C# winform PictureBox显示opencv Mat图片

在winform设计器托一个PictureBox、一个按钮，界面如下：

代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using OpenCvSharp;   //引入opencv
using OpenCvSharp.Extensions;  //Mat转换时需要该模块

namespace PictureBoxShowMat
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Multiselect = false;   //是否可以选择多个文件
            dialog.Title = "请选择文件夹";
            dialog.Filter = "所有文件(*.*)|*.*";
            dialog.RestoreDirectory = true;

            string imgName = "";

            if (dialog.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                imgName = dialog.FileName;

                //读取本地的图片
                Mat srcImg = new Mat(imgName, ImreadModes.Color);
          
                //把Mat格式的图片转换成Bitmap
                Bitmap bitmap = BitmapConverter.ToBitmap(srcImg);

                //显示图片
                pictureBox1.Image = bitmap;
            }
        }
    }
}

运行结果

Mat转Bitmap需要调用OPenCVSharp拓展模块OpenCvSharp.Extensions, 调用该模块BitmapConverter类的一些方法即可完成相应的转换，该类声明如下： BitmapConverter类定义了一些静态方法，可以把Mat转为Bitmap, 也可以把Bitmap转为Mat. 来看看转Bitmap的源码，在OpenCVSharp源码中查找BitmapConverter类的实现，ToBitmap的实现如下：

/// 
        /// Converts Mat to System.Drawing.Bitmap
        /// 
        /// Mat
        /// 
        public static Bitmap ToBitmap(this Mat src)
        {
            if (src == null)
            {
                throw new ArgumentNullException(nameof(src));
            }

            PixelFormat pf;
            switch (src.Channels())
            {
                case 1:
                    pf = PixelFormat.Format8bppIndexed; break;
                case 3:
                    pf = PixelFormat.Format24bppRgb; break;
                case 4:
                    pf = PixelFormat.Format32bppArgb; break;
                default:
                    throw new ArgumentException("Number of channels must be 1, 3 or 4.", nameof(src));
            }
            return ToBitmap(src, pf);
        }

根据图片的通道数，最终会调用下面这个方法转换

public static unsafe void ToBitmap(this Mat src, Bitmap dst)
        {
            if (src == null)
                throw new ArgumentNullException(nameof(src));
            if (dst == null)
                throw new ArgumentNullException(nameof(dst));
            if (src.IsDisposed)
                throw new ArgumentException("The image is disposed.", nameof(src));
            if (src.Depth() != MatType.CV_8U)
                throw new ArgumentException("Depth of the image must be CV_8U");
            //if (src.IsSubmatrix())
            //    throw new ArgumentException("Submatrix is not supported");
            if (src.Width != dst.Width || src.Height != dst.Height)
                throw new ArgumentException("");

            PixelFormat pf = dst.PixelFormat;

            // 1プレーン用の場合、グレースケールのパレット情報を生成する
            if (pf == PixelFormat.Format8bppIndexed)
            {
                ColorPalette plt = dst.Palette;
                for (int x = 0; x