getting access to pixel data of a special region

Svenja · January 2018

Hi guys,
when working on the data() structure by using your code in the forum disscussion "image buffer reading/writing":

Dim ra As McRegionAccess=im.CreateRegionAccess()
ra.RegionMask=im.Aoi
Dim data(,) As Object
ra.GetArea(data)

I always get the whole image in my data-matrix, but I just want to get a special Region.
How do I have to select a region to get the data-matrix?

Thx,
Svenja

YuriG · February 2018

Here is the project with the macro.

Yuri

YuriG · January 2018

Hi Svenya,

You should open Region Access only for a specified area using aditional parameters of the function, here is the example:

    Public Sub GetROIPixels
        Dim im As McImage=ThisApplication.ActiveImage
        Dim r As Mediacy.IQL.ObjectManager.SINGLERECT=im.Aoi.BoundingRect'get ROI bounding box
        'open only ROI area
        Dim ra As McRegionAccess=im.CreateRegionAccess(,,,r.left,r.top,r.right,r.bottom)
        Dim data(,) As Object
        ra.GetArea(data)
        'process pixels
        '...
        ra.PutArea(data)
    End Sub

Yuri

Svenja · January 2018

Hi Yuri,thank you for your code. We have adapted it like this:

 ' Region ins Array
       'Dim ra As McRegionAccess=im.CreateRegionAccess()
       'ra.RegionMask=im.Aoi'process only active ROI
       lbOut.Items.Clear
       lbwock.Items.Clear

       Dim LOx,LOy,RUx,RUy As Integer
       LOx = CInt(tbLOx.Text)
       LOy = CInt(tbLOy.Text)
       RUx = CInt(tbRUx.Text)
       RUy = CInt(tbRUy.Text)



       Dim R As Mediacy.IQL.ObjectManager.SINGLERECT=im.Aoi.BoundingRect'get ROI bounding box
        'open only ROI area
       Dim ra As McRegionAccess=im.CreateRegionAccess(R.GetType,0,0,LOx,LOy,RUx,RUy)

and then:

If ra Is Nothing Then Exit Sub ' wenn es keine ROI gibt, dann raus.
       Dim data(,) As Object
       Dim W,O,C,K,AGV,AGVS,M As Integer
       Dim GRAD As Double

       'get 2D array of pixel data
       ra.GetArea(data)
       M=0
       AGVS=0
       tbBreite.Text=CStr(data.GetUpperBound(0))
       tbHoehe.Text=CStr(data.GetUpperBound(1))

       ' Durchlaufe Array
       For x As Integer = 0 To data.GetUpperBound(0)
        For y As Integer = 0 To data.GetUpperBound(1)
            lbOut.Items.Add("Data("+CStr(x)+","+CStr(y)+")="+CStr(data(x,y)))
        Next
       Next

Unfortunately my parameter (mean gradient value) is still calculated of the whole image instead of my rectangle ROI. It seems that ROI and image are completely separated objects. Could you please help us again?
Kind regards, Svenja

YuriG · January 2018

Hi Svenja,

How do you calculate "mean gradient value"? Can you post the macro?

Yuri

Svenja · February 2018

Hi Yuri,
here the complete macro for the grey-scale parameters mean gradient value and contrast:

Imports MediaCy.Addins.Scripting
'------------------------------------------------------------------------------
'
'Svenja's Gradient und Constrast
'
'BY:
'
'Svenja Krause
'
'------------------------------------------------------------------------------
'
' Anhand dieses Codes sollen die Formeln für den Gradientenbetrag und den
' Kontrast ausgewertet werden.
' GRAD=1/M ∑_(i,j∈ROI)▒〖AGV(i,j)〗
' GRAD= mittlerer Gradientenbetrag
'  M= Anzahl der definierten zentralen Bildpunkte
'  AGV= absoluter Gradientenwert
'  AGV=√(〖(W-C)〗^2 +〖(O-K)〗^2)
'  W,C,O,K= dem zentralen Bildpunkt i,j benachbarte Bildpunkte
'
' A B   C   D   E
' F G   H   I   J
' K L   x(i,j)  N   O
' P Q   R   S   T
' U V   W   X   Y
'
'
' Kontrast=1/R ∑_(i,j∈ROI)▒〖〖(i-j)〗^2×p(i,j)〗
' R=Anzahl der verschiedenen Pixelpaare
' (i-j)²= relative Grauwertdifferenz zwischen Pixel i und j
' p(i,j)=Häufigkeit des Auftretens einer Grauwertdifferenz
'
'
'
'------------------------------------------------------------------------------
'
'MODIFICATION LOG:
'
'
'------------------------------------------------------------------------------

Public Class Svenja_Gradient_Contrast

    Private Sub MyControl_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyControl.Load
        ' Initialization code goes here
    End Sub

    Protected Overrides Sub Finalize()
        ' Cleanup code goes here
    End Sub

    ' Provides access to underlying Control
    Public ReadOnly Property Control As System.Windows.Forms.UserControl
        Get
            Return MyControl
        End Get
    End Property

