Simd::Motion Namespace Reference

Contains a C++ framework for motion detection. More...

Data Structures
class	Detector
	Motion detector. More...
struct	Event
	An event generated by Simd::Motion::Detector on the current frame. More...
struct	Metadata
	Result of Detector::NextFrame for the current frame. More...
struct	Model
	Scene model used to calibrate Simd::Motion::Detector. More...
struct	Object
	A classified moving object on the current frame. More...
struct	Options
	Options used by Simd::Motion::Detector. More...
struct	Position
	Position of a detected object at one timestamp. More...

Typedefs
typedef double	Time
	Time in seconds. Typical usage copies Frame::timestamp (OpenCV CAP_PROP_POS_MSEC * 0.001).
typedef int	Id
	Object identifier. Object::id and Event::objectId; -1 if the event is not linked to an object.
typedef std::string	String
	Text type. Event::text and the result of ToString().
typedef Simd::Point< ptrdiff_t >	Size
	Screen size in pixels (width and height).
typedef Simd::Point< ptrdiff_t >	Point
	Screen point in pixels (x and y). Origin is the top-left corner. Typical usage is Object::trajectory[].point and DrawLine.
typedef std::vector< Point >	Points
	Vector of screen points.
typedef Simd::Rectangle< ptrdiff_t >	Rect
	Screen rectangle in pixels. Typical usage is Object::rect for DrawRectangle.
typedef Simd::Point< double >	FSize
	ONVIF size (width and height) in range [0, 2]. Model::size; default (0.1, 0.1) is about 0.25% of the screen area.
typedef Simd::Point< double >	FPoint
	ONVIF point (x and y) in range [-1, 1]. Origin is the screen center; X grows right, Y grows up. Used by Model::roi.
typedef std::vector< FPoint >	FPoints
	Vector of ONVIF points. Model::roi polygon.
typedef Simd::View< Simd::Allocator >	View
	Image type. Typical usage wraps OpenCV cv::Mat as Frame input and annotates Object::rect on it.
typedef Simd::Frame< Simd::Allocator >	Frame
	Video frame. Typical usage is Frame(image, false, timestampInSeconds) as NextFrame input.
typedef std::vector< Position >	Positions
	Object::trajectory. Typical usage iterates from 1 to size()-1 and draws lines.
typedef std::vector< Object >	Objects
	Metadata::objects: classified moving objects, including those that disappeared on this frame.
typedef std::vector< Event >	Events
	Metadata::events of the current frame. Typical usage iterates them after objects.

Functions
SIMD_INLINE double	ScreenToOnvifX (ptrdiff_t x, ptrdiff_t screenWidth)
	Converts a screen X-coordinate to an ONVIF X-coordinate. More...
SIMD_INLINE double	ScreenToOnvifY (ptrdiff_t y, ptrdiff_t screenHeight)
	Converts a screen Y-coordinate to an ONVIF Y-coordinate. More...
SIMD_INLINE FPoint	ScreenToOnvif (const Point &point, const Point &screenSize)
	Converts screen 2D-coordinates to ONVIF 2D-coordinates. More...
SIMD_INLINE FSize	ScreenToOnvifSize (const Size &size, const Point &screenSize)
	Converts a screen 2D-size to an ONVIF 2D-size. More...
SIMD_INLINE ptrdiff_t	OnvifToScreenX (double x, ptrdiff_t screenWidth)
	Converts an ONVIF X-coordinate to a screen X-coordinate. More...
SIMD_INLINE ptrdiff_t	OnvifToScreenY (double y, ptrdiff_t screenHeight)
	Converts an ONVIF Y-coordinate to a screen Y-coordinate. More...
SIMD_INLINE Point	OnvifToScreen (const FPoint &point, const Point &screenSize)
	Converts ONVIF 2D-coordinates to screen 2D-coordinates. More...
SIMD_INLINE Size	OnvifToScreenSize (const FSize &size, const Point &screenSize)
	Converts an ONVIF 2D-size to a screen 2D-size. More...
SIMD_INLINE String	ToString (Id id)
	Converts an object ID to a string. More...

Detailed Description

Contains a C++ framework for motion detection.

This is a wrapper around the low-level Motion Detection API.

Typical usage creates a Detector, optionally calls SetModel and SetOptions once, then for every video frame wraps a View as Frame with a timestamp in seconds and calls NextFrame. NextFrame fills Metadata with classified moving objects and events (Event::ObjectIn, Event::ObjectOut, Event::SabotageOn, Event::SabotageOff).

The example annotates Metadata on the input image: DrawRectangle around Object::rect, ToString(Object::id) above the box, DrawLine along Object::trajectory, and a scrolling list of Event::type / Event::objectId. Red marks objects that have an event in the same frame.

SetModel and SetOptions are typically called once before the video loop. Calibration (pyramid scale and ROI mask) runs on the first NextFrame and when the input size changes. The shooting-star example (disabled by #if 0) uses a small Model::size and lowered ClassificationShiftMin / ClassificationTimeMin. A Gray8 Model::mask can restrict ROI (non-zero pixels are inside). Debug annotation is drawn on an optional Bgr24 output Frame of the same size as input.

