FindLines.cpp

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// -*- c-basic-offset: 4 -*-
/***************************************************************************
 *   Copyright (C) 2009 by Tim Nugent                                      *
 *   timnugent@gmail.com                                                   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 ***************************************************************************/

#include "vigra/edgedetection.hxx"
#include "FindLines.h"
#include "FindN8Lines.h"
#include <algorithms/nona/FitPanorama.h>
#include <algorithms/basic/CalculateOptimalROI.h>
#include <nona/RemappedPanoImage.h>
#include <algorithms/optimizer/PTOptimizer.h>
#include "algorithms/basic/CalculateCPStatistics.h"

namespace HuginLines
{

template <class SrcImageIterator, class SrcAccessor, class DestImage>
double resize_image(const vigra::triple<SrcImageIterator, SrcImageIterator, SrcAccessor> src, DestImage& dest, int resize_dimension)
{
    // Re-size to max dimension
    double sizefactor=1.0;
    const vigra::Size2D inputSize(src.second - src.first);
    if (inputSize.width() > resize_dimension || inputSize.height() > resize_dimension)
    {
        int nw;
        int nh;
        if (inputSize.width() >= inputSize.height())
        {
            sizefactor = (double)resize_dimension / inputSize.width();
            // calculate new image size
            nw = resize_dimension;
            nh = static_cast<int>(0.5 + (sizefactor*inputSize.height()));
        }
        else
        {
            sizefactor = (double)resize_dimension / inputSize.height();
            // calculate new image size
            nw = static_cast<int>(0.5 + (sizefactor*inputSize.width()));
            nh = resize_dimension;
        }

        // create an image of appropriate size
        dest.resize(nw, nh);
        // resize the image, using a bi-cubic spline algorithm
        resizeImageNoInterpolation(src, destImageRange(dest));
    }
    else
    {
        dest.resize(inputSize);
        copyImage(src, destImage(dest));
    };
    return 1.0/sizefactor;
}

vigra::BImage* detectEdges(const vigra::UInt8RGBImage& input, const double scale, const double threshold, const unsigned int resize_dimension, double& size_factor)
{
    // Resize image
    vigra::UInt8Image scaled;
    size_factor = resize_image(vigra::srcImageRange(input, vigra::RGBToGrayAccessor<vigra::RGBValue<vigra::UInt8> >()), scaled, resize_dimension);

    // Run Canny edge detector
    vigra::BImage* image = new vigra::BImage(scaled.width(), scaled.height(), 255);
    vigra::cannyEdgeImage(vigra::srcImageRange(scaled), vigra::destImage(*image), scale, threshold, 0);
    return image;
};

vigra::BImage* detectEdges(const vigra::BImage& input, const double scale, const double threshold, const unsigned int resize_dimension, double& size_factor)
{
    // Resize image
    vigra::UInt8Image scaled;
    size_factor=resize_image(vigra::srcImageRange(input), scaled, resize_dimension);

    // Run Canny edge detector
    vigra::BImage* image = new vigra::BImage(scaled.width(), scaled.height(), 255);
    vigra::cannyEdgeImage(vigra::srcImageRange(scaled), vigra::destImage(*image), scale, threshold, 0);
    return image;
};

double calculate_focal_length_pixels(double focal_length,double cropFactor,double width, double height)
{
    double pixels_per_mm = 0;
    if (cropFactor > 1)
    {
        pixels_per_mm= (cropFactor/24.0)* ((width>height)?height:width);
    }
    else
    {
        pixels_per_mm= (24.0/cropFactor)* ((width>height)?height:width);
    }
    return focal_length*pixels_per_mm;
}


Lines findLines(vigra::BImage& edge, double length_threshold, double focal_length,double crop_factor)
{
    unsigned int longest_dimension=(edge.width() > edge.height()) ? edge.width() : edge.height();
    double min_line_length_squared=(length_threshold*longest_dimension)*(length_threshold*longest_dimension);

    int lmin = int(sqrt(min_line_length_squared));
    double flpix=calculate_focal_length_pixels(focal_length,crop_factor,edge.width(),edge.height());

    vigra::BImage lineImage = edgeMap2linePts(edge);
    Lines lines;
    linePts2lineList( lineImage, lmin, flpix, lines );

    return lines;
};

void ScaleLines(Lines& lines,const double scale)
{
    for(unsigned int i=0; i<lines.size(); i++)
    {
        for(unsigned int j=0; j<lines[i].line.size(); j++)
        {
            lines[i].line[j]*=scale;
        };
    };
};

