Source code for ivadomed.transforms

import copy
import functools
import math
import numbers
import random

import numpy as np
import torch
from loguru import logger
from scipy.ndimage import zoom
from scipy.ndimage.filters import gaussian_filter
from scipy.ndimage.interpolation import map_coordinates, affine_transform
from scipy.ndimage.measurements import label, center_of_mass
from scipy.ndimage.morphology import binary_dilation, binary_fill_holes, binary_closing
from skimage.exposure import equalize_adapthist
from torchvision import transforms as torchvision_transforms

from ivadomed.loader import utils as imed_loader_utils

[docs]def multichannel_capable(wrapped): """Decorator to make a given function compatible multichannel images. Args: wrapped: Given function. Returns: Functions' return. """ @functools.wraps(wrapped) def wrapper(self, sample, metadata): if isinstance(sample, list): list_data, list_metadata = [], [] for s_cur, m_cur in zip(sample, metadata): if len(list_metadata) > 0: if not isinstance(list_metadata[-1], list): imed_loader_utils.update_metadata([list_metadata[-1]], [m_cur]) else: imed_loader_utils.update_metadata(list_metadata[-1], [m_cur]) # Run function for each sample of the list data_cur, metadata_cur = wrapped(self, s_cur, m_cur) list_data.append(data_cur) list_metadata.append(metadata_cur) return list_data, list_metadata # If sample is None, then return a pair (None, None) if sample is None: return None, None else: return wrapped(self, sample, metadata) return wrapper
[docs]def two_dim_compatible(wrapped): """Decorator to make a given function compatible 2D or 3D images. Args: wrapped: Given function. Returns: Functions' return. """ @functools.wraps(wrapped) def wrapper(self, sample, metadata): # Check if sample is 2D if len(sample.shape) == 2: # Add one dimension sample = np.expand_dims(sample, axis=-1) # Run transform result_sample, result_metadata = wrapped(self, sample, metadata) # Remove last dimension return np.squeeze(result_sample, axis=-1), result_metadata else: return wrapped(self, sample, metadata) return wrapper
[docs]class ImedTransform(object): """Base class for transforamtions."""
[docs] def __call__(self, sample, metadata=None): raise NotImplementedError("You need to implement the transform() method.")
[docs]class Compose(object): """Composes transforms together. Composes transforms together and split between images, GT and ROI. self.transform is a dict: - keys: "im", "gt" and "roi" - values torchvision_transform.Compose objects. Attributes: dict_transforms (dict): Dictionary where the keys are the transform names and the value their parameters. requires_undo (bool): If True, does not include transforms which do not have an undo_transform implemented yet. Args: transform (dict): Keys are "im", "gt", "roi" and values are torchvision_transforms.Compose of the transformations of interest. """
[docs] def __init__(self, dict_transforms, requires_undo=False): list_tr_im, list_tr_gt, list_tr_roi = [], [], [] for transform in dict_transforms.keys(): parameters = dict_transforms[transform] # Get list of data type if "applied_to" in parameters: list_applied_to = parameters["applied_to"] else: list_applied_to = ["im", "gt", "roi"] # call transform if transform in globals(): if transform == "NumpyToTensor": continue params_cur = {k: parameters[k] for k in parameters if k != "applied_to" and k != "preprocessing"} transform_obj = globals()[transform](**params_cur) else: raise ValueError('ERROR: {} transform is not available. ' 'Please check its compatibility with your model json file.'.format(transform)) # check if undo_transform method is implemented if requires_undo: if not hasattr(transform_obj, 'undo_transform'):'{} transform not included since no undo_transform available for it.'.format(transform)) continue if "im" in list_applied_to: list_tr_im.append(transform_obj) if "roi" in list_applied_to: list_tr_roi.append(transform_obj) if "gt" in list_applied_to: list_tr_gt.append(transform_obj) self.transform = { "im": torchvision_transforms.Compose(list_tr_im), "gt": torchvision_transforms.Compose(list_tr_gt), "roi": torchvision_transforms.Compose(list_tr_roi)}
[docs] def __call__(self, sample, metadata, data_type='im', preprocessing=False): if self.transform[data_type] is None or len(metadata) == 0: # In case self.transform[data_type] is None return None, None else: for tr in self.transform[data_type].transforms: sample, metadata = tr(sample, metadata) if not preprocessing: numpy_to_tensor = NumpyToTensor() sample, metadata = numpy_to_tensor(sample, metadata) return sample, metadata
[docs]class UndoCompose(object): """Undo the Compose transformations. Call the undo transformations in the inverse order than the "do transformations". Attributes: compose (torchvision_transforms.Compose): Args: transforms (torchvision_transforms.Compose): """
[docs] def __init__(self, compose): self.transforms = compose
[docs] def __call__(self, sample, metadata, data_type='gt'): if self.transforms.transform[data_type] is None: # In case self.transforms.transform[data_type] is None return None, None else: numpy_to_tensor = NumpyToTensor() sample, metadata = numpy_to_tensor.undo_transform(sample, metadata) for tr in self.transforms.transform[data_type].transforms[::-1]: sample, metadata = tr.undo_transform(sample, metadata) return sample, metadata
[docs]class UndoTransform(object): """Call undo transformation. Attributes: transform (ImedTransform): Args: transform (ImedTransform): """
[docs] def __init__(self, transform): self.transform = transform
[docs] def __call__(self, sample): return self.transform.undo_transform(sample)
[docs]class NumpyToTensor(ImedTransform): """Converts nd array to tensor object."""
