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author | 即使孤独依旧前行 <56543168+GengchenXU@users.noreply.github.com> | 2020-05-19 16:43:49 +0800 |
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committer | GitHub <noreply@github.com> | 2020-05-19 16:43:49 +0800 |
commit | 2877c63f00d7e91bc366d6fb2d3a5c1e6d5cb15a (patch) | |
tree | 245154aca98a2fb426069c5a996da35debf405e5 | |
parent | f21a011eb4923c59343ec8f8dc1ab3166e9de6ba (diff) |
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-rw-r--r-- | zh-cn/opencv-cn.html.markdown | 145 |
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diff --git a/zh-cn/opencv-cn.html.markdown b/zh-cn/opencv-cn.html.markdown new file mode 100644 index 00000000..60b41100 --- /dev/null +++ b/zh-cn/opencv-cn.html.markdown @@ -0,0 +1,145 @@ +--- +category: tool +tool: OpenCV +filename: learnopencv.py +contributors: + - ["Yogesh Ojha", "http://github.com/yogeshojha"] +translators: + - ["GengchenXU", "https://github.com/GengchenXU"] +lang: zh-cn +--- +### Opencv + +Opencv(开源计算机视觉)是一个编程功能库,主要面向实时计算机视觉。最初由英特尔开发,后来由Willow Garage,然后Itseez(后来被英特尔收购)支持。Opencv 目前支持多种语言,如C++、Python、Java 等 + +#### 安装 +有关在计算机上安装 OpenCV,请参阅这些文章。 + +* Windows 安装说明: [https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_setup/py_setup_in_windows/py_setup_in_windows.html#install-opencv-python-in-windows]() +* Mac 安装说明 (High Sierra): [https://medium.com/@nuwanprabhath/installing-opencv-in-macos-high-sierra-for-python-3-89c79f0a246a]() +* Linux 安装说明 (Ubuntu 18.04): [https://www.pyimagesearch.com/2018/05/28/ubuntu-18-04-how-to-install-opencv]() + +### 在这里,我们将专注于 OpenCV 的 python 实现 + +```python +# OpenCV读取图片 +import cv2 +img = cv2.imread('cat.jpg') + +# 显示图片 +# imshow() 函数被用来显示图片 +cv2.imshow('Image',img) +# 第一个参数是窗口的标题,第二个参数是image +# 如果你得到错误,对象类型为None,你的图像路径可能是错误的。请重新检查图像包 +cv2.waitKey(0) +# waitKey() 是一个键盘绑定函数,参数以毫秒为单位。对于GUI事件,必须使用waitKey()函数。 + +# Writing an image +cv2.imwrite('catgray.png',img) +# 第一个参数是文件名,第二个参数是图像 + +# 转换图像灰度 +gray_image = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) + +# 从摄像头捕捉视频 +cap = cv2.VideoCapture(0) +#0 是你的相机,如果你有多台相机,你需要输入他们的id +while(True): + # 一帧一帧地获取 + _, frame = cap.read() + cv2.imshow('Frame',frame) + # 当用户按下q ->退出 + if cv2.waitKey(1) & 0xFF == ord('q'): + break +# 相机必须释放 +cap.release() + +# 在文件中播放视频 +cap = cv2.VideoCapture('movie.mp4') +while(cap.isOpened()): + _, frame = cap.read() + # 灰度播放视频 + gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) + cv2.imshow('frame',gray) + if cv2.waitKey(1) & 0xFF == ord('q'): + break +cap.release() + +# 在OpenCV中画线 +# cv2.line(img,(x,y),(x1,y1),(color->r,g,b->0 to 255),thickness)(注 color颜色rgb参数 thickness粗细) +cv2.line(img,(0,0),(511,511),(255,0,0),5) + +# 画矩形 +# cv2.rectangle(img,(x,y),(x1,y1),(color->r,g,b->0 to 255),thickness) +# 粗细= -1用于填充矩形 +cv2.rectangle(img,(384,0),(510,128),(0,255,0),3) + +# 画圆 +cv2.circle(img,(xCenter,yCenter), radius, (color->r,g,b->0 to 255), thickness) +cv2.circle(img,(200,90), 100, (0,0,255), -1) + +# 画椭圆 +cv2.ellipse(img,(256,256),(100,50),0,0,180,255,-1) + +# 在图像上增加文字 +cv2.putText(img,"Hello World!!!", (x,y), cv2.FONT_HERSHEY_SIMPLEX, 2, 255) + +# 合成图像 +img1 = cv2.imread('cat.png') +img2 = cv2.imread('openCV.jpg') +dst = cv2.addWeighted(img1,0.5,img2,0.5,0) + +# 阈值图像 +# 二进制阈值 +_,thresImg = cv2.threshold(img,127,255,cv2.THRESH_BINARY) +# Adaptive Thresholding +adapThres = cv2.adaptiveThreshold(img,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY,11,2) + +# 模糊的形象 +# 高斯模糊 +blur = cv2.GaussianBlur(img,(5,5),0) +# 模糊中值 +medianBlur = cv2.medianBlur(img,5) + +# Canny 边缘检测 +img = cv2.imread('cat.jpg',0) +edges = cv2.Canny(img,100,200) + +# 用Haar Cascades进行人脸检测 +# 下载 Haar Cascades 在 https://github.com/opencv/opencv/blob/master/data/haarcascades/ +import cv2 +import numpy as np +face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml') +eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml') + +img = cv2.imread('human.jpg') +gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) + +aces = face_cascade.detectMultiScale(gray, 1.3, 5) +for (x,y,w,h) in faces: + cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2) + roi_gray = gray[y:y+h, x:x+w] + roi_color = img[y:y+h, x:x+w] + eyes = eye_cascade.detectMultiScale(roi_gray) + for (ex,ey,ew,eh) in eyes: + cv2.rectangle(roi_color,(ex,ey),(ex+ew,ey+eh),(0,255,0),2) + +cv2.imshow('img',img) +cv2.waitKey(0) + +cv2.destroyAllWindows() +# destroyAllWindows() destroys all windows. +# 如果您希望销毁特定窗口,请传递您创建的窗口的确切名称。 +``` + +### 进一步阅读: + +* Download Cascade from [https://github.com/opencv/opencv/blob/master/data/haarcascades]() +* OpenCV 绘图函数 [https://docs.opencv.org/2.4/modules/core/doc/drawing_functions.html]() +* 最新的语言参考 [https://opencv.org]() +* 更多的资源 [https://en.wikipedia.org/wiki/OpenCV]() +* 优秀的的 OpenCV 教程 + * [https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_tutorials.html]() + * [https://realpython.com/python-opencv-color-spaces]() + * [https://pyimagesearch.com]() + * [https://www.learnopencv.com]() |