HuginBase::CPVector GetControlPoints(const SingleLine& line,const unsigned int imgNr, const unsigned int lineNr,const unsigned int numberOfCtrlPoints)
{
    HuginBase::CPVector cpv;
    double interval = (line.line.size()-1)/(1.0*numberOfCtrlPoints);
    for(unsigned int k = 0; k < numberOfCtrlPoints; k++)
    {
        int start = (int)(k * interval);
        int stop =  (int)((k+1) * interval);
        HuginBase::ControlPoint cp(imgNr,line.line[start].x, line.line[start].y,
                                   imgNr,line.line[stop].x, line.line[stop].y,lineNr);
        cpv.push_back(cp);
    };
    return cpv;
};

#define MAX_RESIZE_DIM 1600

//return footpoint of point p on line between point p1 and p2
vigra::Point2D GetFootpoint(const vigra::Point2D& p, const vigra::Point2D& p1, const vigra::Point2D& p2, double& u)
{
    hugin_utils::FDiff2D diff = p2 - p1;
    u = ((p.x - p1.x)*(p2.x - p1.x) + (p.y - p1.y)*(p2.y - p1.y)) / hugin_utils::sqr(hugin_utils::norm(diff));
    diff *= u;
    return vigra::Point2D(p1.x + diff.x, p1.y + diff.y);
};

vigra::Point2D GetFootpoint(const vigra::Point2D& p, const vigra::Point2D& p1, const vigra::Point2D& p2)
{
    double u;
    return GetFootpoint(p, p1, p2, u);
};

class VerticalLine
{
public:
    void SetStart(const vigra::Point2D point)
    {
        m_start = point;
    };
    void SetStart(const int x, const int y)
    {
        m_start = vigra::Point2D(x, y);
    };
    void SetEnd(const vigra::Point2D point)
    {
        m_end = point;
    };
    void SetEnd(const int x, const int y)
    {
        m_end = vigra::Point2D(x, y);
    };
    double GetLineLength() const
    {
        return (m_end - m_start).magnitude();
    };
    double GetEstimatedDistance(const VerticalLine& otherLine) const
    {
        auto getDist = [](const vigra::Point2D& p, const vigra::Point2D& p1, const vigra::Point2D& p2)->double
        {
            double t;
            const vigra::Point2D endPoint = GetFootpoint(p, p1, p2, t);
            if (-0.1 < t && t < 1.1)
            {
                return (endPoint - p).magnitude();
            }
            else
            {
                return DBL_MAX;
            };
        };
        return std::min({getDist(otherLine.GetStart(), m_start, m_end), getDist(otherLine.GetEnd(), m_start, m_end),
            getDist(m_start, otherLine.GetStart(), otherLine.GetEnd()), getDist(m_end, otherLine.GetStart(), otherLine.GetEnd())});
    }
    double GetAngle() const
    {
        return atan2(m_end.y - m_start.y, m_end.x - m_start.x);
    };
    const vigra::Point2D& GetStart() const
    {
        return m_start;
    };
    const vigra::Point2D& GetEnd() const
    {
        return m_end;
    };
private:
    vigra::Point2D m_start;
    vigra::Point2D m_end;
};

typedef std::vector<VerticalLine> VerticalLineVector;

//linear fit of given line, returns endpoints of fitted line
VerticalLine FitLine(SingleLine line)
{
    size_t n=line.line.size();
    VerticalLine vl;
    double s_x=0;
    double s_y=0;
    double s_xy=0;
    double s_x2=0;
    for(size_t i=0;i<n;i++)
    {
        s_x+=(double)line.line[i].x/n;
        s_y+=(double)line.line[i].y/n;
        s_xy+=(double)line.line[i].x*line.line[i].y/n;
        s_x2+=(double)line.line[i].x*line.line[i].x/n;
    };
    if(std::abs(s_x2-s_x*s_x)<0.00001)
    {
        //vertical line needs special treatment
        vl.SetStart(s_x, line.line[0].y);
        vl.SetEnd(s_x, line.line[n - 1].y);
    }
    else
    {
        //calculate slope and offset
        double slope=(s_xy-s_x*s_y)/(s_x2-s_x*s_x);
        double offset=s_y-slope*s_x;
        //convert to parametric form
        vigra::Point2D p1(0,offset);
        vigra::Point2D p2(100,100*slope+offset);
        //calculate footpoint of first and last point
        vl.SetStart(GetFootpoint(line.line[0], p1, p2));
        vl.SetEnd(GetFootpoint(line.line[n - 1], p1, p2));
    };
    return vl;
};

