sitk.GetArrayFromImage返回空numpy數組？

Question

我正在使用3D MR圖像數據。爲了計算直方圖，我將sitk.Image轉換爲3維的numpy arrray。雖然我能夠使用matplotlib顯示每個軸向切片，但numpy數組在所有三維中都是完全空的。 有人可以解釋發生了什麼事嗎？

import numpy as np 
import SimpleITK as sitk 
from myshow import myshow 

img = sitk.ReadImage("mri.hdr") 
nda = sitk.GetArrayFromImage(img) 
myshow(img) 
print nda 

輸出：

[[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]] 

[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]] 

[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]] 

..., 
[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]] 

[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]] 

[[ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    ..., 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.] 
    [ 0. 0. 0. ..., 0. 0. 0.]]] 

NOTES：

• myshow.py（https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks/blob/master/Python/myshow.py）

• myshow.py通過使用matplotlib

可視IMG的切片

• MR圖像數據採用hdr/img（分析）格式。

Answer 1

你很好。數據就在那裏，只是打印函數顯示數組從頭開始的數據（很大）。如果打印數據具有內容你會看到一個有效的值的特定像素：

print nda[200,56,87]

該指數被認爲是在有效範圍內。