Thermography is the capturing of the image of an animal, vegetable or mineral subject whereby the temperature (in a digital format) of each pixel of the image is stored and converted to an equivalent colour in the colour spectrum for display or printing.
Thermal Imagining is a nondestructive testing means of determining the characteristics of an article based on the ability of the article to absorb and radiate heat. The article being tested will not be altered or changed any more than it being viewed by a person. The object can be as large as barn (or bigger) or as small as an insect (or smaller). The object can be inches from the Thermal Imaging instrument or as far as the eye can see.
The Thermal Imaging camera records the temperature of the subject, it does not transmit any energy to the subject.
The temperature readings of all pixel points of the image being viewed in the camera’s display unit are recorded in digital format for temperatures from –20c to +350c (depending on the device). These pixel temperature readings and be selectively displayed along with the colour image equivalent for the pixel.
It is basic physics, all elements absorb and radiate heat. Temperature variations within an object of each surface element will vary by the density of the material, moisture content, background material, ambient temperature, etc.
The Thermal Imaging camera will record these variations of temperature for interpretation by a Thermographer with the assistance of sophisticated software to determine anomalies of the image.
Thermography is a Non Destruction Testing process for preventive maintenance tool it is not a repair tool.
A crack, dowels, nails, weld joints, etc. or abnormality in the object will be displayed even if not visible to the eye. A joint no matter how skillfully finished will have a different temperature than the main object. Material used to join / repair an item will present an image different than the base item.