From 27638c84578c6b69f60efd771537040240283f1b Mon Sep 17 00:00:00 2001
From: Salman <salman@tunacode.com>
Date: Sun, 20 Apr 2014 23:20:46 +0500
Subject: [PATCH] BackgroundSubtractor added

---
 src/BackgroundSubtractor.cc | 135 ++++++++++++++++++++++++++++++++++++
 src/BackgroundSubtractor.h  |  21 ++++++
 2 files changed, 156 insertions(+)
 create mode 100644 src/BackgroundSubtractor.cc
 create mode 100644 src/BackgroundSubtractor.h

diff --git a/src/BackgroundSubtractor.cc b/src/BackgroundSubtractor.cc
new file mode 100644
index 0000000..476f663
--- /dev/null
+++ b/src/BackgroundSubtractor.cc
@@ -0,0 +1,135 @@
+#include "BackgroundSubtractor.h"
+#include "Matrix.h"
+#include <iostream>
+
+Persistent<FunctionTemplate> BackgroundSubtractorWrap::constructor;
+
+void
+BackgroundSubtractorWrap::Init(Handle<Object> target) {
+    HandleScope scope;
+
+    // Constructor
+      constructor = Persistent<FunctionTemplate>::New(FunctionTemplate::New(BackgroundSubtractorWrap::New));
+      constructor->InstanceTemplate()->SetInternalFieldCount(1);
+      constructor->SetClassName(String::NewSymbol("BackgroundSubtractor"));
+
+    NODE_SET_METHOD(constructor, "createMOG", CreateMOG);
+    NODE_SET_PROTOTYPE_METHOD(constructor, "applyMOG", ApplyMOG);
+
+    target->Set(String::NewSymbol("BackgroundSubtractor"), constructor->GetFunction());
+};
+
+Handle<Value>
+BackgroundSubtractorWrap::New(const Arguments &args) {
+  HandleScope scope;
+
+  if (args.This()->InternalFieldCount() == 0)
+    JSTHROW_TYPE("Cannot Instantiate without new")
+
+  //Create MOG by default
+  cv::Ptr<cv::BackgroundSubtractor> bg = cv::createBackgroundSubtractorMOG(200, 5, 0.7, 0);
+  BackgroundSubtractorWrap *pt = new BackgroundSubtractorWrap(bg);
+
+  pt->Wrap(args.This());
+
+  return args.This();
+}
+
+Handle<Value>
+BackgroundSubtractorWrap::CreateMOG(const Arguments &args) {
+  HandleScope scope;
+
+  int history = 200;
+  int nmixtures = 5;
+  double backgroundRatio = 0.7;
+  double noiseSigma = 0;
+
+  if(args.Length() > 1){
+    INT_FROM_ARGS(history, 0)
+    INT_FROM_ARGS(nmixtures, 1)
+    DOUBLE_FROM_ARGS(backgroundRatio, 2)
+    DOUBLE_FROM_ARGS(noiseSigma, 3)
+  }
+
+  Local<Object> n = BackgroundSubtractorWrap::constructor->GetFunction()->NewInstance();
+
+  cv::Ptr<cv::BackgroundSubtractor> bg = cv::createBackgroundSubtractorMOG(
+      history, nmixtures, backgroundRatio, noiseSigma
+  );
+  BackgroundSubtractorWrap *pt = new BackgroundSubtractorWrap(bg);
+
+  pt->Wrap(n);
+  return n;
+};
+
+//Fetch foreground mask
+Handle<Value>
+BackgroundSubtractorWrap::ApplyMOG(const Arguments &args) {
+
+  SETUP_FUNCTION(BackgroundSubtractorWrap)
+
+  REQ_FUN_ARG(1, cb);
+
+  Local<Value> argv[2];
+
+  if(args.Length() == 0){
+    argv[0] = String::New("Input image missing");
+    argv[1] = Local<Value>::New(Null());
+    cb->Call(Context::GetCurrent()->Global(), 2, argv);
+    return scope.Close(Undefined());
+  }
+
+  try{
+
+    Local<Object> fgMask = Matrix::constructor->GetFunction()->NewInstance();
+    Matrix *img = ObjectWrap::Unwrap<Matrix>(fgMask);
+    
+
+    cv::Mat mat;
+    
+    if(Buffer::HasInstance(args[0])){
+      uint8_t *buf = (uint8_t *) Buffer::Data(args[0]->ToObject());
+      unsigned len = Buffer::Length(args[0]->ToObject());  
+      cv::Mat *mbuf = new cv::Mat(len, 1, CV_64FC1, buf);
+      mat = cv::imdecode(*mbuf, -1);
+      //mbuf->release();
+    }
+    else{
+      Matrix *_img = ObjectWrap::Unwrap<Matrix>(args[0]->ToObject());
+      mat = (_img->mat).clone();
+    }
+
+    if (mat.empty()){
+      return v8::ThrowException(v8::Exception::TypeError(v8::String::New("Error loading file")));
+    }
+
+    cv::Mat _fgMask;
+    self->subtractor->apply(mat, _fgMask);
+
+    img->mat = _fgMask;
+
+    mat.release();
+
+    argv[0] = Local<Value>::New(Null());
+    argv[1] = fgMask;
+
+    TryCatch try_catch;
+
+    cb->Call(Context::GetCurrent()->Global(), 2, argv);
+      
+    if (try_catch.HasCaught()) {
+        FatalException(try_catch);
+      }
+
+      return scope.Close(v8::Undefined());
+  } 
+  catch( cv::Exception& e ){
+    const char* err_msg = e.what();
+    return v8::ThrowException(v8::Exception::Error(v8::String::New(err_msg)));
+  }
+
+};
+
+BackgroundSubtractorWrap::BackgroundSubtractorWrap(cv::Ptr<cv::BackgroundSubtractor> _subtractor){
+  subtractor = _subtractor;
+};
\ No newline at end of file
diff --git a/src/BackgroundSubtractor.h b/src/BackgroundSubtractor.h
new file mode 100644
index 0000000..001967b
--- /dev/null
+++ b/src/BackgroundSubtractor.h
@@ -0,0 +1,21 @@
+#include "OpenCV.h"
+
+#if CV_MAJOR_VERSION >= 2 && CV_MINOR_VERSION >=4
+
+#include <opencv2/video/background_segm.hpp>
+
+class BackgroundSubtractorWrap: public node::ObjectWrap {
+  public:
+    cv::Ptr<cv::BackgroundSubtractor> subtractor;
+
+    static Persistent<FunctionTemplate> constructor;
+    static void Init(Handle<Object> target);
+    static Handle<Value> New(const Arguments &args);
+
+    BackgroundSubtractorWrap(cv::Ptr<cv::BackgroundSubtractor> bg);
+
+    static Handle<Value> CreateMOG(const v8::Arguments&);
+    static Handle<Value> ApplyMOG(const v8::Arguments&);
+};
+
+#endif
\ No newline at end of file