//filter detected lines
//return fitted lines which have only a small deviation from the vertical
VerticalLineVector FilterLines(Lines lines,double roll)
{
    VerticalLineVector vertLines;
    if(!lines.empty())
    {
        for(Lines::const_iterator it=lines.begin(); it!=lines.end(); ++it)
        {
            if((*it).status==valid_line && (*it).line.size()>2)
            {
                VerticalLine vl=FitLine(*it);
                const vigra::Diff2D diff = vl.GetEnd() - vl.GetStart();
                // check that line is long enough
                if(diff.magnitude()>20)
                {
                    // now check angle with respect to roll angle, accept only deviation of 5° (sin 5°=0.1)
                    if(std::abs((diff.x*cos(DEG_TO_RAD(roll))+diff.y*sin(DEG_TO_RAD(roll)))/diff.magnitude())<0.1)
                    {
                        // check distance and angle to other lines
                        bool distanceBig = true;
                        for (auto& otherLine : vertLines)
                        {
                            // distance should be at least 80 pixel = 5 % from image width
                            if (vl.GetEstimatedDistance(otherLine) < 80)
                            {
                                // now check if line are parallel = have the same angle (tan(3°)=0.05)
                                if (std::abs(vl.GetAngle() - otherLine.GetAngle()) < 0.05)
                                {
                                    distanceBig = false;
                                    // both lines are close to each other, keep only the longer one
                                    if (vl.GetLineLength() > otherLine.GetLineLength())
                                    {
                                        otherLine = vl;
                                    }
                                    continue;
                                };
                            };
                        }
                        if (distanceBig)
                        {
                            vertLines.push_back(vl);
                        };
                    };
                };
            };
        };
    };
    return vertLines;
};

//function to sort HuginBase::CPVector by error distance
bool SortByError(const HuginBase::ControlPoint& cp1, const HuginBase::ControlPoint& cp2)
{
    return cp1.error<cp2.error;
};

class InvertedMaskAccessor
{
public:
    typedef vigra::UInt8 value_type;
    template <class ITERATOR>
    value_type operator()(ITERATOR const & i) const
    {
        return 255 - (*i);
    }
    template <class ITERATOR, class DIFFERENCE>
    value_type operator()(ITERATOR const & i, DIFFERENCE d) const
    {
        return 255 - i[d];
    }
};

template <class ImageType>
HuginBase::CPVector _getVerticalLines(const HuginBase::Panorama& pano,const unsigned int imgNr,ImageType& image, vigra::BImage& mask, const unsigned int nrLines)
{
    HuginBase::CPVector verticalLines;
    HuginBase::CPVector detectedLines;
    const HuginBase::SrcPanoImage& srcImage=pano.getImage(imgNr);
    bool needsRemap=srcImage.getProjection()!=HuginBase::SrcPanoImage::RECTILINEAR;
    double roll=(needsRemap?0:srcImage.getRoll());
    double size_factor=1.0;
    HuginBase::SrcPanoImage remappedImage;
    HuginBase::PanoramaOptions opts;
    vigra::BImage* edge;
    if(!needsRemap)
    {
        //rectilinear image can be used as is
        //detect edges
        edge=detectEdges(image,2,4,MAX_RESIZE_DIM,size_factor);
    }
    else
    {
        //remap all other image to equirectangular
        //create temporary SrcPanoImage, set appropriate image variables
        remappedImage=pano.getSrcImage(imgNr);
        remappedImage.setYaw(0);
        remappedImage.setPitch(0);
        remappedImage.setX(0);
        remappedImage.setY(0);
        remappedImage.setZ(0);
        remappedImage.setExposureValue(0);
        remappedImage.setEMoRParams(std::vector<float>(5, 0.0));
        remappedImage.deleteAllMasks();
        remappedImage.setActive(true);
        //create PanoramaOptions for remapping of image
        opts.setProjection(HuginBase::PanoramaOptions::EQUIRECTANGULAR);
        opts.setWidth(MAX_RESIZE_DIM);
        opts.outputExposureValue=0;
        //calculate output canvas size
        HuginBase::Panorama tempPano;
        tempPano.addImage(remappedImage);
        tempPano.setOptions(opts);

