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pcl::PointCloud to cv::Mat -> optimal way?

asked 2012-07-22 22:43:39 -0500

Flamenco gravatar image

Hi everybody!

I would like to transform my point cloud 3D coordinates:

pcl::PointCloud<pcl::PointXYZ> point_cloud;

to an OpenCV matrix:

cv::Mat point_cloud_matrix;

I could define a 3 channel float matrix with one row per point in the point cloud, like this:

cv::Mat point_cloud_matrix(point_cloud.points.size(), 1, CV_32FC3);

and then manually copy each point on the point cloud to the matrix. But, it feels like a little bit brute force approach.

Can anyone suggest a more elegant way to do it? My ultimate goal is to apply OpenCV's k-means algorithm to extract clusters of points.

Thanks in advance!

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answered 2012-07-23 16:09:31 -0500

Vincent Rabaud gravatar image

if pcl::PointXYZ is just a struct with 3 float, just do a reinterpret_cast of the pointer to your data to a void* and then use one of the cv::Mat constructors using that.

The memory mapping between the pcl vector<pcl::pointxyz> is the same as storing 3 columns and your vector size rows.

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Hi can anyone please explain this with example? I am bit new to C++ and OpenCV.

amitshri gravatar imageamitshri ( 2013-04-06 12:26:56 -0500 )edit

The struct is not only 3 floats.

waschbaer gravatar imagewaschbaer ( 2017-06-14 07:18:20 -0500 )edit
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Asked: 2012-07-22 22:43:39 -0500

Seen: 2,559 times

Last updated: Jul 23 '12