1.IplImage数据结构
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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; |
掌握IplImage的几个重要的数据结构：
- Width
- Height
- Depth: usually use IPL_DEPTH_*U/S/F
- nChannals :can be valued 1,2,3,4
- origin: only can be valued IPL_ORIGIN_TL or IPL_ORIGIN_BL
- dataOrder: can be valued by IPL_DATA_ORDER_PIXEL or IPL_DATA_ORDER_PLANE
- widthStep :临行同列之间的字节数
2.访问图像数据
利用指针遍历（矩阵遍历）的方法，如下程序是最高效的方法：
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#include <cv.h> #include <highgui.h>
//仅最大化hsv图像的 s 和 v 部分 //因为这是一个三通道图像 所以c通道在x行的位置是3*x+c //与CvMat不同的是：IplImage的imageData结构 int saturate_sv(IplImage * img) { if(img->nChannels!=3) return (0); for(int y=0;y<img->height;y++) { uchar * ptr = (uchar *)img->imageData + img->widthStep * y; for(int x=0;x<img->width;x++) { ptr[3*x+1]=255; ptr[3*x+2]=255; } } return 1; } int main() { cvNamedWindow("test-1"); cvNamedWindow("test-2"); IplImage * image=cvLoadImage("I:\\资料\\opencv相关资料\\OpenCV教程\\图像与视频\\airplane.png"); cvShowImage("test-1",image);
int result = saturate_sv(image); cvShowImage("test-2",image);
cvWaitKey(); cvReleaseImage(&image); cvDestroyWindow("test-1"); cvDestroyWindow("test-2"); printf("%d",result); } |
3.ROI
下面的例子说明用imageROI来增加某范围的像素
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int main() { IplImage * src; if((src=cvLoadImage("I:\\资料\\opencv相关资料\\OpenCV教程\\图像与视频\\airplane.png",1)) != 0) { int x = 200; int y = 200; int width = 200;; int height = 200; int add = 150; cvSetImageROI(src,cvRect(x,y,width,height)); cvAddS(src,cvScalar(add),src); cvResetImageROI(src); cvNamedWindow("roi-add"); cvShowImage("roi-add",src); cvWaitKey(); } return 0; } |
其他方法：
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#include <cv.h> #include <highgui.h>
int main() { IplImage * interest_img = cvLoadImage("I:\\资料\\opencv相关资料\\OpenCV教程\\图像与视频\\airplane.png"); CvRect interest_rect = cvRect(100,100,100,100);
IplImage * sub_img = cvCreateImageHeader(cvSize(interest_rect.width,interest_rect.height),interest_img->depth,interest_img->nChannels);
sub_img->origin = interest_img->origin; sub_img->widthStep = interest_img->widthStep; sub_img->imageData = interest_img->imageData + interest_rect.x * interest_img->nChannels + interest_rect.y* interest_img->widthStep;
cvAddS(sub_img,cvScalar(1),sub_img);
cvNamedWindow("roi-add"); cvShowImage("roi-add",sub_img); cvWaitKey(); cvReleaseImageHeader(&sub_img); } |
来源：https://www.cnblogs.com/feng-fan/archive/2013/03/05/2944449.html