Ref: http://docs.opencv.org/2.4.13/
基础数据结构
一、基本几何
矩形
"modules/core/src/drawing.cpp"
CV_IMPL void
cvRectangle( CvArr* _img, CvPoint pt1, CvPoint pt2,
CvScalar color, int thickness,
int line_type, int shift )
{
cv::Mat img = cv::cvarrToMat(_img);
cv::rectangle( img, pt1, pt2, color, thickness, line_type, shift );
}
点
"modules/core/include/opencv2/core/types_c.h"
typedef struct CvPoint
{
int x;
int y;
}
CvPoint;
typedef struct CvPoint3D64f
{
double x;
double y;
double z;
}
CvPoint3D64f;
面积
typedef struct CvSize
{
int width;
int height;
}
CvSize;
大数表示 （例如：表示颜色）
typedef struct CvScalar
{
double val[];
}
CvScalar;
二、矩阵描述
- Mat
Ref: opencv基础知识------IplImage, CvMat, Mat 的关系和相互转换
在openCV中，Mat类型与CvMat和IplImage类型都可以代表和显示图像，
但是，Mat类型侧重于计算，数学性较高，openCV对Mat类型的计算也进行了优化。
而CvMat和IplImage类型更侧重于“图像”，openCV对其中的图像操作（缩放、单通道提取、图像阈值操作等）进行了优化。
三、图片描述
- IplImage
"modules/core/include/opencv2/core/types_c.h"
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[]; /* Ignored by OpenCV */
char channelSeq[]; /* ditto */
int dataOrder; /* 0 - interleaved color channels 隔行扫描, 1 - separate color channels .
cvCreateImage can only create 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[]; /* Ignored by OpenCV. */
int BorderConst[]; /* Ditto. */
char *imageDataOrigin; /* Pointer to very origin of image data
(not necessarily aligned) -
needed for correct deallocation */
}
IplImage;
- CvMat
"modules/core/include/opencv2/core/types_c.h" 708L, 58287C
typedef struct CvMat
{
int type;
int step; /* for internal use only */
int* refcount;
int hdr_refcount; union
{
uchar*;
short* s;
int* i;
float* fl;
double* db;
} data; #ifdef __cplusplus
union
{
int rows;
int height;
}; union
{
int cols;
int width;
};
#else
int rows;
int cols;
#endif }
CvMat;
[1] 初始化一个矩阵
#include "cv.h"
#include <stdio.h> int main()
{
// Create an OpenCV Matrix containing some fixed data.
//
float vals[] = { 0.866025, -0.500000, 0.500000, 0.866025}; CvMat rotmat; cvInitMatHeader(&rotmat, , , CV_32FC1, vals);
printf("Ex 3_3 matrix initialized\n");
}
[2] 相关源代码："modules/core/src/array.cpp"
[3] 初始化细节：Init Matrax ( ):
CV_IMPL CvMat*
cvInitMatHeader( CvMat* arr, int rows, int cols,
int type, void* data, int step )
{
if( !arr )
CV_Error( CV_StsNullPtr, "" ); if( (unsigned)CV_MAT_DEPTH(type) > CV_DEPTH_MAX )
CV_Error( CV_BadNumChannels, "" ); if( rows < || cols <= )
CV_Error( CV_StsBadSize, "Non-positive cols or rows" ); type = CV_MAT_TYPE( type );
arr->type = type | CV_MAT_MAGIC_VAL;
arr->rows = rows;
arr->cols = cols;
arr->data.ptr = (uchar*)data;
arr->refcount = ;
arr->hdr_refcount = ; int pix_size = CV_ELEM_SIZE(type);
int min_step = arr->cols*pix_size; if( step != CV_AUTOSTEP && step != )
{
if( step < min_step )
CV_Error( CV_BadStep, "" );
arr->step = step;
}
else
{
arr->step = min_step;
} arr->type = CV_MAT_MAGIC_VAL | type |
(arr->rows == || arr->step == min_step ? CV_MAT_CONT_FLAG : ); icvCheckHuge( arr );
return arr;
}
[4] 其他相关API：Relevant Functions
// Create a new rows by cols matrix of type ‘type’.
//
CvMat* cvCreateMat( int rows, int cols, int type );
// Create only matrix header without allocating data
//
CvMat* cvCreateMatHeader( int rows, int cols, int type );
// Initialize header on existing CvMat structure
//
CvMat*cvInitMatHeader(
CvMat* mat,
int rows,
int cols,
int type,
void* data = NULL,
int step = CV_AUTOSTEP
);
// Like cvInitMatHeader() but allocates CvMat as well.
//
CvMat cvMat(
int rows,
int cols,
int type,
void* data = NULL
);
// Allocate a new matrix just like the matrix ‘mat’.
//
CvMat* cvCloneMat( const cvMat* mat );
// Free the matrix ‘mat’, both header and data.
