Importing rgbd data from bag file into matlab [closed]

asked 2017-04-27 08:41:09 -0500

Keithicus
51 ●2 ●4 ●8

I'm trying to plot the points measured from a microsoft kinect sensor in matlab. I connected to my sensor using the freenect_launch package, I can visualize the sensor output in rviz, and i recorded the topic /camera/depth_registered/points into a bag file. Unfortunately i dont have the ROS tools for matlab, but i did find this open source solution to read the bag file into matlab:

https://github.com/unl-nimbus-lab/bag...

I can see that the data from the bag file is imported. A single frame looks something like this:

rosbagTimestamp 1.49246E+18
header
seq 205
stamp
secs 1492455101
nsecs 150824989
frame_id camera_rgb_optical_frame
height 480
width 640
fields
name x; offset 0; datatype 7; count 1
name y; offset 4; datatype 7; count 1
name z; offset 8; datatype 7; count 1
name rgb; offset 16; datatype 7; count 1
is_bigendian false
point_step 32
row_step 20480
data [0, 0, 192, 127, 0, 0, 192, 127, 0, 0, 192, 127, 0, 0, 0, 0, 68, 84, 124, 255, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...

My question is how do i convert the values in "data" to xyz points? If i'm interpreting this correctly, each data point is 32 bytes, bytes 0 - 3 correspond to X, bytes 4 - 7 correspond to Y, bytes 8 - 15 correspond to Z, and bytes 16 - 31 correspond to "rgb" (though i dont see how thats an rgb value). I dont know what "datatype 7" means, but it appears that the data is little endian. I'm wondering what datatype X, Y, Z and RGB are (unit32? float?) So that I can make the conversion. Has anyone ever dealt with this before?

Thanks!

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Closed for the following reason the question is answered, right answer was accepted by Keithicus
close date 2017-05-01 16:44:12.618162

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clear; close all; clc; [data, names] = bagReader('myKinectScan.bag'); frameNumber = 1; frameData = data.data{frameNumber,:}; pixelX = 324; pixelY = 243; pixelLocation = (pixelX-1)*32 + (pixelY-1)*32*640 + 1; dataPacket = frameData(pixelLocation:32+pixelLocation); x = typecast(uint8(dataPacket(1:4)),'single'); y = typecast(uint8(dataPacket(5:8)),'single'); z = typecast(uint8(dataPacket(9:12)),'single'); b = uint8(dataPacket(17)); g = uint8(dataPacket(18)); r = uint8(dataPacket(19));

Importing rgbd data from bag file into matlab [closed]

Closed for the following reason the question is answered, right answer was accepted by Keithicus
close date 2017-05-01 16:44:12.618162

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Importing rgbd data from bag file into matlab [closed] edit

Closed for the following reason the question is answered, right answer was accepted by Keithicus close date 2017-05-01 16:44:12.618162

1 Answer

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Importing rgbd data from bag file into matlab [closed]

Closed for the following reason the question is answered, right answer was accepted by Keithicus
close date 2017-05-01 16:44:12.618162