本文详细介绍YoloV3与OpenCV3.4.2在Ubuntu环境下的安装步骤，包括环境配置、依赖安装、代码实现及常见问题解决，适用于希望在计算机视觉项目中应用深度学习目标检测的开发者。
Yolo v3+Opencv3.4.2安装记录
＠wp20180930
目录
一、环境要求
（１）python版本的查看
（２）opencv版本的查看
二、文件下载
三、数据自测
四、问题与解决
（１）提示【ImportError: No module named 'cv2' Python3】？？
（２）Ubuntu---python2和python3多版本共存与切换？？
（３）重新进行opencv3.4.2安装？？
（４）Ubuntu18.04下安装OpenCv依赖包libjasper-dev无法安装的问题？？
（５）Ubuntu18.04下安装OpenCv时出现CMake Error: The source directory？？
五、文件的详细代码
（１）object_detection_yolo.py
（２）object_detection_yolo.cpp
（３）yolo_test3.py
正文
说明：本文是在已训练好的基础上，自测数据看结果的。下面的流程，记录一下自己的实践过程。主要参考：
１，https://blog.youkuaiyun.com/ling_xiobai/article/details/82082614
２，https://blog.youkuaiyun.com/haoqimao_hard/article/details/82081285
３，https://hk.saowen.com/a/8c0f58aa3914c3bef46fb29eb40c77522b25fd7c0672fc9eadb2b3fdc2a8fbfb
一、环境要求
本文是在Ubuntu（仅CPU）、Opencv3.4.2以上、Python3下进行测试的。如果需要，请自行配置相应的环境。
不管是用Python 2.7+还是 Python3+, 都需要用apt-get来安装Opencv所需要的包，库等依赖。在开始正式安装之前, 需要弄清到底是要安装哪一个版本的，两个版本各有利弊。选择一个你看着顺眼的, 这个真没有什么特别的不同，如果觉得用着Python 3+舒服, 就选择 Python 3+； 用习惯Python 2.7+, 就装 Python 2.7+ 版本的。但是如果平时用 Python 来做一些CS相关的开发, 譬如: Machine Learning, Data Mining, NLP或者 Deep Learning, 可能会更倾向于选择 Python 2.7, 至少目前是这样的情况。 这些方面的大部分库和包都是 Python 2.7+的, 譬如: NumPy, Scipy和scikit-learn, 虽然社区里面都在努力地向 Python 3+ 迁移, 但是有那么一部分还是只能在 Python 2.7+下稳定工作的。
（１）Python版本的查看
个人Ubuntu18.04系统下，由于之前其他的工作需要，已经安装了 python2和python3。所以，需要进行 python2和python3自由切换,详见另外的笔记或者自行百度。
查看安装python的版本
方式一，$: ls /usr/bin/python*
方式二，$: python2
$: python3
（２）Opencv版本的查看
一般在安装python的时候，会安装一些opencv相关的依赖项，我们要想知道是否已经安装了opencv以及它的版本号，可以在终端下执行：pkg-config --modversion opencv。
查看python是否支持opencv，可以打开python：python2或者python３，在继续执行import cv2，看是否能正常运行，提示”>>>”则python支持opencv。
下图显示的是重新安装opencv3.4.2（详见后面的４问题与解决）后的显示结果，已经成功好用。
二、文件下载
需要下载yolov3.weights权重文件、yolov3.cfg网络构建文件、coco.names、xxx.jpg、xxx.mp4文件以及其他的object_detection_yolo.cpp、object_detection_yolo.py等文件。
下载链接，参考：
１，https://github.com/JackKoLing/opencv_deeplearning_practice/tree/master/pracice3_opencv_yolov3
２，https://pan.baidu.com/s/12tI6iKTzdwYdJSxgBiyayQ#list/path=%2F&parentPath=%2F，密码：gfg1
三、数据自测
第二步后，运行一下命令：
$ cd /home/wp/opencv_DL/opencv3.4.2_yolov3
$ python3 object_detection_yolo.py --image=bird.jpg
$ python3 object_detection_yolo.py --video=run.mp4
执行命令后，就可以看到结果，并且结果保存在了同文件下了：
bird_yolo_out_py.jpg、run_yolo_out_py.avi
由于视频检测速度比较慢，进行改进一下，视频每帧取两张图片，修改为yolo_test3.py，可以稍微提高一点速度。
$ python3 yolo_test3.py --video=run.mp4
四、问题与解决
配置yolo的Opencv、Python环境时，出现的问题与解决。
（１） 提示【ImportError: No module named 'cv2' Python3】？？？
参考https://stackoverflow.com/questions/45643650/importerror-no-module-named-cv2-python3，问题类似，但是通过提问中的解决方法，没有解决。自行下载opencv3.4.2安装包，进行了重新安装与配置，结果就好用了，但是用pkg-config --modversion opencv命令查看显示opencv3.2.0，原因不明。
（２） Ubuntu---python2和python3多版本共存与切换
可以参考https://blog.youkuaiyun.com/kan2016/article/details/81639292 和 https://www.cnblogs.com/hwlong/p/9216653.html
(2.1)若没有安装python，则可以使用pip（也可以anacanda）安装python。
第一步，度娘ubuntu 安装pip。
