img2txt

End-to-end deep learning model to generate a summary of the content of an image in a sentence.

Overview

Requirements

How to run img2txt

Overview

For a quick overview, please see the slides for the 5-min demo of this project.

Acknowledgement

The model architecture is based on

"Show and Tell: Lessons learned from the 2015 MSCOCO Image Captioning Challenge." Oriol Vinyals, Alexander Toshev, Samy Bengio, Dumitru Erhan. IEEE transactions on pattern analysis and machine intelligence (2016). http://arxiv.org/abs/1609.06647

and the following code in the TensorFlow model zoo is frequently used as a reference,

https://github.com/tensorflow/models/tree/master/im2txt

but the code is written from scratch using TensorFlow APIs, except Inception models whose codes are obtained in the current master version (325609e) of https://github.com/tensorflow/models/tree/master/slim.

Requirements

Library

img2txt is developed on the following environment.

• Ubuntu 16.04.2 LTS
• Python 3.6
• NumPy
• TensorFlow 1.2
• Pillow
• NLTK (NLTK data needed for tokenization; only nltk_data/tokenizers/punkt/PY3/english.pickle needed.)

And its web UI requires the following libraries.

• Flask
• Bokeh (for word embedding visualization)

Datasets

img2txt.dataset contains convenient wrappers for various public caption datasets including MS COCO, Flickr 8k/30k, and PASCAL. Put each downloaded dataset in a separate directory, which will be used during the training of the model.

Using pre-trained convnet models

Inception (v3, v4)

• Get checkpoints from https://github.com/tensorflow/models/tree/master/slim#Pretrained, and put the uncompressed checkpoint files in img2txt/pretrained.

VGG16

• Copy Keras' pretrained model ~/.keras/models/vgg16_weights_tf_dim_ordering_tf_kernels.h5 to in img2txt/pretrained/vgg16_weights.h5.

How to run img2txt

Training

Please see https://github.com/chan-y-park/img2txt/blob/master/img2txt_api_example.ipynb for a step-by-step guide.

Inference

After training the model, put saved files in img2txt/inference, more specifically

• the checkpoint files as img2txt/inference/img2txt.*,
• the configuration file as img2txt/inference/config.json, and
• the vocabulary file as img2txt/inference/vocabulary.json. The run img2txt/web_app.wsgi, open a web browser, and go to http://localhost:9999 to use the web UI for inference.

Performance

When trained on MS COCO training dataset for 500k weight updates, where each update is a training on a minibatch of 32 image-caption pairs, the model gets 25.9 BLEU-4 score and 86.4 CIDEr score, which are evaluated using 4k random selections from MS COCO validation dataset and MS COCO Caption Evaluation API (https://github.com/tylin/coco-caption).