opencv

Wed, 24 Oct 2018 00:00:00 +0000

[TOC]

opencv

opencv既可以从视频文件读取，也可以从视频设备上获取

install

pip install opencv-python

how to use

import cv2
# video_capture = cv2.VideoCapture("/home/alex/1.mp4")
# video_capture = cv.CaptureFromFile('rtsp://192.168.1.2:8080/out.h264')
video_capture = cv2.VideoCapture(0)
while True:
 _, frame = video_capture.read()
 cv2.imshow("image", frame)
 if cv2.waitKey(1) & 0xFF == ord('q'):
 break

可以从本地文件，视频设备，或者远程视频流中获取视频信号。

# 查看本地视频设备号
$ ls /dev/video*
/dev/video0

常见实用示例

# 图片读写
def image_detector(self, imname, wait=0):
 # 读取图片
 image = cv2.imread(imname)

 # 得到新的图片image
 result = self.detect(image)
 self.draw_result(image, result)

 # 显示图片
 # cv2.imshow('Image', image)
 # cv2.waitKey(wait)

 # 保存图片
 cv2.imwrite(imname.replace(".jpg", "_result.jpg"), image)

# 写入视频
def camera_detector(self, cap, wait=10):
 # 获取 原视频的fps，fourcc编码，height，wieght等信息
 fps = int(cap.get(cv2.CAP_PROP_FPS))
 # fourcc = int(cap.get(cv2.CAP_PROP_FOURCC))
 fourcc = cv2.VideoWriter_fourcc(*'MJPG')
 height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
 weidth = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
 print("fourcc: ", fourcc)

 # 创建新的写入writer
 videowriter = cv2.VideoWriter('test/test.avi', fourcc, fps, (weidth, height))

 # 读取一帧图片
 ret, frame = cap.read()

 while frame is not None:
 # 得到新的图片image
 result = self.detect(frame)
 self.draw_result(frame, result)
 # cv2.imshow('Camera', frame)
 # if cv2.waitKey(wait) & 0xFF == ord('q'):
 # break

 # 写入一帧图片
 videowriter.write(frame)

 # 读取下一帧图片
 ret, frame = cap.read()

 # 释放writer
 videowriter.release()

# 调用 camera_detector
cap = cv2.VideoCapture(video_read)
detector.camera_detector(cap, wait=1)

opencv mac error

正常情况下，在mac上面使用opencv是没有问题的，但是在Python子进程中使用opencv会发现子进程的代码会无厘头的没有结果。参考这里，不要问我怎么知道的 /(ㄒoㄒ)/~~

Opencv on My Blog

opencv

opencv

install

how to use

常见实用示例

opencv mac error