ev::SpaceTime_< T, Options, E > Class Template Reference

This class extends ev::EventImage_<T> to draw the events as a cloud in the x-y-t volume seen in perspective. More...

#include <space-time.hpp>

Inheritance diagram for ev::SpaceTime_< T, Options, E >:

Public Member Functions
	SpaceTime_ (const cv::Size canvas, const cv::Size sensor=cv::Size())
	Construct the canvas.
void	setView (const double yaw, const double pitch)
	Set the view angles.
void	setDepth (const double depth)
	Set the depth of the box, that is, how long the time axis is drawn.
void	showAxes (const bool state, const double length=DEFAULT_AXES_LENGTH)
	Draw the x, y and t axes from the sensor origin, labelled at their ends.
void	fadeWithDepth (const bool state, const double strength=DEFAULT_FADE)
	Fade the events towards the background as they recede, so the depth shows.
void	setAxesValue (const typename TypeHelper< T >::Type &value)
	Set the value the axes are drawn with.
void	setAxesColor (const cv::viz::Color &color)
	Set the colour the axes are drawn with. For more information, please refer here.
double	yaw () const
	Yaw of the view.
double	pitch () const
	Pitch of the view.
cv::Size	sensorSize () const
	Sensor size.
cv::Point2d	project (const Event_< E > &e, const double age) const
	Project an event onto the canvas with the current view.
cv::Mat &	render ()
	Render the space-time view.
Public Member Functions inherited from ev::EventImage_< T, RepresentationOptions::NONE, int >
	EventImage_ (Args &&...args)
cv::Mat &	render ()
Public Member Functions inherited from ev::AbstractRepresentation_< T, Options, int >
std::size_t	count () const
	Number of events integrated in the representation.
TimeType	firstTimestamp () const
	Timestamp of the oldest event integrated in the representation.
TimeType	lastTimestamp () const
	Timestamp of the newest event integrated in the representation.
void	clear ()
	Remove all events from the representation.
bool	insert (const Event_< int > &e)
	Insert one event in the representation.
void	setTimeOffset (const Event_< int > &e)
	Set time offset.
void	setValue (const bool polarity, const Type &value)
	Set values for ON and OFF pixels.
void	setValues (const Type &positive, const Type &negative, const Type &reset)
	Set values for ON, OFF, and non-activated pixels.
void	setColor (const bool polarity, const cv::viz::Color &color)
	Set colors for ON and OFF pixels. For more information, please refer here.
void	setColors (const cv::viz::Color &positive, const cv::viz::Color &negative, const cv::viz::Color &reset)
	Set colors for ON, OFF, and non-activated pixels. For more information, please refer here.
void	setColormap (const cv::ColormapTypes cm)
	Set colormap for the representation.
Public Member Functions inherited from ev::Stats_< AbstractRepresentation_< T, Options, int > >
ResultType	duration () const
	Time difference between the last and the first event.
ResultType	rate () const
	Compute event rate as the ratio between the number of events and the time difference between the last and the first event.
ResultType	density (const cv::Size size) const
	Compute event density as the ratio between the number of events and the number of pixels.
std::size_t	activePixels () const
	Count the pixels with at least one event.
ResultType	fillRatio (const cv::Size size) const
	Compute fill ratio as the fraction of pixels with at least one event.
ResultType	polarityRatio (const PolarityType p) const
	Compute polarity ratio as the fraction of events with the given polarity.
Event_< ResultType >	mean () const
	Compute the mean of the events.
cv::Point_< ResultType >	meanPoint () const
	Compute the mean x,y point of the events.
cv::Matx< ResultType, 2, 2 >	covariance () const
	Compute the covariance of the x,y coordinates of the events around meanPoint().
cv::Rect	boundingBox () const
	Compute the smallest rectangle of pixels containing the events.
ResultType	meanTime () const
	Compute the mean time of the events.
ResultType	midTime () const
	Calculate the midpoint time between the oldest and the newest event.
std::size_t	peak () const
	Find the largest number of events on a single pixel.
ResultType	entropy () const
	Compute the Shannon entropy of the spatial distribution of the events.

