faceAverage.cpp

/*
 * Copyright (c) 2016 Satya Mallick <spmallick@learnopencv.com>
 * All rights reserved. No warranty, explicit or implicit, provided.
 */

#include <opencv2/opencv.hpp>
#include <iostream>
#include <fstream>
#include <dirent.h>
#include <stdlib.h>
#include <algorithm>
#include <vector>
using namespace cv;
using namespace std;

// Compute similarity transform given two pairs of corresponding points.
// OpenCV requires 3 pairs of corresponding points.
// We are faking the third one.
void similarityTransform(std::vector<cv::Point2f>& inPoints, std::vector<cv::Point2f>& outPoints, cv::Mat &tform)
{
    
    double s60 = sin(60 * M_PI / 180.0);
    double c60 = cos(60 * M_PI / 180.0);
    
    vector <Point2f> inPts = inPoints;
    vector <Point2f> outPts = outPoints;
    
    inPts.push_back(cv::Point2f(0,0));
    outPts.push_back(cv::Point2f(0,0));
    
    
    inPts[2].x =  c60 * (inPts[0].x - inPts[1].x) - s60 * (inPts[0].y - inPts[1].y) + inPts[1].x;
    inPts[2].y =  s60 * (inPts[0].x - inPts[1].x) + c60 * (inPts[0].y - inPts[1].y) + inPts[1].y;
    
    outPts[2].x =  c60 * (outPts[0].x - outPts[1].x) - s60 * (outPts[0].y - outPts[1].y) + outPts[1].x;
    outPts[2].y =  s60 * (outPts[0].x - outPts[1].x) + c60 * (outPts[0].y - outPts[1].y) + outPts[1].y;
    
    
    tform = cv::estimateRigidTransform(inPts, outPts, false);
}




// Read points from list of text file
void readPoints(vector<string> pointsFileNames, vector<vector<Point2f> > &pointsVec){
    
    for(size_t i = 0; i < pointsFileNames.size(); i++)
    {
        vector<Point2f> points;
        ifstream ifs(pointsFileNames[i]);
        float x, y;
        while(ifs >> x >> y)
            points.push_back(Point2f((float)x, (float)y));
        
        pointsVec.push_back(points);
    }
    
}


// Read names from the directory
void readFileNames(string dirName, vector<string> &imageFnames, vector<string> &ptsFnames)
{
    DIR *dir;
    struct dirent *ent;
    int count = 0;
    
    //image extensions
    string imgExt = "jpg";
    string txtExt = "txt";
    vector<string> files;
    
    if ((dir = opendir (dirName.c_str())) != NULL)
    {
        /* print all the files and directories within directory */
        while ((ent = readdir (dir)) != NULL)
        {
            if(strcmp(ent->d_name,".") == 0 || strcmp(ent->d_name,"..") == 0 )
            {
                //count++;
                continue;
            }
            string temp_name = ent->d_name;
            files.push_back(temp_name);
            
        }
        std::sort(files.begin(),files.end());
        for(int it=0;it<files.size();it++)
        {
            string path = dirName;
            string fname=files[it];
            
            
            if (fname.find(imgExt, (fname.length() - imgExt.length())) != std::string::npos)
            {
                path.append(fname);
                imageFnames.push_back(path);
            }
            else if (fname.find(txtExt, (fname.length() - txtExt.length())) != std::string::npos)
            {
                path.append(fname);
                ptsFnames.push_back(path);
            }
            
        }
        closedir (dir);
    }
    
}

// Calculate Delaunay triangles for set of points
// Returns the vector of indices of 3 points for each triangle
static void calculateDelaunayTriangles(Rect rect, vector<Point2f> &points, vector< vector<int> > &delaunayTri){
    
    // Create an instance of Subdiv2D
    Subdiv2D subdiv(rect);
    
