Stereo.cpp

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/*
Copyright (c) 2010-2016, Mathieu Labbe - IntRoLab - Universite de Sherbrooke
All rights reserved.

Redistribution and use in source and binary forms, with or without
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      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the Universite de Sherbrooke nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

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#include <rtabmap/core/Stereo.h>
#include <rtabmap/core/util2d.h>
#include <rtabmap/utilite/ULogger.h>
#include <opencv2/video/tracking.hpp>

namespace rtabmap {

Stereo * Stereo::create(const ParametersMap & parameters)
{
        bool opticalFlow = Parameters::defaultStereoOpticalFlow();
        Parameters::parse(parameters, Parameters::kStereoOpticalFlow(), opticalFlow);
        if(opticalFlow)
        {
                return new StereoOpticalFlow(parameters);
        }
        else
        {
                return new Stereo(parameters);
        }
}

Stereo::Stereo(const ParametersMap & parameters) :
                winWidth_(Parameters::defaultStereoWinWidth()),
                winHeight_(Parameters::defaultStereoWinHeight()),
                iterations_(Parameters::defaultStereoIterations()),
                maxLevel_(Parameters::defaultStereoMaxLevel()),
                minDisparity_(Parameters::defaultStereoMinDisparity()),
                maxDisparity_(Parameters::defaultStereoMaxDisparity()),
                winSSD_(Parameters::defaultStereoSSD())
{
        this->parseParameters(parameters);
}

void Stereo::parseParameters(const ParametersMap & parameters)
{
        Parameters::parse(parameters, Parameters::kStereoWinWidth(), winWidth_);
        Parameters::parse(parameters, Parameters::kStereoWinHeight(), winHeight_);
        Parameters::parse(parameters, Parameters::kStereoIterations(), iterations_);
        Parameters::parse(parameters, Parameters::kStereoMaxLevel(), maxLevel_);
        Parameters::parse(parameters, Parameters::kStereoMinDisparity(), minDisparity_);
        Parameters::parse(parameters, Parameters::kStereoMaxDisparity(), maxDisparity_);
        Parameters::parse(parameters, Parameters::kStereoSSD(), winSSD_);
}

std::vector<cv::Point2f> Stereo::computeCorrespondences(
                const cv::Mat & leftImage,
                const cv::Mat & rightImage,
                const std::vector<cv::Point2f> & leftCorners,
                std::vector<unsigned char> & status) const
{
        std::vector<cv::Point2f> rightCorners;
        UDEBUG("util2d::calcStereoCorrespondences() begin");
        rightCorners = util2d::calcStereoCorrespondences(
                                        leftImage,
                                        rightImage,
                                        leftCorners,
                                        status,
                                        cv::Size(winWidth_, winHeight_),
                                        maxLevel_,
                                        iterations_,
                                        minDisparity_,
                                        maxDisparity_,
                                        winSSD_);
        UDEBUG("util2d::calcStereoCorrespondences() end");
        return rightCorners;
}

StereoOpticalFlow::StereoOpticalFlow(const ParametersMap & parameters) :
                Stereo(parameters),
                epsilon_(Parameters::defaultStereoEps())
{
        this->parseParameters(parameters);
}

void StereoOpticalFlow::parseParameters(const ParametersMap & parameters)
{
        Stereo::parseParameters(parameters);
        Parameters::parse(parameters, Parameters::kStereoEps(), epsilon_);
}


std::vector<cv::Point2f> StereoOpticalFlow::computeCorrespondences(
                const cv::Mat & leftImage,
                const cv::Mat & rightImage,
                const std::vector<cv::Point2f> & leftCorners,
                std::vector<unsigned char> & status) const
{
        std::vector<cv::Point2f> rightCorners;
        UDEBUG("util2d::calcOpticalFlowPyrLKStereo() begin");
        std::vector<float> err;
        util2d::calcOpticalFlowPyrLKStereo(
                        leftImage,
                        rightImage,
                        leftCorners,
                        rightCorners,
                        status,
                        err,
                        this->winSize(),
                        this->maxLevel(),
                        cv::TermCriteria(cv::TermCriteria::COUNT+cv::TermCriteria::EPS, this->iterations(), epsilon_),
                        cv::OPTFLOW_LK_GET_MIN_EIGENVALS, 1e-4);
        UDEBUG("util2d::calcOpticalFlowPyrLKStereo() end");
        UASSERT(leftCorners.size() == rightCorners.size() && status.size() == leftCorners.size());
        int countFlowRejected = 0;
        int countDisparityRejected = 0;
        for(unsigned int i=0; i<status.size(); ++i)
        {
                if(status[i]!=0)
                {
                        float disparity = leftCorners[i].x - rightCorners[i].x;
                        if(disparity <= this->minDisparity() || disparity > this->maxDisparity())
                        {
                                status[i] = 0;
                                ++countDisparityRejected;
                        }
                }
                else
                {
                        ++countFlowRejected;
                }
        }
        UDEBUG("total=%d countFlowRejected=%d countDisparityRejected=%d", (int)status.size(), countFlowRejected, countDisparityRejected);

        if(countFlowRejected + countDisparityRejected > (int)status.size()/2)
        {
                UWARN("A large number (%d/%d) of stereo correspondences are rejected! "
                                "Optical flow may have failed because images are not calibrated, "
                                "the background is too far (no disparity between the images), "
                                "maximum disparity may be too small (%f) or that exposure between "
                                "left and right images is too different.",
                                countFlowRejected+countDisparityRejected,
                                (int)status.size(),
                                this->maxDisparity());
        }

        return rightCorners;
}

} /* namespace rtabmap */