portal7.info - Download as Word Doc .doc / .docx), PDF File .pdf), Text File .txt) or read online. Night Vision Technology - Free download as Word Doc .doc), PDF File .pdf), Text Download as DOC, PDF, TXT or read online from Scribd Seminar Report. Night Vision Technology Seminar Report pdf. Ajay Khedkar. 21 March This system processes far infrared radiation, which minimizes non-essential.
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Seminar report On NIGHT vision Technology Submitted to: Submitted by: MR. Ajay Khokhar Deepak Ahuja (lectt. In E.C.E deptt.) roll no.- 07/ece/11 Night Vision . Night Vision Technology, Ask Latest information, Abstract, Report, Presentation ( pdf,doc,ppt),Night Vision Technology technology discussion,Night Vision. seminar report on night vision technology. 1. 1 ABSTRACT This paper describes the various Night vision techniques. "Night Vision" is.
Both near-IR and mid-IR are used by a variety of electronic devices, including remote controls. The key difference between thermal-IR and the other two is that thermal-IR is emitted by an object instead of reflected off it. Infrared light is emitted by an object because of what is happening at the atomic level. Atoms Atoms are constantly in motion. They continuously vibrate, move and rotate.
Energy consumption generates heat. In turn, heat causes the atoms in an object to fire off photons in the thermal-infrared spectrum. The hotter the object, the shorter the wavelength of the infrared photon it releases. An object that is very hot will even begin to emit photons in the visible spectrum, glowing red and then moving up through orange, yellow, blue and eventually white.
The detector elements create a very detailed temperature pattern called a thermogram. This information is obtained from several thousand points in the field of view of the detector array. The combination of all the impulses from all of the elements creates the image.
The basic components of a thermal-imaging system Types of Thermal Imaging Devices Most thermal-imaging devices scan at a rate of 30 times per second. They can sense temperatures ranging from -4 degrees Fahrenheit degrees Celsius to 3, F 2, C , and can normally detect changes in temperature of about 0. It is quite easy to see everything during the day.
Thermal imaging lets you see again. The infrared-detector elements are contained in a unit that operates at room temperature. This type of system is completely quiet, activates immediately and has the battery built right in. The advantage of such a system is the incredible resolution and sensitivity that result from cooling the elements.
Cryogenically-cooled systems can "see" a difference as small as 0. While thermal imaging is great for detecting people or working in near-absolute darkness, most night-vision equipment uses image- enhancement technology. Image-enhancement technology is what most people think of when you talk about night vision. In fact, image-enhancement systems are normally called night-vision devices NVDs. NVDs rely on a special tube, called an image-intensifier tube, to collect and amplify infrared and visible light.
The image-intensifier tube changes photons to electrons and back again. Here's how image enhancement works: 1 A conventional lens, called the objective lens, captures ambient light and some near-infrared light. The tube outputs a high voltage, about 5, volts, to the image-tube components. The image-intensifier tube has a photocathode, which is used to convert the photons of light energy into electrons.
An MCP is a tiny glass disc that has millions of microscopic holes microchannels in it, made using fiber-optic technology. The MCP is contained in a vacuum and has metal electrodes on either side of the disc.
Each channel is about 45 times longer than it is wide, and it works as an electron multiplier. When the electrons from the photo cathode hit the first electrode of the MCP, they are accelerated into the glass microchannels by the 5,V bursts being sent between the electrode pair.
As electrons pass through the microchannels, they cause thousands of other electrons to be released in each channel using a process called cascaded secondary emission. The lower the value the better. The EBI level determines the lowest light level at which an image can be detected. Below this light level, objects will be masked by the EBI.
Emission Point: The position of an emission point within the field of view will not move. If an emission point disappears or is only faintly visible when viewing under brighter night time conditions, it is not indicative of a problem.
If the emission point remains bright under all lighting conditions, the system needs to be repaired. Do not confuse an emission point with a point of light source in the scene being viewed. Eye Relief: Figure of Merit FOM: This pattern is inherent in the structure of the micro channel plate and can be seen in virtually all Gen 2 and Gen 3 systems if the light level is high enough.
This is the number of times a night vision device amplifies light input. It is usually measured as tube gain and system gain. Tube gain is measured as the light output in FL divided by the light input in fc. This figure is usually expressed in values of tens of thousands.
If tube gain is pushed too high, the tube will be "noisier" and the signal-to-noise ratio may go down. S military Gen 3 image tubes operate at gains of between 20, and 45, On the other hand, system gain is measured as the light output FL divided by the light input also FL and is what the user actually sees.
System gain is usually seen in the thousands. In any night vision system, the tube gain is reduced by the system's lenses and is affected by the quality of the optics or any filters. Therefore, system gain is a more important measurement to the user. Gallium Arsenide GaAs: GaAs photocathodes have a very high photosensitivity in the spectral region of about to nanometres visible and near-infrared region.
Highlight Shutoff: This feature will turn the system off during periods of extreme bright light conditions. Interpupillary Adjustment: Improperly adjusted binoculars will display a scene that appears egg-shaped or as a reclining. Interpupillary Distance: IR light cannot be seen by the unaided eye; therefore, a night vision device is necessary to see this light.
IR Illuminators provide supplemental infrared illumination of an appropriate wavelength, typically in a range of wavelengths e. IR Laser: Ranges of several thousand meters are common. Most are not eye-safe and are restricted in use. Each IR laser should be marked with a warning label like the one shown here. I2 Image Intensification: IR Infrared: The visible spectrum is between and nanometres. Usually determined from a U.