    // Insert points into subdiv
    for( vector<Point2f>::iterator it = points.begin(); it != points.end(); it++)
        subdiv.insert(*it);
    
    vector<Vec6f> triangleList;
    subdiv.getTriangleList(triangleList);
    vector<Point2f> pt(3);
    vector<int> ind(3);
    
    for( size_t i = 0; i < triangleList.size(); i++ )
    {
        Vec6f t = triangleList[i];
        pt[0] = Point2f(t[0], t[1]);
        pt[1] = Point2f(t[2], t[3]);
        pt[2] = Point2f(t[4], t[5 ]);
        
        if ( rect.contains(pt[0]) && rect.contains(pt[1]) && rect.contains(pt[2])){
            for(int j = 0; j < 3; j++)
                for(size_t k = 0; k < points.size(); k++)
                    if(abs(pt[j].x - points[k].x) < 1.0 && abs(pt[j].y - points[k].y) < 1)
                        ind[j] = k;
            
            delaunayTri.push_back(ind);
        }
    }
    
}

// Apply affine transform calculated using srcTri and dstTri to src
void applyAffineTransform(Mat &warpImage, Mat &src, vector<Point2f> &srcTri, vector<Point2f> &dstTri)
{
    // Given a pair of triangles, find the affine transform.
    Mat warpMat = getAffineTransform( srcTri, dstTri );
    
    // Apply the Affine Transform just found to the src image
    warpAffine( src, warpImage, warpMat, warpImage.size(), INTER_LINEAR, BORDER_REFLECT_101);
}


// Warps and alpha blends triangular regions from img1 and img2 to img
void warpTriangle(Mat &img1, Mat &img2, vector<Point2f> t1, vector<Point2f> t2)
{
    // Find bounding rectangle for each triangle
    Rect r1 = boundingRect(t1);
    Rect r2 = boundingRect(t2);
    
    // Offset points by left top corner of the respective rectangles
    vector<Point2f> t1Rect, t2Rect;
    vector<Point> t2RectInt;
    for(int i = 0; i < 3; i++)
    {
        //tRect.push_back( Point2f( t[i].x - r.x, t[i].y -  r.y) );
        t2RectInt.push_back( Point((int)(t2[i].x - r2.x), (int)(t2[i].y - r2.y)) ); // for fillConvexPoly
        
        t1Rect.push_back( Point2f( t1[i].x - r1.x, t1[i].y -  r1.y) );
        t2Rect.push_back( Point2f( t2[i].x - r2.x, t2[i].y - r2.y) );
    }
    
    // Get mask by filling triangle
    Mat mask = Mat::zeros(r2.height, r2.width, CV_32FC3);
    fillConvexPoly(mask, t2RectInt, Scalar(1.0, 1.0, 1.0), 16, 0);
    
    // Apply warpImage to small rectangular patches
    Mat img1Rect, img2Rect;
    img1(r1).copyTo(img1Rect);
    
    Mat warpImage = Mat::zeros(r2.height, r2.width, img1Rect.type());
    
    applyAffineTransform(warpImage, img1Rect, t1Rect, t2Rect);
    
    // Copy triangular region of the rectangular patch to the output image
    multiply(warpImage,mask, warpImage);
    multiply(img2(r2), Scalar(1.0,1.0,1.0) - mask, img2(r2));
    img2(r2) = img2(r2) + warpImage;
    
}

// Constrains points to be inside boundary
void constrainPoint(Point2f &p, Size sz)
{
    p.x = min(max( (double)p.x, 0.0), (double)(sz.width - 1));
    p.y = min(max( (double)p.y, 0.0), (double)(sz.height - 1));
    
}



int main( int argc, char** argv)
{
    // Directory containing images.
    string dirName = "presidents";

    // Add slash to directory name if missing
    if (!dirName.empty() && dirName.back() != '/')
        dirName += '/';
    
    // Dimensions of output image
    int w = 600;
    int h = 600;
    
    // Read images in the directory
    vector<string> imageNames, ptsNames;
    readFileNames(dirName, imageNames, ptsNames);
    //cout << imageNames.size() << ptsNames.size();
    
    // Exit program if no images or pts are found or if the number of image files does not match with the number of point files
    if(imageNames.empty() || ptsNames.empty() || imageNames.size() != ptsNames.size()){
        exit(EXIT_FAILURE);
    }
        
    
    // Read points
    vector<vector<Point2f> > allPoints;
    readPoints(ptsNames, allPoints);
    
    int n = allPoints[0].size();
    //cout << n<< endl;
    
