Détections faciales avec OpenCV

Le monde des services congnitifs est en plein expansion. Azure propose un service comme ça : Cognitives Services. Le problème, c’est que le traitement de l’image est fait par Azure. Il faut envoyer l’image et le traitement est payant.

Il existe des alternatives open-source comme OpenCV 4.0. les bindings sont en C#, Java et Python.

Voici quelques exemples:

opencv_net

opencv_cpp3

Vous vous demandez si le code est complexe ?

En C#:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.UI;
using Emgu.CV.Cuda;

namespace FaceDetection
{
   static class Program
   {
      ///

      /// The main entry point for the application.
      ///

 

      [STAThread]
      static void Main()
      {
         Application.EnableVisualStyles();
         Application.SetCompatibleTextRenderingDefault(false);
         Run();
      }



      static void Run()
      {
         IImage image;

         //Read the files as an 8-bit Bgr image  

         image = new UMat("Attach01.jpg", ImreadModes.Color); //UMat version
         //image = new Mat("lena.jpg", ImreadModes.Color); //CPU version

         long detectionTime;
         List faces = new List();
         List eyes = new List();

         DetectFace.Detect(
           image, @"data\haarcascades\haarcascade_frontalface_default.xml", @"data\haarcascades\haarcascade_eye.xml", 
           faces, eyes,
           out detectionTime);

         foreach (Rectangle face in faces)
            CvInvoke.Rectangle(image, face, new Bgr(Color.Red).MCvScalar, 2);
         foreach (Rectangle eye in eyes)
            CvInvoke.Rectangle(image, eye, new Bgr(Color.Blue).MCvScalar, 2);

         //display the image 
         using (InputArray iaImage = image.GetInputArray())
         ImageViewer.Show(image, String.Format(
            "Completed face and eye detection using {0} in {1} milliseconds", 
            (iaImage.Kind == InputArray.Type.CudaGpuMat && CudaInvoke.HasCuda) ? "CUDA" :
            (iaImage.IsUMat && CvInvoke.UseOpenCL) ? "OpenCL" 
            : "CPU",
            detectionTime));
      }

   }
}



using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using Emgu.CV;
using Emgu.CV.Structure;
#if !(__IOS__ || NETFX_CORE)
using Emgu.CV.Cuda;
#endif

namespace FaceDetection
{
   public static class DetectFace
   {
      public static void Detect(
         IInputArray image, String faceFileName, String eyeFileName,
         List faces, List eyes,
         out long detectionTime)
      {
         Stopwatch watch;

         using (InputArray iaImage = image.GetInputArray())
         {

#if !(__IOS__ || NETFX_CORE)
            if (iaImage.Kind == InputArray.Type.CudaGpuMat && CudaInvoke.HasCuda)
            {
               using (CudaCascadeClassifier face = new CudaCascadeClassifier(faceFileName))
               using (CudaCascadeClassifier eye = new CudaCascadeClassifier(eyeFileName))
               {
                  face.ScaleFactor = 1.1;
                  face.MinNeighbors = 10;
                  face.MinObjectSize = Size.Empty;
                  eye.ScaleFactor = 1.1;
                  eye.MinNeighbors = 10;
                  eye.MinObjectSize = Size.Empty;
                  watch = Stopwatch.StartNew();
                  using (CudaImage<Bgr, Byte> gpuImage = new CudaImage<Bgr, byte>(image))
                  using (CudaImage<Gray, Byte> gpuGray = gpuImage.Convert<Gray, Byte>())
                  using (GpuMat region = new GpuMat())
                  {
                     face.DetectMultiScale(gpuGray, region);
                     Rectangle[] faceRegion = face.Convert(region);
                     faces.AddRange(faceRegion);
                     foreach (Rectangle f in faceRegion)
                     {
                        using (CudaImage<Gray, Byte> faceImg = gpuGray.GetSubRect(f))
                        {
                           //For some reason a clone is required.
                           //Might be a bug of CudaCascadeClassifier in opencv
                           using (CudaImage<Gray, Byte> clone = faceImg.Clone(null))
                           using (GpuMat eyeRegionMat = new GpuMat())
                           {
                              eye.DetectMultiScale(clone, eyeRegionMat);
                              Rectangle[] eyeRegion = eye.Convert(eyeRegionMat);
                              foreach (Rectangle e in eyeRegion)
                              {
                                 Rectangle eyeRect = e;
                                 eyeRect.Offset(f.X, f.Y);
                                 eyes.Add(eyeRect);
                              }
                           }
                        }
                     }
                  }
                  watch.Stop();
               }
            }
            else
#endif
            {
               //Read the HaarCascade objects
               using (CascadeClassifier face = new CascadeClassifier(faceFileName))
               using (CascadeClassifier eye = new CascadeClassifier(eyeFileName))
               {
                  watch = Stopwatch.StartNew();

