opencv函数cvcvtcolor和cvtcolor有什么区别

Question

I am new to c++ coding . can you tell me what is the difference between opencv function cvcvtcolor and cvtcolor ?

Thank you

Answer 1

There is no difference except that cvCvtColor is a simple wrapper for cvtColor .

1. cvCvtColor is C API - deprecated .
2. cvtColor is C++ API - recommended .

From opencv source (1) you can see that the C API cvCvtColor is wrapper around the C++ cvtColor which does actual conversions like RGB2GRAY etc.

CV_IMPL void cvCvtColor( const CvArr* srcarr, CvArr* dstarr, int code )
{
    cv::Mat src = cv::cvarrToMat(srcarr), dst0 = cv::cvarrToMat(dstarr), dst = dst0;
    CV_Assert( src.depth() == dst.depth() );

    cv::cvtColor(src, dst, code, dst.channels());
    CV_Assert( dst.data == dst0.data );
}

Answer 2

C: void cvCvtColor(const CvArr* src, CvArr* dst, int code)

C++: void cvtColor(InputArray src, OutputArray dst, int code, int dstCn=0 )

That's the difference, cvCvtColor belongs to the old deprecated C API whereas cv::cvtColor belongs to the current C++ OpenCV API. Make use of the cv namespace as much as possible to avoid using legacy code.

Answer 3

They're equivalent , except cvtcolor is the C++ API and cvCvtColor C API.

If you use C++, you only need to care about and are also recommend to use cvtcolor .

Answer 4

cvCvtColor inputs and outputs parameters is cvArray reference image aka "IplImage"

Syntax: cvCvtColor(CvArr *src, CvArr *dst, int code)

cvtColor on the other hand using InputArray images aka "Mat"

Syntax: cvtColor(InputArray src, OutputArray dst, int code)

Notice that cvArray (IplImage) is a reference address to the image, While InputArray (Mat) is the actual image.

As a practical test i have tried both with int code = CV_BGR2HSV, Surprisingly the output was too different, Both tested at same environment (Neon-light White Balance).

cvCvtColor on OpenCV 3.4.3

cvCvtColor(inputIplImage, outputIplImage, CV_BGR2HSV);

cvCvtColor on OpenCV 4.4.0

cvtColor(inputMat, outputMat, CV_BGR2HSV);

Finally you have to know that cvCvtColor Not exist anymore in OpenCV 4.4.0 as IplImage is deprecated and we have to use Mat instead, So I guess you will have to use cvtColor or Stick to the previous version 3.4.3