# Copyright 2020 MONAI Consortium # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # http://www.apache.org/licenses/LICENSE-2.0 # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import logging import os import sys import tempfile from glob import glob import nibabel as nib import numpy as np import torch from ignite.metrics import Accuracy import monai from monai.data import create_test_image_3d from monai.engines import SupervisedEvaluator, SupervisedTrainer from monai.handlers import ( CheckpointSaver, LrScheduleHandler, MeanDice, StatsHandler, TensorBoardImageHandler, TensorBoardStatsHandler, ValidationHandler, ) from monai.inferers import SimpleInferer, SlidingWindowInferer from monai.transforms import ( Activationsd, AsChannelFirstd, AsDiscreted, Compose, KeepLargestConnectedComponentd, LoadNiftid, RandCropByPosNegLabeld, RandRotate90d, ScaleIntensityd, ToTensord, ) def main(tempdir): monai.config.print_config() logging.basicConfig(stream=sys.stdout, level=logging.INFO) # create a temporary directory and 40 random image, mask pairs print(f"generating synthetic data to {tempdir} (this may take a while)") for i in range(40): im, seg = create_test_image_3d(128, 128, 128, num_seg_classes=1, channel_dim=-1) n = nib.Nifti1Image(im, np.eye(4)) nib.save(n, os.path.join(tempdir, f"img{i:d}.nii.gz")) n = nib.Nifti1Image(seg, np.eye(4)) nib.save(n, os.path.join(tempdir, f"seg{i:d}.nii.gz")) images = sorted(glob(os.path.join(tempdir, "img*.nii.gz"))) segs = sorted(glob(os.path.join(tempdir, "seg*.nii.gz"))) train_files = [{"image": img, "label": seg} for img, seg in zip(images[:20], segs[:20])] val_files = [{"image": img, "label": seg} for img, seg in zip(images[-20:], segs[-20:])] # define transforms for image and segmentation train_transforms = Compose( [ LoadNiftid(keys=["image", "label"]), AsChannelFirstd(keys=["image", "label"], channel_dim=-1), ScaleIntensityd(keys="image"), RandCropByPosNegLabeld( keys=["image", "label"], label_key="label", spatial_size=[96, 96, 96], pos=1, neg=1, num_samples=4 ), RandRotate90d(keys=["image", "label"], prob=0.5, spatial_axes=[0, 2]), ToTensord(keys=["image", "label"]), ] ) val_transforms = Compose( [ LoadNiftid(keys=["image", "label"]), AsChannelFirstd(keys=["image", "label"], channel_dim=-1), ScaleIntensityd(keys="image"), ToTensord(keys=["image", "label"]), ] ) # create a training data loader train_ds = monai.data.CacheDataset(data=train_files, transform=train_transforms, cache_rate=0.5) # use batch_size=2 to load images and use RandCropByPosNegLabeld to generate 2 x 4 images for network training train_loader = monai.data.DataLoader(train_ds, batch_size=2, shuffle=True, num_workers=4) # create a validation data loader val_ds = monai.data.CacheDataset(data=val_files, transform=val_transforms, cache_rate=1.0) val_loader = monai.data.DataLoader(val_ds, batch_size=1, num_workers=4) # create UNet, DiceLoss and Adam optimizer device = torch.device("cuda" if torch.cuda.is_available() else "cpu") net = monai.networks.nets.UNet( dimensions=3, in_channels=1, out_channels=1, channels=(16, 32, 64, 128, 256), strides=(2, 2, 2, 2), num_res_units=2, ).to(device) loss = monai.losses.DiceLoss(sigmoid=True) opt = torch.optim.Adam(net.parameters(), 1e-3) lr_scheduler = torch.optim.lr_scheduler.StepLR(opt, step_size=2, gamma=0.1) val_post_transforms = Compose( [ Activationsd(keys="pred", sigmoid=True), AsDiscreted(keys="pred", threshold_values=True), KeepLargestConnectedComponentd(keys="pred", applied_labels=[1]), ] ) val_handlers = [ StatsHandler(output_transform=lambda x: None), TensorBoardStatsHandler(log_dir="./runs/", output_transform=lambda x: None), TensorBoardImageHandler( log_dir="./runs/", batch_transform=lambda x: (x["image"], x["label"]), output_transform=lambda x: x["pred"], ), CheckpointSaver(save_dir="./runs/", save_dict={"net": net}, save_key_metric=True), ] evaluator = SupervisedEvaluator( device=device, val_data_loader=val_loader, network=net, inferer=SlidingWindowInferer(roi_size=(96, 96, 96), sw_batch_size=4, overlap=0.5), post_transform=val_post_transforms, key_val_metric={ "val_mean_dice": MeanDice(include_background=True, output_transform=lambda x: (x["pred"], x["label"])) }, additional_metrics={"val_acc": Accuracy(output_transform=lambda x: (x["pred"], x["label"]))}, val_handlers=val_handlers, # if no FP16 support in GPU or PyTorch version < 1.6, will not enable AMP evaluation amp=True if monai.config.get_torch_version_tuple() >= (1, 6) else False, ) train_post_transforms = Compose( [ Activationsd(keys="pred", sigmoid=True), AsDiscreted(keys="pred", threshold_values=True), KeepLargestConnectedComponentd(keys="pred", applied_labels=[1]), ] ) train_handlers = [ LrScheduleHandler(lr_scheduler=lr_scheduler, print_lr=True), ValidationHandler(validator=evaluator, interval=2, epoch_level=True), StatsHandler(tag_name="train_loss", output_transform=lambda x: x["loss"]), TensorBoardStatsHandler(log_dir="./runs/", tag_name="train_loss", output_transform=lambda x: x["loss"]), CheckpointSaver(save_dir="./runs/", save_dict={"net": net, "opt": opt}, save_interval=2, epoch_level=True), ] trainer = SupervisedTrainer( device=device, max_epochs=5, train_data_loader=train_loader, network=net, optimizer=opt, loss_function=loss, inferer=SimpleInferer(), post_transform=train_post_transforms, key_train_metric={"train_acc": Accuracy(output_transform=lambda x: (x["pred"], x["label"]))}, train_handlers=train_handlers, # if no FP16 support in GPU or PyTorch version < 1.6, will not enable AMP training amp=True if monai.config.get_torch_version_tuple() >= (1, 6) else False, ) trainer.run() if __name__ == "__main__": with tempfile.TemporaryDirectory() as tempdir: main(tempdir)