[docs] def undo_transform(self, sample, metadata=None): """Converts Tensor to nd array.""" return list(sample.numpy()), metadata
[docs] def __call__(self, sample, metadata=None): """Converts nd array to Tensor.""" sample = np.array(sample) # Use np.ascontiguousarray to avoid axes permutations issues arr_contig = np.ascontiguousarray(sample, dtype=sample.dtype) return torch.from_numpy(arr_contig), metadata
[docs]class Resample(ImedTransform): """ Resample image to a given resolution. Args: hspace (float): Resolution along the first axis, in mm. wspace (float): Resolution along the second axis, in mm. dspace (float): Resolution along the third axis, in mm. interpolation_order (int): Order of spline interpolation. Set to 0 for label data. Default=2. """
[docs] def __init__(self, hspace, wspace, dspace=1.): self.hspace = hspace self.wspace = wspace self.dspace = dspace
[docs] @multichannel_capable @two_dim_compatible def undo_transform(self, sample, metadata=None): """Resample to original resolution.""" assert "data_shape" in metadata is_2d = sample.shape[-1] == 1 # Get params original_shape = metadata["preresample_shape"] current_shape = sample.shape params_undo = [x / y for x, y in zip(original_shape, current_shape)] if is_2d: params_undo[-1] = 1.0 # Undo resampling data_out = zoom(sample, zoom=params_undo, order=1 if metadata['data_type'] == 'gt' else 2) # Data type data_out = data_out.astype(sample.dtype) return data_out, metadata
[docs] @multichannel_capable @multichannel_capable # for multiple raters during training/preprocessing @two_dim_compatible def __call__(self, sample, metadata=None): """Resample to a given resolution, in millimeters.""" # Get params # Voxel dimension in mm is_2d = sample.shape[-1] == 1 metadata['preresample_shape'] = sample.shape zooms = list(metadata["zooms"]) if len(zooms) == 2: zooms += [1.0] hfactor = zooms[0] / self.hspace wfactor = zooms[1] / self.wspace dfactor = zooms[2] / self.dspace params_resample = (hfactor, wfactor, dfactor) if not is_2d else (hfactor, wfactor, 1.0) # Run resampling data_out = zoom(sample, zoom=params_resample, order=1 if metadata['data_type'] == 'gt' else 2) # Data type data_out = data_out.astype(sample.dtype) return data_out, metadata
[docs]class NormalizeInstance(ImedTransform): """Normalize a tensor or an array image with mean and standard deviation estimated from the sample itself.""" @multichannel_capable def undo_transform(self, sample, metadata=None): # Nothing return sample, metadata
[docs] @multichannel_capable def __call__(self, sample, metadata=None): data_out = (sample - sample.mean()) / sample.std() return data_out, metadata
[docs]class CroppableArray(np.ndarray): """Zero padding slice past end of array in numpy. Adapted From: """
[docs] def __getitem__(self, item): all_in_slices = [] pad = [] for dim in range(self.ndim): # If the slice has no length then it's a single argument. # If it's just an integer then we just return, this is # needed for the representation to work properly # If it's not then create a list containing None-slices # for dim>=1 and continue down the loop try: len(item) except TypeError: if isinstance(item, int): return super().