ZSCRGAN

A GAN-based Expectation-Maximization Model for Zero-Shot Retrieval of Images from Textual Descriptions.

Table of Contents

• ZSCRGAN
  • Table of Contents
    • Summary
    • About
    • Citation
    • Dependencies
    • Hyperparameters and Options
    • Data for Demo
    • Run Demo
    • Acknowledgement

Summary

Implementation of the proposed algorithm in the paper ZSCRGAN: A GAN-based Expectation-Maximization Model for Zero-Shot Retrieval of Images from Textual Descriptions(to be presented at the ACM International Conference on Information and Knowledge Management (CIKM2020)) by Anurag Roy, Vinay Kumar Verma, Kripabandhu Ghosh, Saptarshi Ghosh. The proposed model performs zero-shot retrieval of images from their textual descriptions . The following image gives a schematic view of our proposed model:

About

ZSCRGAN is a novel Zero-Shot cross modal text to image retrieval model. The model does this by learning a joint probability distribution of text embeddings and relevant image embeddings, maximizing which ensures high similarity between text embeddings and relevant image embeddings. To learn this distribution we use an Expectation-Maximization based training approach of the model involving a Generative Adversarial Network(GAN) which is learnt in the E-step and a Common Space Embedding Mapper(CSEM), which is updated in the M-step. The GAN is used to generate a representative image embedding(a latent variable) and the CSEM is used map them to a common space embedding.

Citation

If you use the codes, please refer to the following paper:

  @inproceedings{roy-cikm20,
   author = {Roy, Anurag and Verma, Vinay and Ghosh, Kripabandhu and Ghosh, Saptarshi},
   title = {{ZSCRGAN: A GAN-based Expectation-Maximization Model for Zero-Shot Retrieval of Images from Textual Descriptions}},
   booktitle = {{Proceedings of the 29th ACM International Conference on Information and Knowledge Management  (CIKM)}},
   year = {2020}
  }

Dependencies

python version: python 2.7

packages:

• tensorflow-gpu
• easydict
• scipy
• six
• numpy
• prettytensor
• pyYAML
• scikit-learn

To install the dependencies run pip install -r requirements.txt

Hyperparameters and Options

Hyperparameters and options in run_exp.py:

• batch_size batch size used during training
• gf_dim hidden layer dimension of generator
• df_dim hidden layer dimension of discriminator
• embed_dim dimension of mu and sigma each
• CSEM_lr learning rate of CSEM
• generator_lr learning rate of generator
• discriminator_lr learning rate of discriminator
• epochs number of epochs
• kl_div_coefficient coefficient of the kl-divergence loss
• mm_reg_coeff coefficient of the max-margin regularizer
• z_dim dimension of the noise vector
• clip_val clipping values of the discriminator in WGAN
• dataset raining dataset folder name

Data for Demo

Following are the datasets on which our experminets have been run:

1. AWA1
2. AWA2
3. CUB
4. FLO
5. NAB(SCS split)
6. NAB(SCE split)
7. WIKI

Download the zip files and extract it inside the datasets folder.

Run Demo

To run the model on a particular dataset use the command:

python2 run_exp.py --dataset <dataset_folder_name>

Precision@50 on the test set will be outputted after every 100 iterations of the E-step and the M-step. The retrieved results can be found inside the retrieved_res/<dataset_folder_name>_res/ folder. For example the command to run the model on the CUB dataset will be python2 run_exp.py --dataset CUB. This will create a folder retrieved_res/CUB_res/ containing files with the the retrieval results. The name of the file will be of the form acc<Prec@50>.pkl. For example the retrieval result which had a Prec@50 value of 0.521 will be saved in the file acc0.521.pkl. The output pickle file contains a list of key value pairs with class id of the text embedding being the key and list of class ids of the retrieved images being the value. For example one element of the list will be:

{3: [3, 3, 3, 25, 25, 48, 3, 25, 3, 25, 25, 25, 3, 3, 3, 48, 3, 22, 25, 25, 3, 48, 25, 22, 48, 25, 3, 3, 25, 3, 48, 3, 48, 3, 3, 48, 3, 3, 48, 3, 25, 3, 3, 25, 48, 3, 3, 3, 25, 3]}

where the key 3 is the class id of the text embedding and the value of list of class ids correspond to those of the retrieved images.

Acknowledgement

Some parts of the code have been borrowed from the StackGAN code repository.