From 0ea548ec8aff80d096d86b1264f6ad7e540203df Mon Sep 17 00:00:00 2001
From: TimZnr <zeunerti74726@th-nuernberg.de>
Date: Wed, 7 Dec 2022 22:22:15 +0100
Subject: [PATCH] Prototype reflection filter

---
 AutonomousMode/Processing/processing.cpp | 62 ++++++++++++++++++++++++
 AutonomousMode/Processing/processing.h   |  2 +-
 AutonomousMode/lfr.cpp                   |  1 +
 3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/AutonomousMode/Processing/processing.cpp b/AutonomousMode/Processing/processing.cpp
index 0dd3462..73398dc 100644
--- a/AutonomousMode/Processing/processing.cpp
+++ b/AutonomousMode/Processing/processing.cpp
@@ -17,6 +17,68 @@ static double angle( Point pt1, Point pt2, Point pt0 )
     return (dx1*dx2 + dy1*dy2)/sqrt((dx1*dx1 + dy1*dy1)*(dx2*dx2 + dy2*dy2) + 1e-10);
 }
 
+void Processing::filterReflections(FrameData& frameData)
+{
+    //Try to filter reflections from the frame data.
+
+    std::vector<int> indicesToDelete;
+    for(int i = 0; i < frameData.contours.size(); i++)
+    {
+
+        // First approach: correct contours nearly fill their bounding box.
+        // So delete all contours with an area smaller than 75% of their bounding box
+        double contourArea = cv::contourArea(frameData.contours[i], false);
+        double boundingBoxArea = double(frameData.boundingBoxes[i].width*frameData.boundingBoxes[i].height);
+        double minRatio = 0.75;
+        if(boundingBoxArea/contourArea < minRatio)
+        {
+            indicesToDelete.push_back(i);
+            continue;
+        }
+
+        // Second approach: The contour should be nearly convex
+        // So delete all contours with an area smaller than 95% of their convex hull.
+        std::vector<Point> hull;
+        cv::convexHull(frameData.contours[i], hull);
+        double hullArea = cv::contourArea(hull, false);
+        double minRatioHull = 0.95;
+        if(contourArea/boundingBoxArea < minRatio)
+        {
+            indicesToDelete.push_back(i);
+            continue;
+        }
+
+        // Third approach:
+        // Calculate the HoughLinesP of the contour.
+        // There should be 4 lines
+        // This one is not really working yet.
+        Rect boundingRect = cv::boundingRect(frameData.contours[i]);
+        Point offset(-boundingRect.x, -boundingRect.y);
+        Mat contourMat = Mat::zeros(frameData.boundingBoxes[i].height, frameData.boundingBoxes[i].width, CV_8UC1);
+        drawContours(contourMat, frameData.contours, i, Scalar(255,255,255), 1, 8, noArray(), 0, offset);
+        std::vector<Vec4i> linesP;
+        HoughLinesP(contourMat, linesP, 1, CV_PI/180, 20, 10, 5 );
+        //imshow("Some window", contourMat);
+        if(linesP.size() < 4)
+        {
+            //indicesToDelete.push_back(i);
+            //continue;
+            //std::cout << linesP.size();
+        }
+    }
+
+    //reverse the vector with the indices so the order isn't messed up when deleting:
+    std::reverse(indicesToDelete.begin(), indicesToDelete.end());
+    for(int index : indicesToDelete)
+    {
+        frameData.boundingBoxes.erase(frameData.boundingBoxes.begin() + index);
+        frameData.contours.erase(frameData.contours.begin() + index);
+        frameData.leftEdges.erase(frameData.leftEdges.begin() + index);
+        frameData.middlePoints.erase(frameData.middlePoints.begin() + index);
+    }
+    return;
+}
+
 void Processing::processImage(Mat& inputPicture, int thresholdBinary, int gaussKernelSize, int thresholdCanny1, int thresholdCanny2, int apertureSizeCanny)
 {
     //Idea here is: Processing module consists of two methods:
diff --git a/AutonomousMode/Processing/processing.h b/AutonomousMode/Processing/processing.h
index 27732f9..82ed15b 100644
--- a/AutonomousMode/Processing/processing.h
+++ b/AutonomousMode/Processing/processing.h
@@ -20,6 +20,6 @@ public:
     ~Processing();
 
     void processImage(Mat& inputPicture, int thresholdBinary, int gaussKernelSize, int thresholdCanny1, int thresholdCanny2, int apertureSizeCanny);
-
+    void filterReflections(FrameData& frameData);
     FrameData calculateLineSegments(const Mat& inputPicture, const cv::Rect& roi);
 };
\ No newline at end of file
diff --git a/AutonomousMode/lfr.cpp b/AutonomousMode/lfr.cpp
index 50da73f..0fb05fc 100644
--- a/AutonomousMode/lfr.cpp
+++ b/AutonomousMode/lfr.cpp
@@ -37,6 +37,7 @@ void LFR::loop()
 
         processing.processImage(processedImage, this->thresholdBinary, this->gaussKernelSize, this->thresholdCanny1, thresholdCanny2, this->apertureSizeCanny);
         FrameData data = processing.calculateLineSegments(processedImage, roi);
+        processing.filterReflections(data);
         this->provideOutput(originalImage, data, roi);
     }
     if(this->videoFlag) {destroyWindow("Display window");}