         break
######################### READ WEBCAM  ############################

#打开网络摄像头
import cv2
frameWidth = 640
frameHeight = 480
cap = cv2.VideoCapture(0)
cap.set(3, frameWidth)
cap.set(4, frameHeight)
cap.set(10,150)
while True:
    success, img = cap.read()
    cv2.imshow("Result", img)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

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4.绘图

import cv2
import numpy as np

img = np.zeros((512,512,3),np.uint8)
#print(img)
#img[:]= 255,0,0

cv2.line(img,(0,0),(img.shape[1],img.shape[0]),(0,255,0),3)
cv2.rectangle(img,(0,0),(250,350),(0,0,255),2)
cv2.circle(img,(400,50),30,(255,255,0),5)
cv2.putText(img," OPENCV  ",(300,200),cv2.FONT_HERSHEY_COMPLEX,1,(0,150,0),3)


cv2.imshow("Image",img)

cv2.waitKey(0)

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5.图像提取并显示

提取固定位置的图像重新铺平显示

import cv2
import numpy as np

img = cv2.imread("Resources/cards.jpg")

width,height = 250,350
pts1 = np.float32([[111,219],[287,188],[154,482],[352,440]])# 获取轮廓
pts2 = np.float32([[0,0],[width,0],[0,height],[width,height]]) # 显示平面
matrix = cv2.getPerspectiveTransform(pts1,pts2)
imgOutput = cv2.warpPerspective(img,matrix,(width,height))


cv2.imshow("Image",img)
cv2.imshow("Output",imgOutput)

cv2.waitKey(0)

7.颜色

import cv2
import numpy as np

def empty(a):
    pass

def stackImages(scale,imgArray):
    rows = len(imgArray)
    cols = len(imgArray[0])
    rowsAvailable = isinstance(imgArray[0], list)
    width = imgArray[0][0].shape[1]
    height = imgArray[0][0].shape[0]
    if rowsAvailable:
        for x in range ( 0, rows)