        HuginBase::CalculateFitPanorama fitPano(tempPano);
        fitPano.run();
        opts.setHFOV(fitPano.getResultHorizontalFOV());
        opts.setHeight(hugin_utils::roundi(fitPano.getResultHeight()));
        if (opts.getVFOV() > 100)
        {
            // limit vertical fov to 100 deg to prevent finding lines
            // near nadir/zenit which are probably wrong with this simple
            // line finding algorithmus
            opts.setHeight(hugin_utils::roundi(opts.getHeight() * 90.0 / opts.getVFOV()));
        };
        tempPano.setOptions(opts);

        //finally remap image
        HuginBase::Nona::RemappedPanoImage<ImageType,vigra::BImage>* remapped=new HuginBase::Nona::RemappedPanoImage<ImageType,vigra::BImage>;
        AppBase::ProgressDisplay* progress=new AppBase::DummyProgressDisplay();
        remapped->setPanoImage(remappedImage,opts,opts.getROI());
        if (mask.size().area() > 0)
        {
            remapped->remapImage(vigra::srcImageRange(image), vigra::srcImage(mask), vigra_ext::INTERP_CUBIC, progress);
        }
        else
        {
            remapped->remapImage(vigra::srcImageRange(image), vigra_ext::INTERP_CUBIC, progress);
        };
        ImageType remappedBitmap=remapped->m_image;
        mask = remapped->m_mask;
        //detect edges
        edge=detectEdges(remappedBitmap,2,4,std::max(remappedBitmap.width(),remappedBitmap.height())+10,size_factor);
        delete remapped;
        delete progress;
    };
    // ignore all edges outside of masked areas
    if (mask.size().area() > 0)
    {
        vigra::initImageIf(vigra::destImageRange(*edge), vigra::srcImage(mask, InvertedMaskAccessor()), vigra::UInt8(255));
    };
    //detect lines
    //we need the focal length
    double focalLength=srcImage.getExifFocalLength();
    if(focalLength==0)
    {
        focalLength=HuginBase::SrcPanoImage::calcFocalLength(
            srcImage.getProjection(),srcImage.getHFOV(),srcImage.getCropFactor(),srcImage.getSize());
    };
    Lines foundLines=findLines(*edge,0.05,focalLength,srcImage.getCropFactor());
    delete edge;
    //filter results
    VerticalLineVector filteredLines=FilterLines(foundLines,roll);
    //create control points
    if(!filteredLines.empty())
    {
        //we need to transform the coordinates to image coordinates because the detection
        //worked on smaller images or in remapped image
        HuginBase::PTools::Transform transform;
        if(needsRemap)
        {
            transform.createTransform(remappedImage,opts);
        };
        for(size_t i=0; i<filteredLines.size(); i++)
        {
            HuginBase::ControlPoint cp;
            cp.image1Nr=0;
            cp.image2Nr=0;
            cp.mode=HuginBase::ControlPoint::X;
            if(!needsRemap)
            {
                cp.x1 = filteredLines[i].GetStart().x*size_factor;
                cp.y1 = filteredLines[i].GetStart().y*size_factor;
                cp.x2 = filteredLines[i].GetEnd().x*size_factor;
                cp.y2 = filteredLines[i].GetEnd().y*size_factor;
            }
            else
            {
                double xout;
                double yout;
                if(!transform.transformImgCoord(xout,yout,filteredLines[i].GetStart().x,filteredLines[i].GetStart().y))
                {
                    continue;
                };
                cp.x1=xout;
                cp.y1=yout;
                if(!transform.transformImgCoord(xout,yout,filteredLines[i].GetEnd().x,filteredLines[i].GetEnd().y))
                {
                    continue;
                };
                cp.x2=xout;
                cp.y2=yout;
            };
            if(cp.x1>=0 && cp.x1<srcImage.getWidth() && cp.y1>=0 && cp.y1<srcImage.getHeight() &&
               cp.x2>=0 && cp.x2<srcImage.getWidth() && cp.y2>=0 && cp.y2<srcImage.getHeight())
            {
                detectedLines.push_back(cp);
            };
        };
        //now a final check of the found vertical lines
        //we optimize the pano with a single image and disregard vertical lines with bigger errors
        //we need at least 2 lines
        if(detectedLines.size()>1)
        {
            HuginBase::Panorama tempPano;
            HuginBase::SrcPanoImage tempImage=pano.getSrcImage(imgNr);