# 1. 更新系统包
sudo apt-get update
sudo apt-get upgrade
# 2. 安装Pip
sudo apt-get install python-pip
# 3. 检查 pip 是否安装成功
pip -V
其次，安装python。
$ sudo apt install python #安装python2，因为系统已经安装了python3
$ sudo apt install python-pip #指定python2的pip，使用为pip
$ sudo apt install python3-pip #指定为python3的pip，使用为pip3
接着，查看python是否安装成功。
$ python --version
$ python3 --version
(2.2)ubuntu切换Python版本
我们可以使用 update-alternatives 来为整个系统更改 Python 版本。参考https://blog.youkuaiyun.com/cym_lmy/article/details/78315139和https://www.cnblogs.com/hwlong/p/9216653.html（图文详情很好）。正常情况基于ubuntu与debian开发的发行版本都支持。
首先，罗列出所有可用的 python 替代版本信息：
$ sudo update-alternatives --list python
update-alternatives: error: no alternatives
for python
如果出现以上所示的错误信息，则表示 Python 的替代版本尚未被 update-alternatives 命令识别。想解决这个问题，需要更新一下替代列表，将 python2.7 和 python3.６ 放入其中。
打开终端分别输入下面两条命令：
$ sudo update-alternatives –install /usr/bin/python python /usr/bin/python2 1
$ sudo update-alternatives –install /usr/bin/python python /usr/bin/python3 2
如果需要重新切换回python只需要在终端输入：
$ sudo update-alternatives --config python
然后选者你需要的python版本，输入序号回车即可
再，终端输入：
$ python
如果无误，此时python版本应该切换到默认的python3了。
最后说明：移除替代版本方法。一旦我们的系统中不再存在某个 Python 的替代版本时，我们可以将其从 update-alternatives 列表中删除掉。例如，我们可以将列表中的 python2.7 版本移除掉。
$ sudo update-alternatives --remove python /usr/bin/python2.7
update-alternatives: removing manually selected alternative - switching python to auto mode
update-alternatives: using
/usr/bin/python3.4 to provide
/usr/bin/python (python)
in auto mode
（３） 重新进行opencv3.4.2安装？？？
解决Ubuntu中opencv2和opencv3多版本共存问题，可以参考
https://blog.youkuaiyun.com/Hansry/article/details/75309906和https://blog.youkuaiyun.com/liuxiaodong400/article/details/81089058。
这里，个人自己重新在python3下安装与配置opencv3.4.2。
第一步，下载opencv源码。
opencv各版本下载地址，https://opencv.org/releases.html（官网）。点击sources源文件下载，本人下载的是3.4.2版本的。
第二步，解压opencv源码。
找到下载的opencv-3.4.2文件夹，进入后：
$ unzip opencv-3.4.2.zip
在解压好的文件夹中打开终端，创建文件夹并打开
mkdir build
cd build
第三步，安装OpenCV依赖文件。
这一步，也可以在第一步或者第二步之前完成。
$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install build-essential
$ sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
$ sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev # 处理图像所需的包
$ sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev liblapacke-dev
$ sudo apt-get install libxvidcore-dev libx264-dev # 处理视频所需的包
$ sudo apt-get install libatlas-base-dev gfortran # 优化opencv功能
$ sudo apt-get install ffmpeg
每一步的解释可以参考https://blog.youkuaiyun.com/abcsunl/article/details/63686496。
第四步，用Cmake配置opencv的编译环境。
首先，需要安装Cmake。如果安装过Cmake，省略这一步即可。
参考https://www.cnblogs.com/TooyLee/p/6052387.html，执行如下安装：
准备工作：官网下载cmake-3.11.4.tar.gz（https://cmake.org/download/），这里注意下载的版本。解压后的文件夹需要包含bootstrap文件（本人下载了几个版本都没有，原来是下载的文件不对。下载最上面的就行了），如下：
1.解压文件tar -xvf cmake-3.11.4.tar.gz，并修改文件权限chmod -R 777 cmake-3.11.4
2.检测gcc和g++是否安装，如果没有则需安装gcc-g++：sudo apt-get install build-essential（或者直接执行这两条命令sudo apt-get install gcc,sudo apt-get install g++）
