如何从 XML 文件中自动获取相同类型的每个对象？

Question

我正在尝试将 XML 文件解析为 TXT 文件。这是我的 XML 文件的样子：

<annotation>
  <folder>training</folder>
  <filename>106310488.jpg</filename>
  <source>
    <database>synthetic initialization</database>
    <annotation>PASCAL VOC2007</annotation>
    <image>synthetic</image>
    <flickrid>none</flickrid>
  </source>
  <owner>
    <flickrid>none</flickrid>
    <name>none</name>
  </owner>
  <size>
    <width>1024</width>
    <height>681</height>
    <depth>3</depth>
  </size>
  <segmented>0</segmented>
  <object>
    <name>shell</name>
    <pose>Unspecified</pose>
    <truncated>0</truncated>
    <difficult>0</difficult>
    <bndbox>
      <xmin>234</xmin>
      <ymin>293</ymin>
      <xmax>281</xmax>
      <ymax>340</ymax>
    </bndbox>
 </object>
 <object>
    <name>shell</name>
    <pose>Unspecified</pose>
    <truncated>0</truncated>
    <difficult>0</difficult>
    <bndbox>
      <xmin>504</xmin>
      <ymin>302</ymin>
      <xmax>551</xmax>
      <ymax>349</ymax>
    </bndbox>
  </object>
  <object>
    <name>shell</name>
    <pose>Unspecified</pose>
    <truncated>0</truncated>
    <difficult>0</difficult>
    <bndbox>
      <xmin>776</xmin>
      <ymin>302</ymin>
      <xmax>823</xmax>
      <ymax>349</ymax>
    </bndbox>
  </object>
</annotation>

我感兴趣的信息在<object>内。我想获取 <name> 和 <bndbox> 中的所有内容。这些是数据集中对象的名称和边界框坐标。我不知道每个 XML 文件中有 <object> 个条目 <bndbox>，所以我想编写一个逻辑来获取所有这些条目。

到目前为止，我的逻辑所做的是仅获取并处理第一次出现的 <object><bndbox></bndbox></object>。如果 XML 文件中有任何其他边界框坐标，我的代码会直接跳过它。我不想要这个。这是我的代码：

for annotations_file in annotations_dir:

  annotations = []
  milliseconds = int(time() * 1000)

  doc = ET.parse('/content/darknet/logorec/openlogo/Annotations/' + annotations_file) # Parsing the XML file
  
  new_annotations_file_name = annotations_file.split('.')[0] # Getting the name of the XML file without the file extension
  
  canvas = cv2.imread('/content/darknet/logorec/openlogo/JPEGImages/' + new_annotations_file_name + '.jpg') # Get the entire image
  
  canvas_shape = canvas.shape # Get the dimensions of the image
  
  root = doc.getroot() # Gets the root of the XML file
  
  annotations_box = root[6][4] # Gets the bounding box coordinates from the XML file

  class_name = root[6][0] # Name of the object within the bounding box
  class_name = class_name.text # Getting the text value

  for ant in annotations_box:
    annotations.append(ant.text) # Appending every sindle bounding box coordinate to an empty list
  
  ''' These are my annotations calculations for the YOLO model'''
  logo_shape_w = int(annotations[2]) - int(annotations[0])
  logo_shape_h = int(annotations[3]) - int(annotations[1])

  x1 = int(annotations[0]) # x1 = xmin
  y1 = int(annotations[3]) # y1 = ymax

  x2 = x1 + logo_shape_w
  y2 = y1 + logo_shape_h

  w = x2 - x1
  h = y2 - y1

  center_x = x1 + (w/2)
  center_y = y1 + (h/2)

  x = center_x / canvas_shape[0]
  y = center_y / canvas_shape[1]

  width = w / canvas_shape[0]
  height = h / canvas_shape[1]
  '''---------------------------------------------------------'''

Answer 1

使用 xpath 解析 XML 可以迭代 objList 项目。仅显示第一项

>>> from lxml import etree                       
>>> tree = etree.parse('test.xml')                                                                                                              
>>> objList = tree.xpath('//object')
>>> bnd = objList[0].xpath('name | bndbox/*')
>>> for e in bnd:
...     e.text
... 
'shell'
'234'
'293'
'281'
'340'

迭代所有对象

>>> for obj in objList:
...      bnd = obj.xpath('name | bndbox/*')
...      for e in bnd:
...          e.text
... 
'shell'
'234'
'293'
'281'
'340'
'shell'
'504'
'302'
'551'
'349'
'shell'
'776'
'302'
'823'

如何从 XML 文件中自动获取相同类型的每个对象？

How to automatically get every object of the same type from an XML file?

python

xml

computer-vision

yolo