'*************************centers() subroutine***********************
'
'   purpose: calls findedge for each point in the history array to find
'            the right and left edges and then computes the average midpoint
'
'   input: SobelData array
'          history array
'
'   output: updated history array
'
'********************************************************************
Sub centers(hcenter As Integer, wcenter As Integer, hisloc As Integer)
    Dim below As Integer 'how far below center to look
    Dim above As Integer 'how far above center to look
    Dim i As Integer 'counter
    Dim middle As Integer 'the middle of the object
    Dim right As Integer ' sum of pixel locations for right edge
    Dim left As Integer 'sum of pixel locations for left edge
    
    right = 0
    left = 0
    below = hcenter - 10
    above = hcenter + 10
    For i = below To above
        right = right + (findedge(wcenter, i, True))
        left = left + (findedge(wcenter, i, False))
    Next i
    middle = ((right / (above - below)) - (left / (above - below))) / 2 + (left / (above - below))
    
    'prevents the points from getting "stuck" at the edge of the image
    If middle > picWIDTH - 15 Then middle = picWIDTH - 15
    If middle < 15 Then middle = 15
    history(hisloc, 1) = middle
End Sub