Node Opencv Addon

2019年8月31日 151次阅读 来源: lgybetter

Opencv Node Addon

Opencv 装置运用

mkdir release
cd release
cmake -G "Unix Makefiles" .. (为Unix 系统生成Makefile，Mac OSX是基于Unix的。未装置cmake 能够经由过程Homebrew装置，未装置Homebrew需装置Homebrew）
make

  • 装置Opencv

make install

  • 装置完成的目次

/usr/local/lib (Opencv库文件)
/usr/local/include (Opencv头文件）
/usr/local/share/ (Opencv xml配置文件)

  • 运用Opencv(C++ Version)

    • 编写CMakeLists.txt文件

      project( ORBFeatureAndCompare ) // 项目的称号
cmake_minimum_required(VERSION 2.8) // cmake的版本请求
find_package( OpenCV REQUIRED ) // 查找对应的Opencv依靠库
find_package(Boost COMPONENTS log log_setup thread filesystem system) // 查找对应的Boost依靠库(下文涌现Boost的装置要领)
add_executable( ORBFeatureAndCompare ORBFeatureAndCompare )  // 指定可运转的文件
// 引入对应的依靠库文件的位置
target_link_libraries(ORBFeatureAndCompare
    ${OpenCV_LIBS}
    ${Boost_LOG_SETUP_LIBRARY}
    ${Boost_LOG_LIBRARY}
    ${Boost_FILESYSTEM_LIBRARY}
    ${Boost_THREAD_LIBRARY}
    ${Boost_SYSTEM_LIBRARY}
)

    • 编写Opencv的cpp文件

      //必要的头文件
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <iostream>
#include <fstream>
#include <cstring>
#include <iterator>
#include <vector>

using namespace boost::filesystem;  
namespace newfs = boost::filesystem;
using namespace cv;
using namespace std;

int main () {
  ....
  return 0;
}

    • 建立一个images(其他定名都能够)的资本文件夹

      cd images
cmake ..
make
./ORBFeatureAndCompare //编译出的可执行顺序

装置运用Boost举行数据序列化

./bootstrap.sh
./b2

  • 引入Boost库举行数据序列化,同样是在CmakeList中引入文件途径, 在cpp文件中运用

封装cpp顺序为Node Addon

  • 依靠装置

    • 全局装置node-gyp

    • 当地装置nan

  • 编写binding.gyp

    {
  "targets": [
  {
    "target_name": "feature",
    "sources": [ "./src/feature.cc" ],
    "include_dirs": [
      "<!(node -e \"require('nan')\")",
      "/usr/local/include/boost",
      "/usr/local/include/opencv2"
    ],
    "conditions": [
      [ "OS==\"linux\" or OS==\"freebsd\" or OS==\"openbsd\" or OS==\"solaris\" or OS==\"aix\"", {
        }
      ],
      ["OS==\"mac\"", {
          "libraries": [
            "/usr/local/lib/libboost_log_setup-mt.dylib",
            "/usr/local/lib/libboost_log-mt.dylib",
            "/usr/local/lib/libboost_filesystem-mt.dylib",
            "/usr/local/lib/libboost_thread-mt.dylib",
            "/usr/local/lib/libboost_system-mt.dylib",
            "/usr/local/lib/libopencv_core.3.2.0.dylib",
            "/usr/local/lib/libopencv_highgui.3.2.0.dylib",
            "/usr/local/lib/libopencv_imgproc.3.2.0.dylib",
            "/usr/local/lib/libopencv_features2d.3.2.0.dylib"
          ]
        }
      ]
    ]
  }
  ]
}

  • 编写node c++ 插件

#include <node.h>
#include <nan.h>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <iostream>
#include <fstream>
#include <string>
#include <iterator>
#include <vector>

using namespace boost::filesystem;
namespace newfs = boost::filesystem;
using namespace v8;
using namespace std;

vector<uchar> matToString(cv::Mat descriptorMat) {
  vector<uchar> buf;
  imencode(".png", descriptorMat, buf);
  return buf;
}

vector<uchar> descriptorMat(cv::Mat image) {
  vector<cv::KeyPoint> keyPoint;
  cv::Ptr<cv::ORB> orb = cv::ORB::create(4000, 1.2f, 8, 31, 0, 2,             cv::ORB::HARRIS_SCORE, 31, 20);
  orb->detect(image, keyPoint);
  cv::Mat descriptorMat;
  orb->compute(image, keyPoint, descriptorMat);
  return matToString(descriptorMat);
}

