353 lines
13 KiB
Python
353 lines
13 KiB
Python
#!/usr/bin/env python
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# Copyright (c) 2020 Computer Vision Center (CVC) at the Universitat Autonoma de
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# Barcelona (UAB).
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#
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# This work is licensed under the terms of the MIT license.
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# For a copy, see <https://opensource.org/licenses/MIT>.
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"""
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Lidar projection on RGB camera example
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"""
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import glob
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import os
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import sys
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try:
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sys.path.append(glob.glob('../carla/dist/carla-*%d.%d-%s.egg' % (
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sys.version_info.major,
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sys.version_info.minor,
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'win-amd64' if os.name == 'nt' else 'linux-x86_64'))[0])
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except IndexError:
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pass
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import carla
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import argparse
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from queue import Queue
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from queue import Empty
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from matplotlib import cm
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try:
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import numpy as np
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except ImportError:
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raise RuntimeError('cannot import numpy, make sure numpy package is installed')
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try:
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from PIL import Image
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except ImportError:
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raise RuntimeError('cannot import PIL, make sure "Pillow" package is installed')
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VIRIDIS = np.array(cm.get_cmap('viridis').colors)
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VID_RANGE = np.linspace(0.0, 1.0, VIRIDIS.shape[0])
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def sensor_callback(data, queue):
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"""
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This simple callback just stores the data on a thread safe Python Queue
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to be retrieved from the "main thread".
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"""
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queue.put(data)
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def tutorial(args):
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"""
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This function is intended to be a tutorial on how to retrieve data in a
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synchronous way, and project 3D points from a lidar to a 2D camera.
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"""
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# Connect to the server
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client = carla.Client(args.host, args.port)
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client.set_timeout(2.0)
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world = client.get_world()
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bp_lib = world.get_blueprint_library()
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traffic_manager = client.get_trafficmanager(8000)
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traffic_manager.set_synchronous_mode(True)
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original_settings = world.get_settings()
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settings = world.get_settings()
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settings.synchronous_mode = True
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settings.fixed_delta_seconds = 3.0
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world.apply_settings(settings)
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vehicle = None
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camera = None
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lidar = None
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try:
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# Search the desired blueprints
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vehicle_bp = bp_lib.filter("vehicle.lincoln.mkz2017")[0]
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camera_bp = bp_lib.filter("sensor.camera.rgb")[0]
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lidar_bp = bp_lib.filter("sensor.lidar.ray_cast")[0]
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# Configure the blueprints
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camera_bp.set_attribute("image_size_x", str(args.width))
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camera_bp.set_attribute("image_size_y", str(args.height))
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if args.no_noise:
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lidar_bp.set_attribute('dropoff_general_rate', '0.0')
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lidar_bp.set_attribute('dropoff_intensity_limit', '1.0')
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lidar_bp.set_attribute('dropoff_zero_intensity', '0.0')
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lidar_bp.set_attribute('upper_fov', str(args.upper_fov))
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lidar_bp.set_attribute('lower_fov', str(args.lower_fov))
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lidar_bp.set_attribute('channels', str(args.channels))
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lidar_bp.set_attribute('range', str(args.range))
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lidar_bp.set_attribute('points_per_second', str(args.points_per_second))
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# Spawn the blueprints
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vehicle = world.spawn_actor(
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blueprint=vehicle_bp,
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transform=world.get_map().get_spawn_points()[0])
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vehicle.set_autopilot(True)
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camera = world.spawn_actor(
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blueprint=camera_bp,
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transform=carla.Transform(carla.Location(x=1.6, z=1.6)),
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attach_to=vehicle)
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lidar = world.spawn_actor(
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blueprint=lidar_bp,
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transform=carla.Transform(carla.Location(x=1.0, z=1.8)),
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attach_to=vehicle)
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# Build the K projection matrix:
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# K = [[Fx, 0, image_w/2],
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# [ 0, Fy, image_h/2],
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# [ 0, 0, 1]]
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image_w = camera_bp.get_attribute("image_size_x").as_int()
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image_h = camera_bp.get_attribute("image_size_y").as_int()
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fov = camera_bp.get_attribute("fov").as_float()
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focal = image_w / (2.0 * np.tan(fov * np.pi / 360.0))
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# In this case Fx and Fy are the same since the pixel aspect
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# ratio is 1
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K = np.identity(3)
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K[0, 0] = K[1, 1] = focal
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K[0, 2] = image_w / 2.0
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K[1, 2] = image_h / 2.0
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# The sensor data will be saved in thread-safe Queues
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image_queue = Queue()
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lidar_queue = Queue()
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camera.listen(lambda data: sensor_callback(data, image_queue))
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lidar.listen(lambda data: sensor_callback(data, lidar_queue))
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for frame in range(args.frames):
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world.tick()
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world_frame = world.get_snapshot().frame
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try:
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# Get the data once it's received.
