doctr.utils#

Complementary tools: visualization, page reconstruction and evaluation metrics.

Visualization#

visualize_page(
page,
image,
words_only=True,
display_artefacts=True,
display_layout=True,
scale=10,
interactive=True,
add_labels=True,
**kwargs,
)[source]#

Visualize a full page with predicted blocks, lines and words

>>> import numpy as np
>>> import matplotlib.pyplot as plt
>>> from doctr.utils.visualization import visualize_page
>>> from doctr.models import ocr_db_crnn
>>> model = ocr_db_crnn(pretrained=True)
>>> input_page = (255 * np.random.rand(600, 800, 3)).astype(np.uint8)
>>> out = model([[input_page]])
>>> visualize_page(out[0].pages[0].export(), input_page)
>>> plt.show()
Parameters:
  • page (dict[str, Any]) – the exported Page of a Document

  • image (ndarray) – np array of the page, needs to have the same shape than page[‘dimensions’]

  • words_only (bool) – whether only words should be displayed

  • display_artefacts (bool) – whether artefacts should be displayed

  • display_layout (bool) – whether detected layout regions should be displayed

  • scale (float) – figsize of the largest windows side

  • interactive (bool) – whether the plot should be interactive

  • add_labels (bool) – for static plot, adds text labels on top of bounding box

  • **kwargs (Any) – keyword arguments for the polygon patch

Returns:

the matplotlib figure

Return type:

Figure

visualize_kie_page(
page,
image,
words_only=False,
display_artefacts=True,
display_layout=True,
scale=10,
interactive=True,
add_labels=True,
**kwargs,
)[source]#

Visualize a full page with predicted blocks, lines and words

>>> import numpy as np
>>> import matplotlib.pyplot as plt
>>> from doctr.utils.visualization import visualize_page
>>> from doctr.models import ocr_db_crnn
>>> model = ocr_db_crnn(pretrained=True)
>>> input_page = (255 * np.random.rand(600, 800, 3)).astype(np.uint8)
>>> out = model([[input_page]])
>>> visualize_kie_page(out[0].pages[0].export(), input_page)
>>> plt.show()
Parameters:
  • page (dict[str, Any]) – the exported Page of a Document

  • image (ndarray) – np array of the page, needs to have the same shape than page[‘dimensions’]

  • words_only (bool) – whether only words should be displayed

  • display_artefacts (bool) – whether artefacts should be displayed

  • display_layout (bool) – whether detected layout regions should be displayed

  • scale (float) – figsize of the largest windows side

  • interactive (bool) – whether the plot should be interactive

  • add_labels (bool) – for static plot, adds text labels on top of bounding box

  • **kwargs (Any) – keyword arguments for the polygon patch

Returns:

the matplotlib figure

Return type:

Figure

draw_boxes(boxes, image, color=None, **kwargs)[source]#

Draw an array of relative straight boxes on an image.

Parameters:
  • boxes (ndarray) – array of relative boxes, of shape (*, 4)

  • image (ndarray) – np array, float32 or uint8

  • color (tuple[int, int, int] | None) – color to use for bounding box edges

  • **kwargs – keyword arguments from matplotlib.pyplot.plot

Reconstitution#

synthesize_page(
page,
draw_proba=False,
font_family=None,
min_font_size=8,
max_font_size=50,
background_color=(255, 255, 255),
text_color=(0, 0, 0),
draw_placeholders=False,
)[source]#

Draw the content of the element page (OCR response) on a blank page.

