[prototype] Extend detection result customization

demo/app.py

@@ -80,6 +80,9 @@ def main(det_archs, reco_archs):
     # Binarization threshold
     bin_thresh = st.sidebar.slider("Binarization threshold", min_value=0.1, max_value=0.9, value=0.3, step=0.1)
     st.sidebar.write("\n")
+    # Box threshold
+    box_thresh = st.sidebar.slider("Box threshold", min_value=0.1, max_value=0.9, value=0.1, step=0.1)
+    st.sidebar.write("\n")
 
     if st.sidebar.button("Analyze page"):
         if uploaded_file is None:
@@ -88,7 +91,7 @@ def main(det_archs, reco_archs):
         else:
             with st.spinner("Loading model..."):
                 predictor = load_predictor(
-                    det_arch, reco_arch, assume_straight_pages, straighten_pages, bin_thresh, forward_device
+                    det_arch, reco_arch, assume_straight_pages, straighten_pages, bin_thresh, box_thresh, forward_device
                 )
 
             with st.spinner("Analyzing..."):

demo/backend/pytorch.py

@@ -35,6 +35,7 @@ def load_predictor(
     assume_straight_pages: bool,
     straighten_pages: bool,
     bin_thresh: float,
+    box_thresh: float,
     device: torch.device,
 ) -> OCRPredictor:
     """Load a predictor from doctr.models
@@ -46,6 +47,7 @@ def load_predictor(
         assume_straight_pages: whether to assume straight pages or not
         straighten_pages: whether to straighten rotated pages or not
         bin_thresh: binarization threshold for the segmentation map
+        box_thresh: minimal objectness score to consider a box
         device: torch.device, the device to load the predictor on
 
     Returns:
@@ -62,6 +64,7 @@ def load_predictor(
         detect_orientation=not assume_straight_pages,
     ).to(device)
     predictor.det_predictor.model.postprocessor.bin_thresh = bin_thresh
+    predictor.det_predictor.model.postprocessor.box_thresh = box_thresh
     return predictor
 
 

demo/backend/tensorflow.py

@@ -34,6 +34,7 @@ def load_predictor(
     assume_straight_pages: bool,
     straighten_pages: bool,
     bin_thresh: float,
+    box_thresh: float,
     device: tf.device,
 ) -> OCRPredictor:
     """Load a predictor from doctr.models
@@ -45,6 +46,7 @@ def load_predictor(
         assume_straight_pages: whether to assume straight pages or not
         straighten_pages: whether to straighten rotated pages or not
         bin_thresh: binarization threshold for the segmentation map
+        box_thresh: threshold for the detection boxes
         device: tf.device, the device to load the predictor on
 
     Returns:
@@ -62,6 +64,7 @@ def load_predictor(
             detect_orientation=not assume_straight_pages,
         )
         predictor.det_predictor.model.postprocessor.bin_thresh = bin_thresh
+        predictor.det_predictor.model.postprocessor.box_thresh = box_thresh
     return predictor
 
 

docs/source/using_doctr/using_models.rst

@@ -398,3 +398,48 @@ For reference, here is a sample XML byte string output:
       </div>
     </body>
   </html>
+
+
+Advanced options
+^^^^^^^^^^^^^^^^
+We provide a few advanced options to customize the behavior of the predictor to your needs:
+
+* Modify the binarization threshold for the detection model.
+* Modify the box threshold for the detection model.
+
+This is useful to detect (possible less) text regions more accurately with a higher threshold, or to detect more text regions with a lower threshold.
+
+
+.. code:: python3
+
+    import numpy as np
+    from doctr.models import ocr_predictor
+    predictor = ocr_predictor('db_resnet50', 'crnn_vgg16_bn', pretrained=True)
+
+    # Modify the binarization threshold and the box threshold
+    predictor.det_predictor.model.postprocessor.bin_thresh = 0.5
+    predictor.det_predictor.model.postprocessor.box_thresh = 0.2
+
+    input_page = (255 * np.random.rand(800, 600, 3)).astype(np.uint8)
+    out = predictor([input_page])
+
+
+* Add a hook to the `ocr_predictor` to manipulate the location predictions before the crops are passed to the recognition model.
+
+.. code:: python3
+
+    from doctr.model import ocr_predictor
+
+    class CustomHook:
+        def __call__(self, loc_preds):
+            # Manipulate the location predictions here
+            # The outpout structure needs to be the same as the input location predictions
+            return loc_preds
+
+    my_hook = CustomHook()
+
+    predictor = ocr_predictor(pretrained=True)
+    # Add a hook in the middle of the pipeline
+    predictor.add_hook(my_hook)
+    # You can also add multiple hooks which will be executed sequentially
+    [predictor.add_hook(hook) for hook in [my_hook, my_hook, my_hook]]

