使用TUM数据集associate.py的小坑

使用从https://vision.in.tum.de/data/datasets/rgbd-dataset/tools下载的associate.py处理rgb.txt和depth.txt，生成配对的文件associate.txt

其中associate.py是python3.6版本使用的是python2.7，

python associate.py rgb.txt depth.txt > associate.txt

所以在运行的是时候报错了：

Traceback (most recent call last):
  File "associate.py", line 118, in <module>
    matches = associate(first_list, second_list,float(args.offset),float(args.max_difference))    
  File "associate.py", line 97, in associate
    first_keys.remove(a)
AttributeError: 'dict_keys' object has no attribute 'remove'

由于Python2和python3语法的差别，需要将associate.py中第86行87行的　　

first_keys = first_list.keys()
second_keys = second_list.keys()
改为
first_keys = list(first_list.keys())
second_keys = list(second_list.keys())

就可以运行了。