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g3dradarprocess.md

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g3dradarprocess

Processes millimeter-wave (mmWave) radar signal data and generates point clouds, clusters, and tracking results. The element acts as a bridge between raw radar data ingestion and advanced radar signal processing algorithms, handling data reordering, pre-processing, DC (Direct Current) removal, and interfacing with the underlying radar library.

Overview

The g3dradarprocess element is designed to process raw radar signal data frame-by-frame. It performs the following operations:

  • Data Layout Transformation: Converts raw data from Chirps * TRN * Samples layout to TRN * Chirps * Samples layout (RadarCube)
  • Signal Conditioning: Performs DC removal to eliminate static clutter and leakage
  • Radar Detection: Generates point clouds containing detected reflection points with range, speed, angle, and SNR
  • Clustering: Groups nearby points into objects
  • Tracking: Tracks objects over time across multiple frames

The element attaches custom GStreamer metadata (GstRadarProcessMeta) to each buffer containing the processing results.

Configuration

Radar Configuration File

The radar-config property accepts a path to a JSON configuration file that contains:

  • Signal Interpretation Parameters: RX/TX count, samples, chirps
  • Algorithm Tuning Parameters: CFAR thresholds, clustering parameters, tracking parameters

The configuration file must match the format expected by the underlying libradar library.

Properties

Property Type Description Default
radar-config String Path to radar configuration JSON file (required) null
frame-rate Double Target frame rate for output (0 = no limit) 0

Pipeline Examples

Basic Processing Pipeline

Process radar data from binary files and display FPS:

gst-launch-1.0 multifilesrc location="radar/%06d.bin" start-index=559 ! \
  application/octet-stream ! \
  g3dradarprocess radar-config=config.json frame-rate=10 ! \
  fakesink

Processing with JSON Output

Process radar data and publish results to JSON file using gvametaconvert and gvametapublish:

gst-launch-1.0 multifilesrc location="radar/%06d.bin" ! \
  application/octet-stream ! \
  g3dradarprocess radar-config=config.json frame-rate=10 ! \
  gvametaconvert format=json json-indent=2 ! \
  gvametapublish file-format=2 file-path=radar_output.json ! \
  fakesink

Processing with Multiple Outputs

Simultaneously publish to JSON file and send to Kafka:

gst-launch-1.0 multifilesrc location="radar/%06d.bin" ! \
  application/octet-stream ! \
  g3dradarprocess radar-config=config.json ! \
  gvametaconvert format=json ! \
  tee name=t \
  t. ! queue ! gvametapublish file-format=2 file-path=output.json ! fakesink \
  t. ! queue ! gvametapublish method=kafka address=localhost:9092 topic=radar ! fakesink

Input/Output

  • Input Capability: application/octet-stream - Raw binary radar data
  • Output Capability: application/x-radar-processed - Processed data with attached metadata

Input Requirements

The input buffer size must match the expected size calculated from the configuration:

Total Size = TRN * Num_Chirps * ADC_Samples * sizeof(complex<float>)
where TRN = Num_RX * Num_TX

Metadata Structure

The element attaches GstRadarProcessMeta to each output buffer containing:

RadarPointClouds

Detected radar points with arrays of:

  • ranges[]: Distance to each reflection point
  • speeds[]: Doppler velocity of each point
  • angles[]: Azimuth angle of each point
  • snrs[]: Signal-to-noise ratio for each detection

ClusterResult

Grouped point clouds representing objects:

  • cluster_idx[]: Cluster index for each point cloud (mapping points to clusters)
  • cx[], cy[]: Cluster center coordinates
  • rx[], ry[]: Cluster extents (size)
  • av[]: Average velocity per cluster

TrackingResult

Multi-frame object tracking:

  • tracker_ids[]: Unique identifier for each tracked object
  • x[], y[]: Current position estimates
  • vx[], vy[]: Velocity vectors

Processing Pipeline

The element performs the following sequential operations for each buffer:

  1. Data Validation: Verifies buffer size matches expected configuration
  2. Pre-processing: Transforms data layout from Chirps * TRN * Samples to TRN * Chirps * Samples
  3. DC Removal: Calculates and subtracts mean from each sample set to remove static clutter
  4. RadarCube Preparation: Prepares data structure for radar library
  5. Detection: Calls radarDetection to generate point clouds
  6. Clustering: Calls radarClustering to group points into objects
  7. Tracking: Calls radarTracking for multi-frame object tracking
  8. Metadata Attachment: Attaches results as GStreamer metadata (GstRadarProcessMeta)
  9. Frame Rate Control: Throttles processing if frame-rate is set

Downstream Consumption

The metadata can be consumed by downstream GStreamer elements:

  • gvametaconvert: Converts GstRadarProcessMeta to JSON format
  • gvametapublish: Publishes JSON metadata to files, Kafka, MQTT, etc.
  • fakesink: Simple sink for testing and benchmarking
  • 3ddatarender (in development): Real-time visualization element
  • Custom elements can retrieve metadata using gst_buffer_get_meta() with GST_RADAR_PROCESS_META_API_TYPE

Element Details (gst-inspect-1.0)

Pad Templates:
  SINK template: 'sink'
    Availability: Always
    Capabilities:
      application/octet-stream
  
  SRC template: 'src'
    Availability: Always
    Capabilities:
      application/x-radar-processed

Element has no clocking capabilities.
Element has no URI handling capabilities.

Pads:
  SINK: 'sink'
    Pad Template: 'sink'
  SRC: 'src'
    Pad Template: 'src'

Element Properties:

  frame-rate          : Frame rate for output (0 = no limit)
                        flags: readable, writable
                        Double. Range:               0 -   1.797693e+308 Default:               0 
  
  name                : The name of the object
                        flags: readable, writable
                        String. Default: "radarprocess0"
  
  parent              : The parent of the object
                        flags: readable, writable
                        Object of type "GstObject"
  
  qos                 : Handle Quality-of-Service events
                        flags: readable, writable
                        Boolean. Default: false
  
  radar-config        : Path to radar configuration JSON file
                        flags: readable, writable
                        String. Default: null