Parameters:
  • page (dict[str, Any]) – exported Page object to represent

  • draw_proba (bool) – if True, draw words in colors to represent confidence. Blue: p=1, red: p=0

  • font_family (str | None) – family of the font

  • min_font_size (int) – minimum font size

  • max_font_size (int) – maximum font size

  • background_color (tuple[int, int, int]) – RGB color of the page background

  • text_color (tuple[int, int, int]) – RGB color of the rendered text

  • draw_placeholders (bool) – if True, draw the grid of the recognized tables and outline the layout regions holding no text of their own

Returns:

the synthesized page

Return type:

ndarray

synthesize_kie_page(
page,
draw_proba=False,
font_family=None,
min_font_size=8,
max_font_size=50,
background_color=(255, 255, 255),
text_color=(0, 0, 0),
draw_placeholders=False,
)[source]#

Draw the content of the element page (KIE OCR response) on a blank page.

Parameters:
  • page (dict[str, Any]) – exported Page object to represent

  • draw_proba (bool) – if True, draw words in colors to represent confidence. Blue: p=1, red: p=0

  • font_family (str | None) – family of the font

  • min_font_size (int) – minimum font size

  • max_font_size (int) – maximum font size

  • background_color (tuple[int, int, int]) – RGB color of the page background

  • text_color (tuple[int, int, int]) – RGB color of the rendered text

  • draw_placeholders (bool) – if True, draw the grid of the recognized tables and outline the layout regions holding no text of their own

Returns:

the synthesized page

Return type:

ndarray

Task evaluation#

Metrics to evaluate models on each task, used by the evaluation scripts of the references and in the model zoo.

class TextMatch[source]#

Implements text match metric (word-level accuracy) for recognition task.

The raw aggregated metric is computed as follows:

\[\forall X, Y \in \mathcal{W}^N, TextMatch(X, Y) = \frac{1}{N} \sum\limits_{i=1}^N f_{Y_i}(X_i)\]

with the indicator function \(f_{a}\) defined as:

\[\begin{split}\forall a, x \in \mathcal{W}, f_a(x) = \left\{ \begin{array}{ll} 1 & \mbox{if } x = a \\ 0 & \mbox{otherwise.} \end{array} \right.\end{split}\]

where \(\mathcal{W}\) is the set of all possible character sequences, \(N\) is a strictly positive integer.

>>> from doctr.utils import TextMatch
>>> metric = TextMatch()
>>> metric.update(['Hello', 'world'], ['hello', 'world'])
>>> metric.summary()
update(gt, pred)[source]#

Update the state of the metric with new predictions

Parameters:
  • gt (list[str]) – list of groung-truth character sequences

  • pred (list[str]) – list of predicted character sequences

summary()[source]#

Computes the aggregated metrics

Returns:

a dictionary with the exact match score for the raw data, its lower-case counterpart, its anyascii counterpart and its lower-case anyascii counterpart

Return type:

dict[str, float]

class LocalizationConfusion(iou_thresh=0.5, use_polygons=False)[source]#

Implements common confusion metrics and mean IoU for localization evaluation.

The aggregated metrics are computed as follows:

\[\begin{split}\forall Y \in \mathcal{B}^N, \forall X \in \mathcal{B}^M, \\ Recall(X, Y) = \frac{1}{N} \sum\limits_{i=1}^N g_{X}(Y_i) \\ Precision(X, Y) = \frac{1}{M} \sum\limits_{i=1}^M g_{X}(Y_i) \\ meanIoU(X, Y) = \frac{1}{M} \sum\limits_{i=1}^M \max\limits_{j \in [1, N]} IoU(X_i, Y_j)\end{split}\]

with the function \(IoU(x, y)\) being the Intersection over Union between bounding boxes \(x\) and \(y\), and the function \(g_{X}\) defined as:

\[\begin{split}\forall y \in \mathcal{B}, g_X(y) = \left\{ \begin{array}{ll} 1 & \mbox{if } y\mbox{ has been assigned to any }(X_i)_i\mbox{ with an }IoU \geq 0.5 \\ 0 & \mbox{otherwise.} \end{array} \right.\end{split}\]

where \(\mathcal{B}\) is the set of possible bounding boxes, \(N\) (number of ground truths) and \(M\) (number of predictions) are strictly positive integers.