3.进入cmake-3.6.3 进入命令 cd cmake-3.6.3
4.执行sudo ./bootstrap
5.执行sudo make
6.执行 sudo make install
7.执行 cmake –version，返回cmake版本信息，则说明安装成功。
其次，这里配置编译opencv (无NVIDIA CUDA版本)，执行如下命令：
cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/home/wp/opencv3.4.2/install \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D INSTALL_C_EXAMPLES=OFF \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib-3.2.0/modules \
-D PYTHON3_EXECUTABLE=/usr/bin/python3 \
-D PYTHON_INCLUDE_DIR=/usr/include/python3.6 \
-D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6m.so \
-D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.6/dist-packages/numpy/core/include \
-D WITH_TBB=ON \
-D WITH_V4L=ON \
-D WITH_QT=ON \
-D WITH_GTK=ON \
-D WITH_OPENGL=ON \
-DBUILD_EXAMPLES=ON ...
但是这个时候，总是运行不过去，马上就碰到了个文件路径没有找到的问题，解决方法是去掉-D后面的空格，成功解决。在程序中输入：
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local PYTHON3_EXECUTABLE=/usr/bin/python3 PYTHON_INCLUDE_DIR=/usr/include/python3.6 PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6m.so PYTHON3_NUMPY_INCLUDE_DIRS=/usr/local/lib/python3.6/dist-packages/numpy/core/include ..
等待一会儿，配置完成。
第五步，opencv编译。
$ cd build
$ sudo make -j8
$ sudo make install
等待，编译完成。
第六步，opencv测试。
安装完成以后，重启下电脑。
如果导入cv2模块报错，运行下面代码：
$ sudo pip install opencv-python
方法一：打开python console，检测opencv的版本
import cv2
cv2.__version__
如果正确安装的话则会输出3.4.2。
方法二：新建文件 test.py, 输入一下内容
import cv2
if __name__ == '__main__':
print(cv2.__version__)
（４） Ubuntu18.04下安装OpenCv依赖包libjasper-dev无法安装的问题？？？
可以参考https://blog.youkuaiyun.com/weixin_41053564/article/details/81254410解决问题。
在ubuntu18.04系统上安装opencv但是在安装依赖包的过程中，有一个依赖包，libjasper-dev在使用命令：
$ sudo apt-get install libjaster-dev
提示：errorE: unable to locate libjasper-dev
则通过如下方式解决：
$ sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
$ sudo apt update
$ sudo apt install libjasper-dev
【不好用，可改用$ sudo apt install libjasper1 libjasper-dev】
这样，可以成功的解决问题，其中libjasper1是libjasper-dev的依赖包。
（５） Ubuntu18.04下安装OpenCv时出现CMake Error: The source directory？？
Ubuntu环境下OpenCV编译时：CMake error the source directory does not exist，解决办法是：去掉-D后面的空格。可以参考https://blog.youkuaiyun.com/sparkexpert/article/details/70941449，https://blog.youkuaiyun.com/wangleiwavesharp/article/details/80610529。
五、文件的详细代码
（５.1）object_detection_yolo.py
=============object_detection_yolo.py===========
#每一步详细解释见网址：https://www.learnopencv.com/deep-learning-based-object-detection-using-yolov3-with-opencv-python-c/
https://hk.saowen.com/a/8c0f58aa3914c3bef46fb29eb40c77522b25fd7c0672fc9eadb2b3fdc2a8fbfb
# This code is written at BigVision LLC. It is based on the OpenCV project. It is subject to the license terms in the LICENSE file found in this distribution and at http://opencv.org/license.html
# Usage example: python3 object_detection_yolo.py --video=run.mp4
# python3 object_detection_yolo.py --image=bird.jpg
import cv2 as cv
import argparse
import sys
