| # Camera calibration |
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| The same brand and model of capture device is represented by three camera-extrinsic configurations. The internal IDs 1403, 2650 and 1203 are calibration indices; they are not three robot types or three capture-device models. |
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| | Calibration ID | Intrinsic provenance | Camera-to-camera extrinsics | |
| | --- | --- | --- | |
| | rig_1403_0722_0724_v1 | Main/left/right dated 0722; USB Wide dated 0724 | USB→main and PnP left→right; left/right→main unavailable | |
| | rig_2650_0730_0804_v1 | Main/left/right and USB Alice dated 0730 | Left/right/USB→main dated 0804; left→right derived | |
| | rig_1203_0810_0812_v1 | Main/left/right dated 0812; USB David dated 0810 | Left/right/USB→main dated 0812; left→right derived | |
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| Each profile contains a manifest, four available intrinsic records, and its existing extrinsic records. Across profiles there are 12 intrinsic records and 10 camera-to-camera transforms. Three configurations does not mean there are only three transform matrices. |
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| Intrinsic JSON contains K, D, parameter order, calibrated image width/height, camera role and provenance hashes. Main and auxiliary grayscale cameras use OpenCV rational eight-coefficient models in the order k1,k2,p1,p2,k3,k4,k5,k6. USB cameras use five coefficients k1,k2,p1,p2,k3. The word fisheye in a camera-role name does not select the four-coefficient OpenCV fisheye API. Legacy coefficient labels were ambiguous; the registered vector interpretation follows the existing processing convention, and source hashes are retained. |
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| Extrinsics use column-vector points in optical axes X-right, Y-down, Z-forward, with translation in metres: |
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| ```text |
| P_target = R @ P_source + t_m |
| ``` |
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| Transform filenames and source_frame/target_frame define direction. Intrinsics use pixel units. Images are exported in their original orientation and dimensions; resizing, cropping or rotating images requires a corresponding update to K and/or the coordinate convention. |
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| ## Known limitations |
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| - Profile 1403 has no measured left→main or right→main transform in the registered calibration. Do not substitute a midpoint or parallel-axis assumption as measured calibration. |
| - Its main–USB historical median epipolar error is about 17.9 pixels. It is not high-precision geometric ground truth. |
| - Left→right transforms for 2650 and 1203 are derived from the other camera transforms and are labelled accordingly. |
| - Existing normalized production parameters are preserved. For example, the 1203 USB baseline label in a legacy file was 45.25 mm, while the stored translation vector has norm about 45.50 mm; geometric computation uses the vector, not the label. |
| - Calibration availability does not imply image availability. The 200 main-only recordings reference the applicable main-camera intrinsics but do not include auxiliary or real target images. |
| - Camera-pair calibration is separate from SDK body-to-optical, tool or robot TCP mappings. These mappings are not fabricated from camera-pair extrinsics. |
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| If hardware was remounted, calibration applicability must be reviewed and versioned rather than inferred solely from a device identifier. Known applicability limits should remain attached to the corresponding profile. |
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| ## Optional USB intrinsic refits |
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| The 2026-10-29 [Alice and David USB intrinsic refit candidates](USB_INTRINSIC_REFITS_20261029.md) are stored separately from the three historical rig profiles. They do not update episode calibration references or the existing USB-to-main extrinsics. |
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