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Mega Pixel - a technical view
Tue, 06/10/2009 - 1:04pm | Tim Norton
The CCTV industry is pushing Mega Pixel (MP) High Definition (HD) as the big thing in cameras but is it really replacing the analogue camera.
The following takes a technical view at some of the prose and cons based the comparison of a 35X analogue PTZ compared to a fixed position 5MP camera looking across a typical sports stadium.
Effective resolution of digital zoom
My research has highlighted to me that digital zoom of a mega-pixel camera also has the inverse square law applied.
This means that for every 2X zoom, you divide the pixel count by 4. for 3X zoom, by 9. And the killer, an 8X zoom is divided by 64. Therefore if you have a 5MP camera at each zoom step, you will end up with the following effective pixel count.
|
Digital Zoom |
0X |
2X |
4X |
6X |
8X |
|
Pixels H x V |
2592 x 1944 |
1296 x 972 |
648 x 486 |
432 x 324 |
324 x 243 |
|
Relative MP Size |
5MP |
1.2MP |
0.32MP |
0.14MP |
0.08MP |
|
Equivalent lens |
16mm |
32mm |
64mm |
96mm |
128mm |
|
Near 720P HD |
Same as VGA |
Same as CIF |
IP Video for Dummies
Mon, 31/12/2007 - 8:43pm | Visitor
Like it or not, most forms of communication will be transported over the worlds IP networks within 5 years. Cabled networks and remote areas equipped with a “matrix” of wireless networks will enable Internet protocols (IP) to reach the world with radio broadcasts (pod casts), television (video pod casts), telephony (skype springs to mind) and of course security/surveillance video.
Does Size Matter? New 720p HD 25ips 10X PTZ
Fri, 12/03/2010 - 9:35pm | Tim Norton
I recently had the opportunity to preview the 720p HD real time IP-PTZ with 10X zoom and true day/night switching.
First thoughts was that 10X would not be large enough to compare with the 35X SD IP-PTZ that is the industry norm. The reality is that the 10X combined with the HD resolution significantly out performs the 35X SD camera. Additionally the 16:9 aspect ratio gives more useable video, which combined with the progressive scan results in a much better match to viewing on LCD monitors.
CCTV HLI – Is it just a buzz word?
Mon, 05/04/2010 - 5:51am | Tim Norton
The concept of integrating CCTV and access control to provide seamless operation has been thrown around for about 4 years now but has it really achieved what was expected?
The term High Level Integration simply means instead of using a piece of wire from every sensing device to tell us something happened on an external system, we are bringing in a data stream on either a RS232, 485 or Ethernet, which is extremely generic. Many tender documents have a statement like “must communicate with the access control system via a HLI”, which could mean anything complies from one alarm action to reporting on every fine detail.
Time Lapse Recording
The following shows using IndigoVision cameras to take a snapshot of a construction site, which started on the 9 June 2010 and is still in progress.
The first camera is a HD model with a 125 degree lens
The second camera is a SD model with a 70 degree lens
The first camera is a HD model with a 125 degree lens
The second camera is a SD model with a 70 degree lens
Redundancy and Reliability in IP Video Systems
Wed, 28/07/2010 - 2:17pm | Tim Norton
Recently I was invited to present an IP Video solution as an alternative to an analogue matrix in a 24/7 control room. The target client has been using analogue matrix switchers for the past 15 years and had some concerns about the ability of an IP based system to give the same results.
The specific concerns were:
- Reliability
- Latency of PTZ control
- Ability to recover from a major failure
Can You Pick The Better Image?
Defining image quality of a camera was once an easy task. We could state the number of lines resolution and get a fairly consistent result between 2 products.
That all changed when CCTV moved away from analogue and started recording in digital. The resolution of the camera remained consistent but the recorded quality varied depending on how it was compressed and stored on a DVR. Now with IP CCTV becoming the norm, the ability to define what is good and bad has become even harder to measure and state on a written document.
Take for example the following 2 images. Which one is the better quality?
It’s obvious isn't it! The one from Camera 2 is.