            tempImage.setYaw(0);
            tempImage.setPitch(0);
            tempImage.setRoll(0);
            tempImage.setX(0);
            tempImage.setY(0);
            tempImage.setZ(0);
            tempPano.addImage(tempImage);
            for(size_t i=0; i<detectedLines.size(); i++)
            {
                tempPano.addCtrlPoint(detectedLines[i]);
            };
            HuginBase::PanoramaOptions opt2;
            opt2.setProjection(HuginBase::PanoramaOptions::EQUIRECTANGULAR);
            tempPano.setOptions(opt2);
            HuginBase::OptimizeVector optVec;
            std::set<std::string> imgopt;
            imgopt.insert("p");
            imgopt.insert("r");
            optVec.push_back(imgopt);
            tempPano.setOptimizeVector(optVec);
            // ARGH the panotools optimizer uses global variables is not reentrant
#pragma omp critical
            {
                HuginBase::PTools::optimize(tempPano);
            }
            //first filter stage
            //we disregard all lines with big error
            //calculate statistic and determine limit
            double minError,maxError,mean,var;
            HuginBase::CalculateCPStatisticsError::calcCtrlPntsErrorStats(tempPano,minError,maxError,mean,var);
            detectedLines=tempPano.getCtrlPoints();
            double limit=mean+sqrt(var);
            maxError=0;
            for(int i=detectedLines.size()-1; i>=0; i--)
            {
                if(detectedLines[i].error>limit)
                {
                    detectedLines.erase(detectedLines.begin()+i);
                }
                else
                {
                    //we need the max error of the remaining lines for the next step
                    maxError=std::max(detectedLines[i].error,maxError);
                };
            };
            if(!detectedLines.empty() && maxError>0) //security check, should never be false
            {
                //now keep only the best nrLines lines
                //we are using error and line length as figure of merrit
                for(size_t i=0;i<detectedLines.size();i++)
                {
                    double length=sqrt(hugin_utils::sqr(detectedLines[i].x2-detectedLines[i].x1)+hugin_utils::sqr(detectedLines[i].y2-detectedLines[i].y1));
                    //calculate number of merrit
                    detectedLines[i].error=detectedLines[i].error/maxError+(1.0-std::min(length,500.0)/500.0);
                };
                std::sort(detectedLines.begin(),detectedLines.end(),SortByError);
                //only save best nrLines control points
                for(size_t i=0;i<detectedLines.size() && i<nrLines; i++)
                {
                    HuginBase::ControlPoint cp=detectedLines[i];
                    cp.image1Nr=imgNr;
                    cp.image2Nr=imgNr;
                    cp.error=0;
                    verticalLines.push_back(cp);
                };
            };
        }
        else
        {
            //if only one line was detected we do a special check
            //the allow deviation between line and roll angle is checked more narrow than in the first check
            if(detectedLines.size()==1)
            {
                vigra::Diff2D diff((double)detectedLines[0].x2-detectedLines[0].x1,(double)detectedLines[0].y2-detectedLines[0].y1);
                if(std::abs((diff.x*cos(DEG_TO_RAD(roll))+diff.y*sin(DEG_TO_RAD(roll)))/diff.magnitude())<0.05)
                {
                    HuginBase::ControlPoint cp=detectedLines[0];
                    cp.image1Nr=imgNr;
                    cp.image2Nr=imgNr;
                    cp.error=0;
                    verticalLines.push_back(cp);
                };
            };
        };
    };
    return verticalLines;
};

HuginBase::CPVector GetVerticalLines(const HuginBase::Panorama& pano,const unsigned int imgNr,vigra::UInt8RGBImage& image, vigra::BImage& mask, const unsigned int nrLines)
{
    return _getVerticalLines(pano, imgNr, image, mask, nrLines);
};

HuginBase::CPVector GetVerticalLines(const HuginBase::Panorama& pano,const unsigned int imgNr,vigra::BImage& image, vigra::BImage& mask, const unsigned int nrLines)
{
    return _getVerticalLines(pano, imgNr, image, mask, nrLines);
};

}; //namespace