PIDNet

A three-branch semantic segmentation network that adds a dedicated boundary branch to a proportional-integral-derivative-inspired design, aimed at real-time inference. LibreYOLO ships it for semantic segmentation only.

Tasks
semantic
Sizes
s, m, l at 1024 px
Install
pip install libreyolo
Support tier
Inference only, since v. Predict, validate and export only. Training features do not apply.
Upstream
PIDNet by Jiacong Xu, MIT. Paper, source
Licenses
Code MIT, weights MIT. Commercial use

Install

PIDNet needs no optional extra. Everything it imports is in the base install.

bash
pip install libreyolo

Predict

Weights download from Hugging Face on first use and are cached locally. The -sem filename suffix is required for this family.

Python
from libreyolo import LibreYOLO, SAMPLE_IMAGE model = LibreYOLO("LibrePIDNets-sem.pt")result = model(SAMPLE_IMAGE, save=True) mask = result.semantic_maskprint(mask.data.shape)   # (H, W) class idsprint(mask.classes)      # sorted class ids present in the image
CLI
libreyolo predict model=LibrePIDNets-sem.pt source=https://raw.githubusercontent.com/LibreYOLO/libreyolo/release/libreyolo/assets/parkour.jpg save=True

Semantic segmentation returns one class id per pixel, not boxes, so result.semantic_mask carries a (H, W) array on .data and the list of class ids present in the image on .classes. conf, iou and max_det are accepted for API parity but have no effect: the model assigns a class to every pixel by argmax, with no confidence threshold or NMS step. See prediction for sources, streaming and result handling.

Variants

Three sizes, all at a fixed 1024 px input. The published checkpoints are conversions of the official PIDNet Cityscapes weights, 19 classes.

LibreYOLO does not train PIDNet: train() raises NotImplementedError for this family, which the support tier above marks as inference only.

Validate

val() returns metrics/mIoU and metrics/pixel_accuracy, measured against any dataset in the format you trained on.

Python
from libreyolo import LibreYOLO model = LibreYOLO("LibrePIDNets-sem.pt")metrics = model.val(data="my-dataset.yaml") print(metrics["metrics/mIoU"])print(metrics["metrics/pixel_accuracy"])
CLI
libreyolo val model=LibrePIDNets-sem.pt data=my-dataset.yaml

Export

TaskONNXTorchScriptExecuTorchTensorRTOpenVINOPaddleMNNRKNNncnnTFLiteCoreMLCore AI
semanticsemantic to ONNX: supported. semantic to TorchScript: supported. semantic to ExecuTorch: supported. semantic to TensorRT: supported. semantic to OpenVINO: supported. semantic to Paddle: not supportedsemantic to MNN: not supportedsemantic to RKNN: not supportedsemantic to ncnn: supported. semantic to TFLite: supported. semantic to CoreML: not supportedsemantic to Core AI: supported.

An exported artifact loads back through LibreYOLO() on its file suffix, so a .onnx or .engine file behaves like a checkpoint and returns the same Results. Export lists the arguments every format accepts.

Python
from libreyolo import LibreYOLO model = LibreYOLO("LibrePIDNets-sem.pt")model.export(format="onnx")model.export(format="tensorrt", half=True)
CLI
libreyolo export model=LibrePIDNets-sem.pt format=onnxlibreyolo export model=LibrePIDNets-sem.pt format=tensorrt half=True
Use the exported file
from libreyolo import LibreYOLO, SAMPLE_IMAGE # The factory routes on the file suffix, so an exported artifact loads# like any checkpoint and returns the same Results object.model = LibreYOLO("LibrePIDNets-sem.onnx")result = model(SAMPLE_IMAGE) print(result.semantic_mask.data.shape)

Checkpoints

Every published weight file for this family.

FileInput (px)Weights license
semantic
LibrePIDNets-sem.pt1024mit
LibrePIDNetm-sem.pt1024mit
LibrePIDNetl-sem.pt1024mit

Every file above exists in the LibreYOLO org today and downloads on first use.

Licensing

Check the license on the Hugging Face repository of the specific weights you download. Every checkpoint in the LibreYOLO org carries one, and they are not always the same across a family. That repository is the authoritative source; the summary below describes what applied when this page was last verified.

This is a description of the licenses involved, not legal advice. If the answer matters commercially, read the licenses yourself and take your own counsel.

Original work
PIDNet, Jiacong Xu
Upstream license
MIT
LibreYOLO code
MIT
Weights
MIT, republished at huggingface.co/LibreYOLO
Interpretation
MIT is a permissive license, so this code and these weights can be used in commercial and closed-source products. It asks only that you keep the copyright and license notice with any copy you redistribute. LibreYOLO's checkpoints are conversions of the official PIDNet Cityscapes weights, which upstream licenses as MIT. The Cityscapes dataset itself carries separate research-oriented terms and is not redistributed by LibreYOLO.

Citation

@misc{xu2022pidnet,
      title={PIDNet: A Real-time Semantic Segmentation Network Inspired from PID Controller}, 
      author={Jiacong Xu and Zixiang Xiong and Shankar P. Bhattacharyya},
      year={2022},
      eprint={2206.02066},
      archivePrefix={arXiv},
      primaryClass={cs.CV}
}

Copied from the authors' citation block at github.com/XuJiacong/PIDNet#bibtex-citation.

Verified against LibreYOLO v1.5.0. Support tables, checkpoints and benchmark numbers on this page are generated from the released library and the published weights, not written by hand.