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Nearest Neighbor as Reference: A Simple Way to Boost the Performance of Image Captioning

Created by Junhua Mao


This package provides a simple way to boost the performance of image captioning task by reranking the hypotheses sentences according to the captions of nearest neighbor images in the training set. We denote this method as consensus reranking for the rest of this document.

It also provides images features (both refined by the m-RNN model and the original VGG feature ) on MS COCO Train2014, Val2014, and Test2014 dataset. We take the m-RNN model as an example to generate the hypotheses descriptions of an image.

The details is described in Section 8 of the latest version of the m-RNN paper: Deep Captioning with Multimodal Recurrent Neural Networks (m-RNN). The work is inspired by the nearest neighbor captions retrieval method.

Citing m-RNN and consensus reranking

If you find this package useful in your research, please consider citing:

  title={Deep Captioning with Multimodal Recurrent Neural Networks (m-RNN)},
  author={Mao, Junhua and Xu, Wei and Yang, Yi and Wang, Jiang and Huang, Zhiheng and Yuille, Alan},


Basic installation (sufficient for the demo)

  1. install MS COCO caption toolkit

  2. Suppose that toolkit is install on $PATH_COCOCap and this package is install at $PATH_mRNN_CR. Create a soft link to COCOCap as follows:

ln -sf ./external/coco-caption $PATH_COCOCap
  1. Setup the package (will download necessary data, including refined features of m-RNN, ~1.5G)
bash setup.sh


Run cr_mRNN_demo.py or view cr_mRNN_demo.ipynb

You can set up the file path, dir or hyperparamters in the script here: ./concensus_reranking_utils/conf_cr.py

Additional data

  1. run download_mRNN_cache.sh to get the consensus reranking sample results on MS COCO crVal set (should be the same after running cr_mRNN_demo.py) and the nearest images index for MS COCO test 2014. (totally ~1.1G)

  2. run download_VGG_orignial_feature.sh to get the extracted feature from original VGGnet on MS COCO train, val and test2014 (totally ~2.1G)

For more information about the format of the data, please refer to the Readme.md file in folder image_features_mRNN, mscoco_anno_files, and hypotheses_mRNN

MS COCO test 2014 data

According to the rule of the MS COCO evaluation server, we cannot release the hypotheses on MS COCO test2014 set. But we release the all the image features (both refined and original VGG features) as well as nearest neighbor images.