void imageFeature(const FunctionCallbackInfo<Value>& args) {
  Isolate* isolate = args.GetIsolate();
  if (args.Length() < 1) {
    isolate->ThrowException(Exception::TypeError(String::NewFromUtf8(isolate, "Wrong number of arguments")));
    return;
  }
  if (!args[0]->IsString()) {
    isolate->ThrowException(Exception::TypeError(String::NewFromUtf8(isolate, "Wrong arguments")));
    return;
  }
  String::Utf8Value pathValue(Local<String>::Cast(args[0]));
  string path = string(*pathValue);
  cv::Mat image = cv::imread(path, 1);
  if (image.empty()) {
    isolate->ThrowException(Exception::TypeError(String::NewFromUtf8(isolate, "Input image error")));
    return;
  }
  vector<uchar> descriptorString = descriptorMat(image);
  Local<Object> buf = Nan::NewBuffer(descriptorString.size()).ToLocalChecked();
  uchar* data = (uchar*) node::Buffer::Data(buf);
  memcpy(data, &descriptorString[0], descriptorString.size());
  v8::Local<v8::Object> globalObj = Nan::GetCurrentContext()->Global();
  v8::Local<v8::Function> bufferConstructor = v8::Local<v8::Function>::Cast(globalObj->Get(Nan::New<String>("Buffer").ToLocalChecked()));
  v8::Local<v8::Value> constructorArgs[3] = {buf, Nan::New<v8::Integer>((unsigned)descriptorString.size()), Nan::New<v8::Integer>(0)};
  v8::Local<v8::Object> actualBuffer = bufferConstructor->NewInstance(3, constructorArgs);
  args.GetReturnValue().Set(actualBuffer);
}

int bfMatcherCompare (cv::Mat &descriptors1, cv::Mat &descriptors2) {
  cv::BFMatcher matcher(cv::NORM_HAMMING);
  vector<cv::DMatch> matches;
  matcher.match(descriptors1, descriptors2, matches);
  double max_dist = 0;
  double min_dist = 100;
  /*
  for (int i = 0; i < descriptors1.rows; i++)
  {
    double dist = matches[i].distance;
    if (dist < min_dist)
      min_dist = dist;
    if (dist > max_dist)
      max_dist = dist;
  }
  vector<cv::DMatch> good_matches;
  for (int i = 0; i < descriptors1.rows; i++)
  {
    if (matches[i].distance < 3 * min_dist)
      good_matches.push_back(matches[i]);
  }
  return good_matches.size();
  */
  for (int i = 0; i < descriptors1.rows; i++) {
    double dist = matches[i].distance;
    if (dist < min_dist) {
      min_dist = dist;
    }
    if (dist > max_dist) {
      max_dist = dist;
    }
  }
  std::vector<cv::DMatch> good_matches;
  double good_matches_sum = 0.0;

  for (int i = 0; i < descriptors1.rows; i++) {
    double distance = matches[i].distance;
    if (distance <= std::max(2 * min_dist, 0.02)) {
      good_matches.push_back(matches[i]);
      good_matches_sum += distance;
    }
  }
  return (double) good_matches_sum / (double) good_matches.size();
}

void similarity(const FunctionCallbackInfo<Value>& args) {
  Isolate* isolate = args.GetIsolate();
  Local<Object> arg1 = args[0]->ToObject();
  int size1 = args[1]->NumberValue();
  Local<Object> arg2 = args[2]->ToObject();
  int size2 = args[3]->NumberValue();
  if (args.Length() < 4) {
    isolate->ThrowException(Exception::TypeError(String::NewFromUtf8(isolate, "Wrong number of arguments")));
    return;
  }
  uchar*buffer1 = (uchar*) node::Buffer::Data(arg1);
  std::vector<uchar> vec1(buffer1, buffer1 +  (unsigned int) size1);
  cv::Mat img_decode1;
  img_decode1 = cv::imdecode(vec1, CV_8U);
  uchar*buffer2 = (uchar*) node::Buffer::Data(arg2);
  std::vector<uchar> vec2(buffer2, buffer2 +  (unsigned int) size2);
  cv::Mat img_decode2;
  img_decode2 = cv::imdecode(vec2, CV_8U);
  int similarity = bfMatcherCompare(img_decode1, img_decode2);
  args.GetReturnValue().Set(similarity);
}

void init(Local<Object> exports, Local<Object> module) {
  NODE_SET_METHOD(exports, "imageFeature", imageFeature);
  NODE_SET_METHOD(exports, "similarity", similarity);
}

NODE_MODULE(addon, init)

  • 编写Js文件

const feature = require('./build/Release/feature');

exports.getImageFeature = (filePath) => {
  return feature.imageFeature(filePath).toString('utf8');
};

exports.getImageSimilarity = (descriptor1, descriptor2) => {
  let matBuffer1 = Buffer.from(descriptor1);
  let matBuffer2 = Buffer.from(descriptor2);
  return feature.similarity(matBuffer1, matBuffer1.length, matBuffer2, matBuffer2.length);
};

  • 编译运转

node-gyp configure build
node test.js
    原文作者：lgybetter
    原文地址: https://segmentfault.com/a/1190000009128792
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