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SSG2: A New Modelling Paradigm for Semantic Segmentation

Official repository for our manuscript SSG2: A New Modelling Paradigm for Semantic Segmentation (arxiv 1st version)

Update

The article is now published in the journal ISPRS of Photogrammetry and Remote Sensing SSG2: A New Modelling Paradigm for Semantic Segmentation

Status

Things that work:

• Dataset Preprocessing script for ISPRS
• Training script for ISPRS example.
• Tutorial on RocksDB training dataset (see the readme in ssg2/data/).
• There will be minimal upgrades here (if any) now that the paper is published.

SSG2 brief

The core of SSG2 lies in its dual-encoder, single-decoder network, which is further augmented by a sequence model. This unique architecture accepts a target image along with a collection of support images. Unlike traditional approaches that rely on single, static images, SSG2 innovates by introducing a "temporal" dimension through a sequence of observables for each static input image. Within these sequence elements, the base model predicts the set intersection, union, and difference of labels from the dual-input images. This allows for more nuanced and accurate segmentation results.

The sequence model then takes the reins, synthesizing the final segmentation mask by aggregating these partial views and filtering out noise at each sequence step. The methodology is inspired by techniques in fields like astronomy and MRI, where multiple observations are utilized to enhance data quality. It capitalizes on the strong correlation of true signals and the uncorrelated nature of noise across different sequence elements, offering a potential for statistical filtering and thereby reducing error rates.

Data

Data for the ISPRS Potsdam and and ISIC 2018 need to be sourced from their official distribution sites due to licensing issues. Currently the internal dataset UrbanMonitor (Darwin, WA), is not provided.

Software envinment

Under location ssg2/docker exist instructions for both NVIDIA and ROCM Graphics accelerators (ROCM: tested with MI250 on Pawsey Setonix). Containers ready for use can be found on

• NVIDIA: docker pull fdiakogiannis/trchprosthesis_requirements:23.04-py3
• AMD: docker pull fdiakogiannis/trchprosthesis_requirements:rocm.5.6.latest.12sep2023
  It is recommended to use these containers for your test runs. Alternatively files ssg2/docker/requirements.txt contain all libraries required for running these experiments.

Data Preprocessing

We provide a RocksDB custom implementation for the case of the ISPRS Potsdam dataset. At a later stage we will also provide same functionality for the ISIC2018 dataset. See file ssg2/data/isprs/create_isprs_db.py. The user needs to place in appropriate location the raw ISPRS data for this to work (or, location ssg2/data/isprs/DataRaw/ in this repository. The definitions for the dataset can be found in the file ssg2/data/isprs/DatasetCreation_defs.py.

Training

Two examples are provided, one for the SSG2 modelling ssg2/training/ptavitssg2/main.py and another for the UNet-like run ssg2/training/ptavit/main.py. These can be run with command:
torchrun --standalone --nnodes=1 --nproc_per_node=4 mnist_ddp.py. Appropriate modifications need to take place to run in a distributed setting that relate to the custom environment of the HPC host and go beyond the purposes of this repository.

License

CSIRO MIT/BSD LICENSE

As a condition of this licence, you agree that where you make any adaptations, modifications, further developments, or additional features available to CSIRO or the public in connection with your access to the Software, you do so on the terms of the BSD 3-Clause Licence template, a copy available at: http://opensource.org/licenses/BSD-3-Clause.

CITATION

If you find this work / part of this work useful please star our repo and cite our work:

@article{DIAKOGIANNIS202444,
	author = {Foivos I. Diakogiannis and Suzanne Furby and Peter Caccetta and Xiaoliang Wu and Rodrigo Ibata and Ondrej Hlinka and John Taylor},
	doi = {10.1016/j.isprsjprs.2024.06.011},
	issn = {0924-2716},
	journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
	keywords = {Convolutional neural network, Semantic segmentation, Attention, Transformer, Vision transformer, Sequence modeling, Temporal dimension, Multitask learning, Semantic change detection},
	pages = {44–61},
	title = {SSG2: A new modeling paradigm for semantic segmentation},
	url = {https://www.sciencedirect.com/science/article/pii/S0924271624002491},
	volume = {215},
	year = {2024}
}