__getitem__(item) newitem = [slice(None)] * self.ndim newitem[0] = item item = newitem # We're out of items, just append noop slices if dim >= len(item): all_in_slices.append(slice(0, self.shape[dim])) pad.append((0, 0)) # We're dealing with an integer (no padding even if it's # out of bounds) if isinstance(item[dim], int): all_in_slices.append(slice(item[dim], item[dim] + 1)) pad.append((0, 0)) # Dealing with a slice, here it get's complicated, we need # to correctly deal with None start/stop as well as with # out-of-bound values and correct padding elif isinstance(item[dim], slice): # Placeholders for values start, stop = 0, self.shape[dim] this_pad = [0, 0] if item[dim].start is None: start = 0 else: if item[dim].start < 0: this_pad[0] = -item[dim].start start = 0 else: start = item[dim].start if item[dim].stop is None: stop = self.shape[dim] else: if item[dim].stop > self.shape[dim]: this_pad[1] = item[dim].stop - self.shape[dim] stop = self.shape[dim] else: stop = item[dim].stop all_in_slices.append(slice(start, stop)) pad.append(tuple(this_pad)) # Let numpy deal with slicing ret = super().__getitem__(tuple(all_in_slices)) # and padding ret = np.pad(ret, tuple(pad), mode='constant', constant_values=0) return ret
[docs]class Crop(ImedTransform): """Crop data. Args: size (tuple of int): Size of the output sample. Tuple of size 2 if dealing with 2D samples, 3 with 3D samples. Attributes: size (tuple of int): Size of the output sample. Tuple of size 3. """
[docs] def __init__(self, size): self.size = size if len(size) == 3 else size + [0]
@staticmethod def _adjust_padding(npad, sample): npad_out_tuple = [] for idx_dim, tuple_pad in enumerate(npad): pad_start, pad_end = tuple_pad if pad_start < 0 or pad_end < 0: # Move axis of interest sample_reorient = np.swapaxes(sample, 0, idx_dim) # Adjust pad and crop if pad_start < 0 and pad_end < 0: sample_crop = sample_reorient[abs(pad_start):pad_end, ] pad_end, pad_start = 0, 0 elif pad_start < 0: sample_crop = sample_reorient[abs(pad_start):, ] pad_start = 0 else: # i.e. pad_end < 0: sample_crop = sample_reorient[:pad_end, ] pad_end = 0 # Reorient sample = np.swapaxes(sample_crop, 0, idx_dim) npad_out_tuple.append((pad_start, pad_end)) return npad_out_tuple, sample
[docs] @multichannel_capable @multichannel_capable # for multiple raters during training/preprocessing def __call__(self, sample, metadata): # Get params is_2d = sample.shape[-1] == 1 th, tw, td = self.size fh, fw, fd, h, w, d = metadata['crop_params'][self.__class__.__name__] # Crop data # Note we use here CroppableArray in order to deal with "out of boundaries" crop # e.g. if fh is negative or fh+th out of bounds, then it will pad if is_2d: data_out = sample.view(CroppableArray)[fh:fh + th, fw:fw + tw, :] else: data_out = sample.view(CroppableArray)[fh:fh + th, fw:fw + tw, fd:fd + td] return data_out, metadata
@multichannel_capable @two_dim_compatible def undo_transform(self, sample, metadata=None): # Get crop params is_2d = sample.shape[-1] == 1 th, tw, td = self.size fh, fw, fd, h, w, d = metadata["crop_params"][self.__class__.__name__] # Compute params to undo transform pad_left = fw pad_right = w - pad_left - tw pad_top = fh pad_bottom = h - pad_top - th pad_front = fd if not is_2d else 0 pad_back = d - pad_front - td if not is_2d else 0 npad = [(pad_top, pad_bottom), (pad_left, pad_right), (pad_front, pad_back)] # Check and adjust npad if needed, i.e. if crop out of boundaries npad_adj, sample_adj = self._adjust_padding(npad, sample.copy()) # Apply padding data_out = np.pad(sample_adj, npad_adj, mode='constant', constant_values=0).astype(sample.dtype) return data_out, metadata
[docs]class CenterCrop(Crop): """Make a centered crop of a specified size."""
