Draft implementation of boundary tracing

Treat excpetion at moore neighbor and fix boundary tracing API
Expose trace_boundary in the measure submodule
scikit-image · fbidu · fbidu · fbidu · Jul 18, 2020 · fbidu
diff --git a/skimage/measure/_boundary.py b/skimage/measure/_boundary.py
diff --git a/skimage/measure/_boundary.py b/skimage/measure/_boundary.py
diff --git a/skimage/measure/_boundary.py b/skimage/measure/_boundary.py
diff --git a/skimage/measure/_boundary.py b/skimage/measure/_boundary.py
diff --git a/skimage/measure/_boundary.py b/skimage/measure/_boundary.py
+
+        return backtrack_start, start
+
+    backtrack_start, start = find_boundary_start()
+        current = neighbors_ids[idx]
+        counter += 1
+
+        if np.all(current == start) and np.all(backtrack == backtrack_start):
+        # initilization
+        # starting point is the most upper left point
+        idx_start = 0
+        while True:  # asserting that the starting point is not isolated
-        while True:  # asserting that the starting point is not isolated
+        for start in zip(y, x):
+        y = neighbors_ids[:, 0]
+        x = neighbors_ids[:, 1]
-        y = neighbors_ids[:, 0]
-        x = neighbors_ids[:, 1]
+        y, x = neighbors_ids.T
+        boundary.append(current)
+        backtrack = neighbors_ids[idx - 1]
+        current = neighbors_ids[idx]
+        counter += 1
-        counter += 1
+        raise RuntimeError("The backtrack is not on the neighborhood")
+
+
+def trace_boundary(coords):
+import numpy as np
+
+"""
+Code copied from https://github.com/machine-shop/deepwings/blob/master/deepwings/method_features_extraction/image_processing.py#L185
+    """Coordinates of the region's boundary. The region must not have isolated
+    points.
-    """Coordinates of the region's boundary. The region must not have isolated
-    points.
+    """Coordinates of the region's boundary. The region must be simply connected.
+    boundary : 2D array
+        List of coordinates of pixels in the boundary
+        The first element is the most upper left pixel of the region.
+        The following coordinates are in clockwise order.
+        # initilization
+        # starting point is the most upper left point
+        idx_start = 0
+        while True:  # asserting that the starting point is not isolated
+            start = [y[idx_start], x[idx_start]]
+
+            # Focus Start is a 3x3 matrix centered around start
+            focus_start = binary[start[0] - 1 : start[0] + 2, start[1] - 1 : start[1] + 2]
+
+            # If the current pixel is not the only one set to one in its
+            # 3x3 region, we stop
+            if np.sum(focus_start) > 1:
+                break
+            idx_start += 1
+    current = start
+    backtrack = backtrack_start
+    boundary = []
+    counter = 0
-    counter = 0
+        y = neighbors_ids[:, 0]
+        x = neighbors_ids[:, 1]
+        neighbors = binary[tuple([y, x])]
+        current = neighbors_ids[idx]
+        counter += 1
+
+        if np.all(current == start) and np.all(backtrack == backtrack_start):
+        if np.all(current == start) and np.all(backtrack == backtrack_start):
+            break
+
+    return np.array(boundary)

		return backtrack_start, start

		backtrack_start, start = find_boundary_start()
	while True: # asserting that the starting point is not isolated
	for start in zip(y, x):
	y = neighbors_ids[:, 0]
	x = neighbors_ids[:, 1]
	y, x = neighbors_ids.T
		raise RuntimeError("The backtrack is not on the neighborhood")


		def trace_boundary(coords):
		"""Coordinates of the region's boundary. The region must not have isolated
		points.