text-spotting-0003 (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 64.81%
Source framework PyTorch*

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

Detector model specification

The text-spotting-0003-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. Name: im_data , shape: [1x3x768x1280]. An input image in the [1xCxHxW] format. The expected channel order is BGR.
  2. Name: im_info, shape: [1x3]. 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: [100x5]. 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: [100x28x28]. Text segmentation masks for every output bounding box.
  4. Name: text_features.0, shape [100x64x28x28]. Text features that are fed to a text recognition head.

Encoder model specification

The text-spotting-0003-recognizer-encoder model is a fully-convolutional encoder of text recognition head.

Metric Value
GFlops 2.082
MParams 1.328


Name: input , shape: [1x64x28x28]. Text recognition features obtained from detection part.


Name: output, shape: [1x256x28x28]. Encoded text recognition features.

Decoder model specification

Metric Value
GFlops 0.106
MParams 0.283


  1. Name: encoder_outputs , shape: [1x(28*28)x256]. Encoded text recognition features.
  1. Name: prev_symbol , shape: [1x1]. Index in alphabet of previously generated symbol.
  1. Name: prev_hidden, shape: [1x1x256]. Previous hidden state of GRU.


  1. Name: output, shape: [1x38]. 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.
  1. Name: hidden, shape: [1x1x256]. Current hidden state of GRU.

Legal Information

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