[docs] @multichannel_capable @multichannel_capable # for multiple raters during training/preprocessing @two_dim_compatible def __call__(self, sample, metadata=None): # Crop parameters th, tw, td = self.size h, w, d = sample.shape fh = int(round((h - th) / 2.)) fw = int(round((w - tw) / 2.)) fd = int(round((d - td) / 2.)) params = (fh, fw, fd, h, w, d) metadata['crop_params'][self.__class__.__name__] = params # Call base method return super().__call__(sample, metadata)
[docs]class ROICrop(Crop): """Make a crop of a specified size around a Region of Interest (ROI)."""
[docs] @multichannel_capable @multichannel_capable # for multiple raters during training/preprocessing @two_dim_compatible def __call__(self, sample, metadata=None): # If crop_params are not in metadata, # then we are here dealing with ROI data to determine crop params if self.__class__.__name__ not in metadata['crop_params']: # Compute center of mass of the ROI h_roi, w_roi, d_roi = center_of_mass(sample.astype( h_roi, w_roi, d_roi = int(round(h_roi)), int(round(w_roi)), int(round(d_roi)) th, tw, td = self.size th_half, tw_half, td_half = int(round(th / 2.)), int(round(tw / 2.)), int(round(td / 2.)) # compute top left corner of the crop area fh = h_roi - th_half fw = w_roi - tw_half fd = d_roi - td_half # Crop params h, w, d = sample.shape params = (fh, fw, fd, h, w, d) metadata['crop_params'][self.__class__.__name__] = params # Call base method return super().__call__(sample, metadata)
[docs]class DilateGT(ImedTransform): """Randomly dilate a ground-truth tensor. .. image:: :width: 500px :align: center Args: dilation_factor (float): Controls the number of dilation iterations. For each individual lesion, the number of dilation iterations is computed as follows: nb_it = int(round(dilation_factor * sqrt(lesion_area))) If dilation_factor <= 0, then no dilation will be performed. """
[docs] def __init__(self, dilation_factor): self.dil_factor = dilation_factor
@staticmethod def dilate_lesion(arr_bin, arr_soft, label_values): for lb in label_values: # binary dilation with 1 iteration arr_dilated = binary_dilation(arr_bin, iterations=1) # isolate new voxels, i.e. the ones from the dilation new_voxels = np.logical_xor(arr_dilated, arr_bin).astype( # assign a soft value (]0, 1[) to the new voxels soft_new_voxels = lb * new_voxels # add the new voxels to the input mask arr_soft += soft_new_voxels arr_bin = (arr_soft > 0).astype( return arr_bin, arr_soft def dilate_arr(self, arr, dil_factor): # identify each object arr_labeled, lb_nb = label(arr.astype( # loop across each object arr_bin_lst, arr_soft_lst = [], [] for obj_idx in range(1, lb_nb + 1): arr_bin_obj = (arr_labeled == obj_idx).astype( arr_soft_obj = np.copy(arr_bin_obj).astype(np.float) # compute the number of dilation iterations depending on the size of the lesion nb_it = int(round(dil_factor * math.sqrt(arr_bin_obj.sum()))) # values of the voxels added to the input mask soft_label_values = [x / (nb_it + 1) for x in range(nb_it, 0, -1)] # dilate lesion arr_bin_dil, arr_soft_dil = self.dilate_lesion(arr_bin_obj, arr_soft_obj, soft_label_values) arr_bin_lst.append(arr_bin_dil) arr_soft_lst.append(arr_soft_dil) # sum dilated objects arr_bin_idx = np.sum(np.array(arr_bin_lst), axis=0) arr_soft_idx = np.sum(np.array(arr_soft_lst), axis=0) # clip values in case dilated voxels overlap arr_bin_clip, arr_soft_clip = np.clip(arr_bin_idx, 0, 1), np.clip(arr_soft_idx, 0.0, 1.0) return arr_soft_clip.astype(np.float), arr_bin_clip.astype( @staticmethod def random_holes(arr_in, arr_soft, arr_bin): arr_soft_out = np.copy(arr_soft) # coordinates of the new voxels, i.e. the ones from the dilation new_voxels_xx, new_voxels_yy, new_voxels_zz = np.where(np.logical_xor(arr_bin, arr_in)) nb_new_voxels = new_voxels_xx.shape[0] # ratio of voxels added to the input mask from the dilated mask new_voxel_ratio = random.random() # randomly select new voxel indexes to remove idx_to_remove = random.sample(range(nb_new_voxels), int(round(nb_new_voxels * (1 - new_voxel_ratio)))) # set to zero the here-above randomly selected new voxels arr_soft_out[new_voxels_xx[idx_to_remove], new_voxels_yy[idx_to_remove], new_voxels_zz[idx_to_remove]] = 