/** \brief Read a point cloud data header from a PCD-formatted, binary istream. * * Load only the meta information (number of points, their types, etc), * and not the points themselves, from a given PCD stream. Useful for fast * evaluation of the underlying data structure. * * \attention The PCD data is \b always stored in ROW major format! The * read/write PCD methods will detect column major input and automatically convert it. * * \param[in] binary_istream a std::istream with openmode set to std::ios::binary. * \param[out] cloud the resultant point cloud dataset (only these * members will be filled: width, height, point_step, * row_step, fields[]; data is resized but not written) * \param[out] origin the sensor acquisition origin (only for > PCD_V7 - null if not present) * \param[out] orientation the sensor acquisition orientation (only for > PCD_V7 - identity if not present) * \param[out] pcd_version the PCD version of the file (i.e., PCD_V6, PCD_V7) * \param[out] data_type the type of data (0 = ASCII, 1 = Binary, 2 = Binary compressed) * \param[out] data_idx the offset of cloud data within the file * * \return * * < 0 (-1) on error * * == 0 on success
时间: 2024-02-14 19:20:22 浏览: 28
这段代码是用于从PCD格式的二进制输入流中读取点云数据头的函数。它仅加载元信息(点数、类型等),而不加载点云本身,因此可以用于快速评估底层数据结构。
需要注意的是,PCD数据始终以行优先(ROW major)的格式存储!读/写PCD方法将检测列优先(column major)的输入并自动进行转换。
该函数的参数包括:
- binary_istream:用 std::ios::binary 打开的二进制输入流。
- cloud:点云数据集的结果(只有以下成员将被填充:width,height,point_step,row_step,fields[];数据将被调整大小但不会被写入)。
- origin:传感器采集原点(仅适用于 > PCD_V7 版本 - 如果不存在则为 null)。
- orientation:传感器采集方向(仅适用于 > PCD_V7 版本 - 如果不存在则为 identity)。
- pcd_version:文件的PCD版本(即,PCD_V6,PCD_V7)。
- data_type:数据类型(0 = ASCII,1 = 二进制,2 = 压缩二进制)。
- data_idx:文件中点云数据的偏移量。
该函数返回值为:
- < 0(-1):表示错误
- == 0:表示成功
相关问题
/** \brief Construct a cloud viewer, with a window name. * \param window_name This is displayed at the top of the window */
这是 `pcl::visualization::CloudViewer` 类的构造函数注释,意思是创建一个带有指定窗口名称的点云查看器。你可以使用如下代码创建 `pcl::visualization::CloudViewer` 对象:
```cpp
#include <pcl/visualization/cloud_viewer.h>
int main()
{
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
// 从文件加载点云数据
pcl::io::loadPCDFile("your_pcd_file.pcd", *cloud);
pcl::visualization::CloudViewer viewer("Cloud Viewer");
viewer.showCloud(cloud); // 在窗口中展示点云数据
while (!viewer.wasStopped()) {
// 持续更新窗口
}
return 0;
}
```
在上述代码中,`pcl::visualization::CloudViewer` 对象的构造函数需要一个窗口名称作为参数。创建完毕后,使用 `viewer.showCloud()` 方法将点云数据展示在窗口中,并使用循环不断更新窗口,直到用户关闭窗口。
/** \brief Various PCD file versions. * * PCD_V6 represents PCD files with version 0.6, which contain the following fields: * - lines beginning with # are treated as comments * - FIELDS ... * - SIZE ... * - TYPE ... * - COUNT ... * - WIDTH ... * - HEIGHT ... * - POINTS ... * - DATA ascii/binary * * Everything that follows \b DATA is interpreted as data points and * will be read accordingly. * * PCD_V7 represents PCD files with version 0.7 and has an important * addon: it adds sensor origin/orientation (aka viewpoint) information * to a dataset through the use of a new header field: * - VIEWPOINT tx ty tz qw qx qy qz */
这段代码是对PCD文件版本的说明文档。PCD_V6表示版本为0.6的PCD文件,它包含以下字段:
- 以#开头的行被视为注释
- FIELDS ...
- SIZE ...
- TYPE ...
- COUNT ...
- WIDTH ...
- HEIGHT ...
- POINTS ...
- DATA ascii/binary
在 \b DATA 之后的所有内容都会被解释为数据点,并相应地读取。
PCD_V7表示版本为0.7的PCD文件,并且增加了一个重要的附加信息:通过使用新的头字段,将传感器的起始位置/方向(也称为视点)信息添加到数据集中:
- VIEWPOINT tx ty tz qw qx qy qz