    Private Sub btnGradient_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles btnGradient.Click
       Dim im As McImage=ThisApplication.ActiveImage
       If im Is Nothing Then Exit Sub
       ' Gradienten bestimmen

       ' Region ins Array
       'Dim ra As McRegionAccess=im.CreateRegionAccess()
       'ra.RegionMask=im.Aoi'process only active ROI
       lbOut.Items.Clear
       lbwock.Items.Clear

       Dim LOx,LOy,RUx,RUy As Integer
       LOx = CInt(tbLOx.Text)
       LOy = CInt(tbLOy.Text)
       RUx = CInt(tbRUx.Text)
       RUy = CInt(tbRUy.Text)



       Dim R As Mediacy.IQL.ObjectManager.SINGLERECT=im.Aoi.BoundingRect'get ROI bounding box
        'open only ROI area
       Dim ra As McRegionAccess=im.CreateRegionAccess(R.GetType,0,0,R.left,R.top,R.right,R.bottom)
       If ra Is Nothing Then Exit Sub ' wenn es keine ROI gibt, dann raus.
       Dim data(,) As Object
       Dim W,O,C,K,AGV,AGVS,M As Integer
       Dim GRAD As Double

       'get 2D array of pixel data
       ra.GetArea(data)
       M=0
       AGVS=0
       tbBreite.Text=CStr(data.GetUpperBound(0))
       tbHoehe.Text=CStr(data.GetUpperBound(1))

       ' Durchlaufe Array
       For x As Integer = 0 To data.GetUpperBound(0)
        For y As Integer = 0 To data.GetUpperBound(1)
            lbOut.Items.Add("Data("+CStr(x)+","+CStr(y)+")="+CStr(data(x,y)))
        Next
       Next

       Dim i,j As Integer

        For i = 3 To data.GetUpperBound(0)-2
           For j = 3 To data.GetUpperBound(1)-2
               ' Bestimme W,O,C,K
                K=data(i,j-2)
                W=data(i+2,j)
                O=data(i,j+2)
                C=data(i-2,j)
               ' Berechne AGV (Wurzel aus (W-C)² + (O-K)²
                AGV=((W-C)^2+(O-K)^2)^(1/2) ' neu von Svenja und Fritz
               ' AGV=(((W-C)^2)^(1/2))+(O-K)^2 ' Alt von Papa Andi
               ' Addiere AGV zur AGV-Summe
                AGVS=AGVS+AGV
                'Kontrollausgabe
                tbAGV.Text = CStr(AGV)
                tbSumAGV.Text = CStr(AGVS)
                ' Zähle M hoch
                M=M+1
                lbwock.Items.Add("M:"+CStr(M)+"-> "+CStr(data(i,j))+ _
                                 " C:"+CStr(C)+" O:"+CStr(O)+ _
                                 " W:"+CStr(W)+" K:"+CStr(K)+ _
                                 " AGV:"+CStr(AGV))
                tbM.Text = CStr(M)
            Next
        Next

       GRAD = AGVS / M
       tbGrad.Text = CStr(GRAD)
     '   For i = 1 To data.GetUpperBound(0)
     '      For j = 1 To data.GetUpperBound(1)
     '       data(i,j).
     '      Next
     '   Next
        ra.PutArea(data)

    End Sub


    Private Sub btnKontrast_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles btnKontrast.Click
       Dim im As McImage=ThisApplication.ActiveImage
       If im Is Nothing Then Exit Sub

       ' Region ins Array
       lbOut.Items.Clear
       lbwock.Items.Clear

       Dim LOx,LOy,RUx,RUy As Integer
       LOx = CInt(tbLOx.Text)
       LOy = CInt(tbLOy.Text)
       RUx = CInt(tbRUx.Text)
       RUy = CInt(tbRUy.Text)

       Dim R As Mediacy.IQL.ObjectManager.SINGLERECT=im.Aoi.BoundingRect'get ROI bounding box
        'open only ROI area
       Dim ra As McRegionAccess=im.CreateRegionAccess(R.GetType,0,0,LOx,LOy,RUx,RUy)
       If ra Is Nothing Then Exit Sub ' wenn es keine ROI gibt, dann raus.
       Dim data(,) As Object

       'get 2D array of pixel data
       ra.GetArea(data)

       Dim i,j As Integer

       For i = 0 To 255
        lbOut.Items.Add( "-1")
       Next

       Dim GDiff, test As Integer

        For i = 1 To data.GetUpperBound(0)-1
           For j = 1 To data.GetUpperBound(1)
               ' Relative Grauwertdifferenz bestimmen
               GDiff = Abs(data(i,j) - data(i+1,j))

               lbwock.Items.Add("p("+CStr(i)+","+CStr(j)+"): "+CStr(data(i,j))+ _
                                " - p("+CStr(i+1)+","+CStr(j)+"): "+CStr(data(i+1,j))+ _
                                " = "+CStr(GDiff)+ " bisher: "+CStr(lbOut.Items(GDiff)))
               ' Haben wir diese Differenz schon?
               test = CInt(lbOut.Items(GDiff))
               If test < 0 Then test = 1 Else test = test +1