0.0 arr_bin_out = (arr_soft_out > 0).astype( return arr_soft_out, arr_bin_out @staticmethod def post_processing(arr_in, arr_soft, arr_bin, arr_dil): # remove new object that are not connected to the input mask arr_labeled, lb_nb = label(arr_bin) connected_to_in = arr_labeled * arr_in for lb in range(1, lb_nb + 1): if np.sum(connected_to_in == lb) == 0: arr_soft[arr_labeled == lb] = 0 struct = np.ones((3, 3, 1) if arr_soft.shape[2] == 1 else (3, 3, 3)) # binary closing arr_bin_closed = binary_closing((arr_soft > 0).astype(, structure=struct) # fill binary holes arr_bin_filled = binary_fill_holes(arr_bin_closed) # recover the soft-value assigned to the filled-holes arr_soft_out = arr_bin_filled * arr_dil return arr_soft_out
[docs] @multichannel_capable @two_dim_compatible def __call__(self, sample, metadata=None): # binarize for processing gt_data_np = (sample > 0.5).astype(np.int_) if self.dil_factor > 0 and np.sum(sample): # dilation gt_dil, gt_dil_bin = self.dilate_arr(gt_data_np, self.dil_factor) # random holes in dilated area # gt_holes, gt_holes_bin = self.random_holes(gt_data_np, gt_dil, gt_dil_bin) # post-processing # gt_pp = self.post_processing(gt_data_np, gt_holes, gt_holes_bin, gt_dil) # return gt_pp.astype(np.float32), metadata return gt_dil.astype(np.float32), metadata else: return sample, metadata
[docs]class BoundingBoxCrop(Crop): """Crops image according to given bounding box."""
[docs] @multichannel_capable @two_dim_compatible def __call__(self, sample, metadata): assert 'bounding_box' in metadata x_min, x_max, y_min, y_max, z_min, z_max = metadata['bounding_box'] x, y, z = sample.shape metadata['crop_params'][self.__class__.__name__] = (x_min, y_min, z_min, x, y, z) # Call base method return super().__call__(sample, metadata)
[docs]class RandomAffine(ImedTransform): """Apply Random Affine transformation. Args: degrees (float): Positive float or list (or tuple) of length two. Angles in degrees. If only a float is provided, then rotation angle is selected within the range [-degrees, degrees]. Otherwise, the list / tuple defines this range. translate (list of float): List of floats between 0 and 1, of length 2 or 3 depending on the sample shape (2D or 3D). These floats defines the maximum range of translation along each axis. scale (list of float): List of floats between 0 and 1, of length 2 or 3 depending on the sample shape (2D or 3D). These floats defines the maximum range of scaling along each axis. Attributes: degrees (tuple of floats): translate (list of float): scale (list of float): """
[docs] def __init__(self, degrees=0, translate=None, scale=None): # Rotation if isinstance(degrees, numbers.Number): if degrees < 0: raise ValueError("If degrees is a single number, it must be positive.") self.degrees = (-degrees, degrees) else: assert isinstance(degrees, (tuple, list)) and len(degrees) == 2, \ "degrees should be a list or tuple and it must be of length 2." self.degrees = degrees # Scale if scale is not None: assert isinstance(scale, (tuple, list)) and (len(scale) == 2 or len(scale) == 3), \ "scale should be a list or tuple and it must be of length 2 or 3." for s in scale: if not (0.0 <= s <= 1.0): raise ValueError("scale values should be between 0 and 1") if len(scale) == 2: scale.append(0.0) self.scale = scale else: self.scale = [0., 0., 0.] # Translation if translate is not None: assert isinstance(translate, (tuple, list)) and (len(translate) == 2 or len(translate) == 3), \ "translate should be a list or tuple and it must be of length 2 or 3." for t in translate: if not (0.0 <= t <= 1.0): raise ValueError("translation values should be between 0 and 1") if len(translate) == 2: translate.append(0.0) self.translate = translate
