The PDF format file is about pictures in the book named as "Indoor 3D location perception and activity recognition for smartphones". Every one can download and utilize it for free without any noncommercial activities.

PDF格式文件是《面向智能手机的室内三维位置感知与活动识别》中的所有图片。只要不进行商业行为，所有人都可以免费下载和使用。