In the late 1920’s Television pioneer John Logie-Baird demonstrated a working IR television system which he called the Noctovisor. This used a modified television tube and is perhaps better described as an early thermal imaging camera. It was however in 1965 that the first commercial thermal imaging camera appeared. Designed for high voltage power line inspection. The thermal camera works by recording emissions within the infra-red spectrum which it converts into a visible image. Infra-red radiation is between the visible and the microwave portions of the electromagnetic spectrum. The main source of infra-red energy is heat or thermal radiation. Every object that has a temperature above absolute zero Kelvin (-273.15 Celsius) emits IR energy. The camera detects the IR emissions which are focussed by specially coated optics onto the IR detector. Like the visible light spectra hitting the imaging sensor in a digital camera the IR emissions are converted into a visible image which can be viewed on the viewfinder and stored for later use.
There are several manufacturers of thermal cameras but perhaps the best known is FLIR Systems. The name derives from the acronym ‘Forward Looking Infra Red’ the term which is used for military airborne thermal imaging systems. FLIR Systems. The company was formed in 1978 following the merger of European and US thermal image camera manufacturers. At the consumer end of the product line the FLIR ‘i-series’ is the most affordable and therefore the most likely to be found in flight cases of the most affluent and fortunate ghost investigators. The range comprises the i3 i5 and i7 models. Other models such as the more advanced Infracam and Infracam SD are also used by ghost hunters.
The specifications for these cameras are quite basic though perfectly usable with a resolution of between 3,600 & 19,600 pixels - compare that to a basic digital camera with a resolution of 8 or more mega pixels (8,000,000). Thermal sensitivity, the camera’s ability to detect changes in the emitted temperature of an object is typically 0.1 degree Celsius with a stated accuracy of around +/- 2 Celsius. All models allow the user to record still images to either an internal memory or a plug-in memory card, in both cases the pictures can be easily transferred to a PC using either a USB cable or a memory card reader. Once placed onto a computer the images can be analysed with manufacturer supplied software that permits quite detailed thermal information to be obtained from the information stored within the image.
The thermal camera has become one of the most sought after gadgets for modern ghost hunters after their use of TV programmes such as Most Haunted and Ghost Hunters and perhaps one of the most misunderstood in terms of its capabilities. In order to interpret the thermal images correctly the user needs to know how different materials and conditions can influence temperature readings from the thermal camera. A thermal image is a synthetic or false image, constructed within the software of the camera. Depending upon the mode selected either colours or shades of grey are used to represent the temperature range of the subject. The colour palette and grey scale range is limited and this inevitably leads to the same object appearing as a variable range of colours as the camera adjusts its calibration. Thus an object that might suddenly appear to change its apparent temperature. As with any camera, the dynamic range (thermal exposure) of the image will affect the overall image and thus an object that appears warm (red) against a cool (blue) background will appear as cool (blue) against a hot (red) background. Most TI cameras have an automatic calibration mode which permits it to produce a good overall image but can and does cause colours to suddenly change. The same effect is also seen in grey scale images with sudden changes occurring within the shades of grey being used to represent the temperature.
Thermal Imaging or Thermography can be a useful asset for the ghost hunter but perhaps not in the way that many imagine or indeed use these expensive gadgets. Used correctly, they can permit the investigator to obtain a lot of useful thermal data to be obtained from a location. The thermal camera can also be useful in the detection of fraud, as it permits images to be obtained in total darkness without introducing any additional lighting. Even a night vision camera requires additional IR lighting which although very dim, can be discerned by the human eye and therefore can alert others to the fact that a camera is in use. The thermal camera is totally passive and with its screen turned off (some models permit this) or covered it is not possible to detect the camera is being used. On a number of occasions the author has recorded instances of mal-practice and fraud during an investigation using this technique - Take a look at the examples below:
In image 1 an investigator can be observed to have their thumb hooked under the edge of the table and unseen by the rest of the group is lifting the table.
Using the manual settings on the TI camera it is possible for the camera to see the heat left behind following even a short duration contact between a warm object and a cooler object, such as a warm hand on a cold wall or a jacket for instance. The sensitivity of just 0.1 degree Celsius can often result is such thermal evidence to remain visible for several minutes. Again, properly used the thermal camera can be used to determine is on object has been touched or moved from its original position. The following pair of images taken as part of a sequence illustrates how this property can be further used in the detection and prevention of fraudulent or malpractice during an investigation. Using the grey scale option is less confusing and provides slightly higher image definition and is generally preferred for most thermal image uses, except for those on TV ghost hunting shows….....
The hand in image 2 belong to an investigator / medium who is tapping a member of the public as the group ask for the spirits to indicate their presence by touching someone.
Image 3, The investigator / medium denied touching the person and claimed that the first picture was deliberately misleading and created by using a clever camera angle. Unfortunately, the warm hand of the investigator left a thermal imprint on the jacket of the person. Irrefutable proof that contact had been made…....
One particularly false assumption is that a TI can see ghosts, a claim that many investigators have repeated. It is not necessary to go further than to state that as yet there is no device that can demonstrate the existence or otherwise of ghosts or that ghosts exist at all. To claim that ghosts can then be detected using a thermal camera is therefore erroneous.
One further claim that is frequently seen on some TV shows and in investigation reports is that the TI detected a cold spot. This is simply not possible. The camera relies upon emitted infra red energy and it cannot ‘see’ air… in fact FLIR Systems actually design their cameras to include filters that prevent the temperature of the ambient air from interfering with the correct production of the thermal image. FLIR Systems note this in their training for operators:
“Instrument designers do this by designing the instruments to be sensitive to wavelengths of IR where gases are highly transparent and do not emit IR well. This allows the radiation of surfaces that are of interest (like building surfaces) to suffer minimum attenuation as they travel through the atmosphere on the way to the IR camera.
To view gases, a different camera design approach is desired. We want to view gases at wavelengths where they emit and absorb well. This is precisely what is done with the FLIR GasFindIR cameras.
Infrared Training Center, FLIR Systems”
There is a highly specialised range of TI’s designed by FLIR Systems to detect gas emissions, these ‘Gasfind’ cameras are seriously expensive and are only capable of detecting a tunable narrow range of wavelengths to aid the detection of gas emissions from ruptured pipes for instance.
But perhaps the greatest drawback to the use of a TI is that the users are simply not familiar with the unusually coloured low resolution images that these cameras produce. As such, it is commonplace that normal artefacts within the image are highly likely to be misunderstood or misinterpreted as being anomalous or even paranormal. Used with care the TI can be a genuine asset in many investigations but used without training and a proper understanding of how the camera operates and what the resulting images show the TI can become an easy way to confuse the investigator and mislead the investigation results.
© Steve Parsons 2012