Temperature is one of the important parameters to tell the condition of internal process, material and even quality of the desired output. A qualitative but accurate conclusion can be drawn by observing the temperature profile of any surface. On the other hand higher temperature also indicates obvious loss of energy in the form of heat. Therefore temperature monitoring would give ample indication of the condition of the material, process quality and explore the possibility of energy conservation avenues. 

What is Infrared Thermography ?

Thermography is nothing but the temperature profiling of a surface or point. As the name suggests, infrared thermography is based on Infrared(IR) technique. The principle underlying this technique is that every object emits certain amount of IR energy and the intensity of this IR radiation is a function of temperature. In an electromagnetic spectrum the IR region appears between 0.8 micron to 1000 micron wavelength (See Figure 1). This wavelength of IR spectrum is more than that of a visible spectrum. The IR energy which can directly represent the surface temperature can be detected and quantified by the help of IR scanning system. 

The Thermography Instrument

A thermography instrument can be a thermal pointer or a thermal scanner. The thermal pointer reads the temperature of a specific dimensional point where as a scanner maps the thermal profile of an area surface.

The basic IR system consists of an “IR energy detector” and a “Monitor”. The scanner is an optomechanical device which converts the IR energy received from an object surface to an electrical signal. These signals are further fed into the monitor where it is processed and presented in many forms like simple digital display to indicate temperature level and a video display for thermal profile (See Figure 2). 

Advantages: 

• It is a non-contact type technique.
• Fast, reliable & accurate output.
• A large surface area can be scanned in no time.
• Presented in visual & digital form.
• Software back-up for image processing and analysis.
• Requires very little skill for monitoring.

Disadvantages:

• Cost of instrument is relatively high.
• Unable to detect the inside temperature if the medium is separated by glass/polythenematerial etc.