The field of Parapsychology has done much investigation of experiences of apparitions, hauntings and poltergeists. Part of the research process has been to try to find technologies that can provide more data than what we get from human witnesses.

Technology and the Science behind it have a ways to go before anyone can say for sure that this reading or that photo conclusively indicates a ghost. People who offer up their photos as "proof" of the existence of ghosts or who rely purely on technology are ignorant of what constitutes scientific proof (versus evidence). More importantly, they are generally uneducated as to what decades of research and much discussion has led us to understand ghosts and hauntings might be.

Apparitions (ghosts) and hauntings are phenomena defined by human experience.

An apparition typically represents an experience of a deceased person being seen, heard (a voice, footsteps), felt (a presences, a touch) or smelled (perfume, cologne) by a living person. Our model of an apparition is that he or she is the consciousness (or personality, spirit, soul, mind or whatever you want to call it) that survives the death of the body.

Apparitions are capable of interaction with the living. This interaction happens through mind-to-mind communication (telepathy), not through the ordinary senses. When one "sees" a ghost, it is through the perceptual processes (think data processing) rather than through the eyes. Just like a computer can convert digital information into a picture, the human mind can convert received information from the mind of a ghost into images, voices, smells, and even feelings of being touched.

Hauntings, also called "place memory" or "imprints", seem to represent information recorded into the local environment by actual happenings. When one perceives something like a walking-then-disappearing figure in a haunting, one is actually picking up historical information (even recent history) from the location and converting it into an image. Hauntings are much more common than apparition cases, as every place where people have been and emotional events have occurred has the potential to be haunted.

Both have one important factor in common: unless something is perceived and experienced by a witness, there's nothing to indicate a "ghost" or "haunting" is present. We define hauntings and apparitions by the human experience of the phenomena.

The major differences between apparitions and hauntings are around interaction and source. A ghost or apparition is capable of interacting with a living person and vice versa, like two people at either end of a video conference call. In a haunting, you only perceive a recording, like watching a video or listening to an audio recording of someone or events in the past.

Typically, when we conduct investigations, we do use detectors of electromagnetic fields to provide additional sensors to anything unusual in the environment. Such equipment does not detect ghosts per se, but are useful in looking for physical correlates to the perceptions / sensations / experiences of the witnesses (including psychics). Do human beings have the capacity to detect anomalous magnetic fluxes in the environment? Or are these magnetic (and other detectable energetic anomalies) somehow "footprints" left behind by apparitions and haunting "imprints"?

We're still working on that, just as many scientists are working on the major question of Consciousness itself. After all, if technology cannot be used to detect consciousness IN the body, where we assume it is, how can it be used definitively to detect consciousness after death?

If you are going to use detection gear of any kind (and that especially goes for cameras, both still and video and audio recorders), a single reading (or photo) must be looked over with care. There should be correlation to something else; at the very least someone (witness or psychic) having a perception of the "ghost" or a connection to a spot with a history of reported paranormal phenomena or experiences.

Always know the limitations of your equipment and how "false" readings (or photos!) might come up….false in the sense that they are otherwise explainable and NOT paranormally connected when you look closely.

Do not rely on technology to tell you a place is haunted or a ghost is present. It's clear by what's up on the net that people make incorrect assumptions about places and their evidence. Just the fact that people hang out in cemeteries to get spirit orb photos makes me cringe.

Ghost sightings in cemeteries are extremely rare. Just because a body's buried somewhere doesn't make the place haunted (think of the catacombs in Rome and Paris and the thousands of bodies down there!!). And if you were a ghost, would you hang around in a graveyard?

Parapsychologists do use technology to try to find any environmental anomalies that can be connected to the models we're building of apparitions and hauntings. But at present, what we have is some little evidence, and some leads that certain technology, including detectors of magnetic and geomagnetic fields, can help us better understand what's going on when someone sees a ghost.

But it will take a lot more research and investigation with all sorts of technologies, including computer systems that can take in the readings and correlate them properly, before we can point a gizmo at a spot and say "we got one!!" Unfortunately, it will also take research money to buy the technology; funds which researchers do not have.

In the meantime, if you wish to "detect" a ghost, spend more time interviewing witnesses than taking readings. A reading is a lot less exciting than a good ghost story.