The target is a series of different-sized patterns composed of three horizontal and three vertical lines. A user must be able to distinguish all the horizontal and vertical lines and the spaces between them. Typically, the higher the line pair, the better the image resolution.
The American Eagle in this catalogue is an example of a monocular. MCP Micro channel Plate: MCPs eliminate the distortion characteristic of Gen 0 and Gen 1 systems. The number of holes channels in an MCP is a major factor in determining resolution. Also see IR infrared. The type of material used is a distinguishing characteristic of the different generations.
Photocathode Sensitivity: This criterion specifies the number of electrons released by the Photocathode PC. PC response is always measured in isolation with no amplification stage or ion barrier film. For any particular night vision system, the image intensifier resolution will remain constant while the system resolution can be affected by altering the objective or eyepiece optics by adding magnification or relay lenses.
Often the Radicle Radicle Pattern: A tube's SNR determines the low-light-resolution of the image tube; therefore, the higher the SNR, the better the ability of the tube to resolve objects with good contrast under low- light conditions.
Because SNR is directly related to the photocathode's sensitivity and also accounts for phosphor efficiency and MCP operating voltage, it is the best single indicator of an image intensifier's performance Scintillation: A faint, random, sparkling effect throughout the image area. Scintillation is a normal characteristic of micro channel plate image intensifiers and is more pronounced under low-light-level conditions Screen: Phosphor P is used on the inside surface of the screen to produce the glow, thus producing the picture.
Different phosphors are used in image intensifier tubes, depending on manufacturer and tube generation. P phosphor is used in the systems offered in this catalogue Stereoscopic Night Vision: When the two photographs are viewed in a stereoscopic apparatus, they combine to create a single image with depth and relief. Sometimes this gives two perspectives. However, it is usually not an issue because the object of focus is far enough away for the perspectives to blend into one. System Gain: Variable Gain Control: The BMW system is distinguish from infrared system with active illumination by its long range, and its clearly structured image.
Infrared energy coming from an object is focused by the optics onto an infrared detector. A thermal imaging camera can produce a comprehensive image on which the smallest of the temperature difference can be seen. Contrary to other technologies, such as e.
Improve vision in twilight and darkness and the display does not dazzle by the head lights of the oncoming vehicles. Pronounced highlighting of process, animals and warm objects as well greater overview of driving situation due to display of course of road beyond that illuminated by headlights. It gives magnified image of the distant objects when driving fast through zoom function improved recognition of objects on bends in the road through horizontally adjustable image section.
It enhances personal safety of dark ways and garage entrance through display of living creature. A far infrared camera in the grill, just over an inch in diameter, senses the temperature of everything in front of the vehicles. A computer then converts the data into an image that appears on the navigation display unit into the dashboard. Warmer objects a pedestrians, an animal appears white; cooler objects parked cars, detritus objects a pedestrians, an animal appears white; cooler objects parked cars, detritus appears black.
When the car exceeds 25 mph, the system scans specifically for pedestrians by scanning the road up to yards ahead of the vehicle.
A pedestrian appears with the yellow tint. The thermal image is converted first by the sensor into electrical signals and then with the aid of image- processing software into a visible image in the control display. The sensor elements alter the resistance in proportion to the temperature. The higher the temperature, the higher the electrical signal and the whiter the pixel will be shown.
The sensor can generate a new image up to 60 times per second. This results in a softer and clearer image. Heat radiation is absorbed and dissipated by virtually every solid or liquid body. Heat radiation, however, is not visible to the human eye because it belongs in the long-wave infrared range.
The advantage of utilizing radiation in the Far Infrared range is the greater range compared with Near Infrared systems with a wavelength of 0. These systems require illumination with just this wavelength.
Essentially, FIR systems consist of an optical element, a thermal imaging camera, a control unit and a display. This would markebly decrease the possibility of collisions with terrain or man-made obstructions.
It does permit the user to see objects that normally would not be seen by the unaided eye. Highlighting of illuminated, heat-emitting objects as pedestrian, cyclists, deer, Etc. Disadvantages Lack of color discrimination: Neck strain and fatigue: So there is a chance of neck strain and fatigue. High initial cost to download: Need for recurrent training: Decreased field of aided view: Although generic image processing algorithms have been addressing similar goals for many years, there are several problems that are unique to image processing in automotive application.
For example, It is difficult to distinguish between objects in the foreground and the background of the image the entire image is continuously changing and because pedestrians vary in scale based on their distance to the viewer. We have seen four generation of this device and seen different ranges. But, the near IR detector needs an assist. Special bulbs mounted next to the headlights are aimed straight ahead like a car's high beams, but they don't blind other drivers because the human eye is insensitive to the infrared light.
The NIR system is illuminates the surroundings with infrared light in the wavelength of to nm. The digital signal from the CCD is routed to the image processor that translates it into a format that can be viewed into a black and white head-up display beamed onto the wind-shield.
The far infrared technology detects energy farther up the infrared band that is emitted by objects as heat. This far IR night vision is also called passive, because no special light source is required. The special camera these systems use - essentially a phased array of IR detector elements analogous to the pixels in an ordinary digital camera - creates a temperature pattern called a thermo gram, which is refreshed 30 times a second.
The heat from a pedestrian or an animal is much greater than the heat coming to the camera from its surroundings. A signal processor translates the thermo gram data to an image suitable for display on a monitor.
It has been found out that neither of the technologies has a clear advantage. But, not everyone thinks night vision in cars makes sense. Effective algorithms are required in order to send a warning to the driver fast enough if a pedestrian is detected.