//
void cvReleaseMat( CvMat** mat );
四、存取像素点
- 宏方法
"modules/core/include/opencv2/core/types_c.h"
#define CV_MAT_ELEM_PTR_FAST( mat, row, col, pix_size ) \
(assert( (unsigned)(row) < (unsigned)(mat).rows && \
(unsigned)(col) < (unsigned)(mat).cols ), \
(mat).data.ptr + (size_t)(mat).step*(row) + (pix_size)*(col)) #define CV_MAT_ELEM_PTR( mat, row, col ) \
CV_MAT_ELEM_PTR_FAST( mat, row, col, CV_ELEM_SIZE((mat).type) ) #define CV_MAT_ELEM( mat, elemtype, row, col ) \
(*(elemtype*)CV_MAT_ELEM_PTR_FAST( mat, row, col, sizeof(elemtype)))
宏取值，简单但通用性不强：
#include "cv.h"
#include <stdio.h> int main()
{
CvMat* mat = cvCreateMat( , , CV_32FC1 );
// 1. 指针法
float element_3_2 = 7.7;
*( (float*)CV_MAT_ELEM_PTR( *mat, , ) ) = element_3_2; // 2. 处理“浮点型，单通道矩阵”
cvmSet( mat, , , 0.5000 ); // 3. 较常用
cvSetReal2D( mat, , , 0.3300 ); printf("Exercise 3_5, matrix created and accessed [3,2]=%f, [2,2]=%f, [3,3]=%f\n",
CV_MAT_ELEM( *mat, float, , ),
CV_MAT_ELEM( *mat, float, , ),
CV_MAT_ELEM( *mat, float, , ) );
}
- Get pixel
"modules/core/src/array.cpp"
// CvMat and IplImage element functions
double cvGetReal1D( const CvArr* arr, int idx0 );
double cvGetReal2D( const CvArr* arr, int idx0, int idx1 );
double cvGetReal3D( const CvArr* arr, int idx0, int idx1, int idx2 );
double cvGetRealND( const CvArr* arr, int* idx );
CvScalar cvGet1D( const CvArr* arr, int idx0 );
CvScalar cvGet2D( const CvArr* arr, int idx0, int idx1 );
CvScalar cvGet3D( const CvArr* arr, int idx0, int idx1, int idx2 );
CvScalar cvGetND( const CvArr* arr, int* idx );
返回值类型占用空间大，也有小的方案 as following：
// Pointer access to matrix structures
uchar* cvPtr1D(
const CvArr* arr,
int idx0,
int* type = NULL
);
uchar* cvPtr2D(
const CvArr* arr,
int idx0,
int idx1,
int* type = NULL
);
uchar* cvPtr3D(
const CvArr* arr,
int idx0,
int idx1,
int idx2,
int* type = NULL
);
uchar* cvPtrND(
const CvArr* arr,
int* idx,
int* type = NULL,
int create_node = ,
unsigned* precalc_hashval = NULL
);
- Set Pixel
// Set element functions for CvMat or IplImage.
void cvSetReal1D( CvArr* arr, int idx0, double value );
void cvSetReal2D( CvArr* arr, int idx0, int idx1, double value );
void cvSetReal3D(
CvArr* arr,
int idx0,
int idx1,
int idx2,
double value
);
void cvSetRealND( CvArr* arr, int* idx, double value );
void cvSet1D( CvArr* arr, int idx0, CvScalar value );
void cvSet2D( CvArr* arr, int idx0, int idx1, CvScalar value );
void cvSet3D(
CvArr* arr,
int idx0,
int idx1,
int idx2,
CvScalar value
);
void cvSetND( CvArr* arr, int* idx, CvScalar value );
- 综合性例子
/* License:
Oct. 3, 2008
Right to use this code in any way you want without warrenty, support or any guarentee of it working. BOOK: It would be nice if you cited it:
Learning OpenCV: Computer Vision with the OpenCV Library
by Gary Bradski and Adrian Kaehler
Published by O'Reilly Media, October 3, 2008 AVAILABLE AT:
http://www.amazon.com/Learning-OpenCV-Computer-Vision-Library/dp/0596516134
Or: http://oreilly.com/catalog/9780596516130/
ISBN-10: 0596516134 or: ISBN-13: 978-0596516130 OTHER OPENCV SITES:
* The source code is on sourceforge at:
http://sourceforge.net/projects/opencvlibrary/
* The OpenCV wiki page (As of Oct 1, 2008 this is down for changing over servers, but should come back):
http://opencvlibrary.sourceforge.net/
* An active user group is at:
http://tech.groups.yahoo.com/group/OpenCV/
* The minutes of weekly OpenCV development meetings are at:
http://pr.willowgarage.com/wiki/OpenCV
*/ #include <stdio.h>
#include <cv.h>
#include <highgui.h> float sum( CvMat* mat ) {
float s = 0.0f;
for( int row=; row<mat->height; row++ ) {
float* ptr = mat->data.fl + row * mat->step/;
for( int col=; col<mat->width; col++ ) {
s += *ptr++;
}
}
return( s );
}; int main(int argc, char** argv)
{
CvMat *mat = cvCreateMat(,,CV_32FC1);
float element_3_2 = 7.7;
*((float*)CV_MAT_ELEM_PTR( *mat, ,) ) = element_3_2;
cvmSet(mat,,,0.5000);
cvSetReal2D(mat,,,0.5000);
float s = sum(mat);
printf("%f\n",s);
return ;
}