CODEWITHSUNDEEP
pythonlinuxnumpysaveros
Journey
Journey

Reputation: 31

How can I save scan data(topic) in npy file?

I'm newbie in ros

I'm trying to save LiDAR Laserscan data to npy file to check my test code without launching ros.

The ideal form i wanna save is numpy array file which contains every information in each Laserscan topic data such as header(stamp, seq), angle data(angle_min, --), ranges.

I hope I can use this data at the my test code. It looks like

buffer = np.load('scan_save.npy', allow_pickle = True)

buffer[0] = prev_scan

for scan in buffer[1:]:

    scan.header.stamp - prev_scan.stamp = dt
    function(scan.ranges)
...

I have no idea how to save all of scan data together not only 'ranges' but 'header, angle_min, time_increment'

Also, I want append each scan data every time scan subscriber get the scan data

Only thing I can do is

scandata = msg.ranges # msg is Laserscan
np.save("~/scan_save", scandata)

Upvotes: 1

Views: 583

Answers (1)

Journey
Journey

Reputation: 31

I solved my qustion! here is my code :)

By dong this, I could save all of topic as numpy array

self.scan_data = np.array([]) # define it at __init__

'''at the scan callbalck function'''
buffer = msg # Laserscan msg from subscriber
self.scan_data = np.array(buffer)
self.save_scan = np.append(self.save_scan, scan_data)
np.save("~/record/scan", self.save_scan)

Upvotes: 2

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