F-Theta Camera Intrinsics File Format (DW_FAILURE: FThetaCamera: derivative of distortion within image interior (including edge) is negative)

Autonomous Vehicles DRIVE PX 2 DriveWorks
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1

Specs:
Platform: DRIVE AGX Xavier
Driveworks: 4.0.0
DriveOS: 5.2.6

Hey there, I wanted to switch from the pinhole model to ftheta.
When using the pinhole model everything works but when switching to the F-Theta model I get the following error message. Terminating app due to unexpected exception: DW_FAILURE: FThetaCamera: derivative of distortion within image interior (including edge) is negative
When using the FTheta Model I was implementing the parameters as described in this thread: Ftheta model parameters → j_0=0, j_1= inverse of the focal length, j_2,j_3= radial distortion coefficients, j_4, j_5= tangential distortion coefficients

{
    "constraints": [],
    "focalLengthPixel": [
        981.817474,
        979.962902
    ],
    "image-size": [
        1936,
        1216
    ],
    "model": {
        "center": [
            966.461471,
            602.120647
        ],
        "bw-poly": [
            0.0,
            -0.001018519,
            -0.00190517,
            -0.0277921,
            0.0173957
        ],
        "focal": [
            981.817474,
            979.962902
        ],
        "fov": 1.5566234691909453,
        "image-size": [
            1936,
            1216
        ],
        "is-model-fixed": true,
        "name": "back",
        "type": "ftheta"
    },
    "name": "back",
    "type": "ftheta"
}

Unfortunately I couldn’t find any sample files or explanations on how these files should be build. Therefore I have the following questions:

  • What does "is-model-fixed": true define?

  • Is this "focalLengthPixel": [fx, fy]" the right way of using focalLengthPixel?

  • What does image-size define when it is mentioned outside of the model definition and what does it describe in the model definition?

2

Dear @jan73,
Are you using DRIVE PX2 or DRIVE AGX Xavier platform? what is the driveworks version?

3

Hey @SivaRamaKrishnaNV,
this is the current set up:
Platform: DRIVE AGX Xavier
Driveworks: 4.0.0
DriveOS: 5.2.6