adding example_09-04.cpp example_09-10.cpp example_15-02.cpp example_15-03.cpp example_15-04.cpp

Author: garybradski

CMakeLists.txt

@@ -30,6 +30,7 @@ add_executable( example_08-03 example_08-03.cpp )
 add_executable( example_09-01 example_09-01.cpp )
 add_executable( example_09-02 example_09-02.cpp )
 add_executable( example_09-03 example_09-03.cpp )
+#add_library(examples_09 example_09-04.cpp)
 add_executable( example_10-01 example_10-01.cpp )
 add_executable( example_10-02 example_10-02.cpp )
 add_executable( example_10-03 example_10-03.cpp )
@@ -47,6 +48,7 @@ add_executable( example_14-03 example_14-03.cpp )
 add_executable( example_14-04 example_14-04.cpp )
 add_executable( example_15-01 example_15-01.cpp )
 add_executable( example_15-02 example_15-02.cpp )
+add_executable( example_15-04 example_15-04.cpp )
 #...
 add_executable( example_16-01 example_16-01.cpp )
 
@@ -92,5 +94,6 @@ target_link_libraries( example_14-03 ${OpenCV_LIBS} )
 target_link_libraries( example_14-04 ${OpenCV_LIBS} )
 target_link_libraries( example_15-01 ${OpenCV_LIBS} )
 target_link_libraries( example_15-02 ${OpenCV_LIBS} )
+target_link_libraries( example_15-04 ${OpenCV_LIBS} )
 #...
 target_link_libraries( example_16-01 ${OpenCV_LIBS} )

example_09-04.cpp

@@ -3,6 +3,9 @@
 //connected to the sliders in Figure 9-6
 
 #include <opencv2/opencv.hpp>
+#include <GL/gl.h>
+#include <GL/glut.h>
+
 using namespace std;
 
 void on_opengl( void* param ) {

example_09-10.cpp

@@ -1,13 +1,14 @@
 //Example 9-10. The WxMoviePlayer object source file WxMoviePlayer.cpp
-//This file is incomplete
+//
 #include "WxMoviePlayer.hpp"
 BEGIN_EVENT_TABLE( WxMoviePlayer, wxWindow )
   EVT_PAINT( WxMoviePlayer::OnPaint )
   EVT_TIMER( TIMER_ID, WxMoviePlayer::OnTimer )
   EVT_CHAR( WxMoviePlayer::OnKey )
 END_EVENT_TABLE()
-The first thing we do is to set up the callbacks that will be associated with individual
-events. We do this through macros provided by the wxWidgets framework.17
+
+// The first thing we do is to set up the callbacks that will be associated with individual
+// events. We do this through macros provided by the wxWidgets framework.
 WxMoviePlayer::WxMoviePlayer(
   wxWindow*      parent,
   const wxPoint& pos,
@@ -16,3 +17,69 @@ WxMoviePlayer::WxMoviePlayer(
   m_timer         = NULL;
   m_parent        = parent;
 }
+
+//We will need to
+//know which frame is the parent when it comes time to close the application in
+//response to the Esc key.
+void WxMoviePlayer::OnPaint( wxPaintEvent& event ) {
+	wxPaintDC dc( this );
+	if( !dc.Ok() ) return;
+	int x,y,w,h;
+	dc.BeginDrawing();
+	dc.GetClippingBox( &x, &y, &w, &h );
+	dc.DrawBitmap( m_wx_bmp, x, y );
+	dc.EndDrawing();
+	return;
+}
+
+//The WxMoviePlayer::_copyImage() method will get called whenever a new image is
+//read from the cv::VideoCapture object.
+void WxMoviePlayer::_copyImage( void ) {
+	m_wx_bmp = wxBitmap( m_wx_img );
+	Refresh( FALSE ); // indicate that the object is dirty
+	Update();
+}
+
+//The WxMoviePlayer::open() method also does several important things. The first is
+//to actually open the cv::VideoCapture object, but there is a lot more to be done.
+//Next, an image is read off of the player and is used to create a wxImage object that
+//“points at” the OpenCV cv::Mat image. This is the opposite philosophy to the one
+//we used in the Qt example: in this case, it turns out to be a little more convenient to
+//create the cv::Mat first and have it own the data, and then to create the GUI toolkit’s
+//image object
+
+bool WxMoviePlayer::open( wxString file ) {
+	
+	if( !m_cap.open( std::string( file.mb_str() ) )) {
+	return false;
+	}
+
+	// If we opened the file, set up everything now:
+	//
+	m_cap.read( m_cv_img );
+	m_wx_img = wxImage(
+	m_cv_img.cols,
+	m_cv_img.rows,
+	m_cv_img.data,
+	TRUE // static data, do not free on delete()
+	);
+	_copyImage();
+	m_timer = new wxTimer( this, TIMER_ID );
+	m_timer->Start( 1000. / m_cap.get( cv::CAP_PROP_FPS ) );
+	return true;
+}
+
+//The following handler doesn’t do too much; primarily it just reads a new frame from the video,
+//converts that frame from BGR to RGB for display, and then calls our WxMovie
+//Player::_copyImage() , which makes the next bitmap for us.
+void WxMoviePlayer::OnTimer( wxTimerEvent& event ) {
+	if( !m_cap.isOpened() ) return;
+	m_cap.read( m_cv_img );
+	cv::cvtColor( m_cv_img, m_cv_img, cv::BGR2RGB );
+	_copyImage();
+}
+
+//Handler for keypresses 
+void WxMoviePlayer::OnKey( wxKeyEvent& e ) {
+	if( e.GetKeyCode() == WXK_ESCAPE ) m_parent->Close();
+}