                  using (UMat ugray = new UMat())
                  {
                     CvInvoke.CvtColor(image, ugray, Emgu.CV.CvEnum.ColorConversion.Bgr2Gray);

                     //normalizes brightness and increases contrast of the image
                     CvInvoke.EqualizeHist(ugray, ugray);

                     //Detect the faces  from the gray scale image and store the locations as rectangle
                     //The first dimensional is the channel
                     //The second dimension is the index of the rectangle in the specific channel                     
                     Rectangle[] facesDetected = face.DetectMultiScale(
                        ugray,
                        1.1,
                        10,
                        new Size(20, 20));

                     faces.AddRange(facesDetected);

                     foreach (Rectangle f in facesDetected)
                     {
                        //Get the region of interest on the faces
                        using (UMat faceRegion = new UMat(ugray, f))
                        {
                           Rectangle[] eyesDetected = eye.DetectMultiScale(
                              faceRegion,
                              1.1,
                              10,
                              new Size(20, 20));

                           foreach (Rectangle e in eyesDetected)
                           {
                              Rectangle eyeRect = e;
                              eyeRect.Offset(f.X, f.Y);
                              eyes.Add(eyeRect);
                           }
                        }
                     }
                  }
                  watch.Stop();
               }
            }
            detectionTime = watch.ElapsedMilliseconds;
         }
      }
   }
}

 

En C++:

#ifndef PCH_H
#define PCH_H

// TODO: add headers that you want to pre-compile here
#include "opencv2/objdetect.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <iostream>

using namespace std;
using namespace cv;

#pragma comment(lib, "opencv_world400d.lib")

#endif //PCH_H


// ConsoleApplication1.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include "pch.h"

string cascadeName;
string nestedCascadeName;

void detectAndDraw(Mat& img, CascadeClassifier& cascade,
	CascadeClassifier& nestedCascade,
	double scale, bool tryflip);


int main(int argc, const char** argv)
{
	VideoCapture capture;
	Mat frame, image;
	string inputName;
	bool tryflip;
	CascadeClassifier cascade, nestedCascade;
	double scale;

	cascadeName = "..\\data\\haarcascades\\haarcascade_frontalface_alt.xml";
	nestedCascadeName = "..\\data\\haarcascades\\haarcascade_eye_tree_eyeglasses.xml";
	scale = 1.3;
	inputName = "group3.jpg";
	tryflip = false;

	if (!nestedCascade.load(samples::findFileOrKeep(nestedCascadeName)))
	{
		cerr << "WARNING: Could not load classifier cascade for nested objects" << endl;
		return 1;
	}

	if (!cascade.load(samples::findFile(cascadeName)))
	{
		cerr << "ERROR: Could not load classifier cascade" << endl;
		return 1;
	}
	
	image = imread(samples::findFileOrKeep(inputName), IMREAD_COLOR);
	if (image.empty())
	{
		if (!capture.open(samples::findFileOrKeep(inputName)))
		{
			cout << "Could not read " << inputName << endl;
			return 1;
		}
	}

