accessing both intrinsics and extrinsics for a capture

[monajalal]

For a piece of code I need access to all these items. I want to know if the followings sound correct and how to access camera intrinsics using ros realsense topics?

The code is: https://github.com/PyramidHe/PVNet/blob/master/3dome_data_generator/mask_gen.py

and in the method read_camera_configuration it needs extrinsics, intrinsics, and distortion.

• camera extrinsics --> not sure how to acquire this from ros-realsense?
• camera intrinsics --> I believe this is intrinsics?? K: [616.056884765625, 0.0, 321.5348815917969, 0.0, 616.2793579101562, 235.87950134277344, 0.0, 0.0, 1.0]
• camera distortion --> D: [0.0, 0.0, 0.0, 0.0, 0.0]

^^ is this camera extrinsics? or am I getting it from the wrong topic?

rotation: [0.9999707341194153, 0.002675577299669385, -0.007163900416344404, -0.0026810914278030396, 0.9999961256980896, -0.0007602194091305137, 0.0071618384681642056, 0.0007794042467139661, 0.9999740719795227]
translation: [0.014838425442576408, 7.110021397238597e-05, 0.00028845336055383086]

I get these:

root@186eb653e767:/workspace# rostopic echo /camera/color/camera_info 
header: 
  seq: 308
  stamp: 
    secs: 1701698575
    nsecs: 864586115
  frame_id: "camera_color_optical_frame"
height: 480
width: 640
distortion_model: "plumb_bob"
D: [0.0, 0.0, 0.0, 0.0, 0.0]
K: [616.056884765625, 0.0, 321.5348815917969, 0.0, 616.2793579101562, 235.87950134277344, 0.0, 0.0, 1.0]
R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
P: [616.056884765625, 0.0, 321.5348815917969, 0.0, 0.0, 616.2793579101562, 235.87950134277344, 0.0, 0.0, 0.0, 1.0, 0.0]
binning_x: 0
binning_y: 0
roi: 
  x_offset: 0
  y_offset: 0
  height: 0
  width: 0
  do_rectify: False
---

root@186eb653e767:/workspace# rostopic echo /camera/depth/camera_info 
header: 
  seq: 308
  stamp: 
    secs: 1701698342
    nsecs: 963487148
  frame_id: "camera_depth_optical_frame"
height: 480
width: 640
distortion_model: "plumb_bob"
D: [0.0, 0.0, 0.0, 0.0, 0.0]
K: [385.240478515625, 0.0, 319.2182922363281, 0.0, 385.240478515625, 236.77352905273438, 0.0, 0.0, 1.0]
R: [1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0]
P: [385.240478515625, 0.0, 319.2182922363281, 0.0, 0.0, 385.240478515625, 236.77352905273438, 0.0, 0.0, 0.0, 1.0, 0.0]
binning_x: 0
binning_y: 0
roi: 
  x_offset: 0
  y_offset: 0
  height: 0
  width: 0
  do_rectify: False
---

I also have access to this topic but I am not sure if it is fully related to what I need:

root@186eb653e767:/workspace# rostopic echo /camera/extrinsics/depth_to_color
header: 
  seq: 0
  stamp: 
    secs: 0
    nsecs:         0
  frame_id: "depth_to_color_extrinsics"
rotation: [0.9999707341194153, 0.002675577299669385, -0.007163900416344404, -0.0026810914278030396, 0.9999961256980896, -0.0007602194091305137, 0.0071618384681642056, 0.0007794042467139661, 0.9999740719795227]
translation: [0.014838425442576408, 7.110021397238597e-05, 0.00028845336055383086]
---

[MartyG-RealSense]

Hi @monajalal As you described above, you can list intrinsics from the camera_info topics (camera/depth/camera_info and /camera/color/camera_info) and extrinsics from /extrinsics/color_to_depth

For the D415 and D435-type camera models, all of the distortion parameters are set to zero, as described at IntelRealSense/librealsense#1430 (comment)

On some of the other RealSense models such as D455, the color stream's distortion coefficients are non-zero.