OPENCV筆記(三)擷取部分割槽域顯示
問了能夠在專案中實現對某一部分割槽域的提取和顯示,這裡搜尋了部分部落格,整理如下,專案太緊,大部分是複製過來。
參考部落格:
1. opencv提取截獲影象(總結摘來) http://blog.csdn.net/wuxiaoyao12/article/details/7305865
2. Opencv 擷取圖片中一部分的方法(包括任意區域) http://www.tuicool.com/articles/3mQbYf
3. 原影象中擷取一部分儲存 http://blog.csdn.net/flyingworm_eley/article/details/6523087
一、得到由矩形提取到的影象
第一步,把擷取影象中需要的區域存入矩陣。
CvMat* cvGetSubRect(const CvArr* arr, CvMat* submat, CvRect rect);
把IplImage *傳給arr,IplImage *指向所要擷取的影象;
把CvMat *傳給submat;
rect是要擷取的區域;
返回指向所存矩陣。
例如:
CvMat *pMat = cvCreateMatHeader(100, 100, CV_8UC1); //建立一個100*100的矩陣頭
CvRect rect = cvRect(0, 0, 100, 100); //要擷取的區域,與建立的矩陣大小一樣
cvGetSubRect(pImg, pMat, rect); //pImg為指向影象的指標,
也可以簡化為:
CvMat *pMat = cvGetSubRect(pImg, cvCreateMatHeader(100, 100, CV_8UC1), cvRect(0, 0, 100, 100));
第二步,把剛才存入矩陣的資料轉存為影象。
IplImage* cvGetImage( const CvArr* arr, IplImage* image_header );
把CvMat *傳給arr;image_header;
只需為影象頭就行,不用分配資料儲存空間 ;
返回所存影象的指標。
例如:
IplImage *pSubImg = cvCreateImageHeader(cvSize(100, 100), 8, 1); //建立一個
cvGetImage(pMat, pSubImg); //pMat為儲存資料的矩陣,pSubImg指向影象,返回值與pSubImg相等
也可以簡化為:
IplImage *pSubImg = cvGetImage(pMat, cvCreateImageHeader(cvSize(100, 100), 8, 1));
二、得到任意形狀區域
第一步、在圖片上畫出來
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>
IplImage* inpaint_mask = 0;
IplImage* img0 = 0, *img = 0, *inpainted = 0;
CvPoint prev_pt = {-1,-1};
void on_mouse( int event, int x, int y, int flags, void* zhang)
{
if( !img )
return;
if( event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON) )
prev_pt = cvPoint(-1,-1);//初始化
else if( event == CV_EVENT_LBUTTONDOWN )
prev_pt = cvPoint(x,y);
else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON) )
{//手一直在繪畫
CvPoint pt = cvPoint(x,y);
if( prev_pt.x < 0 )
prev_pt = pt;
cvLine( inpaint_mask, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
cvLine( img, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
prev_pt = pt;
cvShowImage( "image", img );
}
}
int main( int argc, char** argv )
{
char* filename = argc >= 2 ? argv[1] : (char*)"fruits.jpg";
if( (img0 = cvLoadImage(filename,-1)) == 0 )
return 0;
printf( "Hot keys: \n"
cvNamedWindow( "image", 1 );
img = cvCloneImage( img0 );
inpainted = cvCloneImage( img0 );
inpaint_mask = cvCreateImage( cvGetSize(img), 8, 1 );
cvZero( inpaint_mask );
cvZero( inpainted );
cvShowImage( "image", img );
cvShowImage( "watershed transform", inpainted );
cvSetMouseCallback( "image", on_mouse, 0 );
}
第二步、將選擇的區域提取出來
if(event == CV_EVENT_RBUTTONUP)
{
cvFloodFill(maskImg,cvPoint(x,y),cvScalarAll(255));
cvSaveImage("maskImg.bmp",maskImg);
IplImage *segImage=cvCreateImage(cvGetSize(img),8,3);;
cvCopy(img,segImage,maskImg);
cvSaveImage("segImage.bmp",segImage);
cvCopy(segImage,proc->img);
cvReleaseImage(&segImage);
cvDestroyWindow("Key Image");
}
三、使用Rect類截圖
1. 類Rect的定義
template<typename _Tp> class CV_EXPORTS Rect_
{
public:
typedef _Tp value_type;
//! various constructors
Rect_();
Rect_(_Tp _x, _Tp _y, _Tp _width, _Tp _height);
Rect_(const Rect_& r);
Rect_(const CvRect& r);
Rect_(const Point_<_Tp>& org, const Size_<_Tp>& sz);
Rect_(const Point_<_Tp>& pt1, const Point_<_Tp>& pt2);
Rect_& operator = ( const Rect_& r );
//! the top-left corner
Point_<_Tp> tl() const;
//! the bottom-right corner
Point_<_Tp> br() const;
//! size (width, height) of the rectangle
Size_<_Tp> size() const;
//! area (width*height) of the rectangle
_Tp area() const;
//! conversion to another data type
template<typename _Tp2> operator Rect_<_Tp2>() const;
//! conversion to the old-style CvRect
operator CvRect() const;
//! checks whether the rectangle contains the point
bool contains(const Point_<_Tp>& pt) const;
_Tp x, y, width, height; //< the top-left corner, as well as width and height of the rectangle
};
2D矩形的模板類,用下面的引數描述:
- 左上角的座標。不過可能你的演算法是從左下角計算。
- 矩形的寬度和高度
for(int y = roi.y; y < roi.y + rect.height; y++)
for(int x = roi.x; x < roi.x + rect.width; x++)
{
// ...
}
2. 類Rect的說明
除了上面定義的類成員變數,以下計算方式也是正確的:
- (shifting a rectangle by a certain offset)
- (expanding or shrinking a rectangle by a certain amount)
- rect += point, rect -= point, rect +=size, rect -= size (augmenting operations)
- rect = rect1 & rect2 (rectangle intersection)
- rect = rect1 | rect2 (minimum area rectangle containing rect2 and rect3 )
- rect &= rect1, rect |= rect1 (and the corresponding augmenting operations)
- rect == rect1, rect != rect1 (rectangle comparison)
//--------------------------------------【main.cpp】--------------------------
// 檔案說明:主要測試使用Rect進行影象的分割
// 檔案位置:F:\7.專案\...\4.四期工作\專案測試\Demo1\Demo\main.cpp
// 開發測試所用作業系統: Windows 10 64bit
// 開發測試所用IDE版本:Visual Studio 2012
// 開發測試所用OpenCV版本: 2.4.9
// 2015年9月 Revised by @jorg.zhao
//------------------------------------------------------------------------------------------------
#include "highgui.h"
#include <cv.h>
#include <iostream>
using namespace cv;
using namespace std;
Mat srcImg; //原始影象
Mat partImg; //目標影象
//-----------------------------------【函式】----------------------------------
// 描述:main函式入口
//---------------------------------------------------------------------------------------
int main(int argc, char* argv[])
{
//【1】讀取原圖
Mat srcImg = imread("cat.jpg");
//【2】顯示原圖
imshow("srcImg", srcImg);
//【3】設定Rect大小
Rect rect(10/*srcImg.cols/3*/, 0/*srcImg.rows /4*/, srcImg.cols/2, srcImg.rows/2);
//【4】根據Rect大小擷取原圖,並賦值給目標影象
partImg = srcImg(rect);
//【5】顯示目標影象
imshow("partImg", partImg);
cvWaitKey();
return 0;
}