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image_data = image_queue.get(True, 1.0)
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lidar_data = lidar_queue.get(True, 1.0)
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except Empty:
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print("[Warning] Some sensor data has been missed")
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continue
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assert image_data.frame == lidar_data.frame == world_frame
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# At this point, we have the synchronized information from the 2 sensors.
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sys.stdout.write("\r(%d/%d) Simulation: %d Camera: %d Lidar: %d" %
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(frame, args.frames, world_frame, image_data.frame, lidar_data.frame) + ' ')
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sys.stdout.flush()
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# Get the raw BGRA buffer and convert it to an array of RGB of
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# shape (image_data.height, image_data.width, 3).
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im_array = np.copy(np.frombuffer(image_data.raw_data, dtype=np.dtype("uint8")))
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im_array = np.reshape(im_array, (image_data.height, image_data.width, 4))
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im_array = im_array[:, :, :3][:, :, ::-1]
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# Get the lidar data and convert it to a numpy array.
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p_cloud_size = len(lidar_data)
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p_cloud = np.copy(np.frombuffer(lidar_data.raw_data, dtype=np.dtype('f4')))
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p_cloud = np.reshape(p_cloud, (p_cloud_size, 4))
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# Lidar intensity array of shape (p_cloud_size,) but, for now, let's
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# focus on the 3D points.
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intensity = np.array(p_cloud[:, 3])
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# Point cloud in lidar sensor space array of shape (3, p_cloud_size).
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local_lidar_points = np.array(p_cloud[:, :3]).T
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# Add an extra 1.0 at the end of each 3d point so it becomes of
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# shape (4, p_cloud_size) and it can be multiplied by a (4, 4) matrix.
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local_lidar_points = np.r_[
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local_lidar_points, [np.ones(local_lidar_points.shape[1])]]
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# This (4, 4) matrix transforms the points from lidar space to world space.
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lidar_2_world = lidar.get_transform().get_matrix()
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# Transform the points from lidar space to world space.
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world_points = np.dot(lidar_2_world, local_lidar_points)
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# This (4, 4) matrix transforms the points from world to sensor coordinates.
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world_2_camera = np.array(camera.get_transform().get_inverse_matrix())
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# Transform the points from world space to camera space.
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sensor_points = np.dot(world_2_camera, world_points)
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# New we must change from UE4's coordinate system to an "standard"
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# camera coordinate system (the same used by OpenCV):
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# ^ z . z
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# | /
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# | to: +-------> x
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# | . x |
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# |/ |
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# +-------> y v y
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# This can be achieved by multiplying by the following matrix:
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# [[ 0, 1, 0 ],
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# [ 0, 0, -1 ],
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# [ 1, 0, 0 ]]
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# Or, in this case, is the same as swapping:
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# (x, y ,z) -> (y, -z, x)
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point_in_camera_coords = np.array([
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sensor_points[1],
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sensor_points[2] * -1,
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sensor_points[0]])
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# Finally we can use our K matrix to do the actual 3D -> 2D.
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points_2d = np.dot(K, point_in_camera_coords)
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# Remember to normalize the x, y values by the 3rd value.
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points_2d = np.array([
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points_2d[0, :] / points_2d[2, :],
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points_2d[1, :] / points_2d[2, :],
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points_2d[2, :]])
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# At this point, points_2d[0, :] contains all the x and points_2d[1, :]
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# contains all the y values of our points. In order to properly
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# visualize everything on a screen, the points that are out of the screen
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# must be discarted, the same with points behind the camera projection plane.
