| # TOFSense-M ToF Sensor Metadata |
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| Language: English | [简体中文](tof_sensor.zh-CN.md) |
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| The dataset ToF topic is `/nlink_tofsensem_cascade`. It records a six-node Nooploop TOFSense-M cascade using UART query output in 8x8 mode. |
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| ## Collection Configuration |
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| | Field | Value | |
| | --- | --- | |
| | Sensor model | Nooploop TOFSense-M | |
| | Sensor type | Time-of-flight matrix laser ranging sensor | |
| | ROS topic | `/nlink_tofsensem_cascade` | |
| | ROS message | `nlink_parser/TofsenseMCascade` | |
| | Interface | UART | |
| | Output mode | Query | |
| | Cascade nodes | 6 | |
| | Pixel mode | 8x8 | |
| | Pixels per node | 64 | |
| | Expected pixels per cascade message | 384 | |
| | Nominal refresh rate | 15 Hz per node in 8x8 mode | |
| | UART baud rate | 921600 bps | |
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| ## Message Layout |
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| `nlink_parser/TofsenseMCascade` contains `nodes`, an array of `nlink_parser/TofsenseMFrame0`. |
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| Each node has: |
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| | Field | Type | Meaning | |
| | --- | --- | --- | |
| | `id` | `uint8` | Module ID in the cascade | |
| | `system_time` | `uint32` | Sensor-side system time | |
| | `pixel_count` | `uint8` | Expected to be 64 in this dataset | |
| | `pixels` | `TofsenseMFrame0Pixel[]` | Pixel data ordered from index 0 to 63 | |
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| Each pixel has: |
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| | Field | Type | Unit | Meaning | |
| | --- | --- | --- | --- | |
| | `dis` | `float32` | mm | Distance decoded by the current `nlink_parser` output | |
| | `dis_status` | `uint8` | code | Per-pixel distance status | |
| | `signal_strength` | `uint16` | raw count | Return signal strength; larger is stronger | |
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| For validity checks, treat a pixel as usable only when `dis_status == 0` and `dis > 0`. |
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| ## Distance Status Codes |
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| | Code | Meaning | |
| | --- | --- | |
| | 0 | Measurement usable | |
| | 1 | Signal strength too low | |
| | 2 | Phase target | |
| | 3 | Target noise estimate too high | |
| | 4 | Target consistency check failed | |
| | 5 | Measurement not updated | |
| | 6 | Wraparound not performed, usually the first measurement | |
| | 7 | Rate inconsistent | |
| | 8 | Current target signal strength low | |
| | 9 | Large pulse valid range, possibly due to merged targets | |
| | 10 | Usable measurement, but no target was detected in the previous detection | |
| | 11 | Measurement inconsistent | |
| | 12 | Target ambiguous | |
| | 13 | Target detected but data inconsistent, usually when a secondary target exists | |
| | 255 | Target not detected | |
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| ## Sensor Specifications |
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| | Parameter | Value | |
| | --- | --- | |
| | Range at 600 lux | 1.5 cm to 4 m | |
| | Range at 60K lux | 1.5 cm to 2 m | |
| | Range at 100K lux | 1.5 cm to 1.2 m | |
| | Distance resolution | 1 mm | |
| | Typical ranging accuracy | +/- 1.5 cm | |
| | Typical standard deviation | < 1 cm at 4 m indoors / 600 lux | |
| | Field of view | 45 deg horizontal, 45 deg vertical, 65 deg diagonal | |
| | Supported pixel modes | 8x8 and 4x4 | |
| | Refresh rate | 15 Hz at 8x8, 60 Hz at 4x4 | |
| | Laser wavelength | 940 nm | |
| | Laser class | Class 1 | |
| | Typical power | 670 mW | |
| | UART supply voltage | 3.7 V to 5.2 V | |
| | CAN supply voltage | 4.2 V to 5.2 V | |
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| The fixed ToF-to-base extrinsic is not available in this dataset version. Use `calibration/robot_v1_template/tof_to_base.yaml` for the explicit calibration status. |
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