ONVIF coordinates place the origin at the screen center: X in [-1, 1] (left to right), Y in [-1, 1] with +Y up. Screen coordinates are pixels with (0, 0) at the top-left.

Using example (motion detection in the video captured by OpenCV):

#include <iostream>
#include <string>
#include <list>
 
#include "opencv2/opencv.hpp"
#include "opencv2/core/utils/logger.hpp"
#ifndef SIMD_OPENCV_ENABLE
#define SIMD_OPENCV_ENABLE
#endif
#include "Simd/SimdMotion.hpp"
 
using namespace Simd::Motion;
typedef std::list<Event> EventList;
typedef Simd::Pixel::Bgr24 Color;
 
const Color Red(0, 0, 255), Yellow(0, 255, 255), White(255, 255, 255);
 
void Annotate(const Metadata & metadata, const Simd::Font & font, EventList & events, View & image)
{
    for (size_t i = 0; i < metadata.objects.size(); i++)
    {
        const Object & object = metadata.objects[i];
        bool alarmed = false;
        for (size_t j = 0; j < metadata.events.size(); ++j)
        {
            const Event & event = metadata.events[j];
            if (event.objectId == object.id)
            {
                alarmed = true;
                break;
            }
        }
        Color color = alarmed ? Red : Yellow;
        int width = alarmed ? 2 : 1;
        Simd::DrawRectangle(image, object.rect, color, width);
        font.Draw(image, ToString(object.id), Point(object.rect.left, object.rect.top - font.Height()), color);
        for (size_t j = 1; j < object.trajectory.size(); ++j)
            Simd::DrawLine(image, object.trajectory[j - 1].point, object.trajectory[j].point, color, width);
    }
    for (size_t i = 0; i < metadata.events.size(); ++i)
    {
        events.push_front(metadata.events[i]);
        if (events.size()*font.Height() > image.height)
            events.pop_back();
    }
    Point location;
    for (EventList::const_iterator it = events.begin(); it != events.end(); ++it)
    {
        std::stringstream ss;
        Color color = White;
        switch (it->type)
        {
        case Event::ObjectIn:
            ss << "in " << it->objectId;
            break;
        case Event::ObjectOut:
            ss << "out " << it->objectId;
            break;
        case Event::SabotageOn:
            ss << "SABOTAGE ON";
            color = Red;
            break;
        case Event::SabotageOff:
            ss << "SABOTAGE OFF";
            color = Red;
            break;
        };
        font.Draw(image, ss.str(), location, color);
        location.y += font.Height();
    }
}
 
int main(int argc, char * argv[])
{
    if (argc < 2)
    {
        std::cout << "You have to set video source! It can be 0 for camera or video file name." << std::endl;
        return 1;
    }
    std::string source = argv[1], output = argc > 2 ? argv[2] : "";
 
    cv::VideoCapture capture;
    cv::utils::logging::setLogLevel(cv::utils::logging::LOG_LEVEL_ERROR);
    if (source == "0")
        capture.open(0);
    else
        capture.open(source);
    if (!capture.isOpened())
    {
        std::cout << "Can't capture '" << source << "' !" << std::endl;
        return 1;
    }
 
    cv::VideoWriter writer;
    if (output.size())
    {
        writer.open(output, cv::VideoWriter::fourcc('F','M','P','4'), capture.get(cv::CAP_PROP_FPS),
            cv::Size((int)capture.get(cv::CAP_PROP_FRAME_WIDTH), (int)capture.get(cv::CAP_PROP_FRAME_HEIGHT)));
        if (!writer.isOpened())
        {
            std::cout << "Can't open output file '" << output << "' !" << std::endl;
            return 1;
        }
    }
 
    EventList events;
    Detector detector;
    Simd::Font font((int)capture.get(cv::CAP_PROP_FRAME_HEIGHT) / 32);
 
#if 0
    // There is an example of change of parameters to detect shooting star in the night sky:
    Model model;
    model.size = FSize(0.01, 0.01);
    detector.SetModel(model);
 
    Options options;
    options.TrackingAdditionalLinking = 5;
    options.ClassificationShiftMin = 0.01;
    options.ClassificationTimeMin = 0.01;
    options.DifferenceDxFeatureWeight = 0;
    options.DifferenceDyFeatureWeight = 0;
    options.BackgroundStatUpdateTime = 0.2;
    detector.SetOptions(options);
#endif
 
    const char * WINDOW_NAME = "MotionDetector";
    cv::namedWindow(WINDOW_NAME, 1);
    for (;;)
    {
        cv::Mat frame;
        if (!capture.read(frame))
            break;
        View image = frame;
        Frame input(image, false, capture.get(cv::CAP_PROP_POS_MSEC) * 0.001);
        Metadata metadata;
 
        detector.NextFrame(input, metadata);
 
        Annotate(metadata, font, events, image);
 
        cv::imshow(WINDOW_NAME, frame);
        if (writer.isOpened())
            writer.write(frame);
        if (cv::waitKey(1) == 27)// "press 'Esc' to break video";
            break;
    }
    return 0;
}