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rospy_wrapper repository

Repository Summary

Checkout URI https://github.com/sean-hackett/rospy_wrapper.git
VCS Type git
VCS Version master
Last Updated 2019-10-27
Dev Status UNMAINTAINED
CI status No Continuous Integration
Released RELEASED
Tags No category tags.
Contributing Help Wanted (0)
Good First Issues (0)
Pull Requests to Review (0)

Packages

Name Version
rospy_wrapper 1.0.0

README

rospy_wrapper

A package that allows easy interchanging of ROS topics, rosbags, and other sources of and sinks for data.

Note: To use TopicSource or TopicSink, there must have been a previous call to rospy.init_node().

Usage

Instantiate a topic source

from rospywrapper import TopicSource
from sensor_msgs.msg import Image

source = TopicSource(
    topic='/camera/image',
    data_class=Image)

Instantiate a rosbag source

from rospywrapper import BagSource

source = BagSource(
    topic='/camera/image',
    pathname='input.bag')

Use a source to show images

import cv2
import numpy as np

with source:
  for msg, t in source:
    data = np.fromstring(msg['data'], np.uint8)
    img = cv2.imdecode(data, cv2.CV_LOAD_IMAGE_COLOR)
    cv2.imshow(img)
    cv2.waitKey(2)

Instantiate and use a topic sink

from rospywrapper import TopicSink

sink = TopicSink(
    topic='/camera/gray',
    data_class=Image)
with sink:
    # Use sink

Instantiate and use a bag sink

import rosbag
from rospywrapper import BagSink

bag = rosbag.Bag('out.bag', 'w')
sink = BagSink(
    bag=bag,
    topic='/camera/image',
    data_class=Image)
with bag:
    with sink:
        # Use sink

Write from source to sink

import conditional

if use_bag:
    source = BagSource('in.bag', '/camera/image')
    bag = rosbag.Bag('out.bag', 'w')
    sink = BagSink(bag, '/camera/gray', Image)
else:
    source = TopicSource('/camera/image', Image)
    bag = None
    sink = TopicSink('/camera/gray', Image)

with conditional(bag is not None, bag):
    with source, sink:
      for msg, t in source:
        data = np.fromstring(msg['data'], np.uint8)
        img = cv2.imdecode(data, cv2.CV_LOAD_IMAGE_COLOR)
        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
        sink.put(gray, t)

Create a custom source

import cv2
import rospy

from rospywrapper import Source

class VideoFileSource(Source):
  def __init__(self, filename, start_time=0):
      self.filename = filename
      self.time = start_time
      self.step = None

  def __enter__(self):
      self.video = cv2.VideoCapture(self.filename)
      fps = self.video.get(cv2.CAP_PROP_FPS)
      self.step = 1./fps
      return self

  def __exit__(self, *exc):
      self.video.release()

  def __iter__(self):
      return self

  def next(self):
      if not self.video.isOpened():
          raise StopIteration
      _, frame = self.video.read()
      t = self.time
      self.time += self.step
      return frame, rospy.Time.from_sec(t)

Create a custom sink

from rospywrapper import Sink
import csv

class CSVSink(Sink):
    def __init__(self, filename):
        self.filename = filename
        self._file = None
        self._writer = None

    def put(self, topic, data_class, data, t):
        row = [t] + [data[key] for key in data]
        self._writer.writerow(row)

    def __enter__(self):
        self._file = open(self.filename, 'w')
        self._writer = csv.writer(self.file)
        return self

    def __exit__(self, *exc):
        self._file.close()

CONTRIBUTING

No CONTRIBUTING.md found.