ENH: add bbox_area

skimage/measure/_regionprops.py

@@ -21,6 +21,7 @@ STREL_26_3D = np.ones((3, 3, 3), dtype=np.uint8)
 PROPS = {
     'Area': 'area',
     'BoundingBox': 'bbox',
+    'BoundingBoxArea': 'bbox_area',
     'CentralMoments': 'moments_central',
     'Centroid': 'centroid',
     'ConvexArea': 'convex_area',
@@ -121,6 +122,9 @@ class _RegionProperties(object):
         return tuple([self._slice[i].start for i in range(self._ndim)] +
                      [self._slice[i].stop for i in range(self._ndim)])
 
+    def bbox_area(self):
+        return self._label_image.size
+
     def centroid(self):
         return tuple(self.coords.mean(axis=0))
 
@@ -374,6 +378,8 @@ def regionprops(label_image, intensity_image=None, cache=True):
         Bounding box ``(min_row, min_col, max_row, max_col)``.
         Pixels belonging to the bounding box are in the half-open interval
         ``[min_row; max_row)`` and ``[min_col; max_col)``.
+    **bbox_area** : int
+        Number of pixels of bounding box.
     **centroid** : array
         Centroid coordinate tuple ``(row, col)``.
     **convex_area** : int

skimage/measure/tests/test_regionprops.py

@@ -77,6 +77,9 @@ def test_bbox():
     bbox = regionprops(SAMPLE_3D)[0].bbox
     assert_array_almost_equal(bbox, (1, 1, 1, 4, 3, 3))
 
+def test_bbox_area():
+    bbox_area = regionprops(SAMPLE)[0].bbox_area
+    assert_array_almost_equal(bbox_area, SAMPLE.shape[0] * SAMPLE.shape[1])
 
 def test_moments_central():
     mu = regionprops(SAMPLE)[0].moments_central