Python 加快从DICOM结构集中提取坐标

使用

numpy.reformate

帮助很大，使用

map

帮助不大。有可能再加快一点吗

import pydicom
import numpy as np
import cProfile
import pstats


def parse_coords(contour):
    """Given a contour from a DICOM ROIContourSequence, returns coordinates
    [loop][[x0, x1, x2, ...][y0, y1, y2, ...][z0, z1, z2, ...]]"""
    if not hasattr(contour, "ContourSequence"):
        return [] # empty structure
    def _reshape_contour_data(loop):
        return np.reshape(np.array(loop.ContourData),
                          (3, len(loop.ContourData) // 3),
                          order='F')
    return list(map(_reshape_contour_data,contour.ContourSequence))


def profile_load_contours():
    rs = pydicom.dcmread('RS.gyn1.dcm')
    structs = [parse_coords(contour) for contour in rs.ROIContourSequence]


cProfile.run('profile_load_contours()','prof.stats')
p = pstats.Stats('prof.stats')
p.sort_stats('cumulative').print_stats(30)

使用从Varian Eclipse导出的实际结构集

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000   12.165   12.165 {built-in method builtins.exec}
        1    0.151    0.151   12.165   12.165 <string>:1(<module>)
        1    0.000    0.000   12.014   12.014 load_contour_time.py:19(profile_load_contours)
        1    0.000    0.000   11.983   11.983 load_contour_time.py:21(<listcomp>)
       56    0.009    0.000   11.983    0.214 load_contour_time.py:7(parse_coords)
50745/33837    0.129    0.000   11.422    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataset.py:455(__getattr__)
50741/33825    0.152    0.000   10.938    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataset.py:496(__getitem__)
    16864    0.069    0.000    9.839    0.001 load_contour_time.py:12(_reshape_contour_data)
    16915    0.101    0.000    9.780    0.001 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataelem.py:439(DataElement_from_raw)
    16915    0.052    0.000    9.300    0.001 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/values.py:320(convert_value)
    16864    0.038    0.000    7.099    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/values.py:89(convert_DS_string)
    16870    0.042    0.000    7.010    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/valuerep.py:495(MultiString)
    16908    1.013    0.000    6.826    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/multival.py:29(__init__)
  3004437    3.013    0.000    5.577    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/multival.py:42(number_string_type_constructor)
3038317/3038231    1.037    0.000    3.171    0.000 {built-in method builtins.hasattr}

ncalls tottime percall cumtime percall文件名：lineno（函数）
1 0.000 0.000 12.165 12.165{内置方法builtins.exec}
1    0.151    0.151   12.165   12.165 :1()
1 0.000 0.000 12.014 12.014荷载轮廓时间。py:19（剖面荷载轮廓）
1 0.000 0.000 11.983 11.983加载时间。py:21（）
56 0.009 0.000 11.983 0.214加载时间。py:7（解析坐标）
50745/33837 0.129 0.000 11.422 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataset.py:455
50741/33825 0.152 0.000 10.938 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataset.py:496
16864 0.069 0.000 9.839 0.001加载轮廓时间。py:12（重塑轮廓数据）
16915 0.101 0.000 9.780 0 0.001/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataelem.py:439（DataElement_来自_raw）
16915 0.052 0.000 9.300 0.001/home/cf/python/venv/lib/python3.5/site packages/pydicom/values.py:320（转换值）
16864 0.038 0.000 7.099 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/values.py:89（转换为字符串）
16870 0.042 0.000 7.010 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/valuerep.py:495（多字符串）
16908 1.013 0.000 6.826 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/multival.py:29
3004437 3.013 0.000 5.577 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/multival.py:42（数字字符串类型构造函数）
3038317/3038231 1.037 0.000 3.171 0.000{内置方法内置。hasattr}