	cout << "Detecting face(s) in " << inputName << endl;
	if (!image.empty())
	{
		detectAndDraw(image, cascade, nestedCascade, scale, tryflip);
		waitKey(0);
	}

	return 0;
}

void detectAndDraw(Mat& img, CascadeClassifier& cascade,
	CascadeClassifier& nestedCascade,
	double scale, bool tryflip)
{
	double t = 0;
	vector<Rect> faces, faces2;
	const static Scalar colors[] =
	{
		Scalar(255,0,0),
		Scalar(255,128,0),
		Scalar(255,255,0),
		Scalar(0,255,0),
		Scalar(0,128,255),
		Scalar(0,255,255),
		Scalar(0,0,255),
		Scalar(255,0,255)
	};
	Mat gray, smallImg;

	cvtColor(img, gray, COLOR_BGR2GRAY);
	double fx = 1 / scale;
	resize(gray, smallImg, Size(), fx, fx, INTER_LINEAR_EXACT);
	equalizeHist(smallImg, smallImg);

	t = (double)getTickCount();
	cascade.detectMultiScale(smallImg, faces,
		1.1, 2, 0
		//|CASCADE_FIND_BIGGEST_OBJECT
		//|CASCADE_DO_ROUGH_SEARCH
		| CASCADE_SCALE_IMAGE,
		Size(30, 30));
	if (tryflip)
	{
		flip(smallImg, smallImg, 1);
		cascade.detectMultiScale(smallImg, faces2,
			1.1, 2, 0
			//|CASCADE_FIND_BIGGEST_OBJECT
			//|CASCADE_DO_ROUGH_SEARCH
			| CASCADE_SCALE_IMAGE,
			Size(30, 30));
		for (vector<Rect>::const_iterator r = faces2.begin(); r != faces2.end(); ++r)
		{
			faces.push_back(Rect(smallImg.cols - r->x - r->width, r->y, r->width, r->height));
		}
	}
	t = (double)getTickCount() - t;
	printf("detection time = %g ms\n", t * 1000 / getTickFrequency());
	for (size_t i = 0; i < faces.size(); i++)
	{
		Rect r = faces[i];
		Mat smallImgROI;
		vector<Rect> nestedObjects;
		Point center;
		Scalar color = colors[i % 8];
		int radius;

		double aspect_ratio = (double)r.width / r.height;
		if (0.75 < aspect_ratio && aspect_ratio < 1.3)
		{
			center.x = cvRound((r.x + r.width*0.5)*scale);
			center.y = cvRound((r.y + r.height*0.5)*scale);
			radius = cvRound((r.width + r.height)*0.25*scale);
			circle(img, center, radius, color, 3, 8, 0);
		}
		else
			rectangle(img, Point(cvRound(r.x*scale), cvRound(r.y*scale)),
				Point(cvRound((r.x + r.width - 1)*scale), cvRound((r.y + r.height - 1)*scale)),
				color, 3, 8, 0);
		if (nestedCascade.empty())
			continue;
		smallImgROI = smallImg(r);
		nestedCascade.detectMultiScale(smallImgROI, nestedObjects,
			1.1, 2, 0
			//|CASCADE_FIND_BIGGEST_OBJECT
			//|CASCADE_DO_ROUGH_SEARCH
			//|CASCADE_DO_CANNY_PRUNING
			| CASCADE_SCALE_IMAGE,
			Size(30, 30));
		for (size_t j = 0; j < nestedObjects.size(); j++)
		{
			Rect nr = nestedObjects[j];
			center.x = cvRound((r.x + nr.x + nr.width*0.5)*scale);
			center.y = cvRound((r.y + nr.y + nr.height*0.5)*scale);
			radius = cvRound((nr.width + nr.height)*0.25*scale);
			circle(img, center, radius, color, 3, 8, 0);
		}
	}
	imshow("result", img);
}

 

Comme vous pouvez le constater, il est facile de mettre en oeuvre des services techniques performants sans payer.

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