Merge pull request #1119 from 23pointsNorth:lsd

modules/imgproc/include/opencv2/imgproc.hpp

@@ -191,6 +191,12 @@ enum { HOUGH_STANDARD      = 0,
        HOUGH_GRADIENT      = 3
      };
 
+//! Variants of Line Segment Detector
+enum { LSD_REFINE_NONE = 0,
+       LSD_REFINE_STD  = 1,
+       LSD_REFINE_ADV  = 2
+     };
+
 //! Histogram comparison methods
 enum { HISTCMP_CORREL        = 0,
        HISTCMP_CHISQR        = 1,
@@ -829,7 +835,62 @@ protected:
     Point2f bottomRight;
 };
 
+class LineSegmentDetector : public Algorithm
+{
+public:
+/**
+ * Detect lines in the input image with the specified ROI.
+ *
+ * @param _image    A grayscale(CV_8UC1) input image.
+ *                  If only a roi needs to be selected, use
+ *                  lsd_ptr->detect(image(roi), ..., lines);
+ *                  lines += Scalar(roi.x, roi.y, roi.x, roi.y);
+ * @param _lines    Return: A vector of Vec4i elements specifying the beginning and ending point of a line.
+ *                          Where Vec4i is (x1, y1, x2, y2), point 1 is the start, point 2 - end.
+ *                          Returned lines are strictly oriented depending on the gradient.
+ * @param _roi      Return: ROI of the image, where lines are to be found. If specified, the returning
+ *                          lines coordinates are image wise.
+ * @param width     Return: Vector of widths of the regions, where the lines are found. E.g. Width of line.
+ * @param prec      Return: Vector of precisions with which the lines are found.
+ * @param nfa       Return: Vector containing number of false alarms in the line region, with precision of 10%.
+ *                          The bigger the value, logarithmically better the detection.
+ *                              * -1 corresponds to 10 mean false alarms
+ *                              * 0 corresponds to 1 mean false alarm
+ *                              * 1 corresponds to 0.1 mean false alarms
+ *                          This vector will be calculated _only_ when the objects type is REFINE_ADV
+ */
+    virtual void detect(const InputArray _image, OutputArray _lines,
+                        OutputArray width = noArray(), OutputArray prec = noArray(),
+                        OutputArray nfa = noArray()) = 0;
+
+/**
+ * Draw lines on the given canvas.
+ *
+ * @param image     The image, where lines will be drawn.
+ *                  Should have the size of the image, where the lines were found
+ * @param lines     The lines that need to be drawn
+ */
+    virtual void drawSegments(InputOutputArray image, const InputArray lines) = 0;
+
+/**
+ * Draw both vectors on the image canvas. Uses blue for lines 1 and red for lines 2.
+ *
+ * @param image     The image, where lines will be drawn.
+ *                  Should have the size of the image, where the lines were found
+ * @param lines1    The first lines that need to be drawn. Color - Blue.
+ * @param lines2    The second lines that need to be drawn. Color - Red.
+ * @return          The number of mismatching pixels between lines1 and lines2.
+ */
+    virtual int compareSegments(const Size& size, const InputArray lines1, const InputArray lines2, Mat* image = 0) = 0;
+
+    virtual ~LineSegmentDetector() {};
+};
 
+//! Returns a pointer to a LineSegmentDetector class.
+CV_EXPORTS Ptr<LineSegmentDetector> createLineSegmentDetectorPtr(
+    int _refine = LSD_REFINE_STD, double _scale = 0.8,
+    double _sigma_scale = 0.6, double _quant = 2.0, double _ang_th = 22.5,
+    double _log_eps = 0, double _density_th = 0.7, int _n_bins = 1024);
 
 //! returns type (one of KERNEL_*) of 1D or 2D kernel specified by its coefficients.
 CV_EXPORTS int getKernelType(InputArray kernel, Point anchor);

