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AIM 2020 Relighting Challenge

This is YorkU team's source code for the three tracks of AIM 2020 relighting challenge.

As we explained in the challenge report, our solution is based on a normalization network (for track 1 & 3). We'll explain the details of the data used to train our normalizataion network and also how we augment the training data using the WB augmenter.

Normalization Data:

We used training images of track 2 to train the noramlization net. Let assume that the input images of track 2 are located in input directory. Please follow the following steps:

1. Download WB correction and WB augmenter from the following links:

   • WB correction: https://github.com/mahmoudnafifi/WB_sRGB

   • WB augmenter: https://github.com/mahmoudnafifi/WB_color_augmenter

2. Apply WB correction to images in training directory of track 2 -- do not overwrite original images. Name the result directory as gt

3. After white balancing, run generate_gt_normalization.m file. This code will generate gt_images directory that contains the final ground-truth images. Also, the code will delete the temporary gt directory created by the WB_sRGB_Matlab/demo_images.m code. Now, you can use the input and gt_images directories to start training the normalization net.

4. Run the WB augmenter (with its default 2 augmented version in the given code) with the given demo_WB_color_augmentation.m file. Then, run demo_WB_color_augmentation.m. Change the directory to make input directory variable = 'input'. The code will generate for you augmented sets (name the result directory as 'input_aug' and the new gt directory as 'gt_images_aug'). Use those directories to train the normalization net.

Data Augmentation for Track 1 & 2:

Augment input images with WB augmenter to generate 10 augmented images for each original image. We assume the input images (after augmentation) are located in train_t1. For train_t1, the augmented data and new ground truth should be located in train_t1/input_aug and train_t1/target_aug. We have used the modified demo_WB_color_augmentation.m (given) to process input and target images for track 1.

Image Relighting (task 1 & task 3)

This code requires PyTorch. We process downscaled images followed by a guided upsampling and post-processing steps. The code for the post-processing steps is given in relighting/post_processing.m. It depends on Bilateral Guided Upsampling. If you use Windows operating system, we built an exe program for the upsampling and post-processing steps. However, if this does not work, you need to rebuild the post_processing.exe program by downloading the Bilateral Guided Upsampling and build the relighting/post_processing.m code using Matlab.

To begin, please make sure that you prepared the normalization training data and image augmentation as described above.

Run relighting/train.py to train the normalization net, the one-to-one image relighting net, and the one-to-any image relighting net. Please adjust the training image directories accordingly.

To test trained models, run relighting/train.py. You can select the target task using the 'task' argument. If you selected relighting for the task and the input_dir_t was None, the code will run the one-to-one mapping.

Illuminant estimation (task 2)

This code requires Matlab 2019b or higher. To begin, please make sure that your data was augmented as described above.

Run estimation/training_resnet_hist.m to train the color temperature estimation network and estimation/training_resnet.m to train the angle estimation network. Please adjust the training image directory accordingly.

To test the trained models, run testing_code.m.

Trained models

Currently, we are not going to release our trained models, but they may be available soon.

Citation

Please cite the following paper if you used our method:

1. Majed El Helou, et al., AIM 2020: Scene Relighting and Illumination Estimation Challenge. In ECCV workshops, 2020.

If you used the RGB-uv histogram, please cite the following papers:

1. Mahmoud Afifi, Brian Price, Scott Cohen, and Michael S. Brown. When color constancy goes wrong: Correcting improperly white-balanced images. In CVPR, 2019.

2. Mahmoud Afifi and Michael S. Brown. Sensor-independent illumination estimation for DNN models. In BMVC, 2019.

If you used the WB augmenter, please cite the following paper:

1. Mahmoud Afifi and Michael S. Brown. What Else Can Fool Deep Learning? Addressing Color Constancy Errors on Deep Neural Network Performance. In ICCV, 2019.