;; UPDATE: For KITTI users, you may find `br-dired-kitti-label-to-xml' useful
;; Usage for KITTI dataset (M-x means Alt+x):
;; (1) open this file in emacs.
;; (2) modify the above (setq kitti-image-root "/home/user/path-to-kitti-root/training/image/");
;; to your path to KITTI image root
;; (3) Run M-x eval-buffer or (load-file "path-to-your/table-xml.el") to load all the functions in
;; this file as well as the kitti-image-root path (after you have changed it to the correct path).
;; (4) M-x dired (go to label folder of KITTI)
;; (5) `dired-mark' or `dired-mark-files-regexp' function to mark the label files that you want to convert to XML
;; Note: do not mark too many at a time. About 2000 files a time would be good. I experienced some crashes
;; and memory problems with too many files at a time. It's probably due to an emacs internal problem.
;; (6) M-x `br-dired-kitti-label-to-xml'
;; (7) xml files will be created in ./xml folder
;; (optional) change function `etxml-KITTI-print-buffer-to-xml' and etxml-KITTI-dataset-schema to fit
;; your need. Read the below advanced tutorial if you want to know how it works. If you
;; want to customize the output XML file to some other formats, modify etxml-KITTI-dataset-schema
;; variable below.
1 首先在ubuntu下面安装编辑器emacs ：使用命令 sudo apt-get install emacs24
2 运行命令emacs打开程序，打开 exXML_0.47 ，修改KITTI的路径
3 按下ALT+X，然后输入 eval-buffer 加载文件中的函数。
4 按下ALT+X ，输入dired，进入KITTI的label文件夹
5 按下ALT+X 输入dired-mark或者用 “dired-mark-files-regexp” 正则化匹配文件 （怎么选前2000个还不会）
6 按下ALT+X ，输入br-dired-kitti-label-to-xml，运行就转换成功。
这个网址 http://blog.csdn.net/jesse_mx/article/details/65634482 有使用python转换的教程。
二、 PASCAL VOC 11point 方法
1 首先对所有预测结果进行排序，score分高的排在前面，分数低的排在后面
2 按顺序逐个把样本作为正例进行预测，计算出FP和TP
3 再计算 召回率rec和精度prec
4 按照召回率t从0到1之间每0.1一个点，一共11个点，分别计算大于t的最大精度值p ，然后按照 ap=ap+p/11 ，一共计算11次。
5 ap即为检测的值，所有的ap平均值为mAP。