doctr/models/detection/differentiable_binarization/pytorch.py

@@ -100,6 +100,8 @@ class DBNet(_DBNet, nn.Module):
         feature extractor: the backbone serving as feature extractor
         head_chans: the number of channels in the head
         deform_conv: whether to use deformable convolution
+        bin_thresh: threshold for binarization
+        box_thresh: minimal objectness score to consider a box
         assume_straight_pages: if True, fit straight bounding boxes only
         exportable: onnx exportable returns only logits
         cfg: the configuration dict of the model
@@ -112,6 +114,7 @@ def __init__(
         head_chans: int = 256,
         deform_conv: bool = False,
         bin_thresh: float = 0.3,
+        box_thresh: float = 0.1,
         assume_straight_pages: bool = True,
         exportable: bool = False,
         cfg: Optional[Dict[str, Any]] = None,
@@ -160,7 +163,9 @@ def __init__(
             nn.ConvTranspose2d(head_chans // 4, num_classes, 2, stride=2),
         )
 
-        self.postprocessor = DBPostProcessor(assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh)
+        self.postprocessor = DBPostProcessor(
+            assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh, box_thresh=box_thresh
+        )
 
         for n, m in self.named_modules():
             # Don't override the initialization of the backbone

doctr/models/detection/differentiable_binarization/tensorflow.py

@@ -112,6 +112,8 @@ class DBNet(_DBNet, keras.Model, NestedObject):
     ----
         feature extractor: the backbone serving as feature extractor
         fpn_channels: number of channels each extracted feature maps is mapped to
+        bin_thresh: threshold for binarization
+        box_thresh: minimal objectness score to consider a box
         assume_straight_pages: if True, fit straight bounding boxes only
         exportable: onnx exportable returns only logits
         cfg: the configuration dict of the model
@@ -125,6 +127,7 @@ def __init__(
         feature_extractor: IntermediateLayerGetter,
         fpn_channels: int = 128,  # to be set to 256 to represent the author's initial idea
         bin_thresh: float = 0.3,
+        box_thresh: float = 0.1,
         assume_straight_pages: bool = True,
         exportable: bool = False,
         cfg: Optional[Dict[str, Any]] = None,
@@ -159,7 +162,9 @@ def __init__(
             layers.Conv2DTranspose(num_classes, 2, strides=2, kernel_initializer="he_normal"),
         ])
 
-        self.postprocessor = DBPostProcessor(assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh)
+        self.postprocessor = DBPostProcessor(
+            assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh, box_thresh=box_thresh
+        )
 
     def compute_loss(
         self,

doctr/models/detection/linknet/pytorch.py

@@ -91,6 +91,8 @@ class LinkNet(nn.Module, _LinkNet):
     Args:
     ----
         feature extractor: the backbone serving as feature extractor
+        bin_thresh: threshold for binarization of the output feature map
+        box_thresh: minimal objectness score to consider a box
         head_chans: number of channels in the head layers
         assume_straight_pages: if True, fit straight bounding boxes only
         exportable: onnx exportable returns only logits
@@ -102,6 +104,7 @@ def __init__(
         self,
         feat_extractor: IntermediateLayerGetter,
         bin_thresh: float = 0.1,
+        box_thresh: float = 0.1,
         head_chans: int = 32,
         assume_straight_pages: bool = True,
         exportable: bool = False,
@@ -142,7 +145,7 @@ def __init__(
         )
 