>>> import numpy as np
>>> from doctr.utils import LocalizationConfusion
>>> metric = LocalizationConfusion(iou_thresh=0.5)
>>> metric.update(np.asarray([[0, 0, 100, 100]]), np.asarray([[0, 0, 70, 70], [110, 95, 200, 150]]))
>>> metric.summary()
Parameters:
  • iou_thresh (float) – minimum IoU to consider a pair of prediction and ground truth as a match

  • use_polygons (bool) – if set to True, predictions and targets will be expected to have rotated format

update(gts, preds)[source]#

Updates the metric

Parameters:
  • gts (ndarray) – a set of relative bounding boxes either of shape (N, 4) or (N, 5) if they are rotated ones

  • preds (ndarray) – a set of relative bounding boxes either of shape (M, 4) or (M, 5) if they are rotated ones

summary()[source]#

Computes the aggregated metrics

Returns:

a tuple with the recall, precision and meanIoU scores

Return type:

tuple[float | None, float | None, float | None]

class OCRMetric(iou_thresh=0.5, use_polygons=False)[source]#

Implements an end-to-end OCR metric.

The aggregated metrics are computed as follows:

\[\begin{split}\forall (B, L) \in \mathcal{B}^N \times \mathcal{L}^N, \forall (\hat{B}, \hat{L}) \in \mathcal{B}^M \times \mathcal{L}^M, \\ Recall(B, \hat{B}, L, \hat{L}) = \frac{1}{N} \sum\limits_{i=1}^N h_{B,L}(\hat{B}_i, \hat{L}_i) \\ Precision(B, \hat{B}, L, \hat{L}) = \frac{1}{M} \sum\limits_{i=1}^M h_{B,L}(\hat{B}_i, \hat{L}_i) \\ meanIoU(B, \hat{B}) = \frac{1}{M} \sum\limits_{i=1}^M \max\limits_{j \in [1, N]} IoU(\hat{B}_i, B_j)\end{split}\]

with the function \(IoU(x, y)\) being the Intersection over Union between bounding boxes \(x\) and \(y\), and the function \(h_{B, L}\) defined as:

\[\begin{split}\forall (b, l) \in \mathcal{B} \times \mathcal{L}, h_{B,L}(b, l) = \left\{ \begin{array}{ll} 1 & \mbox{if } b\mbox{ has been assigned to a given }B_j\mbox{ with an } \\ & IoU \geq 0.5 \mbox{ and that for this assignment, } l = L_j\\ 0 & \mbox{otherwise.} \end{array} \right.\end{split}\]

where \(\mathcal{B}\) is the set of possible bounding boxes, \(\mathcal{L}\) is the set of possible character sequences, \(N\) (number of ground truths) and \(M\) (number of predictions) are strictly positive integers.

>>> import numpy as np
>>> from doctr.utils import OCRMetric
>>> metric = OCRMetric(iou_thresh=0.5)
>>> metric.update(np.asarray([[0, 0, 100, 100]]), np.asarray([[0, 0, 70, 70], [110, 95, 200, 150]]),
>>>               ['hello'], ['hello', 'world'])
>>> metric.summary()
Parameters:
  • iou_thresh (float) – minimum IoU to consider a pair of prediction and ground truth as a match

  • use_polygons (bool) – if set to True, predictions and targets will be expected to have rotated format

update(gt_boxes, pred_boxes, gt_labels, pred_labels)[source]#

Updates the metric

Parameters:
  • gt_boxes (ndarray) – a set of relative bounding boxes either of shape (N, 4) or (N, 5) if they are rotated ones

  • pred_boxes (ndarray) – a set of relative bounding boxes either of shape (M, 4) or (M, 5) if they are rotated ones

  • gt_labels (list[str]) – a list of N string labels

  • pred_labels (list[str]) – a list of M string labels

summary()[source]#

Computes the aggregated metrics

Returns:

a tuple with the recall & precision for each string comparison and the mean IoU

Return type:

tuple[dict[str, float | None], dict[str, float | None], float | None]

class DetectionMetric(iou_thresh=0.5, use_polygons=False)[source]#

Implements an object detection metric.

