All the materials that are a temperature over the zero absolute one (0 K, -273ºC) emit infrared energy. The energy emitted in the infrared band becomes an electrical signal by the detector (microbolometer), this signal becomes a black and white image in or color. The basic principle is described next.
The infrared radiation is a form of electromagnetic radiation like the radio waveses, the microwaves, ultra-violet rayses, gamma rays, the visible light, etc.... All these forms of radiation altogether give rise to the electromagnetic spectrum. It has in common that all of them emit electromagnetic waveform energy and they propagate at the speed of the light.
The infrared radiation defines like which µm has a wavelength between 0.78 and 1000 µm (microns). The infrared rays are subdivided based on the proximity of wavelength near, average or distant to the visible light like.
The infrared cameras that are used in the industry work all in the average infrared band (they are those that detects the not cooled microbolometers calls).
The infrared cameras detect the invisible infrared radiation that they emit the objects and transforms it into an image within the visible phantom in which the scale of colors (or grays) reflects the different intensities.
The intensity of the infrared radiation is function of the temperature but not only of her, also influence the superficial characteristics of the object, the color and the type of material.
At first the infrared cameras give a value of temperature for each point, without considering that, for the same temperature, two materials can radiate infrared energy with very different intensities.
We see a very graphical example here, a metallic cup with a fervor that is to the same temperature, nevertheless the fervor and the metal of the cup emits infrared energy with very different intensities.
It must to the different emisivity between the metal and the sticky tape.
The emisivity of an object is defined from the concept of black body. A black body is that that absorbs all the infrared radiation that receives, does not reflect or transmits therefore anything. The radiation emitted by a black body is function solely of the temperature.
The emisivity of an object for a temperature is defined as the quotient between the infrared energy emitted by the object and the emitted one by a black body.
The infrared cameras adopt as it generates a emisivity from 0.95 to 0,97. All the AMPERIS cameras adopt by defect a emisivity of 0.95, and also all allows to vary that value between 0.1 and 1. Of this form the different values from emisivity are not translated in readings different from temperature.
Infrared camera operation
Basically basic a infrared camera consists of:
- Detector or microbolometer
- Circuit of processing of the image
- User interface (screen, video output, memory, etc...)
Today, less than 15 companies in the world they are able to make this type of cameras.
A concept very important to consider at the time of valuing an infrared camera is the space resolution then this concept defines until it distances are possible to be seen the objects.
The space resolution is the field of vision of the microsensors that comprise of the detector or microbolometer.
The space resolution defines as the relation between the size of the sensor and the distance between the lenses and the sensor. The more low it is the space distance the more resolution will be possible to be used the camera (or, for the same distance, small objects will be able to be visualized the more).
In the following graph the relation between the size of the objects and the distance to the camera is appraised:
Infrared Thermography “With Infrared, we can see what our eyes cannot”
Infrared thermography is a method to analyse and acquire thermal information from non-contact thermal imaging devices. It detects infrared energy emitted from the object by converting it to the temperature and displaying temperature distribution in the image format. It involves infrared imaging. A measurement camera is used to see and measure thermal energy emitted from an object.
Infrared is invisible to the naked eye as its wavelength is longer than visible light. Brightness or darkness of visible light has nothing to do with infrared. It can be applied to any field as it naturally emits from any object of which temperature is absolute zero or higher. It carries a characteristic of heating an object and sometimes it is called as “heat wave". A kind of light (electromagnetic wave) and it carries the potential to transmit through vacuum. Infrared energy and temperature correlate to each other; therefore, it can be used to measure the temperature of an object.
Even cold objects like ice cubes, emit infrared. Infrared Thermography cameras capture the images of heat rather than light y translating the energy waves into a viewable image to show a "heat picture" of the object. Infrared Thermography helps you to increase efficiency of equipments which can save you from unwanted breakdowns and stoppages. It ultimately helps you to significantly reduce the maintenance costs and production losses.
For electrical, building applications and industrial purposes, Infrared thermography or thermal imaging is a brilliant tool. It can impact significantly on your troubleshooting and maintenance productivity. Thermal imaging tools can help you enhance the current level of productivity from your equipments and machines in production.
Infrared Thermography Equipments
New applications for infrared cameras continually emerge. Infrared Thermography equipments are of great advantage as these cameras as help you to improve manufacturing efficiencies, enhance worker safety, manage energy, improve product quality and ensure productive maintenance. Infrared cameras measure temperature of objects in real time. Infrared thermography cameras are highly valuable diagnostic tools and can be used in many diverse applications. These are extremely cost-effective for their benefits.
Infrared Thermography equipments are highly beneficial to draw comparison of the distribution of surface temperature. With thermography equipments, temperature of moving objects or even dangerous objects where going close is restricted, can be measured easily. Temperature of the small object, food, medicine or chemicals can also be measured. Temperature of objects with drastic temperature change can also be measured.
Infrared inspections and its benefits:
Infrared testing is a process that uses thermography cameras to measure and see the objects. Infrared cameras gather temperature signatures that are far beyond the range of visible light. This is called infrared analyses. This helps in detecting the problems beforehand to save you before they become serious and become costly issues. Infrared testing adds an invaluable contribution with its diagnosis, and it acts and fulfils the objectives of preventative maintenance program for your plant and equipments.
Who can get advantages from Infrared inspections?
- Property owners
- Engineering firms
- Property managers
- General contractors
- Facility managers
- Real estate agents
Infrared Imaging Survey
Infrared imaging survey for temperature measurement and immediate fault detection can help you with:
- Ensure the safety of electrical equipments and systems in the plant.
- Increased energy efficiency.
- Increased capital equipment lifespan.
- Increased safety.
- Reduced risk of fire.
Infrared Images and understanding them:
Evaluating infrared images is not easy, and it requires extensive training and experience. Either you need to train yourself, or you need an Infrared Thermographer with the ability to evaluate an infrared image. You can obtain the aid of certified Infrared Thermographers.
- To learn it yourself, you can initially use images in camera manual and compare them with your captures.
- You can also learn from the free sessions available online or material available on the web.
- You can compare image with other same situations (e.g. exact location on another same type of equipment).Verify that situation is good and capture image for future comparison.
- Capture image of no good situation and the capture new image when repair is made to compare.
Know the Facts:
Is this true that Infrared cameras emit something?
No, they do not emit anything; they only detect the infrared emitted from an object in a passive manner.
The temperature distribution is measured by the wavelength.
No, the amount of infrared energy measures the temperature distribution.
You can see through an object with infrared imaging.
No, you cannot! The infrared emitted is detected through the surface of the object. Therefore, you cannot see through the object.