map_accessibility_analysis.cpp

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/*
 * Copyright 2017 Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0

 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 

#include <cob_map_accessibility_analysis/map_accessibility_analysis.h>
#include <ros/ros.h>

//#define __DEBUG_DISPLAYS__

MapAccessibilityAnalysis::MapAccessibilityAnalysis()
{

}

MapAccessibilityAnalysis::~MapAccessibilityAnalysis()
{

}

void MapAccessibilityAnalysis::inflateMap(const cv::Mat& original_map, cv::Mat& inflated_map, const int robot_radius_pixel)
{
        cv::erode(original_map, inflated_map, cv::Mat(), cv::Point(-1, -1), robot_radius_pixel);
}

void MapAccessibilityAnalysis::checkPoses(const std::vector<cv::Point>& points_to_check, std::vector<bool>& accessibility_flags,
                const cv::Mat& inflated_map, const bool approach_path_accessibility_check, const cv::Point& robot_location)
{
#ifdef __DEBUG_DISPLAYS__
        cv::Mat display_map = inflated_map.clone();
#endif

        // find the individual connected areas
        std::vector<std::vector<cv::Point> > area_contours; // first index=contour index;  second index=point index within contour
        if (approach_path_accessibility_check == true)
        {
                cv::Mat inflated_map_copy = inflated_map.clone();
                cv::findContours(inflated_map_copy, area_contours, cv::RETR_LIST, cv::CHAIN_APPROX_SIMPLE);
        }

        for (unsigned int i = 0; i < points_to_check.size(); ++i)
        {
                const int u = points_to_check[i].x;
                const int v = points_to_check[i].y;
                ROS_INFO_STREAM("Checking accessibility of point (" << u << ", " << v << ")px.");
                if (inflated_map.at<uchar>(v, u) != 0)
                {
                        // check if robot can approach this position
                        if (approach_path_accessibility_check == false ||
                                        isApproachPositionAccessible(robot_location, cv::Point(u, v), area_contours) == true)
                                accessibility_flags[i] = true;
                }

#ifdef __DEBUG_DISPLAYS__
                if (accessibility_flags[i] == false)
                        cv::circle(display_map, cv::Point(u, v), 2, cv::Scalar(32), 10);
                else
                        cv::circle(display_map, cv::Point(u, v), 2, cv::Scalar(192), 10);
#endif
        }

#ifdef __DEBUG_DISPLAYS__
        cv::imshow("points", display_map);
        cv::waitKey();
#endif
}


void MapAccessibilityAnalysis::checkPerimeter(std::vector<Pose>& accessible_poses_on_perimeter,
                const Pose& center, const double radius, const double rotational_sampling_step,
                const cv::Mat& inflated_map, const bool approach_path_accessibility_check, const cv::Point& robot_location)
{
#ifdef __DEBUG_DISPLAYS__
        cv::Mat display_map = inflated_map.clone();
#endif

        // find the individual connected areas
        std::vector<std::vector<cv::Point> > area_contours; // first index=contour index;  second index=point index within contour
        if (approach_path_accessibility_check == true)
        {
                cv::Mat inflated_map_copy = inflated_map.clone();
                cv::findContours(inflated_map_copy, area_contours, cv::RETR_LIST, cv::CHAIN_APPROX_SIMPLE);
        }

        for (double angle = center.orientation; angle < center.orientation + 2 * CV_PI; angle += rotational_sampling_step)
        {
                const double x = center.x + radius * cos(angle);
                const double y = center.y + radius * sin(angle);
                const int u = cvRound(x);
                const int v = cvRound(y);
                bool found_pose = false;
                if (inflated_map.at<uchar>(v, u) != 0)
                {
                        // check if robot can approach this position
                        if (approach_path_accessibility_check == false
                                        || isApproachPositionAccessible(robot_location, cv::Point(u, v), area_contours) == true)
                        {
                                // add accessible point to results
                                Pose pose;
                                pose.x = x;
                                pose.y = y;
                                pose.orientation = angle + CV_PI;
                                while (pose.orientation > 2 * CV_PI)
                                        pose.orientation -= 2 * CV_PI;
                                while (pose.orientation < 0.)
                                        pose.orientation += 2 * CV_PI;
                                accessible_poses_on_perimeter.push_back(pose);
                                found_pose = true;
                        }
                }
#ifdef __DEBUG_DISPLAYS__
                if (found_pose == true)
                        cv::circle(display_map, cv::Point(u, v), 2, cv::Scalar(192), 5);
                else
                        cv::circle(display_map, cv::Point(u, v), 2, cv::Scalar(32), 5);
#endif
        }

#ifdef __DEBUG_DISPLAYS__
        cv::imshow("perimeter", display_map);
        cv::waitKey();
#endif
}


bool MapAccessibilityAnalysis::isApproachPositionAccessible(const cv::Point& robotLocation,
                const cv::Point& potentialApproachPose, std::vector<std::vector<cv::Point> > contours)
{
        // check whether potentialApproachPose and robotLocation are in the same area (=same contour)
        int contourIndexRobot = -1;
        int contourIndexPotentialApproachPose = -1;
        for (unsigned int i = 0; i < contours.size(); i++)
        {
                if (0 <= cv::pointPolygonTest(contours[i], potentialApproachPose, false))
                        contourIndexPotentialApproachPose = i;
                if (0 <= cv::pointPolygonTest(contours[i], robotLocation, false))
                        contourIndexRobot = i;
        }
        ROS_DEBUG_STREAM("contourIndexPotentialApproachPose=" << contourIndexPotentialApproachPose
                                        << "  contourIndexRobot=" << contourIndexRobot);
        if (contourIndexRobot != contourIndexPotentialApproachPose ||
                        (contourIndexRobot == -1 && contourIndexPotentialApproachPose == -1))
                return false;

        return true;
}


void MapAccessibilityAnalysis::computeClosestPointOnPolygon(const cv::Mat& map_with_polygon,
                const Pose& pose_p, Pose& closest_point_on_polygon)
{
        double closest_pixel_distance_squared = 1e10;
        for (int v = 0; v < map_with_polygon.rows; v++)
        {
                for (int u = 0; u < map_with_polygon.cols; u++)
                {
                        double dist_squared = 0.;
                        if (map_with_polygon.at<uchar>(v, u) == 128 &&
                                (dist_squared = (pose_p.x - u) * (pose_p.x - u) + (pose_p.y - v) * (pose_p.y - v)) < closest_pixel_distance_squared)
                        {
                                closest_pixel_distance_squared = dist_squared;
                                closest_point_on_polygon.x = u;
                                closest_point_on_polygon.y = v;
                        }
                }
        }
}