The aggregated metrics are computed as follows:

\[\begin{split}\forall (B, C) \in \mathcal{B}^N \times \mathcal{C}^N, \forall (\hat{B}, \hat{C}) \in \mathcal{B}^M \times \mathcal{C}^M, \\ Recall(B, \hat{B}, C, \hat{C}) = \frac{1}{N} \sum\limits_{i=1}^N h_{B,C}(\hat{B}_i, \hat{C}_i) \\ Precision(B, \hat{B}, C, \hat{C}) = \frac{1}{M} \sum\limits_{i=1}^M h_{B,C}(\hat{B}_i, \hat{C}_i) \\ meanIoU(B, \hat{B}) = \frac{1}{M} \sum\limits_{i=1}^M \max\limits_{j \in [1, N]} IoU(\hat{B}_i, B_j)\end{split}\]

with the function \(IoU(x, y)\) being the Intersection over Union between bounding boxes \(x\) and \(y\), and the function \(h_{B, C}\) defined as:

\[\begin{split}\forall (b, c) \in \mathcal{B} \times \mathcal{C}, h_{B,C}(b, c) = \left\{ \begin{array}{ll} 1 & \mbox{if } b\mbox{ has been assigned to a given }B_j\mbox{ with an } \\ & IoU \geq 0.5 \mbox{ and that for this assignment, } c = C_j\\ 0 & \mbox{otherwise.} \end{array} \right.\end{split}\]

where \(\mathcal{B}\) is the set of possible bounding boxes, \(\mathcal{C}\) is the set of possible class indices, \(N\) (number of ground truths) and \(M\) (number of predictions) are strictly positive integers.

>>> import numpy as np
>>> from doctr.utils import DetectionMetric
>>> metric = DetectionMetric(iou_thresh=0.5)
>>> metric.update(np.asarray([[0, 0, 100, 100]]), np.asarray([[0, 0, 70, 70], [110, 95, 200, 150]]),
>>>               np.zeros(1, dtype=np.int64), np.array([0, 1], dtype=np.int64))
>>> metric.summary()
Parameters:
  • iou_thresh (float) – minimum IoU to consider a pair of prediction and ground truth as a match

  • use_polygons (bool) – if set to True, predictions and targets will be expected to have rotated format

update(gt_boxes, pred_boxes, gt_labels, pred_labels)[source]#

Updates the metric

Parameters:
  • gt_boxes (ndarray) – a set of relative bounding boxes either of shape (N, 4) or (N, 5) if they are rotated ones

  • pred_boxes (ndarray) – a set of relative bounding boxes either of shape (M, 4) or (M, 5) if they are rotated ones

  • gt_labels (ndarray) – an array of class indices of shape (N,)

  • pred_labels (ndarray) – an array of class indices of shape (M,)

summary()[source]#

Computes the aggregated metrics

Returns:

a tuple with the recall & precision for each class prediction and the mean IoU

Return type:

tuple[float | None, float | None, float | None]

class ObjectDetectionMetric(iou_thresholds=None, num_classes=None, use_polygons=False)[source]#

Implements a COCO-style object detection metric (mAP@[.5:.95]) inspired by the COCO evaluation protocol.

