diff --git a/paddleocr.py b/paddleocr.py
index c76f09a4b2e5d299f82f5f70eed40665bdd4090e..dc92cbf6b7c1789af629ba764ad1c0c12b936e4c 100644
--- a/paddleocr.py
+++ b/paddleocr.py
@@ -46,7 +46,7 @@ ppocr = importlib.import_module('ppocr', 'paddleocr')
 ppstructure = importlib.import_module('ppstructure', 'paddleocr')
 from ppocr.utils.logging import get_logger
 from tools.infer import predict_system
-from ppocr.utils.utility import check_and_read, get_image_file_list
+from ppocr.utils.utility import check_and_read, get_image_file_list, alpha_to_color, binarize_img
 from ppocr.utils.network import maybe_download, download_with_progressbar, is_link, confirm_model_dir_url
 from tools.infer.utility import draw_ocr, str2bool, check_gpu
 from ppstructure.utility import init_args, draw_structure_result
@@ -513,7 +513,7 @@ def get_model_config(type, version, model_type, lang):
 
 def img_decode(content: bytes):
     np_arr = np.frombuffer(content, dtype=np.uint8)
-    return cv2.imdecode(np_arr, cv2.IMREAD_COLOR)
+    return cv2.imdecode(np_arr, cv2.IMREAD_UNCHANGED)
 
 
 def check_img(img):
@@ -617,14 +617,17 @@ class PaddleOCR(predict_system.TextSystem):
         super().__init__(params)
         self.page_num = params.page_num
 
-    def ocr(self, img, det=True, rec=True, cls=True):
+    def ocr(self, img, det=True, rec=True, cls=True, bin=False, inv=False, alpha_color=(255, 255, 255)):
         """
-        ocr with paddleocr
+        OCR with PaddleOCR
         args:
-            img: img for ocr, support ndarray, img_path and list or ndarray
-            det: use text detection or not. If false, only rec will be exec. Default is True
-            rec: use text recognition or not. If false, only det will be exec. Default is True
-            cls: use angle classifier or not. Default is True. If true, the text with rotation of 180 degrees can be recognized. If no text is rotated by 180 degrees, use cls=False to get better performance. Text with rotation of 90 or 270 degrees can be recognized even if cls=False.
+            img: img for OCR, support ndarray, img_path and list or ndarray
+            det: use text detection or not. If False, only rec will be exec. Default is True
+            rec: use text recognition or not. If False, only det will be exec. Default is True
+            cls: use angle classifier or not. Default is True. If True, the text with rotation of 180 degrees can be recognized. If no text is rotated by 180 degrees, use cls=False to get better performance. Text with rotation of 90 or 270 degrees can be recognized even if cls=False.
+            bin: binarize image to black and white. Default is False.
+            inv: invert image colors. Default is False.
+            alpha_color: set RGB color Tuple for transparent parts replacement. Default is pure white.
         """
         assert isinstance(img, (np.ndarray, list, str, bytes))
         if isinstance(img, list) and det == True:
@@ -632,7 +635,7 @@ class PaddleOCR(predict_system.TextSystem):
             exit(0)
         if cls == True and self.use_angle_cls == False:
             logger.warning(
-                'Since the angle classifier is not initialized, the angle classifier will not be uesd during the forward process'
+                'Since the angle classifier is not initialized, it will not be used during the forward process'
             )
 
         img = check_img(img)
@@ -643,10 +646,23 @@ class PaddleOCR(predict_system.TextSystem):
             imgs = img[:self.page_num]
         else:
             imgs = [img]
+
+        def preprocess_image(_image):
+            _image = alpha_to_color(_image, alpha_color)
+            if inv:
+                _image = cv2.bitwise_not(_image)
+            if bin:
+                _image = binarize_img(_image)
+            return _image
+
         if det and rec:
             ocr_res = []
             for idx, img in enumerate(imgs):
+                img = preprocess_image(img)
                 dt_boxes, rec_res, _ = self.__call__(img, cls)
+                if not dt_boxes and not rec_res:
+                    ocr_res.append(None)
+                    continue
                 tmp_res = [[box.tolist(), res]
                            for box, res in zip(dt_boxes, rec_res)]
                 ocr_res.append(tmp_res)
@@ -654,7 +670,11 @@ class PaddleOCR(predict_system.TextSystem):
         elif det and not rec:
             ocr_res = []
             for idx, img in enumerate(imgs):
+                img = preprocess_image(img)
                 dt_boxes, elapse = self.text_detector(img)
+                if not dt_boxes:
+                    ocr_res.append(None)
+                    continue
                 tmp_res = [box.tolist() for box in dt_boxes]
                 ocr_res.append(tmp_res)
             return ocr_res
@@ -663,6 +683,7 @@ class PaddleOCR(predict_system.TextSystem):
             cls_res = []
             for idx, img in enumerate(imgs):
                 if not isinstance(img, list):
+                    img = preprocess_image(img)
                     img = [img]
                 if self.use_angle_cls and cls:
                     img, cls_res_tmp, elapse = self.text_classifier(img)
@@ -764,10 +785,15 @@ def main():
         img_name = os.path.basename(img_path).split('.')[0]
         logger.info('{}{}{}'.format('*' * 10, img_path, '*' * 10))
         if args.type == 'ocr':
-            result = engine.ocr(img_path,
-                                det=args.det,
-                                rec=args.rec,
-                                cls=args.use_angle_cls)
+            result = engine.ocr(
+                img_path,
+                det=args.det,
+                rec=args.rec,
+                cls=args.use_angle_cls,
+                bin=args.binarize,
+                inv=args.invert,
+                alpha_color=args.alphacolor
+            )
             if result is not None:
                 lines = []
                 for idx in range(len(result)):
diff --git a/ppocr/utils/utility.py b/ppocr/utils/utility.py
index 0f8660ceb4f0297f3e5c81d3b60f53cecab42070..f788e79cd53a24d4d7f979f359cacd0532a1ff05 100755
--- a/ppocr/utils/utility.py
+++ b/ppocr/utils/utility.py
@@ -75,6 +75,25 @@ def get_image_file_list(img_file):
     imgs_lists = sorted(imgs_lists)
     return imgs_lists
 