import numpy as np
import os.path
# Initialize the parameters
confThreshold = 0.5 #Confidence threshold
nmsThreshold = 0.4 #Non-maximum suppression threshold
inpWidth = 416 #Width of network's input image
inpHeight = 416 #Height of network's input image
parser = argparse.ArgumentParser(description='Object Detection using YOLO in OPENCV')
parser.add_argument('--image', help='Path to image file.')
parser.add_argument('--video', help='Path to video file.')
args = parser.parse_args()
# Load names of classes
classesFile = "coco.names";
classes = None
with open(classesFile, 'rt') as f:
classes = f.read().rstrip('\n').split('\n')
# Give the configuration and weight files for the model and load the network using them.
modelConfiguration = "yolov3.cfg";
modelWeights = "yolov3.weights";
net = cv.dnn.readNetFromDarknet(modelConfiguration, modelWeights)
net.setPreferableBackend(cv.dnn.DNN_BACKEND_OPENCV)
net.setPreferableTarget(cv.dnn.DNN_TARGET_CPU)
# Get the names of the output layers
def getOutputsNames(net):
# Get the names of all the layers in the network
layersNames = net.getLayerNames()
# Get the names of the output layers, i.e. the layers with unconnected outputs
return [layersNames[i[0] - 1] for i in net.getUnconnectedOutLayers()]
# Draw the predicted bounding box
def drawPred(classId, conf, left, top, right, bottom):
# Draw a bounding box.
cv.rectangle(frame, (left, top), (right, bottom), (255, 178, 50), 3)
label = '%.2f' % conf
# Get the label for the class name and its confidence
if classes:
assert(classId < len(classes))
label = '%s:%s' % (classes[classId], label)
#Display the label at the top of the bounding box
labelSize, baseLine = cv.getTextSize(label, cv.FONT_HERSHEY_SIMPLEX, 0.5, 1)
top = max(top, labelSize[1])
cv.rectangle(frame, (left, top - round(1.5*labelSize[1])), (left + round(1.5*labelSize[0]), top + baseLine), (255, 255, 255), cv.FILLED)
cv.putText(frame, label, (left, top), cv.FONT_HERSHEY_SIMPLEX, 0.75, (0,0,0), 1)
# Remove the bounding boxes with low confidence using non-maxima suppression
def postprocess(frame, outs):
frameHeight = frame.shape[0]
frameWidth = frame.shape[1]
classIds = []
confidences = []
boxes = []
# Scan through all the bounding boxes output from the network and keep only the
# ones with high confidence scores. Assign the box's class label as the class with the highest score.
classIds = []
confidences = []
boxes = []
for out in outs:
for detection in out:
scores = detection[5:]
classId = np.argmax(scores)
confidence = scores[classId]
if confidence > confThreshold:
center_x = int(detection[0] * frameWidth)
center_y = int(detection[1] * frameHeight)
width = int(detection[2] * frameWidth)
height = int(detection[3] * frameHeight)
left = int(center_x - width / 2)
top = int(center_y - height / 2)
classIds.append(classId)
confidences.append(float(confidence))
boxes.append([left, top, width, height])
