Unsupervised Image Captioning

by Yang Feng, Lin Ma, Wei Liu, and Jiebo Luo

Introduction

Most image captioning models are trained using paired image-sentence data, which are expensive to collect. We propose unsupervised image captioning to relax the reliance on paired data. For more details, please refer to our paper.

![alt text](http://cs.rochester.edu/u/yfeng23/cvpr19_captioning/framework.png "Framework")

Citation

@InProceedings{feng2019unsupervised,
  author = {Feng, Yang and Ma, Lin and Liu, Wei and Luo, Jiebo},
  title = {Unsupervised Image Captioning},
  booktitle = {CVPR},
  year = {2019}
}

Requirements

mkdir ~/workspace
cd ~/workspace
git clone https://github.com/tensorflow/models.git tf_models
git clone https://github.com/tylin/coco-caption.git
touch tf_models/research/im2txt/im2txt/__init__.py
touch tf_models/research/im2txt/im2txt/data/__init__.py
touch tf_models/research/im2txt/im2txt/inference_utils/__init__.py
wget http://download.tensorflow.org/models/inception_v4_2016_09_09.tar.gz
mkdir ckpt
tar zxvf inception_v4_2016_09_09.tar.gz -C ckpt
git clone https://github.com/fengyang0317/unsupervised_captioning.git
cd unsupervised_captioning
pip install -r requirements.txt
export PYTHONPATH=$PYTHONPATH:`pwd`

Dataset (Optional. The files generated below can be found at Gdrive).

In case you do not have the access to Google, the files are also available at One Drive.

Crawl image descriptions. The descriptions used when conducting the experiments in the paper are available at link. You may download the descriptions from the link and extract the files to data/coco.
```
pip3 install absl-py
python3 preprocessing/crawl_descriptions.py
```
Extract the descriptions. It seems that NLTK is changing constantly. So the number of the descriptions obtained may be different.
```
python -c "import nltk; nltk.download('punkt')"
python preprocessing/extract_descriptions.py
```
Preprocess the descriptions. You may need to change the vocab_size, start_id, and end_id in config.py if you generate a new dictionary.
```
python preprocessing/process_descriptions.py --word_counts_output_file \ 
  data/word_counts.txt --new_dict
```
Download the MSCOCO images from link and put all the images into ~/dataset/mscoco/all_images.
Object detection for the training images. You need to first download the detection model from here and then extract the model under tf_models/research/object_detection.
```
python preprocessing/detect_objects.py --image_path\
  ~/dataset/mscoco/all_images --num_proc 2 --num_gpus 1
```

Generate tfrecord files for images.

python preprocessing/process_images.py --image_path\
  ~/dataset/mscoco/all_images

Training

Train the model without the intialization pipeline.

python im_caption_full.py --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt\
  --multi_gpu --batch_size 512 --save_checkpoint_steps 1000\
  --gen_lr 0.001 --dis_lr 0.001

Evaluate the model. The last element in the b34.json file is the best checkpoint.

CUDA_VISIBLE_DEVICES='0,1' python eval_all.py\
  --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt\
  --data_dir ~/dataset/mscoco/all_images
js-beautify saving/b34.json

Evaluate the model on test set. Suppose the best validation checkpoint is 20000.

python test_model.py --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt\
  --data_dir ~/dataset/mscoco/all_images --job_dir saving/model.ckpt-20000

Initialization (Optional. The files can be found at here).

Train a object-to-sentence model, which is used to generate the pseudo-captions.
```
python initialization/obj2sen.py
```

Find the best obj2sen model.

python initialization/eval_obj2sen.py --threads 8

Generate pseudo-captions. Suppose the best validation checkpoint is 35000.

python initialization/gen_obj2sen_caption.py --num_proc 8\
  --job_dir obj2sen/model.ckpt-35000

Train a captioning using pseudo-pairs.

python initialization/im_caption.py --o2s_ckpt obj2sen/model.ckpt-35000\
  --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt

Evaluate the model.

CUDA_VISIBLE_DEVICES='0,1' python eval_all.py\
  --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt\
  --data_dir ~/dataset/mscoco/all_images --job_dir saving_imcap
js-beautify saving_imcap/b34.json

Train sentence auto-encoder, which is used to initialize sentence GAN.
```
python initialization/sentence_ae.py
```
Train sentence GAN.
```
python initialization/sentence_gan.py
```

Train the full model with initialization. Suppose the best imcap validation checkpoint is 18000.

python im_caption_full.py --inc_ckpt ~/workspace/ckpt/inception_v4.ckpt\
  --imcap_ckpt saving_imcap/model.ckpt-18000\
  --sae_ckpt sen_gan/model.ckpt-30000 --multi_gpu --batch_size 512\
  --save_checkpoint_steps 1000 --gen_lr 0.001 --dis_lr 0.001

Credits

Part of the code is from coco-caption, im2txt, tfgan, resnet, Tensorflow Object Detection API and maskgan.

Xinpeng told me the idea of self-critic, which is crucial to training.