Clicking on a point in an image finds the closest contour points

edit

Update: As suggested. I added my current code that detects all boundaries of each shape (not desired) with another problem that these boundary lines can be a few pixels wide and form inside and outside countour to be recognized

Let say I click on a point inside wanted3 shape/contour (see second image). I would use C#.net OpenCV 2 and/or 3

One Note. The lines denoting shapes can be one or more pixel wide. I would like the recognized points to lay exactly in the middle of that line, so when I do another recognition of surrounding shape I will get an exact point for that shared line recognized in 2 contours

I want the closest contour recognized, that encompasses the pressed point with a mouse left click within it. There can however be a larger encompassing contour (not shown here; think of it as a county encompassing cities/places), and I just want the closest one recognized.

Whan I press inside wanted2 shape I want South-East border to have exactly the same discoverer contour points as wanted3 no matter how thick the bordering line is (so some calculation of where the middle point is necessaryl Thanks Rad

    Sub ProcessImageAndUpdateGUI(sender As Object, arg As EventArgs)
    Try
        If (rdoImageFile.Checked = True) Then                                                                       'if the image file radio button is chosen . . .
            Try
                imgOriginal = New Image(Of Bgr, Byte)(txtFile.Text)                                     'get original image from file name in text box
            Catch ex As Exception
                Return
            End Try
        ElseIf (rdoWebcam.Checked = True) Then                                                                  'else if the webcam radio button is chosen . . .
            Try
                imgOriginal = capWebcam.QueryFrame()                                                                    'get next frame from webcam
            Catch ex As Exception
                Return
            End Try
        Else
            'should never get here
        End If

        If (imgOriginal Is Nothing) Then                                        'if imgOriginal is null
            Return                                                                                  'bail
        End If
        'perform image smoothing
        imgSmoothed = imgOriginal.PyrDown().PyrUp()                                     'Gaussian pyramid decomposition
        imgSmoothed._SmoothGaussian(3)                                                              'Gaussian smooth, argument is size of filter window

        If (ckFilterOnColor.Checked = True) Then                                                                'if filter on color check box is checked, then filter on color
            imgGrayColorFiltered = imgSmoothed.InRange(New Bgr(dblMinBlue, dblMinGreen, dblMinRed), New Bgr(dblMaxBlue, dblMaxGreen, dblMaxRed))
            imgGrayColorFiltered = imgGrayColorFiltered.PyrDown().PyrUp()                       'repeat smoothing process after InRange function call,
            imgGrayColorFiltered._SmoothGaussian(3)                                                                 'seems to work out better this way
        ElseIf (ckFilterOnColor.Checked = False) Then                                                   'if filter on color is not checked,
            imgGrayColorFiltered = imgSmoothed.Convert(Of Gray, Byte)()                 'then convert to gray without filtering
        End If

        'Dim grayCannyThreshold As Gray = New Gray(160)                                 'first Canny threshold, used for both circle detection, and line / triangle / rectangle detection
        'Dim grayCannyThreshold As Gray = New Gray(200)                                 'first Canny threshold, used for both circle detection, and line / triangle / rectangle detection
        Dim grayCannyThreshold As Gray = New Gray(240)                                  'first Canny threshold, used for both circle detection, and line / triangle / rectangle detection
        Dim grayCircleAccumThreshold As Gray = New Gray(100)                        'second Canny threshold for circle detection, higher number = more selective
        Dim grayThreshLinking As Gray = New Gray(80)                                        'second Canny threshold for line / triangle / rectangle detection

        'imgCanny = imgGrayColorFiltered.Canny(grayCannyThreshold, grayThreshLinking)                   'Canny image used for line, triangle, rectangle, and polygon ...