# Perform non maximum suppression to eliminate redundant overlapping boxes with
# lower confidences.
indices = cv.dnn.NMSBoxes(boxes, confidences, confThreshold, nmsThreshold)
for i in indices:
i = i[0]
box = boxes[i]
left = box[0]
top = box[1]
width = box[2]
height = box[3]
drawPred(classIds[i], confidences[i], left, top, left + width, top + height)
# Process inputs
winName = 'Deep learning object detection in OpenCV'
cv.namedWindow(winName, cv.WINDOW_NORMAL)
outputFile = "yolo_out_py.avi"
if (args.image):
# Open the image file
if not os.path.isfile(args.image):
print("Input image file ", args.image, " doesn't exist")
sys.exit(1)
cap = cv.VideoCapture(args.image)
outputFile = args.image[:-4]+'_yolo_out_py.jpg'
elif (args.video):
# Open the video file
if not os.path.isfile(args.video):
print("Input video file ", args.video, " doesn't exist")
sys.exit(1)
cap = cv.VideoCapture(args.video)
outputFile = args.video[:-4]+'_yolo_out_py.avi'
else:
# Webcam input
cap = cv.VideoCapture(0)
# Get the video writer initialized to save the output video
if (not args.image):
vid_writer = cv.VideoWriter(outputFile, cv.VideoWriter_fourcc('M','J','P','G'), 30, (round(cap.get(cv.CAP_PROP_FRAME_WIDTH)),round(cap.get(cv.CAP_PROP_FRAME_HEIGHT))))
while cv.waitKey(1) < 0:
# get frame from the video
hasFrame, frame = cap.read()
# Stop the program if reached end of video
if not hasFrame:
print("Done processing !!!")
print("Output file is stored as ", outputFile)
cv.waitKey(3000)
break
# Create a 4D blob from a frame.
blob = cv.dnn.blobFromImage(frame, 1/255, (inpWidth, inpHeight), [0,0,0], 1, crop=False)
# Sets the input to the network
net.setInput(blob)
# Runs the forward pass to get output of the output layers
outs = net.forward(getOutputsNames(net))
# Remove the bounding boxes with low confidence
postprocess(frame, outs)
# Put efficiency information. The function getPerfProfile returns the overall time for inference(t) and the timings for each of the layers(in layersTimes)
t, _ = net.getPerfProfile()
label = 'Inference time: %.2f ms' % (t * 1000.0 / cv.getTickFrequency())
cv.putText(frame, label, (0, 15), cv.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255))
# Write the frame with the detection boxes
if (args.image):
cv.imwrite(outputFile, frame.astype(np.uint8));
else:
vid_writer.write(frame.astype(np.uint8))
cv.imshow(winName, frame)
===============================结束============================
（５.２）object_detection_yolo.cpp
=============object_detection_yolo.cpp=============
// This code is written at BigVision LLC. It is based on the OpenCV project. It is subject to the license terms in the LICENSE file found in this distribution and at http://opencv.org/license.html
// Usage example: ./object_detection_yolo.out --video=run.mp4
// ./object_detection_yolo.out --image=bird.jpg
#include <fstream>
#include <sstream>
#include <iostream>
#include <opencv2/dnn.hpp>
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
const char* keys =
"{help h usage ? | | Usage examples: \n\t\t./object_detection_yolo.out --image=dog.jpg \n\t\t./object_detection_yolo.out --video=run_sm.mp4}"
"{image i |<none>| input image }"
"{video v |<none>| input video }"
;
using namespace cv;
using namespace dnn;
using namespace std;
// Initialize the parameters
float confThreshold = 0.5; // Confidence threshold
float nmsThreshold = 0.4; // Non-maximum suppression threshold
int inpWidth = 416; // Width of network's input image
int inpHeight = 416; // Height of network's input image
vector<string> classes;
// Remove the bounding boxes with low confidence using non-maxima suppression
void postprocess(Mat& frame, const vector<Mat>& out);
// Draw the predicted bounding box
void drawPred(int classId, float conf, int left, int top, int right, int bottom, Mat& frame);
// Get the names of the output layers
vector<String> getOutputsNames(const Net& net);
int main(int argc, char** argv)
{
CommandLineParser parser(argc, argv, keys);
parser.about("Use this script to run object detection using YOLO3 in OpenCV.");
if (parser.has("help"))
{
parser.printMessage();
return 0;
}
// Load names of classes
string classesFile = "coco.names";
ifstream ifs(classesFile.c_str());
string line;
while (getline(ifs, line)) classes.push_back(line);
// Give the configuration and weight files for the model
String modelConfiguration = "yolov3.cfg";
String modelWeights = "yolov3.weights";
// Load the network
Net net = readNetFromDarknet(modelConfiguration, modelWeights);
net.setPreferableBackend(DNN_BACKEND_OPENCV);
net.setPreferableTarget(DNN_TARGET_CPU);
// Open a video file or an image file or a camera stream.
