Lidar Sensor Model

In chrono:sensor:ChLidarSensor, the synthetic data is generated via GPU-based ray-tracing. By leveraging hardware accelerated support and the headless rendering capabilities provided by NVIDIA Optix Library. For each lidar beam, a group of rays are traced that sample that lidar beam. The number of samples, along with beam divergence angle, are set by the user. The entire frame/scan of the lidar is processed in a single render step. To account for the time difference of rays across the scan, keyframes and motion blur techniques are used. With these keyframes, each beam in the scan traces the scene at a specific time, reproducing the motion of objects and the lidar. The intensity returned by the lidar beams is based on diffuse reflectance.

Creating a Lidar

auto lidar = chrono_types::make_shared<ChLidarSensor>(
parent_body, // body lidar is attached to
update_rate, // scanning rate in Hz
offset_pose, // offset pose
horizontal_samples, // number of horizontal samples
vertical_channels, // number of vertical channels
horizontal_fov, // horizontal field of view
max_vert_angle, // high vertical extent
min_vert_angle, // low vertical extent
max_distance, // maximum range
beam_shape, // set the beam shape to rectangular or elliptical
sample_radius, // configures the number of samples to use per beam
vert_divergence_angle, // vertical beam divergence angle
hori_divergence_angle, // horizontal beam divergence angle
return_mode, // return mode for the lidar when multiple samples used
clip_near // near clipping distance to ensure housing geometry not seen
lidar->SetName("Lidar Sensor");
lidar->SetCollectionWindow(collection_time); // typically time to spin 360 degrees

Lidar Filter Graph

// Access lidar data in raw format (range and intensity)
// Generate point cloud from raw data
// Add noise based on angle, angle, range, intensity
lidar->PushFilter(chrono_types::make_shared<ChFilterLidarNoiseXYZI>(0.01f, 0.001f, 0.001f, 0.01f));
// Access lidar data in point cloud format
// visualize point cloud (<height, width, zoom, name> of visual window)
lidar->PushFilter(chrono_types::make_shared<ChFilterVisualizePointCloud>(640, 480, 2, "Lidar Point Cloud"));
// Add sensor to manager

Lidar Data Access

while () {
if(xyzi_ptr->Buffer) {
// Retrieve and print the first point in the point cloud
PixelXYZI first_point= xyzi_ptr->Buffer[0];
std::cout<<"First Point: [ "<<unsigned(first_point.x) <<", "<<
unsigned(first_point.y) <<", “ <<unsigned(first_point.z) <<", "<<
unsigned(first_point.intensity) <<" ]"<<std::endl;
std::shared_ptr< SensorHostXYZIBuffer > UserXYZIBufferPtr
pointer to a point cloud buffer on the host that has been moved for safety and can be given to the us...
Definition: ChSensorBuffer.h:250