walelignmessele

erik Thank you!

So the new coordinate system is with Z pointing away from the depth, right? At least this is what my test shows me

@jakaskerl @erik Can you please take a look at this and what the coordinate system for the camera should be ?

See the two homogenous transformations:

Camera to world transformation:
 [[-0.91024599 -0.35431617  0.21427153 -0.26236268]
 [ 0.41406236 -0.77620355  0.4754581  -0.58017882]
 [-0.00214417  0.52150561  0.85324516 -1.00511733]
 [ 0.          0.          0.          1.        ]]
World-to-camera transformation:
 [[-9.10245991e-01  4.14062360e-01 -2.14416784e-03 -7.39507557e-04]
 [-3.54316166e-01 -7.76203552e-01  5.21505610e-01 -1.91218764e-02]
 [ 2.14271533e-01  4.75458104e-01  8.53245159e-01  1.18967907e+00]
 [ 0.00000000e+00  0.00000000e+00  0.00000000e+00  1.00000000e+00]]

jakaskerl Thank you! I will be testing different configurations to find out what's going on. I keep you posted here. From your previous explanation (i.e. Color is passed in BGR format, so x is red, y is green and z is blue (also it's the usual color coding), it appears like the world coordinate is defined in the left-hand rule, do you agree?

Thank you jakaskerl ! The confusion comes from https://docs.luxonis.com/projects/api/en/latest/components/nodes/spatial_location_calculator/ (see the screenshot as well)

. From this the camera coordinate systems uses right hand rule with +ve Z facing the depth. But when I do the camera calibration, it gives a -ve values for all, x, y, z from camera to world. If I follow this definition (the one I referenced), I should be getting +ve z at least, right? Are you certain the camera coordinate is left hand with z facing the depth?

I found two problems a bit confusing here and would love to get some help?

1. How is the world coordinate defined? I see the coordinate used on https://github.com/luxonis/depthai-experiments/tree/master/gen2-multiple-devices/multi-cam-calibration for calibration and it uses right-hand rule with the x-axis out as shown in the picture, Can you confirm the this, please?

   

2. Where is the coordinate frame for the camera defined? I see a discussion for IMU coordinate frame in https://discuss.luxonis.com/d/1044-about-oak-d-pro-w-imu-coordinate-system and there it is pointed out as shown

   

   Is this the same for RGB and mono cameras?

   
   

   Highly appreciate the help

   Thanks!

@erik Thank you!

Is this the right channel for getting some Q and A and experiences? I feel like the answers in this channel are so limited and no intention of answering the question directly.

jakaskerl Can you be a bit specific and guide me in the right direction if you do not mind?

erik I just have another question while using one of the examples…https://github.com/luxonis/depthai-experiments/tree/master/gen2-multiple-devices/multi-cam-calibration. Tha algorithm detects the second corner in the chessboard as the center point (origin) as shown in the picture. The question is can I ask for a specific point to be the center as indicated by the circled point? if so How can I do that?

.

Is there an example code for accessing the camera via USB-c? How can I communicate via USB-c? I can't seem to find one.

Thanks!

jakaskerl Thank you!

Hi @jakaskerl,

The depth values are between 627 and 1315. These values are for a camera that's mounted about 86cm from the ground (the target object is sitting on the ground.

jakaskerl Thank you so much! This indeed helps.

From stereo depth node graph (https://docs.luxonis.com/projects/api/en/latest/components/nodes/stereo_depth/#internal-block-diagram-of-stereodepth-node), the unit for the depth is in [mm]. But in my case, this number is very big and does not seem to be in mm. Are there any settings that I need to do to get the right values? Any example of this would be helpful. Thanks!

Do we need to perform lens calibration for OAK-D? The documentation in https://docs.luxonis.com/en/latest/pages/calibration/ suggests no need to do the calibration. If we need to do what scenarios we have to perform camera calibration? For example, if calibrate the camera on a bench, do I need to calibrate it once I put it on a machine in its permanent position?

@erik I did ask this question and waiting for a response. @jakaskerl do you have any other suggestions please?

^^ @erik @jakaskerl Thanks!

1.7m from the camera

The 9 3D box landmarks correspond to the corners in the following pic