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HSN for Remote sensing

This repository contains project codes of following paper: "Hourglass-Shape Network Based Semantic Segmentation for High Resolution Aerial Imagery" (http://www.mdpi.com/2072-4292/9/6/522)

As the project is still in progress, the code for preprocessing, WBP post processing, and evaluation is currently under code review, and will be published progressively in the near future

In this repository you can find:

• HSN nets' caffe prototxt and caffemodel:
  • FCN net prototxt and caffemodel;
  • HSN standard net prototxt and caffemodel;
  • HSN No-Branch net prototxt and caffemodel;
  • HSN No-Inception net proto and caffemodel;
• Python code for the project including:
  • Preprocessing
  • Network training and testing
  • Post-processing with WBP
  • Visualization

Abstract

A new convolution neural network (CNN) architecture for semantic segmentation of high resolution aerial imagery is proposed in this paper. The proposedarchitecture follows an hourglass-shaped network (HSN) design being structuredinto encoding and decoding stages. By taking advantage of recent advances in CNN designs, we use the composed inception module to replace common convolutional layers, providing the network with multi-scale receptive areas withrich context. Additionally, in order to reduce spatial ambiguities in the upsampling stage, skip connections with residual units are also employed to feed forward encoding-stage information directly to the decoder. Moreover, overlap inference is employed to alleviate boundary effects occurring when high resolution images are inferred from small-sized patches. Finally, we also propose a post-processing method based on weighted belief propagation to visually enhance the classification results. Extensive experiments based on the Vaihingen and Potsdam datasets demonstrate that the proposed architectures outperform three reference state-of-the-art network designs both numerically and visually.

Requirement

Modified version of caffe is required to re-produce the experiments. Find the modified caffe from following link: https://github.com/Walkerlikesfish/CaffeGeo.git

And follow the instruction from the original caffe to install this modified version, any problems and questions please consult the orginial caffe communicty. https://github.com/BVLC/caffe/

HSN net Specification

Folder net contains all the net prototxt, solver files and modules.

Dataset

To acquire the mentioned Vaihingen and Potsdam dataset, pleaes refers to ISPRS from the following link:

Vaihingen: http://www2.isprs.org/commissions/comm3/wg4/2d-sem-label-vaihingen.html

Potsdam: http://www2.isprs.org/commissions/comm3/wg4/2d-sem-label-potsdam.html

The normalized DSM data can be acquired from M. Gerke from following link: https://www.itc.nl/library/papers_2015/general/gerke_use.pdf

The nDSM data of Potsdam can be found in following link: http://eostore.itc.utwente.nl:5000/fbsharing/z8O2Xl6f

Please contact the ISPRS for any question concerning the dataset.

How to run

The whole project can be divided into three parts: 1) Data-preprocessing 2) Deep network traninig 3) Weighted Belief Propagation post processing

Data-preprocessing

• Use the fSplit.py to split the provided remote sensing image tile into small patches. (you have to set the setting_data.ini first, specifying the folders and path of the caffe and raw images).
• fTagPost.py can be used to adapt the label map from color labels to class indexes (Specify and check the color mapping first)
• calc_mean.py and convert_protomean.py are helpers to calculate the mean value of the image dataset.

Network Training

• run_gen_proto.py is used to generate the caffe prototxt (the network scheme), protoGen.py is where we specify the details of the network. (you have to set the setting_data.ini first).
• run_check_net_layout.py is the helper script to check the layout of the net, can output network structure as image.
• run_train_net.py is the helper script to train the network in Caffe.
• run_infer.py is used to run the test inference throught specified dataset.

Post processing

• Call infer_XBP.py and set the parameters in the script to run the weighed belief propagation. Please modify the path of the input/output image folders

Visualize

• Since the input image is inferenced in patches, assemble_patch.py is used to perform the overlap inference
• Other scripts are used to color the label map and generate results for visual evaluation.

License and Citation

Please cite the following paper if you find the project helpful to your research.

@article{liu2017hourglass,
title={Hourglass-ShapeNetwork Based Semantic Segmentation for High Resolution Aerial Imagery},
author={Liu, Yu and Minh Nguyen, Duc and Deligiannis, Nikos and Ding, Wenrui and Munteanu, Adrian},
journal={Remote Sensing},
volume={9},
number={6},
pages={522},
year={2017},
publisher={Multidisciplinary Digital Publishing Institute}
}

This code is shared under a Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Creative Commons licensing.

You are free to:

• Share — copy and redistribute the material in any medium or format
• Adapt — remix, transform, and build upon the material The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

• Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
• NonCommercial — You may not use the material for commercial purposes.
• No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

Acknowlegement

The research has been supported by Fonds Wetenschappelijk Onderzoek (project no. G084117), Brussels Institute for Research and Innovation (project 3DLicornea) and Vrije Universiteit Brussel (PhD bursary Duc Minh Nguyen).