Abstract: Various embodiments may include methods of detecting a fold state of a foldable mobile device in which the foldable mobile device includes a hinge coupling the first and second faces pivotally to fold into one or more fold states based on images of a visual element obtained by an image sensor. Embodiments may include measuring, using an image sensor disposed on a first face of the foldable mobile device, a predetermined feature on a second face of the foldable mobile device, and determining a fold state of the foldable mobile device based on the measure of the predetermined feature. In some embodiments, the reported fold state may be based on a dimension determined from the measure of the predetermined feature.