[docs] @multichannel_capable @two_dim_compatible def __call__(self, sample, metadata=None): # Rotation # If angle and metadata have been already defined for this sample, then use them if 'rotation' in metadata: angle, axes = metadata['rotation'] # Otherwise, get random ones else: # Get the random angle angle = math.radians(np.random.uniform(self.degrees[0], self.degrees[1])) # Get the two axes that define the plane of rotation axes = list(random.sample(range(3 if sample.shape[2] > 1 else 2), 2)) axes.sort() # Save params metadata['rotation'] = [angle, axes] # Scale if "scale" in metadata: scale_x, scale_y, scale_z = metadata['scale'] else: scale_x = random.uniform(1 - self.scale[0], 1 + self.scale[0]) scale_y = random.uniform(1 - self.scale[1], 1 + self.scale[1]) scale_z = random.uniform(1 - self.scale[2], 1 + self.scale[2]) metadata['scale'] = [scale_x, scale_y, scale_z] # Get params if 'translation' in metadata: translations = metadata['translation'] else: self.data_shape = sample.shape if self.translate is not None: max_dx = self.translate[0] * self.data_shape[0] max_dy = self.translate[1] * self.data_shape[1] max_dz = self.translate[2] * self.data_shape[2] translations = (np.round(np.random.uniform(-max_dx, max_dx)), np.round(np.random.uniform(-max_dy, max_dy)), np.round(np.random.uniform(-max_dz, max_dz))) else: translations = (0, 0, 0) metadata['translation'] = translations # Do rotation shape = 0.5 * np.array(sample.shape) if axes == [0, 1]: rotate = np.array([[math.cos(angle), -math.sin(angle), 0], [math.sin(angle), math.cos(angle), 0], [0, 0, 1]]) elif axes == [0, 2]: rotate = np.array([[math.cos(angle), 0, math.sin(angle)], [0, 1, 0], [-math.sin(angle), 0, math.cos(angle)]]) elif axes == [1, 2]: rotate = np.array([[1, 0, 0], [0, math.cos(angle), -math.sin(angle)], [0, math.sin(angle), math.cos(angle)]]) else: raise ValueError("Unknown axes value") scale = np.array([[1 / scale_x, 0, 0], [0, 1 / scale_y, 0], [0, 0, 1 / scale_z]]) if "undo" in metadata and metadata["undo"]: transforms = else: transforms = offset = shape - + translations data_out = affine_transform(sample, transforms.T, order=1, offset=offset, output_shape=sample.shape).astype(sample.dtype) return data_out, metadata
@multichannel_capable @two_dim_compatible def undo_transform(self, sample, metadata=None): assert "rotation" in metadata assert "scale" in metadata assert "translation" in metadata # Opposite rotation, same axes angle, axes = - metadata['rotation'][0], metadata['rotation'][1] scale = 1 / np.array(metadata['scale']) translation = - np.array(metadata['translation']) # Undo rotation dict_params = {"rotation": [angle, axes], "scale": scale, "translation": [0, 0, 0], "undo": True} data_out, _ = self.__call__(sample, dict_params) data_out = affine_transform(data_out, np.identity(3), order=1, offset=translation, output_shape=sample.shape).astype(sample.dtype) return data_out, metadata
[docs]class RandomReverse(ImedTransform): """Make a randomized symmetric inversion of the different values of each dimensions."""
[docs] @multichannel_capable @two_dim_compatible def __call__(self, sample, metadata=None): if 'reverse' in metadata: flip_axes = metadata['reverse'] else: # Flip axis booleans flip_axes = [np.random.randint(2) == 1 for _ in [0, 1, 2]] # Save in metadata metadata['reverse'] = flip_axes # Run flip for idx_axis, flip_bool in enumerate(flip_axes): if flip_axes: sample = np.flip(sample, axis=idx_axis).copy() return sample, metadata
@multichannel_capable @two_dim_compatible def undo_transform(self, sample, metadata=None): assert "reverse" in metadata return self.__call__(sample, metadata)
[docs]class RandomShiftIntensity(ImedTransform): """Add a random intensity offset. Args: shift_range (tuple of floats): Tuple of length two. Specifies the range where the offset that is applied is randomly selected from. prob (float): Between 0 and 1. Probability of occurence of this transformation. """
[docs] def __init__(self, shift_range, prob=0.1): self.shift_range = shift_range self.prob = prob
[docs] @multichannel_capable def __call__(self, sample, metadata=None): if np.random.random() < self.prob: # Get random offset offset = np.random.uniform(self.shift_range[0], self.shift_range[1]) else: offset = 0.0 # Update metadata metadata['offset'] = offset # Shift intensity data = (sample + offset).astype(sample.dtype) return data, metadata
@multichannel_capable def undo_transform(self, sample, metadata=None): assert 'offset' in metadata # Get offset offset = metadata['offset'] # Substract offset data = (sample - offset).astype(sample.dtype) return data, metadata
