Showing posts with label Security Cameras. Show all posts
Showing posts with label Security Cameras. Show all posts

Thursday, December 18, 2008

High level basics about Infrared Security Cameras

Light/brightness is measured in lumens.  A lumen is the measure of the perceived power of light. 

Many people have heard of night vision cameras (yes they are cool) but they are not infrared and they work actually in two ways similar but different – both are able to see at lower lumen (light) levels than normal cameras. Differences – night vision have the ability to capture ambient light or and infrared see into the infrared (heat) spectrum. Some infrared cameras are black and white others are color. The color night vision switch to black and white at low light levels.   

Ok, that was still a little too high brow – let’s make it even simpler

  • Night Vision – typically green
  • Infrared differences between black and white the whiter something is the greater the heat signature. 

The infrared are actually thermal infrared. The infrared cameras typically have LED emitters either enclosed in the camera body or separate.  Also they typically come with a power adaptor to supply the IR LEDs.  Like other security cameras they can be IP (network), Coax (CCTV) or Wi-Fi (network) based. 

Trivia:

  • Did you know the LED emitters allow infrared cameras to see in no light?
  • Did you know in extremely low light the LEDs allow you to see an image as if you were in full daylight?

Tuesday, November 18, 2008

What is an auto iris and how does it work?


Like the digital camera, security cameras use a cmos (Complementary metal–oxide–semiconductor) to capture and translate the image the camera sees to data which is translated back into am image that can be viewed on a monitor . An auto iris like the iris of your eye adjusts the light level to maintain a reasonable amount of brightness. The brighter the light the smaller the iris. There are two types of irises – auto (automatic) and manual. 

Manual irises are set to a single level of light while automatic use sensors to adjust exposure. 

Yes, even in technology the iris serves the same purpose and functions much the same as the human eye's iris.

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