Static Public Attributes
static constexpr double	DEFAULT_YAW = 30.0
static constexpr double	DEFAULT_PITCH = 20.0
static constexpr double	DEFAULT_DEPTH = 1.0
static constexpr double	DISTANCE = 2.5
static constexpr int	MARGIN = 2
static constexpr double	LABEL_SCALE = 0.35
static constexpr double	DEFAULT_AXES_LENGTH = 0.25
static constexpr double	DEFAULT_FADE = 0.8

Additional Inherited Members
Public Types inherited from ev::AbstractRepresentation_< T, Options, int >
using	Type
Public Types inherited from ev::Stats_< AbstractRepresentation_< T, Options, int > >
using	ResultType

Detailed Description

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>
class ev::SpaceTime_< T, Options, E >

This class extends ev::EventImage_<T> to draw the events as a cloud in the x-y-t volume seen in perspective.

A background given to clear() is an image in sensor coordinates. It is drawn in perspective on the plane of the oldest events, behind the cloud, and follows the view.

Analogously to OpenCV library, the following aliases are defined for convenience:

using SpaceTime1b = SpaceTime_<uchar>;
using SpaceTime3b = SpaceTime_<cv::Vec3b>;
using SpaceTime1s = SpaceTime_<short>;
using SpaceTime3s = SpaceTime_<cv::Vec3s>;
using SpaceTime1w = SpaceTime_<ushort>;
using SpaceTime3w = SpaceTime_<cv::Vec3w>;
using SpaceTime1i = SpaceTime_<int>;
using SpaceTime3i = SpaceTime_<cv::Vec3i>;
using SpaceTime1f = SpaceTime_<float>;
using SpaceTime3f = SpaceTime_<cv::Vec3f>;
using SpaceTime1d = SpaceTime_<double>;
using SpaceTime3d = SpaceTime_<cv::Vec3d>;
using SpaceTime1 = SpaceTime1b;
using SpaceTime3 = SpaceTime3b;
using SpaceTime = SpaceTime1;

Constructor & Destructor Documentation

SpaceTime_()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

ev::SpaceTime_< T, Options, E >::SpaceTime_ ( const cv::Size canvas, const cv::Size sensor = cv::Size() )

explicit

Construct the canvas.

Parameters

canvas	Canvas size in pixels
sensor	Sensor size in pixels, the canvas size if empty

Member Function Documentation

fadeWithDepth()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::fadeWithDepth ( const bool state, const double strength = DEFAULT_FADE )

inline

Fade the events towards the background as they recede, so the depth shows.

Parameters

state	True to fade them
strength	How transparent the events on the back face are, from 0, opaque, to 1, invisible

pitch()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

double ev::SpaceTime_< T, Options, E >::pitch ( ) const

inlinenodiscard

Pitch of the view.

Returns

Pitch in degrees

project()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

cv::Point2d ev::SpaceTime_< T, Options, E >::project ( const Event_< E > & e, const double age ) const

nodiscard

Project an event onto the canvas with the current view.

Parameters

e	Event
age	Age of the event between 0, the front face, and 1, the back face

Returns

Canvas coordinates

render()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

cv::Mat & ev::SpaceTime_< T, Options, E >::render

(

)

Render the space-time view.

The canvas is restored, the axes are drawn if enabled, and the events inserted since the last clear() are drawn from the oldest to the newest.

sensorSize()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

cv::Size ev::SpaceTime_< T, Options, E >::sensorSize ( ) const

inlinenodiscard

Sensor size.

Returns

Sensor size in pixels

setAxesColor()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::setAxesColor ( const cv::viz::Color & color )

inline

Set the colour the axes are drawn with. For more information, please refer here.

Parameters

color

Axes colour

setAxesValue()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::setAxesValue ( const typename TypeHelper< T >::Type & value )

inline

Set the value the axes are drawn with.

Parameters

value

Axes value

setDepth()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::setDepth

(

const double

depth

)

Set the depth of the box, that is, how long the time axis is drawn.

Parameters

depth

Depth relative to the sensor width

setView()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::setView	(	const double	yaw,
		const double	pitch )

Set the view angles.

Parameters

yaw	Rotation around the vertical axis in degrees, positive turns the right side of the sensor away
pitch	Rotation around the horizontal axis in degrees, positive shows the sensor from above

showAxes()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

void ev::SpaceTime_< T, Options, E >::showAxes ( const bool state, const double length = DEFAULT_AXES_LENGTH )

inline

Draw the x, y and t axes from the sensor origin, labelled at their ends.

Parameters

state	True to draw them
length	Length of each axis as a fraction of its side of the box

yaw()

template<typename T, const RepresentationOptions Options = RepresentationOptions::NONE, typename E = int>

double ev::SpaceTime_< T, Options, E >::yaw ( ) const

inlinenodiscard

Yaw of the view.

Returns

Yaw in degrees

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The documentation for this class was generated from the following file:

• modules/representations/include/openev/representations/space-time.hpp