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Do your monitors have too many camera views to do the job?

Since I have started working with CCTV, I have seen a long history of putting as many camera views onto a single monitor as possible. This seemed to be a way of showing technical expertise as early as the 1990s and I remember a number of trade shows where it seemed that CCTV providers had a competition to create as many multiplexed camera views on one monitor as possible. As we have seen the greater emergence and use of large flat screens in control rooms (40-inch and up), the use of these screens to show multiple camera views makes more sense, provided that the resolution is up to it. However, I still commonly see up to 24 camera views on a 19-inch monitor in front of operators.

I have come up with a set of reasons for putting multiple camera views (eight and up) onto anything smaller than a 20-inch monitor. You can decide how relevant they are.

1. Camera selection.

2. Detection of movement or presence.

3. ID camera shots.

4. Trying to squash as many pictures onto one screen to look effective.

Cameras displayed on screen do make it easier to choose a relevant camera without thinking of the number. This is to some extent a lazy route though, as operators should have an effective camera selection interface, or know a camera well enough to go to relevant areas. If the number of cameras greatly outweighs the available viewing options on the monitor, you are back to the same problem. One other option is to have a macro that allows you to place all cameras in a particular area on a monitor if you need to select cameras in that area – this is quicker and more efficient when tracking or following someone.

Recommended views

As camera views get smaller and smaller as multiple cameras are placed on screen, it becomes impossible to get any appreciable understanding of behaviour, or even descriptions of people. In some cases where there is no movement detection analytics, even relatively small camera views can show movement or presence of people, which may cue operators into a more detailed look. This is provided that the monitor is in line of sight, as camera views of a few centimetres displayed together on screen makes it is very easy to overlook real issues.

Where identification or recognition of people’s faces is important, having multiple camera views showing face and shoulders is feasible. I have not seen many applications where this is valid though. This then brings us to the last point. Where camera views are jammed onto a small monitor it is usually a poorly thought out approach to trying to look as though lots of work is being done.

If fact, it is one of the most limiting factors in CCTV. Many people are familiar with the traditional UK Home Office recommended views of Monitoring, Detection, Recognition, Identification, and more recently, Observation (25% view of groups of people). Yet these are some of the most misunderstood concepts around – for example putting a 50% recognition camera view on a 19-inch monitor with another 23 camera views displayed on it is totally out of line with the original UK Home Office concept. It probably equates to less than the 5% monitoring view in actual practice, which is totally ineffective for recognition.

What monitor to choose

Use of large flat screen monitors does open up a number of options if you have a scenario where you need to place multiple camera views on a single monitor. However, there are still limitations to this, and where a smaller monitor is used, I have got a few sample questions to see if it is fulfilling your needs.

1. If you need an ID shot of a person, or even recognition, can you do it with your current monitor displaying multiple camera views?

2. If you need to pick up the incident before it happens or while happening, can you view if the relevant behaviour is clearly visible on screen?

3. If you need to track a person or persons across a large area, can you do this with your existing views? One advantage of tracking is that you can use a number of elements such as style of walk, shape, posture, hairstyle etc., so size is not always as critical.

4. If you need to associate a suspect with something – an object, car, another person, can you actually clearly see there is an association?

5. If you need to scan an area quickly, can you pick up presence or movement in an area?

6. If you need to audit a process or procedure, can you see all the relevant actions associated with this?

7. If you need to establish a context within the affected area – e.g. how people are positioned, dressed, relating to others, is this possible with the size of camera view displayed?

If you want to do any of these things, and your monitor does not display the camera views to allow you to do it because overcrowding the display with small camera views, then there is a problem. You need to rethink why you have the display unless it is purely for camera selection or movement detection purposes.

Dr Craig Donald is a human factors specialist in security and CCTV. He is a director of Leaderware which provides instruments for the selection of CCTV operators, X-ray screeners and other security personnel in major operations around the world. He also runs CCTV Surveillance Skills and Body Language, and Advanced Surveillance Body Language courses for CCTV operators, supervisors and managers internationally, and consults on CCTV management. He can be contacted on +27 (0)11 787 7811 or [email protected]

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