    // Read images
    vector<Mat> images;
    for(size_t i = 0; i < imageNames.size(); i++)
    {
        Mat img = imread(imageNames[i]);
        
        img.convertTo(img, CV_32FC3, 1/255.0);
        
        if(!img.data)
        {
            cout << "image " << imageNames[i] << " not read properly" << endl;
        }
        else
        {
            images.push_back(img);
        }
    }
    
    if(images.empty())
    {
        cout << "No images found " << endl;
        exit(EXIT_FAILURE);
    }
    
    int numImages = images.size();
    
    
    // Eye corners
    vector<Point2f> eyecornerDst, eyecornerSrc;
    eyecornerDst.push_back(Point2f( 0.3*w, h/3));
    eyecornerDst.push_back(Point2f( 0.7*w, h/3));
    
    eyecornerSrc.push_back(Point2f(0,0));
    eyecornerSrc.push_back(Point2f(0,0));
    
    // Space for normalized images and points.
    vector <Mat> imagesNorm;
    vector < vector <Point2f> > pointsNorm;
    
    // Space for average landmark points
    vector <Point2f> pointsAvg(allPoints[0].size());
    
    // 8 Boundary points for Delaunay Triangulation
    vector <Point2f> boundaryPts;
    boundaryPts.push_back(Point2f(0,0));
    boundaryPts.push_back(Point2f(w/2, 0));
    boundaryPts.push_back(Point2f(w-1,0));
    boundaryPts.push_back(Point2f(w-1, h/2));
    boundaryPts.push_back(Point2f(w-1, h-1));
    boundaryPts.push_back(Point2f(w/2, h-1));
    boundaryPts.push_back(Point2f(0, h-1));
    boundaryPts.push_back(Point2f(0, h/2));
    
    // Warp images and trasnform landmarks to output coordinate system,
    // and find average of transformed landmarks.
    
    for(size_t i = 0; i < images.size(); i++)
    {
        
        vector <Point2f> points = allPoints[i];
        
        // The corners of the eyes are the landmarks number 36 and 45
        eyecornerSrc[0] = allPoints[i][36];
        eyecornerSrc[1] = allPoints[i][45];
        
        // Calculate similarity transform
        Mat tform;
        similarityTransform(eyecornerSrc, eyecornerDst, tform);
        
        // Apply similarity transform to input image and landmarks
        Mat img = Mat::zeros(h, w, CV_32FC3);
        warpAffine(images[i], img, tform, img.size());
        transform( points, points, tform);
        
        // Calculate average landmark locations
        for ( size_t j = 0; j < points.size(); j++)
        {
            pointsAvg[j] += points[j] * ( 1.0 / numImages);
        }
        
        // Append boundary points. Will be used in Delaunay Triangulation
        for ( size_t j = 0; j < boundaryPts.size(); j++)
        {
            points.push_back(boundaryPts[j]);
        }
        
        pointsNorm.push_back(points);
        imagesNorm.push_back(img);
        
        
    }
    
    // Append boundary points to average points.
    for ( size_t j = 0; j < boundaryPts.size(); j++)
    {
        pointsAvg.push_back(boundaryPts[j]);
    }
    
    
    
    // Calculate Delaunay triangles
    Rect rect(0, 0, w, h);
    vector< vector<int> > dt;
    calculateDelaunayTriangles(rect, pointsAvg, dt);
    
    // Space for output image
    Mat output = Mat::zeros(h, w, CV_32FC3);
    Size size(w,h);
    
    // Warp input images to average image landmarks
    
    for(size_t i = 0; i < numImages; i++)
    {
        Mat img = Mat::zeros(h, w, CV_32FC3);
        // Transform triangles one by one
        for(size_t j = 0; j < dt.size(); j++)
        {
            // Input and output points corresponding to jth triangle
            vector<Point2f> tin, tout;
            for(int k = 0; k < 3; k++)
            {
                Point2f pIn = pointsNorm[i][dt[j][k]];
                constrainPoint(pIn, size);
                
                Point2f pOut = pointsAvg[dt[j][k]];
                constrainPoint(pOut,size);
                
                tin.push_back(pIn);
                tout.push_back(pOut);
            }
            
            warpTriangle(imagesNorm[i], img, tin, tout);
        }
        
        // Add image intensities for averaging
        output = output + img;
        
    }
    
    // Divide by numImages to get average
    output = output / (double)numImages;
    
    // Display result
    imshow("image", output);
    waitKey(0);
    
    return 0;
}