OpenIGTLink/ProtocolV2/Type/QTrackingData
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Contents
Summary
The QTDATA message type is intended for transferring 3D positions of surgical tools, markers etc. Its role is almost identical to TDATA, except that QTDATA describes orientation by using quaternion.
Message Types
QTDATA
| Data | Type | Description |
| NAME_1 | char[20] | Name (=Id) of the instrument/tracker |
| TYPE_1 | 8 bit unsigned | 1: tracker, 2: 6D instrument (regular instrument), 3: 3D instrument (only tip of the instrument defined), 4: 5D instrument (tip and handle are defined, but not the normal vector) |
| -- | 8 bit unsigned | Reserved |
| POSITION_1 | float32[3] | (X, Y, Z) |
| QUATERNION_1 | float32[4] | Quaternion (QX, QY, QZ, W) |
| ... | ||
| NAME_N | char[20] | Name (=Id) of the instrument/tracker |
| TYPE_N | 8 bit unsigned | 1: tracker, 2: 6D instrument (regular instrument), 3: 3D instrument (only tip of the instrument defined), 4: 5D instrument (tip and handle are defined, but not the normal vector) |
| -- | 8 bit unsigned | Reserved |
| POSITION_N | float32[3] | (X, Y, Z) |
| QUATERNION_N | float32[4] | Quaternion (QX, QY, QZ, W) |
GET_TDATA
| Data | Type | Description |
STT_TDATA
| Data | Type | Description |
| Resolution | 32 bit unsigned | Minimum time between two frames. Use 0 for as fast as possible. If e.g. 50 ms is specified, the maximum update rate will be 20 Hz. |
| Coordinate system name | char[20] | Coordinate system to use. Can be empty for default coordinate system. (not included if action = 2) |
STP_TDATA
| Data | Type | Description |
RTS_TDATA
Implementations
The TDATA message type is implemented in the following source code.
Contributors
Alexander Schaal
Comments
Junichi:
- How about adding 8- or 16-bit status field in TDATA? This will allow us to indicate that coordinate system is not registered. I would like to keep START_PUSH message simple....
Alexander:
- What status types can be specified?
- In the case the coordinate system is not valid, a STATUS message should be returned.
- Well, I understand that you would like to keep it as simple as possible. We really like to specifiy the coordinate system like "Camera" or "Patient". We could also specifiy a SET_COORD message, but I think this would be overkill. I still vote for a data specific argument field in START_PUSH. Maybe other future data types can also use this field?
- Due to consistency, I think we should add this field to STOP_PUSH, too.
- We would like to allow only one TDATA push for each client at a time, so a second START_PUSH will stop the first and start the second. A STOP_PUSH will stop the push regardless of the arguments in the body. What do you think about that?
Junichi:
- I haven't defined status types... it can be a bit array like: bit 0: registered or not; bit 1: line-of-site error; ....
- Do you think it is useful? if not, we can omit it.
- I agree that we need a way to specify coordinate system. It's good idea to have data specific field in the START_PUSH.
- I agree with the last comment. I would say one TDATA push for each device name, because multiple data sources may exist. The coordinate system can be overwritten by another START_PUSH message with the same device name and type.
Alexander:
- I think we don't need the status type. But maybe we define a TDATA in v3 after collecting some feedback from different users. I could think about other fields like diameter of instruments, etc. But for now I would like to keep TDATA as simple as possible.
- Ok, starting another trackingdata push with the same device name will implictly stop the first one. But if another device name is used, a second push will be started.
