我想使用 SimpleITK 或 wedpy 将 3d 图像转换为 2d 图像。或者我想得到一个三维矩阵，然后我把这个三维矩阵分成一些二维矩阵。
import SimpleITK as ITK
import numpy as np
#from medpy.io import load
url=r'G:\path\to\my.mha'
image = ITK.ReadImage(url)
frame_num, width, height = image_array.shape
print(frame_num,width,height)
然后才得到它：155 240 240
但我想得到 [[1,5,2,3,1...],[54,1,3,5...],[5,8,9,6....]]
只是添加到 Dave Chen 的答案中，因为不清楚您是否想要获得一组 2D SimpleITK 图像或 numpy 数组。以下代码涵盖了所有三个可用选项：
import SimpleITK as sitk
import numpy as np
url = "my_file.mha"
image = sitk.ReadImage(url)
max_index = image.GetDepth() # or image.GetWidth() or image.GetHeight() depending on the axis along which you want to extract
# As list of 2D SimpleITK images
list_of_2D_images = [image[:,:,i] for i in range(max_index)]
# As list of 2D numpy arrays which cannot be modified (no data copied)
list_of_2D_images_np_view = [sitk.GetArrayViewFromImage(image[:,:,i]) for i in range(max_index)]
# As list of 2D numpy arrays (data copied to numpy array)
list_of_2D_images_np = [sitk.GetArrayFromImage(image[:,:,i]) for i in range(max_index)]
此外，如果您真的想使用 URL 而不是本地文件，我建议您查看SimpleITK 笔记本存储库中使用的远程下载方法，相关文件是downloaddata.py。
这没什么大不了的。CT 图像原来都是int16类型的数字，所以不需要处理浮点数。在这种情况下，我们可以认为我们可以很容易地从int16更改为uint16 ，只需去除图像中的负值（CT 图像有一些负数字作为像素值）。请注意，我们确实需要uint16或uint8类型，以便 OpenCV 可以处理它......因为我们在 CT 图像数组中有很多值，所以最好的选择是uint16，这样我们就不会损失太多的精度。好的，现在您只需要执行以下操作：
import SimpleITK as sitk
import numpy as np
import cv2
mha = sitk.ReadImage('/mha/directory') #Importing mha file
array = sitk.GetArrayFromImage(mha) #Converting to array int16 (default)
#Translating each slice to the positive side
for m in range(array.shape[0]):
array[m] = array[m] + abs(np.min(array[m]))
array = np.around(array, decimals=0) #remove any float numbers if exists.. probably not
array = np.asarray(array, dtype='uint16') #From int16 to uint16
在这些步骤之后，数组就可以使用opencv.imwrite模块保存为 png 图像了：
for image in array:
cv2.imwrite('/dir/to/save/'+'name_image.png', image)
请注意，默认情况下 SimpleITK通过轴向视图处理.mha文件。我真的不知道如何更改它，因为我以前从未需要它。无论如何，在这种情况下，通过一些搜索，您可以找到一些东西。
@zivy@Dave Chen 我已经解决了我的问题。事实上，运行这段代码会给你 150 240*240 PNG 图片。这是我想要的。
# -*- coding:utf-8 -*-
import numpy as np
import subprocess
import random
import progressbar
from glob import glob
from skimage import io
np.random.seed(5) # for reproducibility
progress = progressbar.ProgressBar(widgets=[progressbar.Bar('*', '[', ']'), progressbar.Percentage(), ' '])
class BrainPipeline(object):
'''
A class for processing brain scans for one patient
INPUT: (1) filepath 'path': path to directory of one patient. Contains following mha files:
flair, t1, t1c, t2, ground truth (gt)
(2) bool 'n4itk': True to use n4itk normed t1 scans (defaults to True)
(3) bool 'n4itk_apply': True to apply and save n4itk filter to t1 and t1c scans for given patient. This will only work if the
'''
def __init__(self, path, n4itk = True, n4itk_apply = False):
self.path = path
self.n4itk = n4itk
self.n4itk_apply = n4itk_apply
self.modes = ['flair', 't1', 't1c', 't2', 'gt']
# slices=[[flair x 155], [t1], [t1c], [t2], [gt]], 155 per modality
self.slices_by_mode, n = self.read_scans()
# [ [slice1 x 5], [slice2 x 5], ..., [slice155 x 5]]
self.slices_by_slice = n
self.normed_slices = self.norm_slices()
def read_scans(self):
'''
goes into each modality in patient directory and loads individual scans.
transforms scans of same slice into strip of 5 images
'''
print('Loading scans...')
slices_by_mode = np.zeros((5, 155, 240, 240))
slices_by_slice = np.zeros((155, 5, 240, 240))
flair = glob(self.path + '/*Flair*/*.mha')
t2 = glob(self.path + '/*_T2*/*.mha')
gt = glob(self.path + '/*more*/*.mha')
t1s = glob(self.path + '/**/*T1*.mha')
t1_n4 = glob(self.path + '/*T1*/*_n.mha')
t1 = [scan for scan in t1s if scan not in t1_n4]
scans = [flair[0], t1[0], t1[1], t2[0], gt[0]] # directories to each image (5 total)
if self.n4itk_apply:
print('-> Applyling bias correction...')