               'Zurückschreiben
               lbOut.Items(GDiff) = CStr(test)
            Next
        Next

       ' Jetzt noch die Summe und die Anzahl verschiedener Pixelpaare bestimmen
       Dim Anz, Kontrastsumme, wert As Integer
       Anz = 0
       Kontrastsumme = 0
       For i = 0 To 255
         wert = CInt(lbOut.Items(i))
         If wert > 0 Then
            Anz = Anz + wert
            Kontrastsumme = Kontrastsumme + ((i^2)*wert)
         End If
       Next

       Dim Kontrast As Double = Kontrastsumme / Anz

       tbKontrast.Text = CStr(Kontrast)
       tbR.Text = CStr(Anz)
        ra.PutArea(data)
    End Sub
End Class

YuriG · February 2018

Hi Svenya,

I converted your code to a macro and it works correctly for me.
Here is the macro:

    Public Sub btnGradient_Click()
       Dim im As McImage=ThisApplication.ActiveImage
       If im Is Nothing Then Exit Sub
       ' Gradienten bestimmen

       ' Region ins Array
       'Dim ra As McRegionAccess=im.CreateRegionAccess()
       'ra.RegionMask=im.Aoi'process only active ROI
       'lbOut.Items.Clear
       'lbwock.Items.Clear

'       Dim LOx,LOy,RUx,RUy As Integer
'       LOx = CInt(tbLOx.Text)
'       LOy = CInt(tbLOy.Text)
'       RUx = CInt(tbRUx.Text)
'       RUy = CInt(tbRUy.Text)



       Dim R As Mediacy.IQL.ObjectManager.SINGLERECT=im.Aoi.BoundingRect'get ROI bounding box
        'open only ROI area
       Dim ra As McRegionAccess=im.CreateRegionAccess(,,,R.left,R.top,R.right,R.bottom)
       If ra Is Nothing Then Exit Sub ' wenn es keine ROI gibt, dann raus.
       Dim data(,) As Object
       Dim W,O,C,K,AGV,AGVS,M As Integer
       Dim GRAD As Double

       'get 2D array of pixel data
       ra.GetArea(data)
       M=0
       AGVS=0
       'tbBreite.Text=CStr(data.GetUpperBound(0))
       'tbHoehe.Text=CStr(data.GetUpperBound(1))

       ' Durchlaufe Array
       For x As Integer = 0 To data.GetUpperBound(0)
        For y As Integer = 0 To data.GetUpperBound(1)
     '       lbOut.Items.Add("Data("+CStr(x)+","+CStr(y)+")="+CStr(data(x,y)))
        Next
       Next

       Dim i,j As Integer

        For i = 3 To data.GetUpperBound(0)-2
           For j = 3 To data.GetUpperBound(1)-2
               ' Bestimme W,O,C,K
                K=data(i,j-2)
                W=data(i+2,j)
                O=data(i,j+2)
                C=data(i-2,j)
               ' Berechne AGV (Wurzel aus (W-C)² + (O-K)²
                AGV=((W-C)^2+(O-K)^2)^(1/2) ' neu von Svenja und Fritz
               ' AGV=(((W-C)^2)^(1/2))+(O-K)^2 ' Alt von Papa Andi
               ' Addiere AGV zur AGV-Summe
                AGVS=AGVS+AGV
                'Kontrollausgabe
                'tbAGV.Text = CStr(AGV)
                'tbSumAGV.Text = CStr(AGVS)
                ' Zähle M hoch
                M=M+1
'                lbwock.Items.Add("M:"+CStr(M)+"-> "+CStr(data(i,j))+ _
'                                 " C:"+CStr(C)+" O:"+CStr(O)+ _
'                                 " W:"+CStr(W)+" K:"+CStr(K)+ _
'                                 " AGV:"+CStr(AGV))
'                tbM.Text = CStr(M)
            Next
        Next

       GRAD = AGVS / M
      ' tbGrad.Text = CStr(GRAD)
      ThisApplication.Output.Show
      ThisApplication.Output.PrintMessage(String.Format("ROI({0},{1},{2},{3}), Gradient = {4}", R.left,R.top,R.right,R.bottom,GRAD))
     '   For i = 1 To data.GetUpperBound(0)
     '      For j = 1 To data.GetUpperBound(1)
     '       data(i,j).
     '      Next
     '   Next
     '   ra.PutArea(data)

    End Sub

When I move ROI around the image and execute the macro, I get different results:

Image: https://us.v-cdn.net/5020878/uploads/editor/ne/uj897ibajkk9.png

Please test it with my macro.

Yuri

Svenja · February 2018

Hi Yuri,
could you please give me a download file for your complete macro so I can load it in my Premier? Copy/paste dont work reliable.
Svenja

Svenja · February 2018

Dear Yuri,
that works perfectly. Thank you very much for your help! It is now possible to read out the data of a ROI :-)

getting access to pixel data of a special region

Best Answer

Answers