readXYZ

Extract XYZ coordinates from point cloud data

Syntax

xyz = readXYZ(pcloud)

Description

example

xyz = readXYZ(pcloud) extracts the [x y z] coordinates from all points in the PointCloud2 object, pcloud, and returns them as an n-by-3 matrix of n 3-D point coordinates. If the point cloud does not contain the x, y, and z fields, this function returns an error. Points that contain NaN are preserved in the output. To preserve the structure of the point cloud data, see Preserving Point Cloud Structure.

Examples

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Load sample ROS messages including a ROS point cloud message, ptcloud.

exampleHelperROSLoadMessages

Read the XYZ values from the point cloud.

xyz = readXYZ(ptcloud);

Input Arguments

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Point cloud, specified as a PointCloud2 object handle for a 'sensor_msgs/PointCloud2' ROS message.

Output Arguments

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List of XYZ values from point cloud, returned as a matrix. By default, this is a n-by-3 matrix. If the point cloud object being read has the PreserveStructureOnRead property set to true, the points are returned as an h-by-w-by-3 matrix. For more information, see Preserving Point Cloud Structure.

Tips

Point cloud data can be organized in either 1-D lists or in 2-D image styles. 2-D image styles usually come from depth sensors or stereo cameras. The input PointCloud2 object contains a PreserveStructureOnRead property that is either true or false (default). Suppose you set the property to true.

pcloud.PreserveStructureOnRead = true;

Now calling any read functions (readXYZ,readRGB, or readField) preserves the organizational structure of the point cloud. When you preserve the structure, the output matrices are of size m-by-n-by-d, where m is the height, n is the width, and d is the number of return values for each point. Otherwise, all points are returned as a x-by-d list. This structure can only be preserved if the point cloud is organized.

Introduced in R2015a