BS版图形系统 - OpenCV - 第3章笔记-优快云博客

BS版图形系统 - OpenCV - 第3章笔记

3 学习图形用户界面

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3 学习图形用户界面

显示图像结果，处理用户与图像的交互。

3.1 技术要求

3.2 OpenCV用户界面介绍

基于原生用户界面的基本界面： GTK
基于QT库的略微更高级的界面

3.3 OpenCV的基本图形用户界面

highgui模块

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

// OpenCV includes
#include "opencv2/core.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;

const int CV_GUI_NORMAL= 0x10;

int main( int argc, const char** argv )
{
	// Read images
	Mat lena= imread("../lena.jpg");
	Mat photo= imread("../photo.jpg");
	
	// Create windows
	namedWindow("Lena", WINDOW_NORMAL);
	// Checking if Lena image has been loaded
	if (!lena.data) {
	 	cout << "Lena image missing!" << endl;
	 	return -1;
	}
	namedWindow("Photo", WINDOW_AUTOSIZE);
	if (!photo.data) {
	 	cout << "Lena image missing!" << endl;
	 	return -1;
	}
	// Move window
	moveWindow("Lena", 10, 10);
	moveWindow("Photo", 520, 10);
	
	// show images
	imshow("Lena", lena);
	imshow("Photo", photo); 

	// Resize window, only non autosize
	resizeWindow("Lena", 512, 512); 

	// wait for any key press
	waitKey(0);

	// Destroy the windows
	destroyWindow("Lena");
	destroyWindow("Photo");

	// Create 10 windows
	for(int i =0; i< 10; i++)
	{
		ostringstream ss;
		ss << "Photo " << i;
		namedWindow(ss.str());
		moveWindow(ss.str(), 20*i, 20*i);
		imshow(ss.str(), photo);
	}

	waitKey(0);
	// Destroy all windows
	destroyAllWindows();
	return 0;
}

将滑块和鼠标事件添加到界面

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

// OpenCV includes
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;

// Create a variable to save the position value in track
int blurAmount=15;

// Trackbar call back function
static void onChange(int pos, void* userInput);

//Mouse callback
static void onMouse( int event, int x, int y, int, void* userInput );

int main( int argc, const char** argv )
{
	// Read images
	Mat lena= imread("../lena.jpg");
	
	// Create windows
	namedWindow("Lena");
	
	// create a trackbark
	createTrackbar("Lena", "Lena", &blurAmount, 30, onChange, &lena);
	
	setMouseCallback("Lena", onMouse, &lena);

	// Call to onChange to init
	onChange(blurAmount, &lena);
		
	// wait app for a key to exit
	waitKey(0);
	
	// Destroy the windows
	destroyWindow("Lena");
	
	return 0;
}

// Trackbar call back function
static void onChange(int pos, void* userInput)
{
	if(pos <= 0)
		return;
	// Aux variable for result
	Mat imgBlur;

	// Get the pointer input image
	Mat* img= (Mat*)userInput;

	// Apply a blur filter
	blur(*img, imgBlur, Size(pos, pos));	

	// Show the result
	imshow("Lena", imgBlur);
}

//Mouse callback
static void onMouse( int event, int x, int y, int, void* userInput )
{
	if( event != EVENT_LBUTTONDOWN )
	        return;

	// Get the pointer input image
	Mat* img= (Mat*)userInput;
	
	// Draw circle
	circle(*img, Point(x, y), 10, Scalar(0,255,0), 3);

	// Call on change to get blurred image
	onChange(blurAmount, img);

}

3.4 QT图形用户界面

在这里插入图片描述

将按钮添加到用户界面

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

// OpenCV includes
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;

Mat img;
bool applyGray=false;
bool applyBlur=false;
bool applySobel=false;

void applyFilters(){
	Mat result;
	img.copyTo(result);
	if(applyGray){
		cvtColor(result, result, COLOR_BGR2GRAY);
	}
	if(applyBlur){
		blur(result, result, Size(5,5));	
	}
	if(applySobel){
		Sobel(result, result, CV_8U, 1, 1);	
	}
	imshow("Lena", result);
}

void grayCallback(int state, void* userData)
{
	applyGray= true;
	applyFilters();
}
void bgrCallback(int state, void* userData)
{
	applyGray= false;
	applyFilters();
}

void blurCallback(int state, void* userData)
{
	applyBlur= (bool)state;
	applyFilters();
}

void sobelCallback(int state, void* userData)
{
	applySobel= !applySobel;
	applyFilters();
}

int main( int argc, const char** argv )
{
	// Read images
	img= imread("../lena.jpg");
	
	// Create windows
	namedWindow("Lena");
	
	// create Buttons
	createButton("Blur", blurCallback, NULL, QT_CHECKBOX, 0);

	createButton("Gray",grayCallback,NULL,QT_RADIOBOX, 0);
	createButton("RGB",bgrCallback,NULL,QT_RADIOBOX, 1);

	createButton("Sobel",sobelCallback,NULL,QT_PUSH_BUTTON, 0);
	
	// wait app for a key to exit
	waitKey(0);
	
	// Destroy the windows
	destroyWindow("Lena");
	
	return 0;
}

3.5 OpenGL支持

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

// OpenGL includes
#ifdef __APPLE__
#include <OpenGL/gl.h>
#else
#include <GL/gl.h>
#endif

// OpenCV includes
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
using namespace cv;

Mat frame;
GLfloat angle= 0.0;
GLuint texture; 
VideoCapture camera;

int loadTexture() {

    if (frame.data==NULL) return -1;
   
    glBindTexture( GL_TEXTURE_2D, texture ); //bind the texture to it's array
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
    
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, frame.cols, frame.rows,0, GL_BGR, GL_UNSIGNED_BYTE, frame.data);
    return 0;

}

void on_opengl(void* param)
{
    glLoadIdentity();  
    // Load Texture
    glBindTexture( GL_TEXTURE_2D, texture ); 
    // Rotate plane
    glRotatef( angle, 1.0f, 1.0f, 1.0f );
    // Create the plate
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex2d(-1.0,-1.0); 
    glTexCoord2d(1.0,0.0); glVertex2d(+1.0,-1.0); 
    glTexCoord2d(1.0,1.0); glVertex2d(+1.0,+1.0);
    glTexCoord2d(0.0,1.0); glVertex2d(-1.0,+1.0);
    glEnd();

}

int main( int argc, const char** argv )
{
    // Open WebCam
    camera.open(0);
    if(!camera.isOpened()){
        camera.open("Recording3.webm");
        if(!camera.isOpened())
            return -1;
    }

    // Create new windows
    namedWindow("OpenGL Camera", WINDOW_OPENGL);
    
    // Enable texture
    glEnable( GL_TEXTURE_2D );
    glGenTextures(1, &texture);
    
    setOpenGlDrawCallback("OpenGL Camera", on_opengl);

    while(waitKey(30)!='q'){
        camera >> frame;
        // Create first texture
        loadTexture();
        updateWindow("OpenGL Camera");
        angle =angle+4;
    }
    
	
	// Destroy the windows
	destroyWindow("OpenGL Camera");
	
	return 0;
}