大部分时间都在

convert\u DS\u string

中。有可能使它更快吗？我想部分问题是坐标在DICOM文件中存储效率不高

编辑：

---

为了避免在

MultiVal.\uuuuu init\uuuuu

末尾出现循环，我想知道如何获取每个轮廓数据的原始双字符串，并在其上使用

numpy.fromstring

。但是，我无法获得原始的双字符串。

消除了

多变量中的循环。\uuuu init\uuuu

并使用

numpy。fromstring

提供了超过4倍的加速。我将在pydicom github上发表文章，看看是否有人对将其纳入库代码感兴趣。有点难看。我希望得到进一步改进的建议

import pydicom
import numpy as np
import cProfile
import pstats


def parse_coords(contour):
    """Given a contour from a DICOM ROIContourSequence, returns coordinates
    [loop][[x0, x1, x2, ...][y0, y1, y2, ...][z0, z1, z2, ...]]"""
    if not hasattr(contour, "ContourSequence"):
        return [] # empty structure
    cd_tag = pydicom.tag.Tag(0x3006, 0x0050) # ContourData tag
    def _reshape_contour_data(loop):
        val = super(loop.__class__, loop).__getitem__(cd_tag).value
        try:
            double_string = val.decode(encoding='utf-8')
            double_vec = np.fromstring(double_string, dtype=float, sep=chr(92)) # 92 is '/'
        except AttributeError: # 'MultiValue'  has no 'decode' (bytes does)
            # It's already been converted to doubles and cached
            double_vec = loop.ContourData
        return np.reshape(np.array(double_vec),
                          (3, len(double_vec) // 3),
                          order='F')
    return list(map(_reshape_contour_data, contour.ContourSequence))


def profile_load_contours():
    rs = pydicom.dcmread('RS.gyn1.dcm')
    structs = [parse_coords(contour) for contour in rs.ROIContourSequence]


profile_load_contours()
cProfile.run('profile_load_contours()','prof.stats')
p = pstats.Stats('prof.stats')
p.sort_stats('cumulative').print_stats(15)

结果

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        1    0.000    0.000    2.800    2.800 {built-in method builtins.exec}
        1    0.017    0.017    2.800    2.800 <string>:1(<module>)
        1    0.000    0.000    2.783    2.783 load_contour_time3.py:29(profile_load_contours)
        1    0.000    0.000    2.761    2.761 load_contour_time3.py:31(<listcomp>)
       56    0.006    0.000    2.760    0.049 load_contour_time3.py:9(parse_coords)
  153/109    0.001    0.000    2.184    0.020 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataset.py:455(__getattr__)
   149/97    0.001    0.000    2.182    0.022 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataset.py:496(__getitem__)
       51    0.000    0.000    2.178    0.043 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataelem.py:439(DataElement_from_raw)
       51    0.000    0.000    2.177    0.043 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/values.py:320(convert_value)
       44    0.000    0.000    2.176    0.049 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/values.py:255(convert_SQ)
       44    0.035    0.001    2.176    0.049 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/filereader.py:427(read_sequence)
   152/66    0.000    0.000    2.171    0.033 {built-in method builtins.hasattr}
    16920    0.147    0.000    1.993    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/filereader.py:452(read_sequence_item)
    16923    0.116    0.000    1.267    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/filereader.py:365(read_dataset)
    84616    0.113    0.000    0.699    0.000 /home/cf/python/venv/lib/python3.5/site-packages/pydicom/dataset.py:960(__setattr__)

ncalls tottime percall cumtime percall文件名：lineno（函数）
1 0.000 0.000 2.800 2.800{内置方法builtins.exec}
1    0.017    0.017    2.800    2.800 :1()
1 0.000 0.000 2.783 2.783载荷轮廓时间3.py:29（轮廓载荷轮廓）
1 0.000 0.000 2.761 2.761加载时间3.py:31（）
56 0.006 0.000 2.760 0.049加载时间3.py:9（解析坐标）
153/109 0.001 0.000 2.184 0.020/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataset.py:455
149/97 0.001 0.000 2.182 0.022/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataset.py:496
51 0.000 0.000 2.178 0.043/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataelem.py:439（DataElement_来自_raw）
51 0.000 0.000 2.177 0.043/home/cf/python/venv/lib/python3.5/site packages/pydicom/values.py:320（转换值）
44 0.000 0.000 2.176 0.049/home/cf/python/venv/lib/python3.5/site packages/pydicom/values.py:255（转换为SQ）
44 0.035 0.001 2.176 0.049/home/cf/python/venv/lib/python3.5/site packages/pydicom/filereader.py:427（读取顺序）
152/66 0.000 0.000 2.171 0.033{内置方法内置。hasattr}
16920 0.147 0.000 1.993 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/filereader.py:452（读取顺序项目）
16923 0.116 0.000 1.267 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/filereader.py:365（读取数据集）
84616 0.113 0.000 0.699 0.000/home/cf/python/venv/lib/python3.5/site packages/pydicom/dataset.py:960