OpenCV: src.size() == dst.size() && dst.type() == CV_32FC1 Error in .Net C#

Question

I have an image loaded from a video:

 Image<Gray, byte> imGray=cap.QueryGrayFrame();  

Now, I want to use the cvCornerHarris function from openCv as following:

 Image<Gray, byte> harRes = new Image<Gray, byte>(imGray.Size);  
 CvInvoke.cvCornerHarris(imGray, harRes, 8, 3, 0.04); 

But I get an cvException:

OpenCV: src.size() == dst.size() && dst.type() == CV_32FC1 Error

How should I fix this?

Answer 1

I am not sure about the C# wrapper, but in C++, you can change the pixel format using this line:

imGray.convertTo(A, CV_32F);

The error says, the size of images should match (which your code do the same) and the pixel format should be float32, which probably yours are not.

Answer 2

You can deduce from the given exception, that the type of the destination image should be CV_32FC1 .

In your case, the destination image is harRes , which you have declared as:

Image<Gray, byte> harRes = new Image<Gray, byte>(imGray.Size);

The type of this image is CV_8UC1 .

It should be declared as:

Image<Gray, float> harRes = new Image<Gray, float>(imGray.Size);

Now its type is CV_32FC1 , which is the type expected by the function cvCornerHarris .