From ae1d898295ecec19df7f4782f52949780e56d211 Mon Sep 17 00:00:00 2001
From: Jyotishman Das <107503099+rishi02102017@users.noreply.github.com>
Date: Thu, 12 Nov 2026 19:27:38 +0530
Subject: [PATCH] fix(python): convert palette and CMYK images before OCR
 (#773)

img_to_ndarray passed the raw PIL array straight to convert_img. For
palette (P) images that array holds palette indices, so a typical
two-colour PNG reaches the detector as an almost black image and no
text is found. CMYK images give four ink channels that were treated as
RGBA, so a CMYK JPEG also returned no result.

Convert P images to RGBA, which keeps any palette transparency for the
existing alpha handling, and CMYK images to RGB. Path, bytes and PIL
inputs all go through this function.
---
 python/rapidocr/utils/load_image.py |  7 ++++
 python/tests/test_input.py          | 54 +++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/python/rapidocr/utils/load_image.py b/python/rapidocr/utils/load_image.py
index e740459..e6c9466 100644
--- a/python/rapidocr/utils/load_image.py
+++ b/python/rapidocr/utils/load_image.py
@@ -124,6 +124,13 @@ class LoadImage:
         if img.mode == "1":
             img = img.convert("L")
             return np.array(img)
+
+        # The raw arrays of these modes hold palette indices or ink values,
+        # not the colours later steps expect.
+        if img.mode == "P":
+            img = img.convert("RGBA")
+        elif img.mode == "CMYK":
+            img = img.convert("RGB")
         return np.array(img)
 
     def convert_img(self, img: np.ndarray, origin_img_type: Any) -> np.ndarray:
diff --git a/python/tests/test_input.py b/python/tests/test_input.py
index e5948ba..2bfbbaa 100644
--- a/python/tests/test_input.py
+++ b/python/tests/test_input.py
@@ -8,6 +8,7 @@ from pathlib import Path
 import cv2
 import numpy as np
 import pytest
+from PIL import Image
 from pytest import mark
 
 root_dir = Path(__file__).resolve().parent.parent
@@ -314,6 +315,59 @@ def test_mode_one_img(engine):
     assert result.txts[0] == "TEST"
 
 
+@pytest.mark.parametrize("input_type", ["path", "bytes", "pil"])
+def test_palette_img_loads_palette_colors(tmp_path, input_type):
+    img = Image.new("P", (3, 1))
+    img.putpalette([255, 255, 255, 0, 0, 0, 200, 30, 10])
+    img.putdata([0, 1, 2])
+    path = tmp_path / "palette.png"
+    img.save(path)
+    inputs = {"path": path, "bytes": path.read_bytes(), "pil": img}
+
+    result = LoadImage()(inputs[input_type])
+
+    expected = np.array([[[255, 255, 255], [0, 0, 0], [10, 30, 200]]], dtype=np.uint8)
+    np.testing.assert_array_equal(result, expected)
+
+
+def test_palette_img_with_transparency_uses_alpha():
+    img = Image.new("P", (2, 1))
+    img.putpalette([0, 0, 0, 0, 0, 0])
+    img.putdata([0, 1])
+    img.info["transparency"] = 0
+
+    result = LoadImage()(img)
+
+    expected = np.array([[[255, 255, 255], [0, 0, 0]]], dtype=np.uint8)
+    np.testing.assert_array_equal(result, expected)
+
+
+@pytest.mark.parametrize("input_type", ["path", "bytes", "pil"])
+def test_cmyk_img_loads_as_bgr(tmp_path, input_type):
+    img = Image.new("CMYK", (3, 1))
+    img.putdata([(0, 0, 0, 0), (0, 0, 0, 255), (0, 255, 255, 0)])
+    path = tmp_path / "cmyk.tif"
+    img.save(path)
+    inputs = {"path": path, "bytes": path.read_bytes(), "pil": img}
+
+    result = LoadImage()(inputs[input_type])
+
+    expected = np.array([[[255, 255, 255], [0, 0, 0], [0, 0, 255]]], dtype=np.uint8)
+    np.testing.assert_array_equal(result, expected)
+
+
+def test_palette_img(engine, tmp_path):
+    gray = cv2.imread(str(test_dir / "en.jpg"), cv2.IMREAD_GRAYSCALE)
+    img = Image.new("P", (gray.shape[1], gray.shape[0]))
+    img.putpalette([255, 255, 255, 0, 0, 0])
+    img.putdata((gray < 128).astype(np.uint8).flatten().tolist())
+    path = tmp_path / "palette.png"
+    img.save(path)
+
+    result = engine(path)
+    assert len(result) > 0
+
+
 @mark.parametrize(
     "img_name,gt_len,gt_first_len",
     [