example_15-02.cpp

@@ -10,7 +10,7 @@ using namespace std;
 //
 // Float, 3-channel images
 //
-cv::Mat image; //, rawImage;
+cv::Mat image;
 cv::Mat IavgF, IdiffF, IprevF, IhiF, IlowF;
 cv::Mat tmp, tmp2, mask;
 
@@ -173,8 +173,8 @@ int main( int argc, char** argv) {
 	while(1) {
 		cout << "frame#: " << frame_count << endl;
 		cap >> image;
-		if(frame_count == 0) { AllocateImages(image);}
 		if( !image.data ) exit(1); // Something went wrong, abort
+		if(frame_count == 0) { AllocateImages(image);}
 		accumulateBackground( image );
 		cv::imshow( argv[0], image );
 		frame_count++;

example_15-03.cpp

@@ -0,0 +1,94 @@
+//Example 15-3. Computing the on and off-diagonal elements of a variance/covariance model
+
+vector<cv::Mat> planes(3);
+vector<cv::Mat> sums(3);
+vector<cv::Mat> xysums(6);
+int image_count = 0;
+
+//A function to accumulate
+// the information we need for our variance computation:
+void accumulateVariance(
+	cv::Mat& I
+) {
+	if( sum.empty ) {
+		sum = cv::Mat::zeros( I.size(), CV_32FC(I.channels()) );
+		sqsum = cv::Mat::zeros( I.size(), CV_32FC(I.channels()) );
+	}
+	cv::accumulate( I, sum );
+	cv::accumulateSquare( I, sqsum );
+	image_count++;
+}
+
+//The associated variance computation function would then be:
+// (note that 'variance' is sigma^2)
+//
+void computeVariance(
+	cv::Mat& variance
+	) {
+	double one_by_N = 1.0 / image_count;
+	variance = one_by_N * sqsum – (one_by_N * one_by_N) * sum.mul(sum);
+}
+
+
+
+
+void accumulateCovariance(
+cv::Mat& I
+) {
+	int i, j, n;
+
+	if( sum.empty ) {
+		for( i=0; i<3; i++ ) {
+			// the r, g, and b sums
+			sums[i]
+			= cv::Mat::zeros( I.size(), CV::F32C1 );
+		}
+		for( n=0; n<6; n++ ) {
+			// the rr, rg, rb, gg, gb, and bb elements
+			xysums[n] = cv::Mat::zeros( I.size(), CV::F32C1 ) );
+		}
+	}
+	cv::split( I, planes );
+	for( i=0; i<3; i++ ) {
+		cv::accumulate( planes[i], sums[i] );
+	}
+	n = 0;
+	for( i=0; i<3; i++ ) {
+		// "row" of Sigma
+		for( j=i; j<3; j++ ) {
+			// "column" of Sigma
+			n++;
+			cv::accumulateProduct( planes[i], planes[j], xysums[n] );
+		}
+	}
+	image_count++;
+}
+
+//The corresponding compute function is also just a slight extension of the compute
+//function for the variances we saw earlier.
+//   note that 'variance' is sigma^2
+//
+void computeVariance(
+	cv::Mat& covariance
+	// a six-channel array, channels are the
+	// rr, rg, rb, gg, gb, and bb elements of Sigma_xy
+) {
+	double one_by_N = 1.0 / image_count;
+	
+	// reuse the xysum arrays as storage for individual entries
+	//
+	int n = 0;
+	for( int i=0; i<3; i++ ) {
+		// "row" of Sigma
+		for( int j=i; j<3; j++ ) {
+			// "column" of Sigma
+			n++;
+			xysums[n] = one_by_N * xysums[n]
+			– (one_by_N * one_by_N) * sums[i].mul(sums[j]);
+		}
+	}
+	
+	// reassemble the six individual elements into a six-channel array
+	//
+	cv::merge( xysums, covariance );
+}