2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/32798An important concept in digital geometry for computer imagery is that of tunnel. In this paper we obtain a formula for the number of tunnels as a function of the number of the object vertices, pixels, holes, connected components, and 2x2 grid squares. It can be used to test for tunnel-freedom a digital object, in particular a digital curve.9 pages, 4 figuresDiscrete MathematicsComputational GeometryComputer Vision and Pattern RecognitionG.2.1; F.2.2; I.4.6; I.5.1text