tagdetect.py

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#!/usr/bin/env python
 
# Copyright 2021 Roboception GmbH
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#    * Redistributions of source code must retain the above copyright
#      notice, this list of conditions and the following disclaimer.
#
#    * Redistributions in binary form must reproduce the above copyright
#      notice, this list of conditions and the following disclaimer in the
#      documentation and/or other materials provided with the distribution.
#
#    * Neither the name of the {copyright_holder} nor the names of its
#      contributors may be used to endorse or promote products derived from
#      this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
 
from __future__ import absolute_import
 
import rospy
 
from tf2_msgs.msg import TFMessage
from geometry_msgs.msg import TransformStamped
from visualization_msgs.msg import Marker, MarkerArray
from std_msgs.msg import ColorRGBA
 
from rc_reason_msgs.srv import DetectTags
 
from .rest_client import RestClient
 
 
def tag_to_tf(tag):
    tf = TransformStamped()
    tf.header.frame_id = tag.header.frame_id
    tf.child_frame_id = "{}_{}".format(tag.tag.id, tag.instance_id)
    tf.header.stamp = tag.header.stamp
    tf.transform.translation.x = tag.pose.pose.position.x
    tf.transform.translation.y = tag.pose.pose.position.y
    tf.transform.translation.z = tag.pose.pose.position.z
    tf.transform.rotation = tag.pose.pose.orientation
    return tf
 
 
class TagClient(RestClient):
 
    def __init__(self, rest_name):
        super(TagClient, self).__init__(rest_name)
        self.tag_markers = []
 
        self.publish_tf = rospy.get_param("~publish_tf", True)
        self.publish_markers = rospy.get_param("~publish_markers", True)
 
        self.pub_tf = rospy.Publisher('/tf', TFMessage, queue_size=10)
        self.pub_markers = rospy.Publisher('visualization_marker_array', MarkerArray, queue_size=10)
 
        rospy.on_shutdown(self.stop)
 
        self.start()
 
        self.add_rest_service(DetectTags, 'detect', self.detect_callback)
 
 
    def start(self):
        rospy.loginfo("starting %s", self.rest_name)
        self.call_rest_service('start')
 
    def stop(self):
        rospy.loginfo("stopping %s", self.rest_name)
        self.call_rest_service('stop')
 
    def detect_callback(self, srv_name, srv_type, request):
        response = self.call_rest_service(srv_name, srv_type, request)
        if response.return_code.value == 0:
            self.publish_tags(response.tags)
        return response
 
    def publish_tags(self, tags):
        if tags and self.publish_tf:
            transforms = [tag_to_tf(tag) for tag in tags]
            self.pub_tf.publish(TFMessage(transforms=transforms))
        if self.publish_markers:
            self.publish_tag_markers(tags)
 
    def publish_tag_markers(self, tags):
        def create_marker(tag, id):
            m = Marker(action=Marker.ADD, type=Marker.CUBE)
            m.color = ColorRGBA(r=0.0, g=1.0, b=0.0, a=0.5)
            m.header.stamp = tag.pose.header.stamp
            m.header.frame_id = "{}_{}".format(tag.tag.id, tag.instance_id)
            m.pose.orientation.w = 1.0
            m.pose.position.x = tag.tag.size / 2
            m.pose.position.y = tag.tag.size / 2
            m.pose.position.z = 0.001 / 2
            m.scale.x = tag.tag.size
            m.scale.y = tag.tag.size
            m.scale.z = 0.001
            m.id = id
            m.ns = self.rest_name+ "_tags"
            return m
 
        new_markers = []
        for i, tag in enumerate(tags):
            m = create_marker(tag, i)
            if i < len(self.tag_markers):
                self.tag_markers[i] = m
            else:
                self.tag_markers.append(m)
            new_markers.append(m)
        for i in range(len(tags), len(self.tag_markers)):
            # delete old markers
            self.tag_markers[i].action = Marker.DELETE
        self.pub_markers.publish(MarkerArray(markers=self.tag_markers))
        self.tag_markers = new_markers
 
 
def main(rest_node='rc_april_tag_detect'):
    client = TagClient(rest_node)
 
    try:
        rospy.spin()
    except KeyboardInterrupt:
        pass
 
 
def rc_april_tag_detect_client():
    main(rest_node='rc_april_tag_detect')
 
 
def rc_qr_code_detect_client():
    main(rest_node='rc_qr_code_detect')
 
 
if __name__ == '__main__':
    main()