Algorithms Overview

Algorithms implemented in the SDK can be grouped into categories based on their function.

Processors

Processors are algorithms that can be used to process data either to change some of their characteristics (e.g. flip the x coordinate of every event) or perform some advanced analysis (e.g. tracking objects or extracting spatio/temporal patterns).

• Algorithms taking events as input and outputting the same number of events but with a transformation applied:

Name	Module	C++ API	Python API	Samples
FlipXAlgorithm	Core	FlipX	FlipX	C++ Get Started
FlipYAlgorithm	Core	FlipY	FlipY	None
PolarityInverterAlgorithm	Core	PolarityInverter	PolarityInverter	None
RotateEventsAlgorithm	Core	RotateEvents	RotateEvents	None
TransposeEventsAlgorithm	Core	TransposeEvents	TransposeEvents	metavision_counting in C++ metavision_counting in Python

Note

The Python bindings of those algorithms offers two ways to process the events: with an output buffer or directly on the input.

For example, FlipXAlgorithm can be called either with process_events() that does not change the input events:

flip_x = metavision_sdk_core.FlipXAlgorithm(width - 1)
flipped_events_buffer = flip_x.get_empty_output_buffer()
flip_x.process_events(ev, flipped_events_buffer)

or with process_events_() which performs processing in-place:

flip_x = metavision_sdk_core.FlipXAlgorithm(width - 1)
flip_x.process_events_(ev)

• Algorithms processing events as input and outputting some data from the event (counting, tracking, optical flow, etc):

Name	Module	C++ API	Python API	Samples
FrequencyAlgorithm	CV	Frequency	Frequency	metavision_ground_plane_calibration
PeriodAlgorithm	CV	Period	Period	None
SparseOpticalFlowAlgorithm	CV	SparseOpticalFlow	SparseOpticalFlow	metavision_sparse_optical_flow in C++ metavision_sparse_optical_flow in Python
PlaneFittingFlowAlgorithm	CV	PlaneFittingFlow	PlaneFittingFlow	metavision_dense_optical_flow in C++ metavision_dense_optical_flow in Python
TimeGradientFlowAlgorithm	CV	TimeGradientFlowAlgorithm	TimeGradientFlowAlgorithm	metavision_dense_optical_flow in C++ metavision_dense_optical_flow
TripletMatchingFlowAlgorithm	CV	TripletMatchingFlow	TripletMatchingFlow	metavision_dense_optical_flow in C++ metavision_dense_optical_flow
ModulatedLightDetectorAlgorithm	CV	ModulatedLightDetectorAlgorithm		metavision_active_marker_2d_tracking in C++
ActiveMarkerTrackerAlgorithm	CV	ActiveMarkerTrackerAlgorithm		metavision_active_marker_2d_tracking in C++
ActiveMarkerPoseEstimatorAlgorithm	CV3D	ActiveMarkerPoseEstimatorAlgorithm		metavision_active_marker_3d_tracking in C++
CountingAlgorithm	Analytics	Counting	Counting	metavision_counting in C++ metavision_counting in Python
DominantValueEventsAlgorithm	Analytics	DominantValueEvents	DominantFrequencyEventsAlgorithm DominantPeriodEventsAlgorithm	None
JetMonitoringAlgorithm	Analytics	JetMonitoring	JetMonitoring	metavision_jet_monitoring in C++ metavision_jet_monitoring in Python
PsmAlgorithm	Analytics	Psm	Psm	metavision_psm in C++ metavision_psm in Python
SpatterTrackerAlgorithm	Analytics	SpatterTracker	SpatterTracker	metavision_spatter_tracking in C++ metavision_spatter_tracking in Python
TrackingAlgorithm	Analytics	Tracking	Tracking	metavision_generic_tracking in C++ metavision_generic_tracking in Python
DftHighFreqScorerAlgorithm	Calibration	DftHighFreqScorer		metavision_blinking_pattern_focus