string str, outputFile;
VideoCapture cap;
VideoWriter video;
Mat frame, blob;
try {
outputFile = "yolo_out_cpp.avi";
if (parser.has("image"))
{
// Open the image file
str = parser.get<String>("image");
ifstream ifile(str);
if (!ifile) throw("error");
cap.open(str);
str.replace(str.end()-4, str.end(), "_yolo_out_cpp.jpg");
outputFile = str;
}
else if (parser.has("video"))
{
// Open the video file
str = parser.get<String>("video");
ifstream ifile(str);
if (!ifile) throw("error");
cap.open(str);
str.replace(str.end()-4, str.end(), "_yolo_out_cpp.avi");
outputFile = str;
}
// Open the webcaom
else cap.open(parser.get<int>("device"));
}
catch(...) {
cout << "Could not open the input image/video stream" << endl;
return 0;
}
// Get the video writer initialized to save the output video
if (!parser.has("image")) {
video.open(outputFile, VideoWriter::fourcc('M','J','P','G'), 28, Size(cap.get(CAP_PROP_FRAME_WIDTH), cap.get(CAP_PROP_FRAME_HEIGHT)));
}
// Create a window
static const string kWinName = "Deep learning object detection in OpenCV";
namedWindow(kWinName, WINDOW_NORMAL);
// Process frames.
while (waitKey(1) < 0)
{
// get frame from the video
cap >> frame;
// Stop the program if reached end of video
if (frame.empty()) {
cout << "Done processing !!!" << endl;
cout << "Output file is stored as " << outputFile << endl;
waitKey(3000);
break;
}
// Create a 4D blob from a frame.
blobFromImage(frame, blob, 1/255.0, cvSize(inpWidth, inpHeight), Scalar(0,0,0), true, false);
//Sets the input to the network
net.setInput(blob);
// Runs the forward pass to get output of the output layers
vector<Mat> outs;
net.forward(outs, getOutputsNames(net));
// Remove the bounding boxes with low confidence
postprocess(frame, outs);
// Put efficiency information. The function getPerfProfile returns the overall time for inference(t) and the timings for each of the layers(in layersTimes)
vector<double> layersTimes;
double freq = getTickFrequency() / 1000;
double t = net.getPerfProfile(layersTimes) / freq;
string label = format("Inference time for a frame : %.2f ms", t);
putText(frame, label, Point(0, 15), FONT_HERSHEY_SIMPLEX, 0.5, Scalar(0, 0, 255));
// Write the frame with the detection boxes
Mat detectedFrame;
frame.convertTo(detectedFrame, CV_8U);
if (parser.has("image")) imwrite(outputFile, detectedFrame);
else video.write(detectedFrame);
imshow(kWinName, frame);
}
cap.release();
if (!parser.has("image")) video.release();
return 0;
}
// Remove the bounding boxes with low confidence using non-maxima suppression
void postprocess(Mat& frame, const vector<Mat>& outs)
{
vector<int> classIds;
vector<float> confidences;
vector<Rect> boxes;
for (size_t i = 0; i < outs.size(); ++i)
{
// Scan through all the bounding boxes output from the network and keep only the
// ones with high confidence scores. Assign the box's class label as the class
// with the highest score for the box.
