def Seuil (img):
    rows, cols = img.shape

    c1 = int (np.min (img))
    c2 = int (np.max (img))
    sommedeplacement = 255

    while sommedeplacement > 0:
        sum1 = 0
        sum2 = 0
        k    = 0
        for i in range(rows):
            for j in range (cols):
                d1 = abs(img[i, j] - c1)
                d2 = abs(img[i, j] - c2)
                if d1 <= d2:
                    sum1 += img[i, j]
                    k  += 1
                else:
                    sum2 += img[i, j]
        sum1 /= k
        sum2 /= (img.size - k)
        sommedeplacement = (abs(sum1-c1) + abs(sum2-c2))
        c1 = sum1
        c2 = sum2
    return ((c1+c2)/2)