Get total surface of pixels over threshold without counting objects

gmcocoi128

Hi,
Is there a way to just get the total amount of pixels thresholded in an image without having to create and count all the objects.
Thank you

YuriG

You can use Histogram to calculate total object area and percentage area.
The macro below assumes that the background intensity is 0 and objects have intensities above 0 (as on thresholded image).

    '
    'Calculates object area on image using histogram
    'objects are any pixels with values above 0
    '
    Public Sub GetObjectAreaUsingHist
        Dim im As McImage=ThisApplication.ActiveImage
        If im Is Nothing Then Exit Sub
        Dim pixSize As Double = 1
        If im.SpatialCalibration IsNot Nothing Then
            'calibrated pixel size
            pixSize = im.SpatialCalibration.PixelSizeX * im.SpatialCalibration.PixelSizeY
        End If
        Dim hist As MediaCy.IQL.Operations.McHistogram=im.Histogram
        'calculate areas using histogram
        'get all bin values
        Dim allVals As Double() = hist.Values(-1, 0)'use mono image or channel 1
        Dim areaPix As Double = 0
        For bin As Integer = allVals.GetLowerBound(0) To allVals.GetUpperBound(0)
            areaPix = areaPix + allVals(bin)
        Next
        Dim zeroArea As Double = allVals(allVals.GetLowerBound(0)) 'number of pixels in 0 bin
        'Area in calibrated units
        Debug.Print "Total Object Area = " & (areaPix - zeroArea) * pixSize
        'AreaPercent
        If areaPix > 0 Then
            Debug.Print "Area Percentage = " & ( 100.0 * (areaPix - zeroArea) / areaPix)
        End If
    End Sub

Yuri