Poltergeist: German word for "noisy ghost;" energetic or non-spirit entity; mischievous and sometimes destructive kinetic energy released in the form of knocking, thumping, and banging sounds, levitating or moving objects, stone-throwing, and unexplainable fires. Often associated with prepubescent children. Identical phenomena attributed to poltergeists have been reported from all parts of the world and throughout all ages.

Ed is one of the PAS investigators and the Research Department Manager.

Computer Aided Investigation Techniques

Bringing Paranormal Investigation to a higher level

   It all started during my first investigation where we encountered two cases of poltergeist activity which we detected after it already had taken place. One of the poltergeist items where the glasses of the former owner, who died in the house, and a statue which seemed to be moving by itself and always pointing in the same direction. In particular I was interested in the statue which moved during the investigation. During analyzing the pictures as part of the examining the evidence it became clear that the statue had moved. The fact that nobody was assigned to keep an eye on the statue the whole night we can not conclude for 100% that the statue moved by itself or accidentally by the new owners of the house or one of the onsite investigators. This was also the time to think about a solution to capture a movement in future investigations.

   After reading many books about ghost hunting, I noticed that the common way of doing paranormal investigations is walking through a location with different tools such as digital cameras, EVP recorders, EMF meters and hoping that you or any other investigator will be at the right place at the right time to capture a paranormal anomaly. It feels like walking into a dark room shoot a gun and hope that you hit any target who might be there at the same time. Also a lot of paranormal evidence is based on personal experiences and examining the evidence after the investigation already took place. This part could be very challenging, because hours of tape could reveal nothing at all and you do not want to miss the only image where a paranormal anomaly took place, because you where almost sleeping from boredom...

The beginning

   As being a scientist myself I started to do some research first and looked into possible ways to detect activity and collect as much data as possible at the moment when an anomaly is really taking place. The captured data should be easy to analyze afterwards or even during the investigation by firing triggers when reaching a specified threshold value or after detecting motion in the captured photos or video.

   During my search for information I ran into two other Ghost Hunters Websites where they created their own computer aided ghost hunting equipment. Both projects where a great help to get started and they describing how to capture data coming from external sensors but none used the technique to add some eye by controlling taking of images when paranormal anomalies are taking place.

The first steps

   My initial start of the project was to focus on motion caused by a poltergeist and take a series of pictures of the object. My first successful proof of concept was to implement an algorithm to detect motion detection between two images which where coming from a simple webcam which I got when I signed up with my cable company. The first algorithm was quite simple and did nothing more than compare all points in a bitmap between the two pictures and calculates a percentage of difference. Based on a certain threshold value this approach detected motion between the two pictures. The algorithm was written for Proof of concept only and is not used anymore because other changes, such as turning on a light switch, could already trigger a false positive.

   As being an all-round software developer by profession, I started writing a program called Ghost Lab© (written in C# on a .NET 2.0 Framework) to collect data coming from Vernier Go!Motion Detector and a Canon PowerShot A640 Digital Camera.

Vernier Go! Motion Detector

The Verniers Go!Motion detector works with ultra sound and is able to detect movement as close as 15 cms (+/- 6 in) until a maximal range of 6 meters (+/-19.6 feet). The motion detector collects data internally in buffer first and Ghost Lab© needs to call this motion detector to retrieve the data and clean the buffer through the interface build in Ghost Lab©. Luckily Vernier provides a free and easy to download SDK (software development kit)

which assist and makes it easy to write an interface around the motion detector in C#. The SDK provide also code for other Vernier devices which makes it very easy to add new sensors, such as Go!Temp, in a later stage to the Ghost Lab program.

Canon PowerShot A640

At this moment there are not that many brands out there that provide a digital camera which supports remote capturing. So far I only found digital cameras from Canon and Nikon in an affordable price range which where suitable for remote capturing and useable for computer aided paranormal research.

With remote capturing the program can control the camera through code and take pictures on command. The Canon PowerShot A640 Digital Camera allows remote capturing and downloads them directly into Ghost Lab©. Canon delivers a SDK for most of their cameras but can only be downloaded through the Canon Web site after licensing and explaining the reasons of the download. After filling in all details the confirmation process takes up to two working days and you will be informed with a download link when approved by Canon. It is recommended to download the SDK first before buying one of the Cameras.

Poltergeist Script

Ghost Lab© works with specialized scripts which are written for a certain task. The poltergeist script is developed to capture movements of the subject under investigation. To catch the movement, or rule out any tampering with the evidence, a picture is taken as soon as a motion is detected.

Before the script start collecting data the investigator is able to configure the camera by changing the zoom and brightness. When the investigator starts the investigation of the subject, a base picture will be taken and stored in a special case folder on the computer. During the investigation every second Ghost Lab© will collect all data from the Motion Detector and determine if there was any data which reach the threshold value. To determine that there is movement the first hundreds values are used as a base value. When any value is out of range of the base values it will fire an event which will tell Ghost Lab© to take a picture and log it into the case file.

All data coming from the Vernier Go!Motion detector is considered evidence of an investigation. To keep this evidence all measurements coming from the detector are stored into a XML file which is stored locally on the hard drive.

At this moment there is some delay with collecting the motion data from the Vernier Go!Motion detector and triggering the remote camera to take a picture. Luckily the Canon PowerShot camera provides a mechanism, called live viewer, where it sends a steady stream of bitmap images to the Ghost Lab© application. Those bitmap images are kept in an internal buffer and when the there is a movement detected all bitmap images in the buffer will be saved to the hard drive. These bitmap images can also be used to create an .avi movie and show the movement which triggered Ghost Lab© to take the picture.


The first tests with Ghost Lab are promising. Ghost Lab is able to capture minimal poltergeist activity which could be very hard to detect with the naked eye. The Verniers Go!Motion detector has proven to be working fine at close distances but in larger area, such as a room, it generated some false positives during the test runs.

It is very important to understand the sensor and camera to determine the strengths and limitation to assist in the field during investigations. It is also a learning process for all investigators to start using computers during investigations.

The future of Computer Aided Investigation Techniques

The main goal is to improve Computer Aided Investigation Techniques by adding more sensors, cameras and advanced video techniques to Ghost Lab application to assist computer aided paranormal research in more details. All data collected by Ghost Lab has the same structure as our online case manager, which is still in development, and some functionality will be added to synchronize the case data and evidence.


· www.vernier.com - Vernier Software and Technology provides a broad range of sensors which are mainly developed for schools but very suitable for paranormal investigation. The SDK can be downloaded from the following page www.vernier.com/downloads and look for Go! I/O Software Development Kit on the bottom of the page.

· www.canon.com - Canons official web site and to license the download of the SDK read and follow the licensing steps on the following page www.usa.canon.com/consumer/controller?act=SDKHomePageAct&keycode=Sdk_Lic&fcategoryid=139&modelid=8280&id=3464.

· www.codeproject.com - The Code Project is the best resource for computer developers with tons of useful information on different subjects. This web site also contains an excellent article, with sample code, for a wrapper application around the Canon PowerShot A640 digital camera www.codeproject.com/cs/media/Canon_camera_wrapper.asp.

· www.ghostgadgets.com/ghostgadgets_com/htdocs/_arcadia - The Ghost Gadgets web site provide detailed information of the ARCADIA (Analog - Reading - Computer - Aided - Digital - Input - Analyzer) project. Ghost web seems to be the first paranormal research group with Computer Aided Investigation project published on the web.