Merge pull request opencv#1119 from 23pointsNorth:lsd

Author: Roman Donchenko

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 @@ class CV_EXPORTS_W Subdiv2D
     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);