CODEWITHSUNDEEP
opencviplimage
n0bod1
n0bod1

Reputation: 365

Explanation of IplImage* img

I just started learning OpenCV with "Learning OpenCV Computer Vision with the OpenCV Library".

In the first example which demonstrates how to display a picture, it has a line 

IplImage* img = cvLoadImage("name.type")

Although the book explains it, I still do not fully know what exactly IplImage* img does.

Does cvLoadImage loads the image to img which IplImage is pointing to? Can anyone explain this to me please? Thank you

Upvotes: 17

Views: 31243

Answers (1)

Smash
Smash

Reputation: 3802

  • img is the name of the variable, might as well be blahblahblah;

  • IplImage is the type of the variable, it's just a struct that contains the image data itself plus some info (size, color depth, etc.) on the image;

    typedef struct _IplImage {
int                  nSize;
int                  ID;
int                  nChannels;
int                  alphaChannel;
int                  depth;
char                 colorModel[4];
char                 channelSeq[4];
int                  dataOrder;
int                  origin;
int                  align;
int                  width;
int                  height;
struct _IplROI*      roi;
struct _IplImage*    maskROI;
void*                imageId;
struct _IplTileInfo* tileInfo;
int                  imageSize;
char*                imageData;
int                  widthStep;
int                  BorderMode[4];
int                  BorderConst[4];
char*                imageDataOrigin;
} IplImage;

For more info on IplImage: Other question about IplImage

  • cvLoadImage provides a pointer to an IplImage, which means it creates an IplImage when it loads it and returns you it's emplacement.

Do not forget to do cvReleaseImage(&img) when you are finished with it, if you do not want to have memory leaks.

Upvotes: 25

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