Night-Safe Displays & Night-vision

Many people associate night-vision with red or green images however when designing a display system that optimizes image detail and preserves a users ability to see in low light other factors are worth considering:

• Color palette: Tuning the color palette for night-safe colors may help preserve image information and usability. Factors to consider:
  • De-saturating shorter wavelength colors, ie those towards the blue end of the spectrum.
  • Adjusting the gamma curve to emphasize detail in low light areas of the image.
  • Combining all colors to Red mono or Green mono.
  • Using the Red or Green channel only.
• Brightness: When working in a low light environment a night-save setting may require a maximum limit on the display brightness setting. When invoked it makes sense that brightness adjustment operates with a suitable level of adjustment resolution over the new limit.
• Controls: Being able to invoke the night-safe easily and effectively will be a key element:
  • Auto settings: For example an light sensor is used to invoke the night-safe settings.
  • External control: This is where external equipment switches the display system to its night-safe settings, it could be a clock or as part of a larger display and system infrastrcture.
  • User control: To make things easy for a user a single button access for night-safe settings as well as controls that remain readily accessible and readable in low light conditions.

IMAGES

The top image is the original; the 2nd is with blue removed, gamma adjusted to bring out detail in shadows and is suitable for having the brightness reduced in low light conditions; the 3rd image is red only; the 4th is green only. (Note: It seems that the pictures align properly on the right in Firefox and Safari but not in Internet Explorer).

Various Digital View controllers support all of the above, details can be found from the individual controller manuals, the application notes for RS-232 and the Serial Utility as well as from Digital View directly. A good model to consider is the SVX-1920 or upcoming harsh environments version the HX-1920.