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import os
import nibabel as nib
import pandas as pd
import numpy as np
import torch
import monai
import torch.nn.functional as F
from multiprocessing import Pool
from tqdm import tqdm
def read_nii_files(directory):
"""
Retrieve paths of all NIfTI files in the given directory.
Args:
directory (str): Path to the directory containing NIfTI files.
Returns:
list: List of paths to NIfTI files.
"""
nii_files = []
for root, dirs, files in os.walk(directory):
for file in files:
if file.endswith('1.nii.gz'):
nii_files.append(os.path.join(root, file))
return nii_files
def read_nii_data(file_path):
"""
Read NIfTI file data.
Args:
file_path (str): Path to the NIfTI file.
Returns:
np.ndarray: NIfTI file data.
"""
try:
nii_img = nib.load(file_path)
nii_data = nii_img.get_fdata()
return nii_data
except Exception as e:
print(f"Error reading file {file_path}: {e}")
return None
def resize_array(array, current_spacing, target_spacing):
"""
Resize the array to match the target spacing.
Args:
array (torch.Tensor): Input array to be resized.
current_spacing (tuple): Current voxel spacing (z_spacing, xy_spacing, xy_spacing).
target_spacing (tuple): Target voxel spacing (target_z_spacing, target_x_spacing, target_y_spacing).
Returns:
np.ndarray: Resized array.
"""
# Calculate new dimensions
original_shape = array.shape[2:]
scaling_factors = [
current_spacing[i] / target_spacing[i] for i in range(len(original_shape))
]
new_shape = [
int(original_shape[i] * scaling_factors[i]) for i in range(len(original_shape))
]
# Resize the array
resized_array = F.interpolate(array, size=new_shape, mode='trilinear', align_corners=False).cpu().numpy()
return resized_array
def process_file(file_path):
"""
Process a single NIfTI file.
Args:
file_path (str): Path to the NIfTI file.
Returns:
None
"""
monai_loader = monai.transforms.Compose(
[
monai.transforms.LoadImaged(keys=['image']),
monai.transforms.AddChanneld(keys=['image']),
monai.transforms.Orientationd(axcodes="LPS", keys=['image']), # zyx
# monai.transforms.Spacingd(keys=["image"], pixdim=(1, 1, 3), mode=("bilinear")),
monai.transforms.CropForegroundd(keys=["image"], source_key="image"),
monai.transforms.ToTensord(keys=["image"]),
]
)
dictionary = monai_loader({'image':file_path})
img_data = dictionary['image']
file_name = os.path.basename(file_path)
row = df[df['VolumeName'] == file_name]
slope = float(row["RescaleSlope"].iloc[0])
intercept = float(row["RescaleIntercept"].iloc[0])
xy_spacing = float(row["XYSpacing"].iloc[0][1:][:-2].split(",")[0])
z_spacing = float(row["ZSpacing"].iloc[0])
# Define the target spacing values for SAT segmentation
target_x_spacing = 1.0
target_y_spacing = 1.0
target_z_spacing = 3.0
current = (z_spacing, xy_spacing, xy_spacing)
target = (target_z_spacing, target_x_spacing, target_y_spacing)
img_data = slope * img_data + intercept
img_data = img_data[0].numpy()
img_data = img_data.transpose(2, 0, 1)
tensor = torch.tensor(img_data)
tensor = tensor.unsqueeze(0).unsqueeze(0)
resized_array = resize_array(tensor, current, target)
resized_array = resized_array[0][0]
resized_array = resized_array.transpose(1,2,0)
# print('resized:',resized_array.shape)
# resized: (231, 387, 387)
save_folder = "../upload_data/valid_preprocessed/" #save folder for preprocessed
folder_path_new = os.path.join(save_folder, "valid_" + file_name.split("_")[1], "valid_" + file_name.split("_")[1] + file_name.split("_")[2]) #folder name for train or validation
os.makedirs(folder_path_new, exist_ok=True)
save_path = os.path.join(folder_path_new, file_name)
# np.savez(save_path, resized_array)
# Create an identity matrix
image_nifti = nib.Nifti1Image(resized_array,affine = np.eye(4))
nib.save(image_nifti, save_path)
# Example usage:
if __name__ == "__main__":
split_to_preprocess = '../src_data/valid' #select the validation or test split
nii_files = read_nii_files(split_to_preprocess)
df = pd.read_csv("../src_data/metadata/validation_metadata.csv") #select the metadata
num_workers = 18 # Number of worker processes
# # Process files using multiprocessing with tqdm progress bar
with Pool(num_workers) as pool:
list(tqdm(pool.imap(process_file, nii_files), total=len(nii_files)))
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