opencv基础入门

安装opencv

pip install opencv-python

 

读取图片

import cv2 as cv

img = cv.imread("images/luo.jpg")
cv.imshow("罗翔",img)

# 等待
cv.waitKey(0)
cv.destroyAllWindows()

 

 改变灰度

import cv2 as cv

img = cv.imread("images/luo.jpg")

# 灰度处理
hd_img = cv.cvtColor(img,cv.COLOR_BGR2GRAY)
cv.imshow("罗翔",hd_img)


# 等待
cv.waitKey(0)
cv.destroyAllWindows()

 

 修改图片尺寸

import cv2 as cv

img = cv.imread("images/luo.jpg")

# 修改尺寸
resize_img = cv.resize(img,dsize=(200,200))

# 显示原图
cv.imshow("luo",img)
# 显示改变
cv.imshow("luo2",resize_img)

# 打印大小
print("原图",img.shape)
print("原图",resize_img.shape)


# 等待
cv.waitKey(0)
cv.destroyAllWindows()

 

 对图片人脸识别

import cv2 as cv

def face_detect_demo():
    hd = cv.cvtColor(img,cv.COLOR_BGR2GRAY)
    # 引入OpenCV源码里分类器
    face_detect = cv.CascadeClassifier("D:/opencv-4.5.5/data/haarcascades/haarcascade_frontalface_alt2.xml")
    face = face_detect.detectMultiScale(hd,1.2,5,0,(100,100),(300,300))
    for x,y,w,h in face:
        cv.rectangle(img,(x,y),(x+w,y+h),color=(0,0,255),thickness=2)
    cv.imshow("result",img)

if __name__ == "__main__":
    img = cv.imread("images/luo.jpg")
    # 调用人脸检测函数
    face_detect_demo()
    # 等待
    cv.waitKey(0)
    cv.destroyAllWindows()