float* data = (float*)outs[i].data;
for (int j = 0; j < outs[i].rows; ++j, data += outs[i].cols)
{
Mat scores = outs[i].row(j).colRange(5, outs[i].cols);
Point classIdPoint;
double confidence;
// Get the value and location of the maximum score
minMaxLoc(scores, 0, &confidence, 0, &classIdPoint);
if (confidence > confThreshold)
{
int centerX = (int)(data[0] * frame.cols);
int centerY = (int)(data[1] * frame.rows);
int width = (int)(data[2] * frame.cols);
int height = (int)(data[3] * frame.rows);
int left = centerX - width / 2;
int top = centerY - height / 2;
classIds.push_back(classIdPoint.x);
confidences.push_back((float)confidence);
boxes.push_back(Rect(left, top, width, height));
}
}
}
// Perform non maximum suppression to eliminate redundant overlapping boxes with
// lower confidences
vector<int> indices;
NMSBoxes(boxes, confidences, confThreshold, nmsThreshold, indices);
for (size_t i = 0; i < indices.size(); ++i)
{
int idx = indices[i];
Rect box = boxes[idx];
drawPred(classIds[idx], confidences[idx], box.x, box.y,
box.x + box.width, box.y + box.height, frame);
}
}
// Draw the predicted bounding box
void drawPred(int classId, float conf, int left, int top, int right, int bottom, Mat& frame)
{
//Draw a rectangle displaying the bounding box
rectangle(frame, Point(left, top), Point(right, bottom), Scalar(0, 0, 255));
//Get the label for the class name and its confidence
string label = format("%.2f", conf);
if (!classes.empty())
{
CV_Assert(classId < (int)classes.size());
label = classes[classId] + ":" + label;
}
//Display the label at the top of the bounding box
int baseLine;
Size labelSize = getTextSize(label, FONT_HERSHEY_SIMPLEX, 0.5, 1, &baseLine);
top = max(top, labelSize.height);
putText(frame, label, Point(left, top), FONT_HERSHEY_SIMPLEX, 0.5, Scalar(255,255,255));
}
// Get the names of the output layers
vector<String> getOutputsNames(const Net& net)
{
static vector<String> names;
if (names.empty())
{
//Get the indices of the output layers, i.e. the layers with unconnected outputs
vector<int> outLayers = net.getUnconnectedOutLayers();
//get the names of all the layers in the network
vector<String> layersNames = net.getLayerNames();
// Get the names of the output layers in names
names.resize(outLayers.size());
for (size_t i = 0; i < outLayers.size(); ++i)
names[i] = layersNames[outLayers[i] - 1];
}
return names;
}
==========================结束=========================
（５.3）yolo_test3.py
=====================yolo_test3.py==============================
## -*- coding: utf-8 -*-
# This code is written at BigVision LLC. It is based on the OpenCV project. It is subject to the license terms in the LICENSE file found in this distribution and at http://opencv.org/license.html
# Usage example: python3 object_detection_yolo.py --video=run.mp4
# python3 object_detection_yolo.py --image=bird.jpg
import cv2 as cv
import argparse
import sys
import numpy as np
import os.path
import os
import time
# Initialize the parameters
confThreshold = 0.5 #Confidence threshold
nmsThreshold = 0.4 #Non-maximum suppression threshold
inpWidth = 416 #Width of network's input image
inpHeight = 416 #Height of network's input image
parser = argparse.ArgumentParser(description='Object Detection using YOLO in OPENCV')
parser.add_argument('--image', help='Path to image file.')
parser.add_argument('--video', help='Path to video file.')