• Algorithms processing events as input and outputting display-related data (e.g. frames):

Name	Module	C++ API	Python API	Samples
EventFrameDiffGenerationAlgorithm	Core	EventFrameDiffGenerationAlgorithm		metavision_event_frame_generation in C++
EventFrameHistoGenerationAlgorithm	Core	EventFrameHistoGenerationAlgorithm		metavision_event_frame_generation in C++
OnDemandFrameGenerationAlgorithm	CV	OnDemandFrameGeneration	OnDemandFrameGeneration	metavision_psm in C++ metavision_psm in Python etc.
PeriodicFrameGenerationAlgorithm	CV	PeriodicFrameGeneration	PeriodicFrameGeneration	C++ Get Started Python Get Started etc.
TimeDecayFrameGenerationAlgorithm	CV	TimeDecayFrameGeneration		None
DenseFlowFrameGeneratorAlgorithm	CV	DenseFlowFrameGenerator	DenseFlowFrameGenerator	metavision_dense_optical_flow in C++ metavision_dense_optical_flow in Python
SparseFlowFrameGeneratorAlgorithm	CV	SparseFlowFrameGenerator	SparseFlowFrameGenerator	metavision_sparse_optical_flow in C++ metavision_sparse_optical_flow in Python
DominantValueMapAlgorithm	Analytics	DominantValueMap	DominantValueMap	metavision_vibration_estimation in C++ metavision_vibration_estimation in Python
FrequencyMapAsyncAlgorithm	Analytics	FrequencyMapAsync	FrequencyMapAsync	metavision_vibration_estimation in C++ metavision_vibration_estimation in Python
HeatMapFrameGeneratorAlgorithm	Analytics	HeatMapFrameGenerator	HeatMapFrameGenerator	metavision_vibration_estimation in C++ metavision_vibration_estimation in Python
MapGeneratorAsyncAlgorithm	Analytics	MapGeneratorAsync		None
PeriodMapAsyncAlgorithm	Analytics	PeriodMapAsync	PeriodMapAsync	None
BlinkingFrameGeneratorAlgorithm	Calibration	BlinkingFrameGenerator		metavision_blinking_pattern_focus

Filters

Filters are algorithms taking events as input and outputting only the events that satisfy certain conditions.

Name	Module	C++ API	Python API	Samples
PolarityFilterAlgorithm	Core	PolarityFilter	PolarityFilter	metavision_filtering in C++ metavision_filtering in Python etc.
RoiFilterAlgorithm	Core	RoiFilter	RoiFilter	metavision_filtering in C++ metavision_filtering in Python etc.
AntiFlickerAlgorithm	CV	AntiFlicker	AntiFlicker	metavision_data_rate in C++ metavision_data_rate in Python etc.
ActivityNoiseFilterAlgorithm	CV	ActivityNoiseFilter	ActivityNoiseFilter	metavision_psm in C++ metavision_psm in Python etc.
ProximityFilterAlgorithm	CV	ProximityFilterAlgorithm	ProximityFilterAlgorithm	metavision_model_3d_tracking in C++
RoiMaskAlgorithm	Core	RoiMask	RoiMask	None
SpatioTemporalContrastAlgorithm	CV	SpatioTemporalContrast	SpatioTemporalContrast	metavision_generic_tracking in C++ metavision_spatter_tracking in Python etc.
TrailFilterAlgorithm	CV	TrailFilter	TrailFilter	metavision_noise_filtering in C++ metavision_noise_filtering in Python etc.

Note

Our C++ algorithms are independent of the HAL layer/module. They don’t rely on Prophesee sensors and files formats. So as long as you have buffers of events as described in the API documentation, you will be able to leverage them in your application

See also

For an overview of how to use and tune the SDK algorithms, check our programming guide on Processing Events with Algorithms. Alternatively, you can also check Metavision Viewer page where we mention how a filter algorithm can be applied to the event stream.