Do Monitors Waste Higher Resolution Surveillance Cameras?By: John Honovich, Published on Jun 18, 2011
One fear we commonly hear about using higher resolution cameras is that capturing more pixels than can be displayed live on the monitor is a waste. For instance, if you have a 1920 x 1080 camera but display it on a 1280 x 720 monitor, the greater resolution of the camera will be essentially 'thrown away' displaying only the maximum resolution of the monitor. The same situation (or worse) goes for higher resolution cameras - 3MP, 5MP, 10MP, etc.
This is quite misleading and ignores the most powerful practical value of higher resolution cameras.
On the negative side, critics are correct in noting that a monitor's resolution will restrict what can be seen live at any given moment. For instance, if you were watching a Blu Ray disk on a 1970s TV, you would not get anywhere close to the resolution / quality of the Blu Ray regardless of its native quality. To the extent that you use surveillance video like watching movies, this criticism is valid.
On the other hand, real world surveillance use makes use of two techniques that allows for higher resolution cameras to provide value on lower resolution monitors:
- Live Digital Zoom: An operator can digitally zoom the live video feed of a camera to focus on a specific area. This will increase the displayed details on the monitor for a certain area of interest. This is a quite common, but not ubiquituous, feature in today's Video Management Software. This functions in a similar manner to optical zoom in traditional PTZs. Instead of adjusting the focal length of the camera lens, digital zoom instructs the computer to display more pixels in a certain region of the image. The operator can now see more, take advantage of the higher resolution of the camera and overcome the limitations of the monitor.
- Investigations: In practice, investigations is the most common way that surveillance users benefit from having cameras with higher resolution than monitors. As the investigator reviews video, regardless of how low the monitor's resolution is, they can simply digitally zoom in and important details with be 'revealed'. With megapixel cameras, you often cannot see the details of a person's face or the characters of a license plate when the camera's feed is displayed full screen. However, a simple digital zoom often overcomes this.
Gigapixel cameras (with ~1000 times greater resolution than HD surveillance camera) shows why cameras can have higher resolution than monitors. The most famous example is the US 2009 Presidential Inaguaration gigapixel capture. No monitor can display this at full resolution but that is irrelevant because you can simply digitally zoom into any area of interest - just like you can with a megapixel surveillance camera.
Digital zoom is key to making higher resolution cameras work. In traditional video surveillance, monitor resolution and camera resolution were low and about the same. Today, surveillance users can and should make use of digital zoom. By doing so, they will get the most out of even very high resolution cameras on any monitor.
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