OpenCV选择图像中矩形区域并保存

本文实例为大家分享了OpenCV选择图像中矩形区域并保存的具体代码，供大家参考，具体内容如下

根据《Learning OpenCV》中的example4.1改写:

// An example program in which the
// user can draw boxes on the screen.
//
//#include <cv.h>
//#include <highgui.h>
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
using namespace cv;
// Define our callback which we will install for
// mouse events.
//
void my_mouse_callback(
int event, int x, int y, int flags, void* param
);

CvRect box;
bool drawing_box = false;
bool isRectDrawn = false;

// A litte subroutine to draw a box onto an image_copy
void draw_box( IplImage* img, CvRect rect ) {
cvRectangle (
img,
cvPoint(box.x,box.y),
cvPoint(box.x+box.width,box.y+box.height),
cvScalar(0x00,0x00,0xff) /* blue */
);
}

void draw_box_green( IplImage* img, CvRect rect ) {
cvRectangle (
img,
cvPoint(box.x,box.y),
cvPoint(box.x+box.width,box.y+box.height),
cvScalar(0x00,0xff,0x00) /* green */
);
}

int main( int argc, char* argv[] ) {

box = cvRect(-1,-1,0,0);
IplImage* image_input = cvLoadImage(argv[1]);
IplImage* image = cvCloneImage( image_input );
IplImage* image_copy = cvCloneImage( image );
IplImage* temp = cvCloneImage( image_copy );
cvNamedWindow( "Box Example" );
// Here is the crucial moment that we actually install
// the callback. Note that we set the value ‘param' to
// be the image_copy we are working with so that the callback
// will have the image_copy to edit.
//
cvSetMouseCallback(
"Box Example",
my_mouse_callback,
(void*) image_copy
);
// The main program loop. Here we copy the working image_copy
// to the ‘temp' image_copy, and if the user is drawing, then
// put the currently contemplated box onto that temp image_copy.
// display the temp image_copy, and wait 15ms for a keystroke,
// then repeat…
//
while( 1 ) {
//cvCopyImage( image_copy, temp );
cvCopy( image_copy, temp );
if( drawing_box ) draw_box( temp, box );
cvShowImage( "Box Example", temp );
//if( cvWaitKey( 15 )==27 ) break;
int key = cvWaitKey( 15 );
if(key == 27) break;
if(isRectDrawn){
if(key == 's' || key == 'S'){
// draw green box
draw_box_green( image_copy, box );
cvCopy( image_copy, image );

// save roi image
static int index = 0;
char save_image_name[128];
sprintf(save_image_name, "rect_%d.jpg", index++);
cvSetImageROI(image_input, box);
cvSaveImage(save_image_name, image_input);
cvResetImageROI(image_input);

isRectDrawn = false;
}

if(key == 'q' || key == 'Q'){
cvCopy( image, image_copy );
isRectDrawn = false;
}
}
}
// Be tidy
//
cvReleaseImage( &image_copy );
cvReleaseImage( &temp );
cvDestroyWindow( "Box Example" );
}

// This is our mouse callback. If the user
// presses the left button, we start a box.
// when the user releases that button, then we
// add the box to the current image_copy. When the
// mouse is dragged (with the button down) we
// resize the box.
//
void my_mouse_callback(
int event, int x, int y, int flags, void* param
) {
IplImage* image_copy = (IplImage*) param;
switch( event ) {
case CV_EVENT_MOUSEMOVE: {
if( drawing_box ) {
box.width = x-box.x;
box.height = y-box.y;
}
}
break;
case CV_EVENT_LBUTTONDOWN: {
drawing_box = true;
box = cvRect(x, y, 0, 0);
}
break;
case CV_EVENT_LBUTTONUP: {
drawing_box = false;
isRectDrawn = true;
if(box.width<0) {
box.x+=box.width;
box.width *=-1;
}
if(box.height<0) {
box.y+=box.height;
box.height*=-1;
}
draw_box(image_copy, box);
}
break;
}
}

使用方法：

载入图像后，用鼠标在图像上点击确定矩形起始点，拖动鼠标画矩形，抬起鼠标键时会画出一个红色矩形区域。按下s或S键，红色矩形变成绿色，并保存这个ROI区域。如果按下q或Q键，将会取消这次选择，红色矩形框消失。可以连续选取多个区域。按ESC键退出程序。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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