Conversion to grayscale using emguCV in C#

Question

I am new to EmguCV. I want to convert an rgb image into gray scale. For the conversion I have used the code

Image<Gray,byte> grayImage = ColordImage.Convert<Gray, byte>();

Now when i compile this code in C# it gives no error,but when i run it then after a few seconds it gives me the exception at this line of code that this type of conversion is not supported by OpenCV. Now can any one help me solve this problem.

Regards Amal

Tom Wright's answer worked for me. If it worked for you, please accept the answer. — Chad, Sep 30 '16 at 15:53

score 15 · Answer 1 · answered Jun 28 '10 at 12:26

It may depend on the type of colour that ColordImage is.

For instance, this works:

Capture cap = new Capture(1);
Image <Bgr,Byte> ColordImage = cap.QueryFrame();
Image <Gray,Byte> grayImage = ColordImage.Convert<Gray, Byte>();
imageBox1.Image = grayImage;

If you could supply more of your code, it might become more obvious what's going on.

score 5 · Answer 2 · answered Aug 03 '12 at 22:23

5

You should paste opencv_imgproc220.dll(if you use emgu cv 2.2.1.1150) to your project bin/debug folder.

answered Aug 03 '12 at 22:23

Abu Yousuf

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This answer looks stupid but its the correct answer. I checked ColordImage.Convert() in ILSpy, the function uses Image.ConvertColor() which contains try/catch block that catches everything, including dll load errors. – Markos Nov 09 '12 at 20:19

score 5 · Answer 3 · answered Dec 12 '10 at 17:02

Alternately, if you don't want to use Convert (e.g. in case your ColoredImage is some other data type such as IntPtr), there are numerous constructors available such as:

Image<Gray, byte> grayFrame = new Image<Gray, byte>(width, height, stride, imageData);

Here is a full list:
http://www.emgu.com/wiki/files/2.1.0.0/html/cb45d54d-ebce-44b6-0352-3e1105c0862a.htm

There are also some more examples (including usage of Convert) on the emgu Wiki: http://www.emgu.com/wiki/index.php/Working_with_Images

score 4 · Answer 4 · answered Sep 02 '14 at 18:32

4

One simple way is to pass BitMap of color image in the constructor;

Image<Bgr, byte> inputImage = //your original bgr image
Image<Gray, Byte> result = new Image<Gray,byte>(inputImage.Bitmap);

answered Sep 02 '14 at 18:32

vincent mathew

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Conversion to grayscale using emguCV in C#

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