Which camera is left and which is right? It looks as though you have CAM_A as left but I think the X: 3.6 value means it's defined as 3.6cm to the right of the right camera. Try changing it to -3.6 and see if the error changes.
Here's the definition from my 3P board for comparison, the layout as viewed from behind the camera
In reality:
left <--> 2.89cm <--> centre <--> 2.89cm <--> right
In the definition:
left is -5.78cm from the right
centre is -2.89 from the right
I've no idea why but it gets cranky if I don't reference the positions from the right camera. I think I've messed around with the calibration_utils
script a bit too much though so all bets are off. I can calibrate fine though so it's working at least.
{
"board_config": {
"name": "FFC-3P",
"revision": "R1M0E1",
"cameras": {
"CAM_A": {
"name": "rgb",
"hfov": 90,
"type": "color",
"extrinsics": {
"to_cam": "CAM_C",
"specTranslation": {
"x": -2.89,
"y": 0,
"z": -9.45
},
"rotation": {
"r": 0,
"p": 0,
"y": 0
}
}
},
"CAM_B": {
"name": "left",
"hfov": 110,
"type": "color",
"extrinsics": {
"to_cam": "CAM_C",
"specTranslation": {
"x": -5.78,
"y": 0,
"z": 0
},
"rotation": {
"r": 0,
"p": 0,
"y": 0
}
}
},
"CAM_C": {
"name": "right",
"hfov": 110,
"type": "color"
}
},
"stereo_config": {
"left_cam": "CAM_B",
"right_cam": "CAM_C"
}
}
}