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points_2d = points_2d.T
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intensity = intensity.T
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points_in_canvas_mask = \
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(points_2d[:, 0] > 0.0) & (points_2d[:, 0] < image_w) & \
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(points_2d[:, 1] > 0.0) & (points_2d[:, 1] < image_h) & \
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(points_2d[:, 2] > 0.0)
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points_2d = points_2d[points_in_canvas_mask]
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intensity = intensity[points_in_canvas_mask]
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# Extract the screen coords (uv) as integers.
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u_coord = points_2d[:, 0].astype(np.int)
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v_coord = points_2d[:, 1].astype(np.int)
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# Since at the time of the creation of this script, the intensity function
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# is returning high values, these are adjusted to be nicely visualized.
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intensity = 4 * intensity - 3
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color_map = np.array([
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np.interp(intensity, VID_RANGE, VIRIDIS[:, 0]) * 255.0,
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np.interp(intensity, VID_RANGE, VIRIDIS[:, 1]) * 255.0,
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np.interp(intensity, VID_RANGE, VIRIDIS[:, 2]) * 255.0]).astype(np.int).T
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if args.dot_extent <= 0:
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# Draw the 2d points on the image as a single pixel using numpy.
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im_array[v_coord, u_coord] = color_map
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else:
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# Draw the 2d points on the image as squares of extent args.dot_extent.
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for i in range(len(points_2d)):
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# I'm not a NumPy expert and I don't know how to set bigger dots
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# without using this loop, so if anyone has a better solution,
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# make sure to update this script. Meanwhile, it's fast enough :)
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im_array[
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v_coord[i]-args.dot_extent : v_coord[i]+args.dot_extent,
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u_coord[i]-args.dot_extent : u_coord[i]+args.dot_extent] = color_map[i]
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# Save the image using Pillow module.
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image = Image.fromarray(im_array)
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image.save("_out/%08d.png" % image_data.frame)
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finally:
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# Apply the original settings when exiting.
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world.apply_settings(original_settings)
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# Destroy the actors in the scene.
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if camera:
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camera.destroy()
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if lidar:
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lidar.destroy()
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if vehicle:
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vehicle.destroy()
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def main():
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"""Start function"""
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argparser = argparse.ArgumentParser(
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description='CARLA Sensor sync and projection tutorial')
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argparser.add_argument(
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'--host',
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metavar='H',
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default='127.0.0.1',
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help='IP of the host server (default: 127.0.0.1)')
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argparser.add_argument(
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'-p', '--port',
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metavar='P',
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default=2000,
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type=int,
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help='TCP port to listen to (default: 2000)')
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argparser.add_argument(
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'--res',
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metavar='WIDTHxHEIGHT',
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default='680x420',
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help='window resolution (default: 1280x720)')
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argparser.add_argument(
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'-f', '--frames',
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metavar='N',
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default=500,
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type=int,
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help='number of frames to record (default: 500)')
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argparser.add_argument(
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'-d', '--dot-extent',
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metavar='SIZE',
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default=2,
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type=int,
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help='visualization dot extent in pixels (Recomended [1-4]) (default: 2)')
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argparser.add_argument(
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'--no-noise',
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action='store_true',
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help='remove the drop off and noise from the normal (non-semantic) lidar')
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argparser.add_argument(
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'--upper-fov',
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metavar='F',
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default=30.0,
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type=float,
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help='lidar\'s upper field of view in degrees (default: 15.0)')
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argparser.add_argument(
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'--lower-fov',
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metavar='F',
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default=-25.0,
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type=float,
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help='lidar\'s lower field of view in degrees (default: -25.0)')
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argparser.add_argument(
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'-c', '--channels',
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metavar='C',
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default=64.0,
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type=float,
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help='lidar\'s channel count (default: 64)')
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argparser.add_argument(
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'-r', '--range',
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metavar='R',
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default=100.0,
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type=float,
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help='lidar\'s maximum range in meters (default: 100.0)')
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argparser.add_argument(
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'--points-per-second',
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metavar='N',
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default='100000',
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type=int,
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help='lidar points per second (default: 100000)')
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args = argparser.parse_args()
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args.width, args.height = [int(x) for x in args.res.split('x')]
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args.dot_extent -= 1
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try:
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tutorial(args)
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except KeyboardInterrupt:
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print('\nCancelled by user. Bye!')
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if __name__ == '__main__':
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main()
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