# ros_numpy

**Repository Path**: fu-zihao/ros_numpy

## Basic Information

- **Project Name**: ros_numpy
- **Description**: 无00000000000
- **Primary Language**: Python
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2023-03-30
- **Last Updated**: 2023-03-30

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# ros_numpy
Tools for converting ROS messages to and from numpy arrays. Contains two functions:

* `arr = numpify(msg, ...)` - try to get a numpy object from a message
* `msg = msgify(MessageType, arr, ...)` - try and convert a numpy object to a message

Currently supports:

* `sensor_msgs.msg.PointCloud2` ↔ structured `np.array`:
   
   ```python
   data = np.zeros(100, dtype=[
     ('x', np.float32),
     ('y', np.float32),
     ('vectors', np.float32, (3,))
   ])
   data['x'] = np.arange(100)
   data['y'] = data['x']*2
   data['vectors'] = np.arange(100)[:,np.newaxis]
   
   msg = ros_numpy.msgify(PointCloud2, data)
   ```
   
   ```
   data = ros_numpy.numpify(msg)
   ```

* `sensor_msgs.msg.Image` ↔ 2/3-D `np.array`, similar to the function of `cv_bridge`, but without the dependency on `cv2`
* `nav_msgs.msg.OccupancyGrid` ↔ `np.ma.array`
* `geometry.msg.Vector3` ↔ 1-D `np.array`. `hom=True` gives `[x, y, z, 0]`
* `geometry.msg.Point` ↔ 1-D `np.array`. `hom=True` gives `[x, y, z, 1]`
* `geometry.msg.Quaternion` ↔ 1-D `np.array`, `[x, y, z, w]`
* `geometry.msg.Transform` ↔ 4×4 `np.array`, the homogeneous transformation matrix
* `geometry.msg.Pose` ↔ 4×4 `np.array`, the homogeneous transformation matrix from the origin

Support for more types can be added with:

```python
@ros_numpy.converts_to_numpy(SomeMessageClass)
def convert(my_msg):
    return np.array(...)

@ros_numpy.converts_from_numpy(SomeMessageClass)
def convert(my_array):
    return SomeMessageClass(...)
```

Any extra args or kwargs to `numpify` or `msgify` will be forwarded to your conversion function


## Future work

* Add simple conversions for:

  * `geometry_msgs.msg.Inertia`