+def binarize_img(img):
+    if len(img.shape) == 3 and img.shape[2] == 3:
+        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) # conversion to grayscale image
+        # use cv2 threshold binarization
+        _, gray = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)
+        img = cv2.cvtColor(gray, cv2.COLOR_GRAY2BGR)
+    return img
+
+def alpha_to_color(img, alpha_color=(255, 255, 255)):
+    if len(img.shape) == 3 and img.shape[2] == 4:
+        B, G, R, A = cv2.split(img)
+        alpha = A / 255
+
+        R = (alpha_color[0] * (1 - alpha) + R * alpha).astype(np.uint8)
+        G = (alpha_color[1] * (1 - alpha) + G * alpha).astype(np.uint8)
+        B = (alpha_color[2] * (1 - alpha) + B * alpha).astype(np.uint8)
+
+        img = cv2.merge((B, G, R))
+    return img
 
 def check_and_read(img_path):
     if os.path.basename(img_path)[-3:] in ['gif', 'GIF']:
diff --git a/ppstructure/utility.py b/ppstructure/utility.py
index 28ef3d9f4723be0f202331f32ea7b060ad06148f..4ab4b88b9bc073287ec33b29eea9fca471da8470 100644
--- a/ppstructure/utility.py
+++ b/ppstructure/utility.py
@@ -16,7 +16,7 @@ import ast
 import PIL
 from PIL import Image, ImageDraw, ImageFont
 import numpy as np
-from tools.infer.utility import draw_ocr_box_txt, str2bool, init_args as infer_args
+from tools.infer.utility import draw_ocr_box_txt, str2bool, str2int_tuple, init_args as infer_args
 import math
 
 
@@ -100,6 +100,21 @@ def init_args():
         type=str2bool,
         default=False,
         help='Whether to use pdf2docx api')
+    parser.add_argument(
+        "--invert",
+        type=str2bool,
+        default=False,
+        help='Whether to invert image before processing')
+    parser.add_argument(
+        "--binarize",
+        type=str2bool,
+        default=False,
+        help='Whether to threshold binarize image before processing')
+    parser.add_argument(
+        "--alphacolor",
+        type=str2int_tuple,
+        default=(255, 255, 255),
+        help='Replacement color for the alpha channel, if the latter is present; R,G,B integers')
 
     return parser
 
diff --git a/tools/infer/predict_system.py b/tools/infer/predict_system.py
index 3ddcfda619242cd3f8c9e69da3c4077791b647cc..8af45b4cf52eb6355c9d4e08bc609e6ea91dfb43 100755
--- a/tools/infer/predict_system.py
+++ b/tools/infer/predict_system.py
@@ -65,15 +65,25 @@ class TextSystem(object):
         self.crop_image_res_index += bbox_num
 
     def __call__(self, img, cls=True):
-        time_dict = {'det': 0, 'rec': 0, 'csl': 0, 'all': 0}
+        time_dict = {'det': 0, 'rec': 0, 'cls': 0, 'all': 0}
+
+        if img is None:
+            logger.debug("no valid image provided")
+            return None, None, time_dict
+
         start = time.time()
         ori_im = img.copy()
         dt_boxes, elapse = self.text_detector(img)
         time_dict['det'] = elapse
-        logger.debug("dt_boxes num : {}, elapse : {}".format(
-            len(dt_boxes), elapse))
+
         if dt_boxes is None:
-            return None, None
+            logger.debug("no dt_boxes found, elapsed : {}".format(elapse))
+            end = time.time()
+            time_dict['all'] = end - start
+            return None, None, time_dict
+        else:
+            logger.debug("dt_boxes num : {}, elapsed : {}".format(
+                len(dt_boxes), elapse))
         img_crop_list = []
 
         dt_boxes = sorted_boxes(dt_boxes)
@@ -89,12 +99,12 @@ class TextSystem(object):
             img_crop_list, angle_list, elapse = self.text_classifier(
                 img_crop_list)
             time_dict['cls'] = elapse
-            logger.debug("cls num  : {}, elapse : {}".format(
+            logger.debug("cls num  : {}, elapsed : {}".format(
                 len(img_crop_list), elapse))
 
         rec_res, elapse = self.text_recognizer(img_crop_list)
         time_dict['rec'] = elapse
-        logger.debug("rec_res num  : {}, elapse : {}".format(
+        logger.debug("rec_res num  : {}, elapsed : {}".format(
             len(rec_res), elapse))
         if self.args.save_crop_res:
             self.draw_crop_rec_res(self.args.crop_res_save_dir, img_crop_list,
diff --git a/tools/infer/utility.py b/tools/infer/utility.py
index fcd8ba7f4de25055d1c98d82ff9fb7d83482fbe9..b064cbf18941a40bdca57e4d7e4ec68dc42e6fc6 100644
--- a/tools/infer/utility.py
+++ b/tools/infer/utility.py
@@ -29,8 +29,10 @@ from ppocr.utils.logging import get_logger
 
 
 def str2bool(v):
-    return v.lower() in ("true", "t", "1")
+    return v.lower() in ("true", "yes", "t", "y", "1")
 
+def str2int_tuple(v):
+    return tuple([int(i.strip()) for i in v.split(",")])
 
 def init_args():
     parser = argparse.ArgumentParser()