Line detection

unshred/features/lines.py

@@ -0,0 +1,51 @@
+import cv2
+import numpy
+from unshred.features import AbstractShredFeature
+
+
+class LinesFeatures(AbstractShredFeature):
+    TAG_HAS_LINES_FEATURE = "has lines"
+    TAG_PARALLEL_FEATURE = "parallel"
+    TAG_PERPENDECULAR_FEATURE = "perpendecular"
+
+    def get_info(self, shred, contour, name):
+
+        tags = []
+        params = {}
+
+        _, _, _, mask = cv2.split(shred)
+        #
+        # # expanding mask for future removal of a border
+        kernel = numpy.ones((5,5),numpy.uint8)
+        mask = cv2.morphologyEx(mask, cv2.MORPH_ERODE, kernel, iterations=2)
+        _, mask = cv2.threshold(mask, 240, 0, cv2.THRESH_TOZERO)
+        #
+        # # thresholding our shred
+        gray = cv2.cvtColor(shred, cv2.COLOR_BGR2GRAY)
+        gray_blur = cv2.GaussianBlur(gray, (9, 9), 0)
+        edges = cv2.adaptiveThreshold(gray_blur, 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
+                                      cv2.THRESH_BINARY_INV, 5, 1)
+        # attemting to remove borders
+        edges = edges & mask
+        # reducing noise
+        edges = cv2.morphologyEx(edges, cv2.MORPH_ERODE, (6, 6), iterations=2)
+        # removing small white noise
+        edges = cv2.medianBlur(edges, 3)
+        # const: uncomment for debug
+        cv2.imwrite('../debug/edges_%s.png' % name, edges)
+        cv2.imwrite('../debug/mask_%s.png' % name, mask)
+
+        _, _, r_w, r_h = cv2.boundingRect(contour)
+
+        # Line len should be at least 80% of shred's width, gap - 20%
+        lines = cv2.HoughLinesP(edges, 1, numpy.pi / 180, 30, minLineLength=r_w*0.7, maxLineGap=r_w*0.2)
+        if not lines is None:
+            # const: uncomment for debug
+            for x1, y1, x2, y2 in lines[0]:
+                cv2.line(shred, (x1, y1), (x2, y2), (255, 255, 0, 0), 2)
+            cv2.imwrite('../debug/houghlines_%s.png' % name, shred)
+
+            params['Lines Count'] = len(lines[0])
+            tags.append(self.TAG_HAS_LINES_FEATURE)
+
+        return params, tags