args = parser.parse_args()
# Load names of classes
classesFile = "coco.names";
classes = None
with open(classesFile, 'rt') as f:
classes = f.read().rstrip('\n').split('\n')
# Give the configuration and weight files for the model and load the network using them.
modelConfiguration = "yolov3.cfg";
modelWeights = "yolov3.weights";
net = cv.dnn.readNetFromDarknet(modelConfiguration, modelWeights)
net.setPreferableBackend(cv.dnn.DNN_BACKEND_OPENCV)
net.setPreferableTarget(cv.dnn.DNN_TARGET_CPU)
# Get the names of the output layers
def getOutputsNames(net):
# Get the names of all the layers in the network
layersNames = net.getLayerNames()
# Get the names of the output layers, i.e. the layers with unconnected outputs
return [layersNames[i[0] - 1] for i in net.getUnconnectedOutLayers()]
# Draw the predicted bounding box
def drawPred(classId, conf, left, top, right, bottom):
# Draw a bounding box.
cv.rectangle(frame, (left, top), (right, bottom), (255, 178, 50), 2)
label = '%.2f' % conf
# Get the label for the class name and its confidence
if classes:
assert(classId < len(classes))
label = '%s:%s' % (classes[classId], label)
#Display the label at the top of the bounding box
labelSize, baseLine = cv.getTextSize(label, cv.FONT_HERSHEY_SIMPLEX, 0.5, 1)
top = max(top, labelSize[1])
#cv.rectangle(frame, (left, top - round(1.5*labelSize[1])), (left + round(1.5*labelSize[0]), top + baseLine), (255, 255, 255), cv.FILLED)
#cv.putText(frame, label, (left, top), cv.FONT_HERSHEY_SIMPLEX, 0.75, (0,0,0), 1)
# Remove the bounding boxes with low confidence using non-maxima suppression
def postprocess(frame, outs):
frameHeight = frame.shape[0]
frameWidth = frame.shape[1]
classIds = []
confidences = []
boxes = []
# Scan through all the bounding boxes output from the network and keep only the
# ones with high confidence scores. Assign the box's class label as the class with the highest score.
classIds = []
confidences = []
boxes = []
for out in outs:
for detection in out:
scores = detection[5:]
classId = np.argmax(scores)
confidence = scores[classId]
if confidence > confThreshold:
center_x = int(detection[0] * frameWidth)
center_y = int(detection[1] * frameHeight)
width = int(detection[2] * frameWidth)
height = int(detection[3] * frameHeight)
left = int(center_x - width / 2)
top = int(center_y - height / 2)
classIds.append(classId)
confidences.append(float(confidence))
boxes.append([left, top, width, height])
# Perform non maximum suppression to eliminate redundant overlapping boxes with
# lower confidences.
indices = cv.dnn.NMSBoxes(boxes, confidences, confThreshold, nmsThreshold)
for i in indices:
i = i[0]
box = boxes[i]
left = box[0]
top = box[1]
width = box[2]
height = box[3]
drawPred(classIds[i], confidences[i], left, top, left + width, top + height)
# Process inputs
winName = 'Deep learning object detection in OpenCV'
cv.namedWindow(winName, cv.WINDOW_NORMAL)
outputFile = "yolo_out_py.jpg"
pic_number = 1
g = os.walk(r"./车辆图片")
for path,dir_list,file_list in g:
for file_name in file_list:
time.sleep(2)
path_name = os.path.join(path, file_name)
print(path_name)
print(file_name)
frame = cv.imread(path_name)
print(frame.shape)
outputFile = str(pic_number) + '_yolo_out_py.jpg'
pic_number += 1
# Create a 4D blob from a frame.
blob = cv.dnn.blobFromImage(frame, 1/255, (inpWidth, inpHeight), [0,0,0], 1, crop=False)
# Sets the input to the network
net.setInput(blob)
# Runs the forward pass to get output of the output layers
outs = net.forward(getOutputsNames(net))
# Remove the bounding boxes with low confidence
postprocess(frame, outs)
# Put efficiency information. The function getPerfProfile returns the overall time for inference(t) and the timings for each of the layers(in layersTimes)
t, _ = net.getPerfProfile()
label = 'Inference time: %.2f ms' % (t * 1000.0 / cv.getTickFrequency())
cv.putText(frame, label, (0, 15), cv.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255))
# Write the frame with the detection boxes
cv.imwrite(outputFile, frame.astype(np.uint8));
cv.imshow(winName, frame)
=======================================结束=================================================
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