Fixed issue #158

python/rapidocr_openvino/utils.py

@@ -135,7 +135,12 @@ class LoadImage:
         not_a = cv2.cvtColor(not_a, cv2.COLOR_GRAY2BGR)
 
         new_img = cv2.bitwise_and(new_img, new_img, mask=a)
-        new_img = cv2.add(new_img, not_a)
+
+        mean_color = np.mean(new_img)
+        if mean_color <= 0.0:
+            new_img = cv2.add(new_img, not_a)
+        else:
+            new_img = cv2.bitwise_not(new_img)
         return new_img
 
     @staticmethod

python/rapidocr_paddle/utils.py

@@ -217,7 +217,12 @@ class LoadImage:
         not_a = cv2.cvtColor(not_a, cv2.COLOR_GRAY2BGR)
 
         new_img = cv2.bitwise_and(new_img, new_img, mask=a)
-        new_img = cv2.add(new_img, not_a)
+
+        mean_color = np.mean(new_img)
+        if mean_color <= 0.0:
+            new_img = cv2.add(new_img, not_a)
+        else:
+            new_img = cv2.bitwise_not(new_img)
         return new_img
 
     @staticmethod

python/tests/test_paddle.py

@@ -20,6 +20,25 @@ img_path = tests_dir / "ch_en_num.jpg"
 package_name = "rapidocr_paddle"
 
 
+@pytest.mark.parametrize(
+    "img_name,gt",
+    [
+        (
+            "black_font_color_transparent.png",
+            "我是中国人",
+        ),
+        (
+            "white_font_color_transparent.png",
+            "我是中国人",
+        ),
+    ],
+)
+def test_transparent_img(img_name: str, gt: str):
+    img_path = tests_dir / img_name
+    result, _ = engine(img_path)
+    assert result[0][1] == gt
+
+
 @pytest.mark.parametrize(
     "img_name,gt_len,gt_first_len",
     [

python/tests/test_vino.py

@@ -20,6 +20,25 @@ img_path = tests_dir / "ch_en_num.jpg"
 package_name = "rapidocr_openvino"
 
 
+@pytest.mark.parametrize(
+    "img_name,gt",
+    [
+        (
+            "black_font_color_transparent.png",
+            "我是中国人",
+        ),
+        (
+            "white_font_color_transparent.png",
+            "我是中国人",
+        ),
+    ],
+)
+def test_transparent_img(img_name: str, gt: str):
+    img_path = tests_dir / img_name
+    result, _ = engine(img_path)
+    assert result[0][1] == gt
+
+
 @pytest.mark.parametrize(
     "img_name,gt_len,gt_first_len",
     [