In this paper we propose two techniques to qualitatively estimate distance in monocular vision.
Two kinds of approaches are described, the former based on texture analysis and the latter on
histogram inspection. Although both the methods allow only to determine whether a point within
an image is nearer or farther than another with respect to the observer, they can be usefully
exploited in all those cases where precision is not critical or single images are the only source
of information available. Moreover, combined with previously studied techniques, they could be used
to provide more accurate results. Step by step algorithms will be presented, along with examples
illustrating their application to real images.