workspace.image_from_{page,segment}: consider AlternativeImage w/o co…

…mments c.f. qurator-spk/sbb_textline_detection#47
OCR-D · Oct 23, 2020 · c87dc01 · c87dc01
1 parent 2506e7e
commit c87dc01
Showing 1 changed file with 4 additions and 4 deletions.
diff --git a/ocrd/ocrd/workspace.py b/ocrd/ocrd/workspace.py
@@ -415,7 +415,7 @@ def image_from_page(self, page, page_id,
                 # search from the end, because by convention we always append,
                 # and among multiple satisfactory images we want the most recent:
                 for alternative_image in reversed(alternative_images):
-                    features = alternative_image.get_comments()
+                    features = alternative_image.get_comments() or ''
                     if (all(feature in features
                             for feature in feature_selector.split(',') if feature) and
                         not any(feature in features
@@ -425,7 +425,7 @@ def image_from_page(self, page, page_id,
                         alternative_image = None
             else:
                 alternative_image = alternative_images[-1]
-                features = alternative_image.get_comments()
+                features = alternative_image.get_comments() or ''
             if alternative_image:
                 log.debug("Using AlternativeImage %d (%s) for page '%s'",
                           alternative_images.index(alternative_image) + 1,
@@ -752,7 +752,7 @@ def image_from_segment(self, segment, parent_image, parent_coords,
                 # search from the end, because by convention we always append,
                 # and among multiple satisfactory images we want the most recent:
                 for alternative_image in reversed(alternative_images):
-                    features = alternative_image.get_comments()
+                    features = alternative_image.get_comments() or ''
                     if (all(feature in features
                             for feature in feature_selector.split(',') if feature) and
                         not any(feature in features
@@ -762,7 +762,7 @@ def image_from_segment(self, segment, parent_image, parent_coords,
                         alternative_image = None
             else:
                 alternative_image = alternative_images[-1]
-                features = alternative_image.get_comments()
+                features = alternative_image.get_comments() or ''
             if alternative_image:
                 log.debug("Using AlternativeImage %d (%s) for segment '%s'",
                           alternative_images.index(alternative_image) + 1,