【OpenCV】——b站达尔闻

达尔闻OpenCV学习

计算机视觉导论

一、计算机视觉解决的基本问题

分类，检测，分隔

二、计算机视觉的前沿进展

深度学习 海量数据

边缘计算

图像分类领域：

目标检测领域

CS231n 李飞飞教授 公开课

原始论文

安装配置Opencv-Python

https://github.com/opencv/opencv

Resources

• Homepage:

  https://opencv.org

  • Courses: https://opencv.org/courses

• Docs: https://docs.opencv.org/master/

• Q&A forum: http://answers.opencv.org

• Issue tracking: https://github.com/opencv/opencv/issues

pip换源

pip config set global.index-url https://mirrors.aliyun.com/pypi/simple/


pip install opencv-python

#当前查看版本

import cv2
cv2.__version__

案例

边缘计算

import cv2
cap = cv2.VideoCapture(0)
cap.open(0)

while cap.isOpened():
    flag, frame = cap.read()
    cv2.imshow('my_window',frame)
    key_pressed = cv2.waitKey(60)
    print('键盘被按下的键是：',key_pressed)
    if key_pressed == 27:
        break

cap.release()
cv2.destroyAllWindows()

#边缘检测
import cv2
#cap = cv2.VideoCapture(0)
import numpy as npcap = cv2.VideoCapture(0,cv2.CAP_DSHOW)
cap.open(0)
while cap.isOpened():
    flag, frame = cap.read()
    if not flag:
        break
    key_pressed = cv2.waitKey(60)
    print('键盘被按下的键是：',key_pressed)
    
    frame = cv2.Canny(frame,100,200)
    frame = np.dstack(frame,frame,frame)
    cv2.imshow('my_window2',frame)
    
    if key_pressed == 27:
        break
cap.release()
cv2.destroyAllWindows()

#CannyScanV1.py
import cv2
import numpy as np
cap = cv2.VideoCapture(0)
#import numpy as npcap = cv2.VideoCapture(0,cv2.CAP_DSHOW)
cap.open(0)
while cap.isOpened():
    flag, frame = cap.read()
    if not flag:
        break
    key_pressed = cv2.waitKey(60)
    print('键盘被按下的键是：',key_pressed)
    
    frame = cv2.Canny(frame,100,200)
    frame = np.dstack((frame,frame,frame))
    cv2.imshow('my_window2',frame)
    
    if key_pressed == 27:
        break
cap.release()
cv2.destroyAllWindows()

import cv2
import numpy as np

cap = cv2.VideoCapture(0)
while(1):
    # get a frame
    ret, frame = cap.read()
    # show a frame
    cv2.imshow("capture", frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
cap.release()
cv2.destroyAllWindows() 

#CannyScanV1.py

import cv2
import numpy as np

cap = cv2.VideoCapture(0)

while(True):
    ret, frame = cap.read()
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xff == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()   

import cv2
import numpy as np
cap = cv2.VideoCapture(0)
#import numpy as npcap = cv2.VideoCapture(0,cv2.CAP_DSHOW)
cap.open(0)
while cap.isOpened():
    flag, frame = cap.read()
    if not flag:
        break
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    gray =  cv2.blur(gray,ksize = (5, 5))
    grayframe = cv2.Canny(gray,100,200)
    frame = cv2.Canny(frame,100,200)
    ##frame = np.dstack(frame,frame,frame)
    cv2.imshow('my_window',frame)
    cv2.imshow('my_window2',grayframe)
    if cv2.waitKey(1) & 0xff == ord('q'):
        break
    
cap.release()
cv2.destroyAllWindows()

笑脸检测

#SmileCaptureV1.py
import cv2

#人脸检测 眼睛检测，微笑检测

face_cascade = cv2.CascadeClassifier(cv2.data.haarcascades+'haarcascade_frontalface_default.xml')

eye_cascade = cv2.CascadeClassifier(cv2.data.haarcascades+'haarcascade_eye.xml')

smile_cascade = cv2.CascadeClassifier(cv2.data.haarcascades+'haarcascade_smile.xml')

cap = cv2.VideoCapture(0)
while(True):
    ret,frame = cap.read()
    faces = face_cascade.detectMultiScale(frame,1.3,2)
    img = frame
    for (x,y,w,h) in faces:
        img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
        face_area = img[y:y+h,x:x+w]
        eyes = eye_cascade.detectMultiScale(face_area,1.3,10)
        for (ex,ey,ew,eh) in eyes:
            cv2.rectangle(face_area,(ex,ey),(ex+ew,ey+eh),(0,255,0),1)
            
        smiles = smile_cascade.detectMultiScale(face_area,scaleFactor = 1.16,minNeighbors=65,minSize=(25,25),flags = cv2.CASCADE_SCALE_IMAGE)
        for (ex,ey,ew,eh) in smiles:
            cv2.rectangle(face_area,(ex,ey),(ew+ex,ey+eh),(0,0,255),1)
            cv2.putText(img,'Smile',(x,y-7),3,1.2,(0,0,255),2,cv2.LINE_AA)
    cv2.imshow("frame2",img)
    if cv2.waitKey(5) & 0xff == ord('q'):
        break
    
cap.release()
cv2.destoryAllWindows()

视频

调用摄像头：

#
import cv2
cap  = cv2.VideoCapture(0)
if not cap.isOpened():
    print("无法打开摄像头")
    exit()
    
while True:
    ret, frame = cap.read()
    if not ret:
        print("无法打开摄像头")
        break
        
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    cv2.imshow("frame_window",gray)
    
    if cv2.waitKey(1) == ord('q'):
        break
        
cap.release()
cv2.destroyAllWindows()
        

本地视频

# VedioCapv1.py
import cv2
cap  = cv2.VideoCapture("test.mp4")
if not cap.isOpened():
    print("无法打开视频")
    exit()

print('WIDTH',cap.get(3))
print('HIGTH',cap.get(4))
while True:
    ret, frame = cap.read()
    if not ret:
        print("无法打开摄像头")
        break
        
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    cv2.imshow("frame_window",gray)
    
    if cv2.waitKey(25) == ord('q'):
        break
        
cap.release()
cv2.destroyAllWindows()

保存处理后的视频

import numpy as np
import cv2 as cv
cap = cv.VideoCapture(0)
fourcc = cv.VideoWriter_fourcc(*'DIVX')
# Define the codec and create VideoWriter object
# 指定输出文件,fourCC视频编码，FPS
out = cv.VideoWriter('output.avi',fourcc,20.0,(640,480))

while cap.isOpened():
    ret,frame = cap.read()
    if not ret:
        print("无法打开摄像头")
        break
    frame = cv.flip(frame,0) ## 翻转视频
    
    out.write(frame)
    
    cv.imshow('frame',frame)
    if cv.waitKey(1) == ord('q'):
        break
        
cap.release()
out.release()# 若注释掉，没有预览图片
cv.destoryAllWindows()

目标检测

综述和YOLO的介绍