MotionDetection

' translated in VB:NET from c#

' by Giuseppe Di Santo - Studio IT

Imports System

Imports System.Collections.Generic

Imports System.ComponentModel

Imports System.Data

Imports System.Drawing

Imports System.Text

Imports System.Windows.Forms

Imports Emgu.CV

Imports Emgu.CV.Structure

Imports Emgu.Util

Imports System.Threading

Imports System.Runtime.InteropServices

Public Class MotionDetection

    Private _capture As Capture

    Private _motionHistory As MotionHistory

    Private _forgroundDetector As VideoSurveillance.IBGFGDetector(Of Bgr)

    Private Sub MotionDetection_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        'try to create the capture

        If _capture Is Nothing Then

            Try

                _capture = New Capture()

            Catch excpt As NullReferenceException

                'show errors if there is any

                MessageBox.Show(excpt.Message)

            End Try

        End If

        If _capture IsNot Nothing Then

            'if camera capture has been successfully created

            'in second, the duration of motion history you wants to keep

            'in second, parameter for cvCalcMotionGradient

            _motionHistory = New MotionHistory(1.0, 0.05, 0.5)

            'in second, parameter for cvCalcMotionGradient

            AddHandler Application.Idle, AddressOf ProcessFrame

        End If

    End Sub

    Private Sub ProcessFrame(ByVal sender As Object, ByVal e As EventArgs)

        Using image As Image(Of Bgr, [Byte]) = _capture.QueryFrame()

            Using storage As New MemStorage()

                'create storage for motion components

                If _forgroundDetector Is Nothing Then

                    '_forgroundDetector = new BGCodeBookModel<Bgr>();

                    '_forgroundDetector = new FGDetector<Bgr>(Emgu.CV.CvEnum.FORGROUND_DETECTOR_TYPE.FGD);

                    _forgroundDetector = New VideoSurveillance.BGStatModel(Of Bgr)(image, Emgu.CV.CvEnum.BG_STAT_TYPE.FGD_STAT_MODEL)

                End If

                _forgroundDetector.Update(image)

                capturedImageBox.Image = image

                'update the motion history

                _motionHistory.Update(_forgroundDetector.ForgroundMask)

                '#Region "get a copy of the motion mask and enhance its color"

                Dim minValues As Double(), maxValues As Double()

                Dim minLoc As Point(), maxLoc As Point()

                _motionHistory.Mask.MinMax(minValues, maxValues, minLoc, maxLoc)

                Dim motionMask As Image(Of Gray, [Byte]) = _motionHistory.Mask.Mul(255.0 / maxValues(0))

                '#End Region

                'create the motion image

                Dim motionImage As Image(Of Bgr, [Byte]) = New Image(Of Bgr, Byte)(motionMask.Size)

                'display the motion pixels in blue (first channel)

                motionImage(0) = motionMask

                'Threshold to define a motion area, reduce the value to detect smaller motion

                Dim minArea As Double = 100

                storage.Clear()

                'clear the storage

                Dim motionComponents As Seq(Of MCvConnectedComp) = _motionHistory.GetMotionComponents(storage)

                'iterate through each of the motion component

                For Each comp As MCvConnectedComp In motionComponents

                    'reject the components that have small area;

                    If comp.area < minArea Then

                        Continue For

                    End If

                    ' find the angle and motion pixel count of the specific area

                    Dim angle As Double, motionPixelCount As Double

                    _motionHistory.MotionInfo(comp.rect, angle, motionPixelCount)

                    'reject the area that contains too few motion

                    If motionPixelCount < comp.area * 0.05 Then

                        Continue For

                    End If

                    'Draw each individual motion in red

                    DrawMotion(motionImage, comp.rect, angle, New Bgr(Color.Red))

                Next

                ' find and draw the overall motion angle

                Dim overallAngle As Double, overallMotionPixelCount As Double

                _motionHistory.MotionInfo(motionMask.ROI, overallAngle, overallMotionPixelCount)

                DrawMotion(motionImage, motionMask.ROI, overallAngle, New Bgr(Color.Green))

                'Display the amount of motions found on the current image

                UpdateText([String].Format("Total Motions found: {0}; Motion Pixel count: {1}", motionComponents.Total, overallMotionPixelCount))

                'Display the image of the motion

                motionImageBox.Image = motionImage

            End Using

        End Using

    End Sub

    Private Sub UpdateText(ByVal text As [String])

        label3.Text = text

    End Sub

    Private Shared Sub DrawMotion(ByVal image As Image(Of Bgr, [Byte]), ByVal motionRegion As Rectangle, ByVal angle As Double, ByVal color As Bgr)

        Dim circleRadius As Single = (motionRegion.Width + motionRegion.Height) >> 2

        Dim center As New Point(motionRegion.X + motionRegion.Width >> 1, motionRegion.Y + motionRegion.Height >> 1)

        Dim circle As New CircleF(center, circleRadius)

        Dim xDirection As Integer = CInt(Math.Truncate(Math.Cos(angle * (Math.PI / 180.0)) * circleRadius))

        Dim yDirection As Integer = CInt(Math.Truncate(Math.Sin(angle * (Math.PI / 180.0)) * circleRadius))

        Dim pointOnCircle As New Point(center.X + xDirection, center.Y - yDirection)

        Dim line As New LineSegment2D(center, pointOnCircle)

        image.Draw(circle, color, 1)

        image.Draw(line, color, 2)

    End Sub

End Class

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