The aggregated metrics are computed as follows:

\[ \begin{align}\begin{aligned}\begin{split}\forall (B, C) \in \mathcal{B}^N \times \mathcal{C}^N, \forall (\hat{B}, \hat{C}, S) \in \mathcal{B}^M \times \mathcal{C}^M \times \mathbb{R}^M, \\\end{split}\\\begin{split}AP_t(C) = \frac{1}{101} \sum\limits_{r \in \{0, 0.01, \dots, 1.0\}} \max_{\tilde{r} \geq r} Precision_t(\tilde{r}, C) \\\end{split}\\mAP@[.5:.95] = \frac{1}{|\mathcal{T}|} \sum\limits_{t \in \mathcal{T}} \frac{1}{|\mathcal{C}|} \sum\limits_{c \in \mathcal{C}} AP_t(c)\end{aligned}\end{align} \]
where:
  • \(\mathcal{B}\) is the set of possible bounding boxes,

  • \(\mathcal{C}\) is the set of possible class indices,

  • \(S\) are confidence scores associated to predictions,

  • \(\mathcal{T} = \{0.5, 0.55, \dots, 0.95\}\) is the set of IoU thresholds,

  • \(AP_t(c)\) is the Average Precision for class \(c\) at IoU threshold \(t\).

For a given class and IoU threshold, predictions from all images are aggregated and sorted globally by decreasing confidence score.

Each prediction is greedily matched to the unmatched ground-truth box with the highest IoU, provided that:

  • the IoU is greater than or equal to the threshold,

  • the ground-truth box has not already been matched.

True positives and false positives are accumulated to build a precision-recall curve.

Average Precision is computed using the COCO 101-point interpolated precision-recall curve.

>>> import numpy as np
>>> from doctr.utils import ObjectDetectionMetric
>>> metric = ObjectDetectionMetric()
>>> metric.update(
...     np.asarray([[0, 0, 100, 100]]),
...     np.asarray([[0, 0, 80, 80], [120, 120, 200, 200]]),
...     np.asarray([0]),
...     np.asarray([0, 1]),
...     np.asarray([0.9, 0.3])
... )
>>> metric.summary()
Parameters:
  • iou_thresholds (ndarray | None) – sequence of IoU thresholds used to compute the metric (defaults to np.arange(0.5, 1.0, 0.05))

  • num_classes (int | None) – total number of classes. If None, inferred from data

  • use_polygons (bool) – if set to True, predictions and targets will be expected to have rotated format

summary()[source]#

Computes the aggregated metrics

Returns:

a dictionary with the mAP@[.5 – .95], AP@[.5], AP@[.75] and AP per IoU threshold

Return type:

dict[str, float | dict[float, float]]

class TableCellMetric(iou_thresh=0.5, use_polygons=False)[source]#

Implements a table-structure-recognition metric.

Predicted cells are matched to ground-truth cells by maximising the total IoU (Hungarian assignment); a pair counts as a match when its IoU is at least iou_thresh. From the matches it reports cell-detection recall, precision, F1 and the structure accuracy (the fraction of matched cells whose logical coordinates [start_col, end_col, start_row, end_row] exactly equal the ground-truth ones).

>>> import numpy as np
>>> from doctr.utils import TableCellMetric
>>> metric = TableCellMetric(iou_thresh=0.5)
>>> gt = np.array([[0, 0, 1, 1]], dtype=np.float32)
>>> metric.update(gt, np.array([[0, 0, 0, 0]]), gt, np.array([[0, 0, 0, 0]]))
>>> metric.summary()
Parameters:
  • iou_thresh (float) – minimum IoU for a predicted/ground-truth cell pair to be considered a match

  • use_polygons (bool) – if set to True, predictions and targets will be expected to have polygon format

update(gt_cells, gt_logic, pred_cells, pred_logic)[source]#

Update the metric with one sample.

Parameters:
  • gt_cells (ndarray) – ground-truth cells, shape (N, 4) or (N, 4, 2) when use_polygons=True

  • gt_logic (ndarray) – ground-truth logical coordinates, shape (N, 4)

  • pred_cells (ndarray) – predicted cells, shape (M, 4) or (M, 4, 2) when use_polygons=True

  • pred_logic (ndarray) – predicted logical coordinates, shape (M, 4)

summary()[source]#

Compute the aggregated metrics.

Returns:

a dict with recall, precision, f1 (cell detection) and structure_acc

Return type:

dict[str, float | None]