[docs]class ElasticTransform(ImedTransform): """Applies elastic transformation. .. seealso:: Simard, Patrice Y., David Steinkraus, and John C. Platt. "Best practices for convolutional neural networks applied to visual document analysis." Icdar. Vol. 3. No. 2003. 2003. Args: alpha_range (tuple of floats): Deformation coefficient. Length equals 2. sigma_range (tuple of floats): Standard deviation. Length equals 2. """
[docs] def __init__(self, alpha_range, sigma_range, p=0.1): self.alpha_range = alpha_range self.sigma_range = sigma_range self.p = p
[docs] @multichannel_capable @two_dim_compatible def __call__(self, sample, metadata=None): # if params already defined, i.e. sample is GT if "elastic" in metadata: alpha, sigma = metadata["elastic"] elif np.random.random() < self.p: # Get params alpha = np.random.uniform(self.alpha_range[0], self.alpha_range[1]) sigma = np.random.uniform(self.sigma_range[0], self.sigma_range[1]) # Save params metadata["elastic"] = [alpha, sigma] else: metadata["elastic"] = [None, None] if any(metadata["elastic"]): # Get shape shape = sample.shape # Compute random deformation dx = gaussian_filter((np.random.rand(*shape) * 2 - 1), sigma, mode="constant", cval=0) * alpha dy = gaussian_filter((np.random.rand(*shape) * 2 - 1), sigma, mode="constant", cval=0) * alpha dz = gaussian_filter((np.random.rand(*shape) * 2 - 1), sigma, mode="constant", cval=0) * alpha if shape[2] == 1: dz = 0 # No deformation along the last dimension x, y, z = np.meshgrid(np.arange(shape[0]), np.arange(shape[1]), np.arange(shape[2]), indexing='ij') indices = np.reshape(x + dx, (-1, 1)), \ np.reshape(y + dy, (-1, 1)), \ np.reshape(z + dz, (-1, 1)) # Apply deformation data_out = map_coordinates(sample, indices, order=1, mode='reflect') # Keep input shape data_out = data_out.reshape(shape) # Keep data type data_out = data_out.astype(sample.dtype) return data_out, metadata else: return sample, metadata
[docs]class AdditiveGaussianNoise(ImedTransform): """Adds Gaussian Noise to images. Args: mean (float): Gaussian noise mean. std (float): Gaussian noise standard deviation. """
[docs] def __init__(self, mean=0.0, std=0.01): self.mean = mean self.std = std
[docs] @multichannel_capable def __call__(self, sample, metadata=None): if "gaussian_noise" in metadata: noise = metadata["gaussian_noise"] else: # Get random noise noise = np.random.normal(self.mean, self.std, sample.shape) noise = noise.astype(np.float32) # Apply noise data_out = sample + noise return data_out.astype(sample.dtype), metadata
[docs]class Clahe(ImedTransform): """ Applies Contrast Limited Adaptive Histogram Equalization for enhancing the local image contrast. .. seealso:: Zuiderveld, Karel. "Contrast limited adaptive histogram equalization." Graphics gems (1994): 474-485. Default values are based on: .. seealso:: Zheng, Qiao, et al. "3-D consistent and robust segmentation of cardiac images by deep learning with spatial propagation." IEEE transactions on medical imaging 37.9 (2018): 2137-2148. Args: clip_limit (float): Clipping limit, normalized between 0 and 1. kernel_size (tuple of int): Defines the shape of contextual regions used in the algorithm. Length equals image dimension (ie 2 or 3 for 2D or 3D, respectively). """
[docs] def __init__(self, clip_limit=3.0, kernel_size=(8, 8)): self.clip_limit = clip_limit self.kernel_size = kernel_size
[docs] @multichannel_capable def __call__(self, sample, metadata=None): assert len(self.kernel_size) == len(sample.shape) # Run equalization data_out = equalize_adapthist(sample, kernel_size=self.kernel_size, clip_limit=self.clip_limit).astype(sample.dtype) return data_out, metadata
[docs]class HistogramClipping(ImedTransform): """Performs intensity clipping based on percentiles. Args: min_percentile (float): Between 0 and 100. Lower clipping limit. max_percentile (float): Between 0 and 100. Higher clipping limit. """
[docs] def __init__(self, min_percentile=5.0, max_percentile=95.0): self.min_percentile = min_percentile self.max_percentile = max_percentile
[docs] @multichannel_capable def __call__(self, sample, metadata=None): data = np.copy(sample) # Run clipping percentile1 = np.percentile(sample, self.min_percentile) percentile2 = np.percentile(sample, self.max_percentile) data[sample <= percentile1] = percentile1 data[sample >= percentile2] = percentile2 return data, metadata
