[人工智能]OpenCVSharp 笑脸检测

利用Harra Cascade?分类器进行人脸检测和进一步进行笑脸检测，采用训练好的分类模型，在OpenCVSharp里变得非常简单，两三条语句就搞定了：

?CascadeClassifier face_cascade = new CascadeClassifier(facemodelfile);? //创建一个人脸分类器
?face_cascade .DetectMultiScale(image);? ?//检测人脸

?CascadeClassifier smile_cascade = new CascadeClassifier(smilemodelfile);? //创建一个笑脸分类器

?smile_cascade.DetectMultiScale(image);? ?//检测笑脸

?

?下面是完整的代码：

using System;
using System.Drawing;
using System.Windows.Forms;
using OpenCvSharp;

namespace SmileDetect
{
    public partial class Form1 : Form
    {
        string filename = "";
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "图片文件|*.jpg;*.png;*.bmp;*.gif";
            ofd.CheckFileExists = true;
            if(ofd.ShowDialog()== DialogResult.OK)
            {
                filename = ofd.FileName;
                pictureBox1.Image = DetectSmile(filename);
            }
        }

        private Bitmap DetectSmile(string filename)
        {
            double scaleFactor = Convert.ToDouble(textBox1.Text);
            if (scaleFactor <= 1.00)
                scaleFactor = 1.01;
            int miniNeighbors = Convert.ToInt16(textBox2.Text);

            string facemodel = @"D:\OpenCV4.5\build\etc\haarcascades\haarcascade_frontalface_default.xml";            
            string smilemodel = @"D:\OpenCV4.5\build\etc\haarcascades\haarcascade_smile.xml";

            CascadeClassifier face_cascade = new CascadeClassifier(facemodel);
            CascadeClassifier eye_cascade = new CascadeClassifier(eyemodel);
            CascadeClassifier smile_cascade = new CascadeClassifier(smilemodel);

            Mat input = new Mat(filename, ImreadModes.Color);
            Mat grayInput = new Mat();
            Cv2.CvtColor(input, grayInput, ColorConversionCodes.BGR2GRAY);

            Rect[] faces = face_cascade.DetectMultiScale(input, 1.3, 5);

            for (int i = 0; i < faces.Length; i++)
            {
                Cv2.Rectangle(input, faces[i], Scalar.Red,2);
                Mat faceMat = grayInput[faces[i]];
                Mat faceMatColor = input[faces[i]];
                Rect[] smiles = smile_cascade.DetectMultiScale(faceMat, scaleFactor, miniNeighbors);
                for (int j = 0; j < smiles.Length; j++)
                {
                    Cv2.Rectangle(faceMatColor, smiles[j], Scalar.Green,2);
                }
            }
            return OpenCvSharp.Extensions.BitmapConverter.ToBitmap(input);
        }

        private void button2_Click(object sender, EventArgs e)
        {

            if(filename.Length>0)
            {
                if(pictureBox1.Image != null)
                {
                    pictureBox1.Image = DetectSmile(filename);
                }
            }
        }
    }
}

模型文件可以在这里下载：https://github.com/opencv/opencv/tree/master/data/haarcascades