kinect-点云数据、深度数据&ros中相关主题

0.首先聊聊kinect是什么。

kinect是微软推出的一种体感周边设备，导入了即时动态捕捉、影像辨识、麦克风输入、社群互动等功能。“你就是遥控器”这个理念无疑吸引着大量的游戏玩家，这种全新的游戏体验就是kinect设计者追求的一种创新。kinect利用摄像头捕捉人的肢体动作。除了捕捉图像的摄像头，kinect还拥有一个传感器探测力度和深度，四个麦克风负责采集声音。再讲讲我们能从kinect获取什么数据呢。根据微软官网中kinect的硬件的关键功能：

，我们知道了kinect拥有：彩色图像数据、深度图像数据、红外数据。（这些数据的格式就不详细研究了，猜想openni，libfreenect等获得的数据格式不同？？？）。

1.深度数据

深度数据是kinect能够获取的一项数据。深度数据是一种普遍的三维场景信息的表达方式。深度图像的每一个像素点的灰度值可以表征场景中某一点距离摄像机的远近。

2.点云数据

点云数据中的每一个像素点包含三维坐标信息，有的包含颜色信息或者反射强度信息。深度图像经过坐标转换可以计算为点云数据；有规则及必要信息的点云数据可以反算为深度图像。我们通过kinect可以获取深度数据，因此通过公式计算，我们同样可以获得点云数据。

具体转化关系如图：

3.具体到ros。kinect的驱动支持较多平台，windows、ubuntu等上都支持kinect驱动的安装。在ros中，我使用了libfreenect驱动kinect。在成功安装后，使用：rostopic list查看所有主题，其中，与kinect相关的主题（即kinect发送数据的主题）为：

/camera/debayer/parameter_descriptions
/camera/debayer/parameter_updates
/camera/depth_registered/hw_registered/image_rect_raw
/camera/depth_registered/hw_registered/image_rect_raw/compressed
/camera/depth_registered/hw_registered/image_rect_raw/compressed/parameter_descriptions
/camera/depth_registered/hw_registered/image_rect_raw/compressed/parameter_updates
/camera/depth_registered/hw_registered/image_rect_raw/compressedDepth
/camera/depth_registered/hw_registered/image_rect_raw/compressedDepth/parameter_descriptions
/camera/depth_registered/hw_registered/image_rect_raw/compressedDepth/parameter_updates
/camera/depth_registered/hw_registered/image_rect_raw/theora
/camera/depth_registered/hw_registered/image_rect_raw/theora/parameter_descriptions
/camera/depth_registered/hw_registered/image_rect_raw/theora/parameter_updates
/camera/depth_registered/points
/camera/depth_registered_rectify_depth/parameter_descriptions
/camera/depth_registered_rectify_depth/parameter_updates
/camera/rectify_color/parameter_descriptions
/camera/rectify_color/parameter_updates
/camera/rectify_mono/parameter_descriptions
/camera/rectify_mono/parameter_updates
/camera/rgb/image_color
/camera/rgb/image_color/compressed
/camera/rgb/image_color/compressed/parameter_descriptions
/camera/rgb/image_color/compressed/parameter_updates
/camera/rgb/image_color/compressedDepth
/camera/rgb/image_color/compressedDepth/parameter_descriptions
/camera/rgb/image_color/compressedDepth/parameter_updates
/camera/rgb/image_color/theora
/camera/rgb/image_color/theora/parameter_descriptions
/camera/rgb/image_color/theora/parameter_updates
/camera/rgb/image_mono
/camera/rgb/image_mono/compressed
/camera/rgb/image_mono/compressed/parameter_descriptions
/camera/rgb/image_mono/compressed/parameter_updates
/camera/rgb/image_mono/compressedDepth
/camera/rgb/image_mono/compressedDepth/parameter_descriptions
/camera/rgb/image_mono/compressedDepth/parameter_updates
/camera/rgb/image_mono/theora
/camera/rgb/image_mono/theora/parameter_descriptions
/camera/rgb/image_mono/theora/parameter_updates
/camera/rgb/image_rect_color
/camera/rgb/image_rect_color/compressed
/camera/rgb/image_rect_color/compressed/parameter_descriptions
/camera/rgb/image_rect_color/compressed/parameter_updates
/camera/rgb/image_rect_color/compressedDepth
/camera/rgb/image_rect_color/compressedDepth/parameter_descriptions
/camera/rgb/image_rect_color/compressedDepth/parameter_updates
/camera/rgb/image_rect_color/theora
/camera/rgb/image_rect_color/theora/parameter_descriptions
/camera/rgb/image_rect_color/theora/parameter_updates
/camera/rgb/image_rect_mono
/camera/rgb/image_rect_mono/compressed
/camera/rgb/image_rect_mono/compressed/parameter_descriptions
/camera/rgb/image_rect_mono/compressed/parameter_updates
/camera/rgb/image_rect_mono/compressedDepth
/camera/rgb/image_rect_mono/compressedDepth/parameter_descriptions
/camera/rgb/image_rect_mono/compressedDepth/parameter_updates
/camera/rgb/image_rect_mono/theora
/camera/rgb/image_rect_mono/theora/parameter_descriptions
/camera/rgb/image_rect_mono/theora/parameter_updates
/depthimage_to_laserscan/parameter_descriptions
/depthimage_to_laserscan/parameter_updates

/camera/rgb表示彩色图像，/camera/depth_registered/表示深度图像。