         self.postprocessor = LinkNetPostProcessor(
-            assume_straight_pages=self.assume_straight_pages, bin_thresh=bin_thresh
+            assume_straight_pages=self.assume_straight_pages, bin_thresh=bin_thresh, box_thresh=box_thresh
         )
 
         for n, m in self.named_modules():

doctr/models/detection/linknet/tensorflow.py

@@ -98,6 +98,8 @@ class LinkNet(_LinkNet, keras.Model):
     ----
         feature extractor: the backbone serving as feature extractor
         fpn_channels: number of channels each extracted feature maps is mapped to
+        bin_thresh: threshold for binarization of the output feature map
+        box_thresh: minimal objectness score to consider a box
         assume_straight_pages: if True, fit straight bounding boxes only
         exportable: onnx exportable returns only logits
         cfg: the configuration dict of the model
@@ -111,6 +113,7 @@ def __init__(
         feat_extractor: IntermediateLayerGetter,
         fpn_channels: int = 64,
         bin_thresh: float = 0.1,
+        box_thresh: float = 0.1,
         assume_straight_pages: bool = True,
         exportable: bool = False,
         cfg: Optional[Dict[str, Any]] = None,
@@ -152,7 +155,9 @@ def __init__(
             ),
         ])
 
-        self.postprocessor = LinkNetPostProcessor(assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh)
+        self.postprocessor = LinkNetPostProcessor(
+            assume_straight_pages=assume_straight_pages, bin_thresh=bin_thresh, box_thresh=box_thresh
+        )
 
     def compute_loss(
         self,

doctr/models/kie_predictor/pytorch.py

@@ -106,6 +106,10 @@ def forward(
         # Rectify crops if aspect ratio
         dict_loc_preds = {k: self._remove_padding(pages, loc_pred) for k, loc_pred in dict_loc_preds.items()}
 
+        # Apply hooks to loc_preds if any
+        for hook in self.hooks:
+            dict_loc_preds = hook(dict_loc_preds)
+
         # Crop images
         crops = {}
         for class_name in dict_loc_preds.keys():

doctr/models/kie_predictor/tensorflow.py

@@ -103,6 +103,10 @@ def __call__(
         # Rectify crops if aspect ratio
         dict_loc_preds = {k: self._remove_padding(pages, loc_pred) for k, loc_pred in dict_loc_preds.items()}
 
+        # Apply hooks to loc_preds if any
+        for hook in self.hooks:
+            dict_loc_preds = hook(dict_loc_preds)
+
         # Crop images
         crops = {}
         for class_name in dict_loc_preds.keys():

doctr/models/predictor/base.py

@@ -3,7 +3,7 @@
 # This program is licensed under the Apache License 2.0.
 # See LICENSE or go to <https://opensource.org/licenses/Apache-2.0> for full license details.
 
-from typing import Any, List, Optional, Tuple
+from typing import Any, Callable, List, Optional, Tuple
 
 import numpy as np
 
@@ -48,6 +48,7 @@ def __init__(
         self.doc_builder = DocumentBuilder(**kwargs)
         self.preserve_aspect_ratio = preserve_aspect_ratio
         self.symmetric_pad = symmetric_pad
+        self.hooks: List[Callable] = []
 
     @staticmethod
     def _generate_crops(
@@ -149,3 +150,12 @@ def _process_predictions(
                 _idx += page_boxes.shape[0]
 
         return loc_preds, text_preds
+
+    def add_hook(self, hook: Callable) -> None:
+        """Add a hook to the predictor
+
+        Args:
+        ----
+            hook: a callable that takes as input the `loc_preds` and returns the modified `loc_preds`
+        """
+        self.hooks.append(hook)

doctr/models/predictor/pytorch.py

@@ -108,6 +108,10 @@ def forward(
         # Rectify crops if aspect ratio
         loc_preds = self._remove_padding(pages, loc_preds)
 
