//裁剪图片
#include <stdio.h>
#include <stdlib.h>
#include "opencv2/opencv.hpp"
void CutIplImage(IplImage* src, IplImage* dst, int x, int y)
{
CvSize size = cvSize(dst->width, dst->height);//区域大小
cvSetImageROI(src, cvRect(x, y, size.width, size.height));//设置源图像ROI
cvCopy(src, dst); //复制图像
cvResetImageROI(src);//源图像用完后,清空ROI
}
这是一个使用opencv裁剪图片的函数。
IplImage是OpenCV中的数据结构,用来表示图像。(详见附录)
src是原图像 ,dst为裁剪后的图像,x, y 为ROI左上角座标。
对IplImage用cvSetImageROI函数设置了ROI后,
对图像的处理都将仅限于ROI区域,相当于该图像变为了ROI中的图像,
使用ROI需要cvResetImageROI清除ROI。
分解
CvSize size = cvSize(dst->width, dst->height);//区域大小
CvSize是存储图像长和宽的数据结构,cvSize函数对这一结构进行赋值。
cvSetImageROI(src, cvRect(x, y, size.width, size.height));//设置源图像ROI
基于给定的矩形设置图像的ROI(详见附录)
cvCopy(src, dst); //复制图像
将 src 复制到 dst
cvResetImageROI(src);//源图像用完后,清空ROI
cvResetImageROI与cvSetImageROI相对应
清空之前设置的ROI
附录
ROI(region of interest),感兴趣区域。机器视觉、图像处理中,从被处理的图像以方框、圆、椭圆、不规则多边形等方式勾勒出需要处理的区域,称为感兴趣区域。
typedef struct _IplImage
{
int nSize; /* sizeof(IplImage) */
int ID; /* version (=0)*/
int nChannels; /* Most of OpenCV functions support 1,2,3 or 4 channels */
int alphaChannel; /* Ignored by OpenCV */
int depth; /* Pixel depth in bits: IPL_DEPTH_8U, IPL_DEPTH_8S, IPL_DEPTH_16S,
IPL_DEPTH_32S, IPL_DEPTH_32F and IPL_DEPTH_64F are supported. */
char colorModel[4]; /* Ignored by OpenCV */
char channelSeq[4]; /* ditto */
int dataOrder; /* 0 - interleaved color channels, 1 - separate color channels.
cvCreateImage can only create interleaved images */
int origin; /* 0 - top-left origin,
1 - bottom-left origin (Windows bitmaps style). */
int align; /* Alignment of image rows (4 or 8).
OpenCV ignores it and uses widthStep instead. */
int width; /* Image width in pixels. */
int height; /* Image height in pixels. */
struct _IplROI *roi; /* Image ROI. If NULL, the whole image is selected. */
struct _IplImage *maskROI; /* Must be NULL. */
void *imageId; /* " " */
struct _IplTileInfo *tileInfo; /* " " */
int imageSize; /* Image data size in bytes
(==image->height*image->widthStep
in case of interleaved data)*/
char *imageData; /* Pointer to aligned image data. */
int widthStep; /* Size of aligned image row in bytes. */
int BorderMode[4]; /* Ignored by OpenCV. */
int BorderConst[4]; /* Ditto. */
char *imageDataOrigin; /* Pointer to very origin of image data
(not necessarily aligned) -
needed for correct deallocation */
}
IplImage;
typedef struct CvSize
{
int width;
int height;
}
CvSize;
CV_INLINE CvSize cvSize( int width, int height )
{
CvSize s;
s.width = width;
s.height = height;
return s;
}
希望得以指正和交流,谢谢。