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I am trying to do something like the following:

public partial class Form1 : Form

{

const string path = @"lena.png";



public Form1()

{

    InitializeComponent();



    Image<Bgr, byte> color = new Image<Bgr, byte>(path);



    Matrix<byte> matrix = new Matrix<byte>(color.Rows, color.Cols);



    matrix.Data = color.ToMatrix();// just an analogy



    pictureBox1.Image = col.Bitmap;

    pictureBox2.Image = gray.Bitmap;

}

}

How can I convert Image to Matrix in EmguCV?

How can I convert Matrix to Bitmap?

Converting Image to Matrix

The important thing to notice here is that both Image and Matrix inherit from CvArray. That means it is possible to use the (inherited) method CopyTo to copy the data from an Image instance to a Matrix instance of identical depth and dimensions.

NB: There are 3 dimensions of relevance -- width, height, and channel count.

Image<Bgr, byte> color = ... ; // Initialized in some manner



Matrix<byte> matrix = new Matrix<byte>(color.Rows, color.Cols, color.NumberOfChannels);



color.CopyTo(matrix);

NB: There's a cost involved with this approach, due to the necessity to make a copy of the entire data array.

Converting Matrix to Bitmap

This one is actually quite simple. Matrix inherits the property Mat, which returns a Mat header (meaning a thin wrapper around an existing data array) for the array data. Since this just creates a header, it's very quick (no copies involved).

NB: Due to being a header, I assume based on my experience with the C++ API (even though this doesn't seem documented) that the Mat object is valid as long as the underlying Matrix object stays in scope.

Mat provides a Bitmap property, which behaves identically to Image.Bitmap.

Bitmap b = matrix.Mat.Bitmap;

The other option is to use the same approach as before to copy the data back to the Image instance.

matrix.CopyTo(color);

Then you could use the Bitmap property (fast, but requires the Image instance to live as long as you use the Bitmap).

Bitmap b = color.Bitmap;

Another alternative would be to use the ToBitmap method, which copies the data, and therefore doesn't carry the dependency on the source Image instance.

Bitmap b = color.ToBitmap();

Source used for testing:

using System;

using System.Drawing;

using Emgu.CV;

using Emgu.CV.Structure;

// ============================================================================

namespace CS1 {

// ============================================================================

class Test

{

    static void Main()

    {

        Image<Bgr, byte> color = new Image<Bgr, byte>(2, 2);

        for (int r = 0; r < color.Rows; r++) {

            for (int c = 0; c < color.Cols; c++) {

                int n = (c + r * color.Cols) * 3;

                color[r, c] = new Bgr(n, n+1, n+2);

            }

        }



        Matrix<byte> matrix = new Matrix<byte>(color.Rows, color.Cols, color.NumberOfChannels);



        color.CopyTo(matrix);



        Bitmap b = matrix.Mat.Bitmap;



        matrix.CopyTo(color);



        b = color.Bitmap;



        b = color.ToBitmap();

    }

}

// ============================================================================

} // namespace CS1

// ============================================================================

The CMake file I used to generate a solution to compile this:

cmake_minimum_required(VERSION 3.11)

project(CS1 VERSION 0.1.0 LANGUAGES CSharp)



add_executable(cs1

    src/test.cs

)



set_property(TARGET cs1

    PROPERTY VS_DOTNET_TARGET_FRAMEWORK_VERSION "v4.6.1"

)



set_property(TARGET cs1 

    PROPERTY VS_DOTNET_REFERENCES

    "System"

    "System.Drawing"

)



set_target_properties(cs1 PROPERTIES 

    VS_DOTNET_REFERENCE_emgu_cv_world "deps/Emgu.CV.World.dll"

)