The Breakdown - Definitions to Assist

The Breakdown - Definitions to Assist

Autogating: Autogating is a mechanism that rapidly turns the system on and off to prevent excessive light from reaching the photocathode. This helps maintain a high-quality image in bright or fluctuating light conditions, preventing "blooming" which makes it hard to see around light sources.

Automatic Brightness Control (ABC): This feature automatically adjusts the voltages in the device to keep the brightness optimal, ensuring the image stays clear even when moving between dark and bright areas.

Biocular: A biocular system uses one objective lens and two ocular lenses. Both eyes share the same optical components, as seen in devices like the PVS-7s. This is different from binocular devices, which have separate optics for each eye.

Binocular: In a binocular system, each eye views through its own set of objective and ocular lenses, allowing for independent optical components per eye. An example of this type is RNVGs.

Black Spots/Dark Spots ("Blems"): These are imperfections in the image that appear as dark spots. They can be caused by debris during manufacturing or by external factors like high-intensity light sources.

Blooming: Blooming occurs when a bright light source overloads the intensifier tube, creating a "halo" effect and whitening out parts of the image. It's more common in older generation devices.

Bright Spots: These are small, bright areas in the image caused by defects in the microchannel plate's film. They often disappear when the light is blocked.

Bright Spot Protection (BSP): This function reduces voltage to the photocathode under bright light conditions to protect the device and extend its life, although it may lower the resolution.

Chicken Wire or "fixed pattern noise": This refers to a pattern of dark lines that may appear across the image under bright conditions, typically forming hexagonal or square shapes.

Daylight Cover/Day Cap: A protective cover, often made of rubber, with a small pinhole to limit light exposure. It's used for training purposes to prevent damage when the device is not in use.

Diopter: A measurement of the refractive power of the lenses, adjusted to compensate for individual eyesight differences.

Distortion: This includes optical distortion, where lines at the field of view's edge appear curved, and manufacturing distortions in fiber optics that may affect the image.

Edge Glow: A defect causing a bright area in the peripheral view. Using a rubber eyecup can minimize this effect.

Emission Point: A persistent bright spot in the image that doesn't shift position. It indicates a need for system repair if it remains bright in all conditions.

Equivalent Background Illumination (EBI): The background light seen through the device when no external light hits the photocathode, affected by the device's temperature.

Eye Relief: The distance between the eyepiece and the user's eye that provides an optimal image.

Field of View (FOV): The total area visible through an optic device.

Figure of Merit (FOM): A rating that combines resolution and signal to noise ratio to measure tube performance.

Foot-lambert: A unit of brightness measurement, typically used to compare light conditions in testing environments.

Gain: The amount by which the device amplifies light. System gain takes into account losses from system components, and is essential for evaluating device performance.

Gallium Arsenide (GaAs): A material used in third-generation photocathodes, enhancing sensitivity and performance.

Generations of Night Vision: Describes the evolution from Generation 0 devices, which were basic and required external IR light, to Generation 3 devices, which use advanced technology for enhanced performance. Theoretical Generation 4 would involve improvements but is not officially recognized due to high failure rates in prototypes.

Interpupillary Adjustment: Adjusts the optics to fit the distance between a user's eyes, ensuring a clear and correctly shaped image.

Infrared Light: Light that is not visible to the naked eye, used in night vision to illuminate scenes without detectable light.

IR Illuminator: A device that emits infrared light to enhance night vision capabilities, often built into night vision devices.

Lp/mm (Line pairs per millimeter): A measure of the resolution of an image intensifier, indicating the clarity of the image.

MCP (Microchannel Plate): A component in Gen 2 and Gen 3 devices that amplifies electrons to enhance the image without the distortion seen in earlier generations.

Monocular: A single-channel optical device used for night vision, like the PVS-14.

Near Infrared (NIR): The part of the infrared spectrum closest to visible light, used in night vision.

Photocathode: The part of the device that converts light into an electronic signal, crucial for image intens

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