opencvdetectandblurface.cs

opencvdetectandblurface.cs

//    Copyright (c) 2022
//    Author      : Bruno Capuano
//    Create Time : 2022 Feb
//    Change Log  :
//    - Open a camera feed from a local USB webcam and analyze each frame to detect faces using haar cascades
//    - When a face is detected, the app will blur the face zone in the main window
//    - When a face is detected, the app will show the original detected face in a separated window
//    - Press [F] to enable / disable the face detection process
//    - Press [Q] to quit the app
//
//    The MIT License (MIT)
//
//    Permission is hereby granted, free of charge, to any person obtaining a copy
//    of this software and associated documentation files (the "Software"), to deal
//    in the Software without restriction, including without limitation the rights
//    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//    copies of the Software, and to permit persons to whom the Software is
//    furnished to do so, subject to the following conditions:
//
//    The above copyright notice and this permission notice shall be included in
//    all copies or substantial portions of the Software.
//
//    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//    THE SOFTWARE.

using OpenCvSharp;

var faceCascade = new CascadeClassifier();
faceCascade.Load("haarcascade_frontalface_default.xml");

using var capture = new VideoCapture(0);
{
    var image = new Mat();
    var showFace = true;
    var run = true;
    using var window = new Window("El Bruno - Blur Face");
    using var windowFace = new Window("El Bruno - Face");

    while (run)
    {
        capture.Read(image);
        if (image.Empty())
            break;

        var newSize = new Size(640, 480);
        using var smallFrame = new Mat();
        Cv2.Resize(image, smallFrame, newSize);

        if (showFace)
        {
            using var gray = new Mat();
            Cv2.CvtColor(smallFrame, gray, ColorConversionCodes.BGR2GRAY);

            var faces = faceCascade.DetectMultiScale(gray, 1.3, 5);
            foreach (var face in faces)
            {
                Cv2.Rectangle(smallFrame, face, Scalar.Red);

                // create a new Mat with the detected face
                var faceImg = new Mat(smallFrame,
                    new OpenCvSharp.Range(face.Top, face.Top + face.Width),
                    new OpenCvSharp.Range(face.Left, face.Left + face.Height));
                windowFace.Image = faceImg;

                // blur the face area in the original frame
                var faceBlur = new Mat();
                Cv2.GaussianBlur(faceImg, faceBlur, new Size(23, 23), 30);
                smallFrame[face] = faceBlur;
            }
        }

        window.Image = smallFrame;
        switch ((char)Cv2.WaitKey(100))
        {
            case (char)27: // ESC
                run = false;
                break;
            case 'f':
                showFace = !showFace;
                break;
        }
    }
}