Talk Image Intensifier Tube
Engineer Manager Name: Sophia
WhatsApp/ Wechat: 0086-18109189213
What are the parameters to look for when comparing IITs?
Figure of Merit (FOM) – Image intensifier tube (IIT) specification designation, calculated on line pair per mm x signal to noise. (FOM=lp/mm * SNR).The large the value, the better the image qualiy and the more details it can show.
Resolution -The ability of an image intensifier or night vision system to distinguish between objects close together. Image intensifier resolution is measured in line pairs per millimeter (lp/mm). Typically, the higher the line pair, the better the image resolution.
Black Spots – These are cosmetic blemishes in the image intensifier or can be dirt or debris between the lenses. Black spots that are in the image intensifier do not affect the performance or reliability of a night vision device and are inherent in the manufacturing processes.
Photocathode sensitivity - A measure of how well the image intensifier tube converts light into an electronic signal so it can be amplified. The measuring units of photocathode sensitivity are micro- amps/lumen (?A/lm) or microamperes per lumen. Even though it is a very important attribute, Photonis unfortunately does not display the value on its specs.
Signal-to-Noise Ratio (SNR) – A measure of the light signal reaching the eye divided by the perceived noise as seen by the eye. 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. the smaller the noise and distortion of the image, and the clear the image.
Autogated – Autogating offers the tube better protection and preventing resolution loss in high light conditions.
Gain – IIT work by collecting low levels of light, amplifying them to levels that can be easily observed. The tube gain (which is also referred to as brightness gain or luminance gain) is the magnitude, or number of times the image intensifier amplifies the light input.
Difference Of IIT
The key difference between the night vision generations is the intensifier technology.
Gen1 was first developed in the Vietnam area, and is recognized as the now entry level into night vision devices, use an intensifier tube that amplifies ambient light by accelerating electrons and striking a green phosphorus surface (just like a television). Gen1 used under optimal conditions give you 75-100 yds visibility.
Gen2 devices have added a micro-channel plate that multiplies the number of electrons before they make contact on the phosphorus screen (thus increasing clarity, quality and brightness). Gen2 devices can come in white or green phosphorus variants. The white phosphorus typically run more, as they provide enhanced clarity, as well as lower eye fatigue. Gen2 devices under optical conditions can expect visibility in 150-200 yds.
Gen3 is currently what the US Military uses and have added a Gallium Arsenide photocathode which creates significantly more photoelectrons than Gen2 devices and is more efficient at amplifying existing light or IR illumination. Gen3 devices are significantly brighter and better in optical clarity than other generations and under optimal conditions allow visibility out to 350-400 yds. Lastly, Digital Night Vision was released in the early 2000’s, as it plays on same principal as your NV modes on digital cameras. Digital NV uses CCD (charged coupling devices) to process light prior to sending to an LCD (liquid crystal display) image. Utilizing this technology, Digital NV is not damaged by large amount of natural light and are able to be used in both night and day. As with most technology Digital NV has offered a significant bang for your buck, as it is typically cost comparative to Gen1 devices, but offers resolution and clarity of a Gen2 device.
Engineer Manager Name: Sophia
WhatsApp/ Wechat: 0086-18109189213
