LHDR_PyTorch

The official PyTorch implementation of paper "LHDR: HDR Reconstruction for Legacy Content using a Lightweight DNN" (paper (ArXiv), paper, supplementary material) in ACCV2022.

@inproceedings{guo2022lhdr,
  title={LHDR: HDR Reconstructionfor Legacy Content using a Lightweight DNN}, 
  author={Guo, Cheng and Jiang Xiuhua},
  booktitle={Proceedings of the 16th Asian Conference on Computer Vision},
  year={2022},
  pages={3155-3171}
}

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1. Overview

1.1 Our scope

This method belongs to computer vision (CV) -> image-to-image (I2I) -> low-level vision -> high dynamic range (HDR) related.

NOTE THAT this method DONNOT belong to multi-exposure HDR imaging which takes merge multiple images into HDR, it belongs to single-image reconstruction (SI-HDR) who predict HDR from single image.

1.2 Key features

Our LHDR tackles 2 issues of current methods:

• The first L: current methods could not well process Legacy content with degradations e.g. camera noise, JPEG compression and over-exposure etc.
• The second L: current methods are too bulky for real application, so we have to design a more Lightweight network.

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2. Getting Started

2.1 Prerequisites

• Python
• PyTorch
• OpenCV
• NumPy
• NVIDIA GPU, cnDNN, CUDA (only for training)

2.2 How to test

Run test.py with below configuration(s):

python test.py imgName.jpg

When batch processing, use wildcard *:

python test.py imgPath/*.jpg

Add below configuration(s) for specific propose:

Propose	Configuration
Specify output path	-out resultDir/
Resize image before inference	-resize True -height newH -width newW
Add filename tag	-tag yourTag
Force CPU processing	-use_gpu False
Change precision to half (when GRAM OMM)	-half True
Save result in another format (defalut .hdr)	-out_format suffix png as 16bit .png exr require extra package openEXR
Donnot linerize the output HDR	-linearize False

2.3 How to train

Put our network.py under your own PyTorch scheme, e.g. BasicSR, and change the dataloader etc., remember to:

• Normalize input SDR (img) by dividing 255.0. Note that the input to network is a tuple [img,s_cond,c_cond], see line145 in test.py for detail.
• Transfer the normalized label HDR to non-linear domain by 0.45 exponent (as our pre-processing specified in paper).
• Change channel order BGR (if so) to RGB.

Contact

Guo Cheng (Andre Guo) guocheng@cuc.edu.cn

• State Key Laboratory of Media Convergence and Communication (MCC), Communication University of China (CUC), Beijing, China.
• Peng Cheng Laboratory (PCL), Shenzhen, China.