Thermography
Thermography is a type of infrared imaging, sometimes called thermal imaging, or even thermal imaging. In this method, the thermography camera or thermovision receives infrared (infrared) radiation with an electromagnetic spectrum of 9 to 14 µm and prepares a thermogram from these spectra.
According to Planck’s law, blackbody radiation emits infrared radiation from any object that has a temperature above absolute zero or zero Kelvin (K). These radiations allow the object to be seen in conditions of visible light and absolute darkness. The amount of infrared radiation emitted from each object depends on the body’s thermal changes. This principle makes invisible temperature changes visible in infrared imaging.
Thermal or thermographic camera
This sensitive device is an electronic and accurate device that collects infrared thermal waves emitted from objects by its sensitive sensors and converts the emitted radiation into a quality color image with details through its precision and industrial microprocessors. he does. Of course, it should be noted that the images created by the thermal camera are basically black and white images that are converted into a color image with the help of the internal processor of the thermal camera.
Applications of Thermographic Thermal Cameras
- Infrared imaging in medical diagnoses and mammography of breast cancer
- Archaeological excavations
- Display of defective parts due to the heat produced by them
- Display temperature and image in inaccessible and dangerous environments
- Display of heat and energy losses in buildings and facilities
- Seeing objects in complete darkness
- Assessing the probability and assessment of fire
Thermographic measurement by thermal camera
One of these methods is condition monitoring and prediction of defects of mechanical and electrical equipment, which is based on the principle of conflict of mechanical equipment with each other, as well as current passing through electrical equipment and resistance due to current passing. The heat emitted from the external surfaces of objects is in the form of infrared radiation that is not visible to the naked eye. This radiation is detected by thermographic cameras, also known as thermal cameras.
Temperature analyzes can be used to identify and analyze defects in equipment and connections such as improper electrical connections, instability of parts and equipment, metallurgical changes, excessive electrical load drop on the part, failure to use a suitable heatsink for cooling, improper applied voltage, dirty Existence of electrical equipment, the impact of environmental pollution, phosphating and oxidation of joints, lack of coaxiality and excessive vibration of mechanical parts and so on.
Thermography and its application in industry
Thermography and demography have many applications, but as mentioned earlier, one of the most common applications is as an important technique in monitoring the condition and diagnosing defects of electrical, mechanical and other tools and equipment. Some experts believe that thermographic images are a way to diagnose Defects are not the cause of defects in industrial devices. The principles of this method are very simple, and the thermal camera troubleshooting method is based on the premise that when system components or industrial equipment do not work properly, they cause an increase in temperature in the device or part range. An increase in heat in an electronic-electrical circuit can be caused by incorrect connections.
At the level of equipment and mechanical devices of temperature distribution, when this equipment works in ideal conditions, it has a reasonable temperature predicted by the manufacturer. By changing the temperature on the parts, it is possible to detect a defect in the suspicious part of the device. Sometimes the type of thermal pattern on the device, if interpreted correctly, can also determine the type and cause of the defect.
Today, the most common thermographic instruments used in the inspection of working machinery and equipment are infrared thermometers known as laser thermometers and infrared cameras, also known as thermovision, thermal imaging or thermographic cameras. The mechanism of operation of both thermometers The use of infrared spectra emitted from the object under test to measure the surface temperature of the object. The working mechanism of these thermometers is non-contact, which prevents the reduction of production and the occurrence of such events by preventing the device from turning off.
Field of view (FOV) in thermographic cameras
Field of View is one of the main features of thermovision cameras, which refers to the breadth of human vision and equipment with a video and photography lens, which is abbreviated as (FOV).
The field of vision in humans refers to the limitations caused by human vision based on the abilities of the retina or the presence of glasses in the eye, and که which is defined as the degree of angle of view of humans at a fixed length, which is the same for camera equipment. The definition is correct.
Field of view in cameras and other equipment
In cameras, thermographic or thermovision cameras adjust the focal length of the lens and the size of the imaging sensor to establish a constant relationship between the field of view and the working distance. Clarity has a direct impact
IFOV instantaneous field of view and ratio of measuring distance to point D: S
Instantaneous field of view is the amount of sharpness of a space for shooting or shooting from a distance, known as space resolution or geometric resolution, or IFOV instantaneous field of view. In view or coverage, a single pixel is called in the device, and the number of pixels used to calculate the temperature or minimum quality of a point image is called the ratio of the measured distance to the point, which is (D: S) or (DTS). Is written.