Feature/370 subsegment error

CHANGELOG.md

@@ -23,6 +23,7 @@ Version 0.1.35
 - #374 Support pyzbar
 - #372 Support pydmtxlib
 - #371 Ugly error message when opening file with non-ascii characters in name
+- #370 OpenCV Error when subsegmenting
 - #369 Keyboard shortcuts box too tall on some displays
 - #368 Ugly error message when creating a new inselect document on Mac OS X
 - #367 Reveal file doesn't work on Windows

inselect/lib/segment.py

@@ -369,15 +369,19 @@ def segment_grabcut(image, window=None, seeds=[]):
  initial = np.zeros((h, w), np.uint8)
  initial[:] = cv2.GC_BGD
  initial[mag0 == 255] = cv2.GC_FGD
- for i, rect in enumerate(rects):
+ for rect in rects:
  cv2.drawContours(initial, [rect[4]], -1, int(cv2.GC_FGD), -1)
 
  initial[display[:, :, 0] > 0] = cv2.GC_PR_FGD
+ if 0 not in initial:
+ # Crude solution to https://github.com/NaturalHistoryMuseum/inselect/issues/370
+ # See also http://stackoverflow.com/a/7546787/1773758
+ # Only ever seen in one image
+ initial[0, :] = 0
  bgmodel = np.zeros((1, 65), np.float64)
  fgmodel = np.zeros((1, 65), np.float64)
  mask = initial
- rect = None
- cv2.grabCut(image, mask, rect, bgmodel, fgmodel, 1, cv2.GC_INIT_WITH_MASK)
+ cv2.grabCut(image, mask, None, bgmodel, fgmodel, 1, cv2.GC_INIT_WITH_MASK)
  mask2 = np.where((mask == 2) | (mask == 0), 0, 1).astype('uint8')
 
  contours, hierarchy = _find_contours(mask2.copy(),

inselect/tests/gui/test_subsegment.py

@@ -4,11 +4,14 @@
 from mock import patch
 from pathlib import Path
 
+import cv2
+
 from PyQt5.QtCore import QPointF, QRect
 from PyQt5.QtWidgets import QMessageBox
 
 from inselect.gui.roles import MetadataRole, RectRole
 from inselect.gui.sort_document_items import SortDocumentItems
+from inselect.lib.segment import segment_grabcut
 
 from .gui_test import GUITest
 
@@ -95,5 +98,10 @@ def test_subsegment_no_seeds(self, mock_warning):
  self.assertTrue(expected in mock_warning.call_args[0])
 
 
+ def test_subsegment_grabcut_fail(self):
+ "Subsegment image that has caused problems for cv2's grabcut function"
+ # https://github.com/NaturalHistoryMuseum/inselect/issues/370
+ segment_grabcut(cv2.imread(str(TESTDATA / 'grabcut_problem.jpg')))
+
 if __name__ == '__main__':
  unittest.main()