for t1_path in t1:
self.n4itk_norm(t1_path) # normalize files
scans = [flair[0], t1_n4[0], t1_n4[1], t2[0], gt[0]]
elif self.n4itk:
scans = [flair[0], t1_n4[0], t1_n4[1], t2[0], gt[0]]
for scan_idx in xrange(5):
# read each image directory, save to self.slices
slices_by_mode[scan_idx] = io.imread(scans[scan_idx], plugin='simpleitk').astype(float)
for mode_ix in xrange(slices_by_mode.shape[0]): # modes 1 thru 5
for slice_ix in xrange(slices_by_mode.shape[1]): # slices 1 thru 155
slices_by_slice[slice_ix][mode_ix] = slices_by_mode[mode_ix][slice_ix] # reshape by slice
return slices_by_mode, slices_by_slice
def norm_slices(self):
'''
normalizes each slice in self.slices_by_slice, excluding gt
subtracts mean and div by std dev for each slice
clips top and bottom one percent of pixel intensities
if n4itk == True, will apply n4itk bias correction to T1 and T1c images
'''
print('Normalizing slices...')
normed_slices = np.zeros((155, 5, 240, 240))
for slice_ix in xrange(155):
normed_slices[slice_ix][-1] = self.slices_by_slice[slice_ix][-1]
for mode_ix in xrange(4):
normed_slices[slice_ix][mode_ix] = self._normalize(self.slices_by_slice[slice_ix][mode_ix])
print('Done.')
return normed_slices
def _normalize(self, slice):
'''
INPUT: (1) a single slice of any given modality (excluding gt)
(2) index of modality assoc with slice (0=flair, 1=t1, 2=t1c, 3=t2)
OUTPUT: normalized slice
'''
b, t = np.percentile(slice, (0.5,99.5))
slice = np.clip(slice, b, t)
if np.std(slice) == 0:
return slice
else:
return (slice - np.mean(slice)) / np.std(slice)
def save_patient(self, reg_norm_n4, patient_num):
'''
INPUT: (1) int 'patient_num': unique identifier for each patient
(2) string 'reg_norm_n4': 'reg' for original images, 'norm' normalized images, 'n4' for n4 normalized images
OUTPUT: saves png in Norm_PNG directory for normed, Training_PNG for reg
'''
print('Saving scans for patient {}...'.format(patient_num))
progress.currval = 0
if reg_norm_n4 == 'norm': #saved normed slices
for slice_ix in progress(xrange(155)): # reshape to strip
strip = self.normed_slices[slice_ix].reshape(1200, 240)
if np.max(strip) != 0: # set values < 1
strip /= np.max(strip)
if np.min(strip) <= -1: # set values > -1
strip /= abs(np.min(strip))
# save as patient_slice.png
io.imsave('Norm_PNG/{}_{}.png'.format(patient_num, slice_ix), strip)
elif reg_norm_n4 == 'reg':
for slice_ix in progress(xrange(155)):
strip = self.slices_by_slice[slice_ix].reshape(1200, 240)
if np.max(strip) != 0:
strip /= np.max(strip)
io.imsave('Training_PNG/{}_{}.png'.format(patient_num, slice_ix), strip)
else:
for slice_ix in progress(xrange(155)): # reshape to strip
strip = self.normed_slices[slice_ix].reshape(1200, 240)
if np.max(strip) != 0: # set values < 1
strip /= np.max(strip)
if np.min(strip) <= -1: # set values > -1
strip /= abs(np.min(strip))
# save as patient_slice.png
io.imsave('n4_PNG/{}_{}.png'.format(patient_num, slice_ix), strip)
def n4itk_norm(self, path, n_dims=3, n_iters='[20,20,10,5]'):
'''
INPUT: (1) filepath 'path': path to mha T1 or T1c file
(2) directory 'parent_dir': parent directory to mha file
OUTPUT: writes n4itk normalized image to parent_dir under orig_filename_n.mha
'''
output_fn = path[:-4] + '_n.mha'
# run n4_bias_correction.py path n_dim n_iters output_fn
subprocess.call('python n4_bias_correction.py ' + path + ' ' + str(n_dims) + ' ' + n_iters + ' ' + output_fn, shell = True)
def save_patient_slices(patients, type):
'''
INPUT (1) list 'patients': paths to any directories of patients to save. for example- glob("Training/HGG/**")
(2) string 'type': options = reg (non-normalized), norm (normalized, but no bias correction), n4 (bias corrected and normalized)
saves strips of patient slices to approriate directory (Training_PNG/, Norm_PNG/ or n4_PNG/) as patient-num_slice-num
'''
for patient_num, path in enumerate(patients):
a = BrainPipeline(path)
a.save_patient(type, patient_num)
def s3_dump(directory, bucket):
'''
dump files from a given directory to an s3 bucket
INPUT (1) string 'directory': directory containing files to save
(2) string 'bucket': name od s3 bucket to dump files
'''
subprocess.call('aws s3 cp' + ' ' + directory + ' ' + 's3://' + bucket + ' ' + '--recursive')
def save_labels(fns):
'''
INPUT list 'fns': filepaths to all labels
'''
progress.currval = 0
for label_idx in progress(range(len(labels))):
slices = io.imread(labels[label_idx], plugin = 'simpleitk')
for slice_idx in range(len(slices)):
io.imsave(r'{}_{}L.png'.format(label_idx, slice_idx), slices[slice_idx])
if __name__ == '__main__':
url = r'G:\work\deeplearning\BRATS2015_Training\HGG\brats_2013_pat0005_1\VSD.Brain.XX.O.MR_T1.54537\VSD.Brain.XX.O.MR_T1.54537.mha'
labels = glob(url)
save_labels(labels)
# patients = glob('Training/HGG/**')
# save_patient_slices(patients, 'reg')
# save_patient_slices(patients, 'norm')
# save_patient_slices(patients, 'n4')
# s3_dump('Graveyard/Training_PNG/', 'orig-training-png')
我不确定你想要得到什么。但是在 SimpleITK 中很容易从 3d 图像中提取 2d 切片。
要获得 Z=100 的 Z 切片，您可以这样做：zslice = image[100]
要获得 Y=100 的 Y 切片： yslice = image[:, 100]
X=100 的 X 切片： xslice = image[:, :, 100]