text-spotting-0005 (composite)

Use Case and High-Level Description

This is a text spotting composite model that simultaneously detects and recognizes text. The model detects symbol sequences separated by space and performs recognition without a dictionary. The model is built on top of the Mask-RCNN framework with additional attention-based text recognition head.

Alphabet is alphanumeric: abcdefghijklmnopqrstuvwxyz0123456789.


Composite model specification

Metric Value
Word spotting hmean ICDAR2015, without a dictionary 71.29%
Source framework PyTorch*

Hmean Word spotting is defined and measured according to the Incidental Scene Text (ICDAR2015) challenge.

Detector model specification

The text-spotting-0005-detector model is a Mask-RCNN-based text detector with ResNet50 backbone and additional text features output.

Metric Value
GFlops 184.495
MParams 27.010


  1. Image, name: im_data, shape: 1, 3, 768, 1280 in the 1, C, H, W format, where:

    • C - number of channels
    • H - image height
    • W - image width

    The expected channel order is BGR.

  2. Name: im_info, shape: 1, 3. Image information: processed image height, processed image width, and processed image scale with respect to the original image resolution.


  1. Name: labels, shape: 100. Contiguous integer class ID for every detected object, 0 is for text class.
  2. Name: boxes, shape: 100, 5. Bounding boxes around every detected object in the (top_left_x, top_left_y, bottom_right_x, bottom_right_y, confidence) format.
  3. Name: masks, shape: 100, 28, 28. Text segmentation masks for every output bounding box.
  4. Name: text_features.0, shape 100, 64, 28, 28. Text features that are fed to a text recognition head.

Encoder model specification

The text-spotting-0005-recognizer-encoder model is a fully-convolutional encoder of text recognition head.

Metric Value
GFlops 2.082
MParams 1.328


Name: input, shape: 1, 64, 28, 28. Text recognition features obtained from detection part.


Name: output, shape: 1, 256, 28, 28. Encoded text recognition features.

Decoder model specification

Metric Value
GFlops 0.106
MParams 0.283


  1. Name: encoder_outputs, shape: 1, (28*28), 256. Encoded text recognition features.
  2. Name: prev_symbol, shape: 1, 1. Index in alphabet of previously generated symbol.
  3. Name: prev_hidden, shape: 1, 1, 256. Previous hidden state of GRU.


  1. Name: output, shape: 1, 38. Encoded text recognition features. Indices starting from 2 correspond to symbols from the alphabet. The 0 and 1 are special Start of Sequence and End of Sequence symbols correspondingly.
  2. Name: hidden, shape: 1, 1, 256. Current hidden state of GRU.

Training Pipeline

The OpenVINO Training Extensions provide a training pipeline, allowing to fine-tune the model on custom dataset.

Legal Information

[*] Other names and brands may be claimed as the property of others.