modules/imgproc/test/test_lsd.cpp

@@ -0,0 +1,265 @@
+#include "test_precomp.hpp"
+
+#include <vector>
+
+using namespace cv;
+using namespace std;
+
+const Size img_size(640, 480);
+const int LSD_TEST_SEED = 0x134679;
+const int EPOCHS = 20;
+
+class LSDBase : public testing::Test
+{
+public:
+    LSDBase() {};
+
+protected:
+    Mat test_image;
+    vector<Vec4i> lines;
+    RNG rng;
+    int passedtests;
+
+    void GenerateWhiteNoise(Mat& image);
+    void GenerateConstColor(Mat& image);
+    void GenerateLines(Mat& image, const unsigned int numLines);
+    void GenerateRotatedRect(Mat& image);
+    virtual void SetUp();
+};
+
+class Imgproc_LSD_ADV: public LSDBase
+{
+public:
+    Imgproc_LSD_ADV() {};
+protected:
+
+};
+
+class Imgproc_LSD_STD: public LSDBase
+{
+public:
+    Imgproc_LSD_STD() {};
+protected:
+
+};
+
+class Imgproc_LSD_NONE: public LSDBase
+{
+public:
+    Imgproc_LSD_NONE() {};
+protected:
+
+};
+
+void LSDBase::GenerateWhiteNoise(Mat& image)
+{
+    image = Mat(img_size, CV_8UC1);
+    rng.fill(image, RNG::UNIFORM, 0, 256);
+}
+
+void LSDBase::GenerateConstColor(Mat& image)
+{
+    image = Mat(img_size, CV_8UC1, Scalar::all(rng.uniform(0, 256)));
+}
+
+void LSDBase::GenerateLines(Mat& image, const unsigned int numLines)
+{
+    image = Mat(img_size, CV_8UC1, Scalar::all(rng.uniform(0, 128)));
+
+    for(unsigned int i = 0; i < numLines; ++i)
+    {
+        int y = rng.uniform(10, img_size.width - 10);
+        Point p1(y, 10);
+        Point p2(y, img_size.height - 10);
+        line(image, p1, p2, Scalar(255), 3);
+    }
+}
+
+void LSDBase::GenerateRotatedRect(Mat& image)
+{
+    image = Mat::zeros(img_size, CV_8UC1);
+
+    Point center(rng.uniform(img_size.width/4, img_size.width*3/4),
+                 rng.uniform(img_size.height/4, img_size.height*3/4));
+    Size rect_size(rng.uniform(img_size.width/8, img_size.width/6),
+                   rng.uniform(img_size.height/8, img_size.height/6));
+    float angle = rng.uniform(0.f, 360.f);
+
+    Point2f vertices[4];
+
+    RotatedRect rRect = RotatedRect(center, rect_size, angle);
+
+    rRect.points(vertices);
+    for (int i = 0; i < 4; i++)
+    {
+        line(image, vertices[i], vertices[(i + 1) % 4], Scalar(255), 3);
+    }
+}
+
+void LSDBase::SetUp()
+{
+    lines.clear();
+    test_image = Mat();
+    rng = RNG(LSD_TEST_SEED);
+    passedtests = 0;
+}
+
+
+TEST_F(Imgproc_LSD_ADV, whiteNoise)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateWhiteNoise(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_ADV);
+        detector->detect(test_image, lines);
+
+        if(uint(40) >= lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_ADV, constColor)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateConstColor(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_ADV);
+        detector->detect(test_image, lines);
+
+        if(uint(0) == lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_ADV, lines)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        const unsigned int numOfLines = 1;
+        GenerateLines(test_image, numOfLines);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_ADV);
+        detector->detect(test_image, lines);
+
+        if(numOfLines * 2 == lines.size()) ++passedtests;  // * 2 because of Gibbs effect
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_ADV, rotatedRect)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateRotatedRect(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_ADV);
+        detector->detect(test_image, lines);
+
+        if(uint(2) <= lines.size())  ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_STD, whiteNoise)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateWhiteNoise(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+        detector->detect(test_image, lines);
+
+        if(uint(50) >= lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_STD, constColor)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateConstColor(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+        detector->detect(test_image, lines);
+
+        if(uint(0) == lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_STD, lines)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        const unsigned int numOfLines = 1;
+        GenerateLines(test_image, numOfLines);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+        detector->detect(test_image, lines);
+
+        if(numOfLines * 2 == lines.size()) ++passedtests;  // * 2 because of Gibbs effect
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_STD, rotatedRect)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateRotatedRect(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+        detector->detect(test_image, lines);
+
+        if(uint(4) <= lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_NONE, whiteNoise)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateWhiteNoise(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+        detector->detect(test_image, lines);
+
+        if(uint(50) >= lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_NONE, constColor)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateConstColor(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_NONE);
+        detector->detect(test_image, lines);
+
+        if(uint(0) == lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_NONE, lines)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        const unsigned int numOfLines = 1;
+        GenerateLines(test_image, numOfLines);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_NONE);
+        detector->detect(test_image, lines);
+
+        if(numOfLines * 2 == lines.size()) ++passedtests;  // * 2 because of Gibbs effect
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}
+
+TEST_F(Imgproc_LSD_NONE, rotatedRect)
+{
+    for (int i = 0; i < EPOCHS; ++i)
+    {
+        GenerateRotatedRect(test_image);
+        Ptr<LineSegmentDetector> detector = createLineSegmentDetectorPtr(LSD_REFINE_NONE);
+        detector->detect(test_image, lines);
+
+        if(uint(8) <= lines.size()) ++passedtests;
+    }
+    ASSERT_EQ(EPOCHS, passedtests);
+}

samples/cpp/lsd_lines.cpp

@@ -0,0 +1,54 @@
+#include <iostream>
+#include <string>
+
+#include "opencv2/core/core.hpp"
+#include "opencv2/core/utility.hpp"
+#include "opencv2/imgproc/imgproc.hpp"
+#include "opencv2/highgui/highgui.hpp"
+
+using namespace std;
+using namespace cv;
+
+int main(int argc, char** argv)
+{
+    std::string in;
+    if (argc != 2)
+    {
+        std::cout << "Usage: lsd_lines [input image]. Now loading building.jpg" << std::endl;
+        in = "building.jpg";
+    }
+    else
+    {
+        in = argv[1];
+    }
+
+    Mat image = imread(in, IMREAD_GRAYSCALE);
+
+#if 0
+    Canny(image, image, 50, 200, 3); // Apply canny edge
+#endif
+
+    // Create and LSD detector with standard or no refinement.
+#if 1
+    Ptr<LineSegmentDetector> ls = createLineSegmentDetectorPtr(LSD_REFINE_STD);
+#else
+    Ptr<LineSegmentDetector> ls = createLineSegmentDetectorPtr(LSD_REFINE_NONE);
+#endif
+
+    double start = double(getTickCount());
+    vector<Vec4i> lines_std;
+
+    // Detect the lines
+    ls->detect(image, lines_std);
+
+    double duration_ms = (double(getTickCount()) - start) * 1000 / getTickFrequency();
+    std::cout << "It took " << duration_ms << " ms." << std::endl;
+
+    // Show found lines
+    Mat drawnLines(image);
+    ls->drawSegments(drawnLines, lines_std);
+    imshow("Standard refinement", drawnLines);
+
+    waitKey();
+    return 0;
+}