Source code for ivadomed.mixup

import os
import matplotlib.pyplot as plt
import numpy as np
import torch


[docs]def mixup(data, targets, alpha, debugging=False, ofolder=None): """Compute the mixup data. .. seealso:: Zhang, Hongyi, et al. "mixup: Beyond empirical risk minimization." arXiv preprint arXiv:1710.09412 (2017). Args: data (Tensor): Input images. targets (Tensor): Input masks. alpha (float): MixUp parameter. debugging (Bool): If True, then samples of mixup are saved as png files. ofolder (str): If debugging, output folder where "mixup" folder is created and samples are saved. Returns: Tensor, Tensor: Mixed image, Mixed mask. """ indices = torch.randperm(data.size(0)) data2 = data[indices] targets2 = targets[indices] lambda_ = np.random.beta(alpha, alpha) lambda_ = max(lambda_, 1 - lambda_) # ensure lambda_ >= 0.5 lambda_tensor = torch.FloatTensor([lambda_]) data = data * lambda_tensor + data2 * (1 - lambda_tensor) targets = targets * lambda_tensor + targets2 * (1 - lambda_tensor) if debugging: save_mixup_sample(ofolder, data, targets, lambda_tensor) return data, targets
[docs]def save_mixup_sample(ofolder, input_data, labeled_data, lambda_tensor): """Save mixup samples as png files in a "mixup" folder. Args: ofolder (str): Output folder where "mixup" folder is created and samples are saved. input_data (Tensor): Input image. labeled_data (Tensor): Input masks. lambda_tensor (Tensor): """ # Mixup folder mixup_folder = os.path.join(ofolder, 'mixup') if not os.path.isdir(mixup_folder): os.makedirs(mixup_folder) # Random sample random_idx = np.random.randint(0, input_data.size()[0]) # Output fname ofname = str(lambda_tensor.data.numpy()[0]) + '_' + str(random_idx).zfill(3) + '.png' ofname = os.path.join(mixup_folder, ofname) # Tensor to Numpy x = input_data.data.numpy()[random_idx, 0, :, :] y = labeled_data.data.numpy()[random_idx, 0, :, :] # Plot plt.figure(figsize=(20, 10)) plt.subplot(1, 2, 1) plt.axis("off") plt.imshow(x, interpolation='nearest', aspect='auto', cmap='gray') plt.subplot(1, 2, 2) plt.axis("off") plt.imshow(y, interpolation='nearest', aspect='auto', cmap='jet', vmin=0, vmax=1) plt.savefig(ofname, bbox_inches='tight', pad_inches=0, dpi=100) plt.close()