Chris Prillo is answering the question are WiFi security cameras safe for home use?
Ever wonder why most Security CCTV Cameras are placed in housing enclosures?
Let me explain simply – Cameras are in fact electronic devices and while used for security nothing but cameras. So to protect the camera from dust and excessive humidity they are enclosed in housing. This housing protects the camera from excessive moisture, in the case of external housing from excessive cold (via built in fan and heater) and the main lenses from dust. Many normal enclosures are almost air tight and are extremely water resistant. There are some underwater enclosures that are air and water tight.
The main parts of a camera are
CCTV = Closed Circuit TV. In a CCTV security system one or more cameras are used to capture the moving image and send it to a splitter or multiplexer which in tern sends the picture to a VCR(s), DVR(s), or monitor(s). What is the difference between regular and CCTV – simple – CCTV is a closed system and regular is broadcast to the public.
Because CCTV Is a closed system it is the reason many prefer using it for security and monitoring systems.
Have you been in a major department store (Wal-Mart, etc) or a grocery store and seem those housing outside or those mirrored domes? What about driving down the street and seeing the camera housing mounting to a traffic signal or on the highway? How about in the ceiling behind your teller in the bank?
CCTV cameras can be just black and white but most are capable of color in high light conditions and switch to Black and white.
In simple terms the system works by converting the image seen to electrical impulses which are then sent (in the case of RG59 Coax) via the cable then converted back to recognizable images for display on a TV via the devices mentioned earlier. A moving image (motion) is created simply by taking pictures so rapidly their appears to be motion when in fact you are only looking at a series of pictures displayed in rapid succession.
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
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:
With this post am beginning transition to video. Later expect a series on quotes by mentors because our mentors and the values and ethics they instilled in us are important.
Webcams aka Web cameras are a common sight today, so much so that you will even see them integrated into many mainstream laptops and LCD monitors. There are USB, network, and WiFi cameras. In fact as a security option you may want to consider using a webcam with motion detection software to monitor your house or apartment while you are away. Many manufacturers now (depending on the model) offer motion detection that is when an object moves in front of the camera for a certain length of time a trigger is set off and the camera starts to record what happens for a predetermined length of time. In addition some software even offers the option of notifying you of the alarm and in some cases even emailing you the video.
A webcam in fact all cameras including live action take a single picture (frame) at a time. The only difference between a still picture and a live streaming video is the frequency at which the pictures are taken. At 15 fps the image is jerky but it appears moving, 20 more so, 30 fps is considered low end live. To stream live video you will need a high speed internet connection like cable or DSL internet.
Ok, let me break this down as simply as I can – the webcam send an image to the computer which is associated with the webcam software program. The program then converts the image data to a format like jpeg (Joint Photographic Experts Group – so named for the group that developed the compression) then using a web server and FTP (File Transfer Protocol) to send to web (think your chat programs). Using other programs you can even stream the image to your website.
Trivia – Did you know some of the never generations of webcams even incorporate night vision? Example
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.