[docs]def get_subdatasets_transforms(transform_params): """Get transformation parameters for each subdataset: training, validation and testing. Args: transform_params (dict): Returns: dict, dict, dict: Training, Validation and Testing transformations. """ transform_params = copy.deepcopy(transform_params) train, valid, test = {}, {}, {} subdataset_default = ["training", "validation", "testing"] # Loop across transformations for transform_name in transform_params: subdataset_list = ["training", "validation", "testing"] # Only consider subdatasets listed in dataset_type if "dataset_type" in transform_params[transform_name]: subdataset_list = transform_params[transform_name]["dataset_type"] # Add current transformation to the relevant subdataset transformation dictionaries for subds_name, subds_dict in zip(subdataset_default, [train, valid, test]): if subds_name in subdataset_list: subds_dict[transform_name] = transform_params[transform_name] if "dataset_type" in subds_dict[transform_name]: del subds_dict[transform_name]["dataset_type"] return train, valid, test
[docs]def get_preprocessing_transforms(transforms): """Checks the transformations parameters and selects the transformations which are done during preprocessing only. Args: transforms (dict): Transformation dictionary. Returns: dict: Preprocessing transforms. """ original_transforms = copy.deepcopy(transforms) preprocessing_transforms = copy.deepcopy(transforms) for idx, tr in enumerate(original_transforms): if tr == "Resample" or tr == "CenterCrop" or tr == "ROICrop": del transforms[tr] else: del preprocessing_transforms[tr] return preprocessing_transforms
[docs]def apply_preprocessing_transforms(transforms, seg_pair, roi_pair=None): """ Applies preprocessing transforms to segmentation pair (input, gt and metadata). Args: transforms (Compose): Preprocessing transforms. seg_pair (dict): Segmentation pair containing input and gt. roi_pair (dict): Segementation pair containing input and roi. Returns: tuple: Segmentation pair and roi pair. """ if transforms is None: return (seg_pair, roi_pair) metadata_input = seg_pair['input_metadata'] if roi_pair is not None: stack_roi, metadata_roi = transforms(sample=roi_pair["gt"], metadata=roi_pair['gt_metadata'], data_type="roi", preprocessing=True) metadata_input = imed_loader_utils.update_metadata(metadata_roi, metadata_input) # Run transforms on images stack_input, metadata_input = transforms(sample=seg_pair["input"], metadata=metadata_input, data_type="im", preprocessing=True) # Run transforms on images metadata_gt = imed_loader_utils.update_metadata(metadata_input, seg_pair['gt_metadata']) stack_gt, metadata_gt = transforms(sample=seg_pair["gt"], metadata=metadata_gt, data_type="gt", preprocessing=True) seg_pair = { 'input': stack_input, 'gt': stack_gt, 'input_metadata': metadata_input, 'gt_metadata': metadata_gt } if roi_pair is not None and len(roi_pair['gt']): roi_pair = { 'input': stack_input, 'gt': stack_roi, 'input_metadata': metadata_input, 'gt_metadata': metadata_roi } return (seg_pair, roi_pair)
[docs]def prepare_transforms(transform_dict, requires_undo=True): """ This function separates the preprocessing transforms from the others and generates the undo transforms related. Args: transform_dict (dict): Dictionary containing the transforms and there parameters. requires_undo (bool): Boolean indicating if transforms can be undone. Returns: list, UndoCompose: transform lst containing the preprocessing transforms and regular transforms, UndoCompose object containing the transform to undo. """ training_undo_transform = None if requires_undo: training_undo_transform = UndoCompose(Compose(transform_dict.copy())) preprocessing_transforms = get_preprocessing_transforms(transform_dict) prepro_transforms = Compose(preprocessing_transforms, requires_undo=requires_undo) transforms = Compose(transform_dict, requires_undo=requires_undo) tranform_lst = [prepro_transforms if len(preprocessing_transforms) else None, transforms] return tranform_lst, training_undo_transform