Infrared imaging seminar
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This is the infrared imaging ppt which the topic related to the image processing.
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Infrared imaging seminar
- 1. INFRARED IMAGING By Sonawane Swapnil R Sub.: CV Department of Electronics & Telecommunication VIIT, Pune 1
- 2. OUTLINE Infrared light Emissivity Infrared Thermography Principle Image format Image camera Advantages Disadvantages Applications 2
- 3. INFRARED LIGHT 3 Sir William Herschel
- 4. EMISSIVITY a = absorption t = transmission r = reflection For a blackbody, absorptivity=emissivity=1 Practically, absorptivity + transmissivity + reflectivity = 1 4
- 6. INFRARED THERMOGRAPHY Detect the infrared energy emitted from object and produce images of that radiation, called thermograms. 6
- 7. PRINCIPLE 7
- 9. INFRARED CAMERA Infrared cameras operate in wavelengths as long as 14,000 nm (14 µm) 9
- 10. INFRARED CAMERAS... Two types having: Cooled Infrared detectors Uncooled Infrared detectors 10
- 11. Cooled Detector Uncooled detector 1. Use sensors with operating range from 4K to just below room temperature Use a sensor operating at ambient temperature 2. Cooling is necessary for operation of semiconductor materials used Cooling is not necessary. 3. Use sensors that work by catching IR radiations Use sensors that work by change of resistance, voltage or current when heated by infrared radiation 4. Require cryogenic coolers for cooling Do not require such bulky, expensive cryogenic coolers 5. They are expensive both to produce &run They are smaller & less costly 6. Materials used: indium arsenide, lead sulfide Materials used: amorphous silicon, vanadium oxide 11
- 12. ADVANTAGES It shows a visual picture so temperatures over a large area can be compared It is capable of catching moving targets in real time It is able to find deteriorating, i.e., higher temperature components prior to their failure It can be used to measure or observe in areas inaccessible or hazardous for other methods It is a non-destructive test method It can be used to find defects in shafts, pipes, and other metal or plastic parts It can be used to detect objects in dark areas 12
- 13. DISADVANTAGES High price range Images can be difficult to interpret accurately when based upon certain objects Accurate temperature measurements are hindered by differing emissivities and reflections from other surfaces Only able to directly detect surface temperatures 13
- 14. APPLICATIONS Preventive maintenance applications in building systems Moisture inspection Medical imaging Night vision Military Conditional monitoring Veterinary thermal imaging Research Process control Nondestructive testing Chemical imaging Volcanology 14
- 15. REFERENCES Roglski A. Chrzanowski K. 2002, “Infrared devices & Techniques” contributed paper: Opto-electronics review www.wikepedia.org www.howstuffworks.com 15
- 16. THANK YOU 16
Notes de l'éditeur
- A British astronomer named Sir William Herschel discovered infrared. He did so by using a prism to split a ray of sunlight into its different wavelengths and then holding a thermometer near each color of light. He realized that the thermometer detected heat even where there was no visible light -- in other words, in the wavelengths where infrared exists.
- Infrared radiation is energy radiated by the motion of atoms and molecules on the surface of object, where the temperature of the object is more than absolute zero. The intensity of the emittance is a function of the temperature of the material. In other words, the higher the temperature, the greater the intensity of infrared energy that is emitted. As well as emitting infrared energy, materials also reflect infrared, absorb infrared and, in some cases, transmit infrared. When the temperature of the material equals that of its surroundings, the amount of thermal radiation absorbed by the object equals the amount emitted by the object. the extent to which materials reflect, absorb and transmit IR energy is known as the emissivity of the material.
- The graphs show that wavelength and spectral radiant emittance vary with the temperature. They also show that as the temperature rises, the peak of spectral radiant emittance is shifting to shorter wavelengths. This phenomenon is observable in the visible light region as an object at a low temperature appears red, and as the temperature increases, it changes to yellowish and then whitish color—thus shifting to shorter & shorter wavelengths as the temperature increases. Thus it shows that peak energy shifts toward shorter wavelengths as the temperature increases.
- Infrared thermography is equipment or method, which detects infrared energy emitted from object, converts it to temperature, and displays image of temperature distribution. To be accurate, the equipment and the method should be called differently, the equipment to be called as infrared thermograph and the method to be called as infrared thermography.
- Temperature distribution image data of infrared thermography consists of matrix of pixels (number of detector: for example, 320 horizontal X 240 vertical pixels) as shown in the figure above. Thermal image data can be transferred to PC. Subsequently, the data can be calculated and utilized freely. Thermal image data is colored up pixel by pixel based on temperature.
- A thermographic camera (also called an infrared camera or thermal imaging camera) . In 1929, Hungarian physicist Kálmán Tihanyi invented the infrared-sensitive (night vision) electronic television camera for anti-aircraft defense in Britain.[7] The first conventional thermographic cameras began with the development of the first infrared line scanner. This was created by the US military and Texas Instruments in 1947[8] and took one hour to produce a single image. While several approaches were investigated to improve the speed and accuracy of the technology, one of the most crucial factors that needed to be considered dealt with scanning an image, which the AGA company was able to commercialize using a cooled photoconductor.[
- Thermographic imaging is a great technology for predictive/preventative maintenance applications in building systems. For example, electrical components will get hot prior to failure. The thermal differences can be seen before the piece of equipment fails. Military applications include target acquisition, surveillance, night vision, homing and tracking. Non-military uses include thermal efficiency analysis, remote temperature sensing, short-ranged wireless communication, spectroscopy, and weather forecasting.