+        # Apply hooks to loc_preds if any
+        for hook in self.hooks:
+            loc_preds = hook(loc_preds)
+
         # Crop images
         crops, loc_preds = self._prepare_crops(
             pages,

doctr/models/predictor/tensorflow.py

@@ -105,6 +105,10 @@ def __call__(
         # Rectify crops if aspect ratio
         loc_preds = self._remove_padding(pages, loc_preds)
 
+        # Apply hooks to loc_preds if any
+        for hook in self.hooks:
+            loc_preds = hook(loc_preds)
+
         # Crop images
         crops, loc_preds = self._prepare_crops(
             pages, loc_preds, channels_last=True, assume_straight_pages=self.assume_straight_pages

doctr/models/preprocessor/pytorch.py

@@ -35,7 +35,6 @@ def __init__(
         batch_size: int,
         mean: Tuple[float, float, float] = (0.5, 0.5, 0.5),
         std: Tuple[float, float, float] = (1.0, 1.0, 1.0),
-        fp16: bool = False,
         **kwargs: Any,
     ) -> None:
         super().__init__()

doctr/models/preprocessor/tensorflow.py

@@ -35,7 +35,6 @@ def __init__(
         batch_size: int,
         mean: Tuple[float, float, float] = (0.5, 0.5, 0.5),
         std: Tuple[float, float, float] = (1.0, 1.0, 1.0),
-        fp16: bool = False,
         **kwargs: Any,
     ) -> None:
         self.batch_size = batch_size

scripts/detect_text.py

@@ -62,6 +62,7 @@ def main(args):
     detection_model = detection.__dict__[args.detection](
         pretrained=True,
         bin_thresh=args.bin_thresh,
+        box_thresh=args.box_thresh,
     )
     model = ocr_predictor(detection_model, args.recognition, pretrained=True)
     path = Path(args.path)
@@ -86,6 +87,7 @@ def parse_args():
     parser.add_argument("path", type=str, help="Path to process: PDF, image, directory")
     parser.add_argument("--detection", type=str, default="db_resnet50", help="Text detection model to use for analysis")
     parser.add_argument("--bin-thresh", type=float, default=0.3, help="Binarization threshold for the detection model.")
+    parser.add_argument("--box-thresh", type=float, default=0.1, help="Threshold for the detection boxes.")
     parser.add_argument(
         "--recognition", type=str, default="crnn_vgg16_bn", help="Text recognition model to use for analysis"
     )

tests/pytorch/test_models_zoo_pt.py

@@ -16,6 +16,12 @@
 from doctr.models.recognition.zoo import recognition_predictor
 
 
+# Create a dummy callback
+class _DummyCallback:
+    def __call__(self, loc_preds):
+        return loc_preds
+
+
 @pytest.mark.parametrize(
     "assume_straight_pages, straighten_pages",
     [
@@ -121,6 +127,8 @@ def test_trained_ocr_predictor(mock_payslip):
         preserve_aspect_ratio=True,
         symmetric_pad=True,
     )
+    # test hooks
+    predictor.add_hook(_DummyCallback())
 
     out = predictor(doc)
 
@@ -204,6 +212,8 @@ def test_trained_kie_predictor(mock_payslip):
         straighten_pages=True,
         preserve_aspect_ratio=False,
     )
+    # test hooks
+    predictor.add_hook(_DummyCallback())
 
     out = predictor(doc)
 

tests/tensorflow/test_models_zoo_tf.py

@@ -16,6 +16,12 @@
 from doctr.utils.repr import NestedObject
 
 
+# Create a dummy callback
+class _DummyCallback:
+    def __call__(self, loc_preds):
+        return loc_preds
+
+
 @pytest.mark.parametrize(
     "assume_straight_pages, straighten_pages",
     [
@@ -92,6 +98,8 @@ def test_trained_ocr_predictor(mock_payslip):
         straighten_pages=True,
         preserve_aspect_ratio=False,
     )
+    # test hooks
+    predictor.add_hook(_DummyCallback())
 
     out = predictor(doc)
 
@@ -202,6 +210,8 @@ def test_trained_kie_predictor(mock_payslip):
         straighten_pages=True,
         preserve_aspect_ratio=False,
     )
+    # test hooks
+    predictor.add_hook(_DummyCallback())
 
     out = predictor(doc)