Security cameras are an important tool for securing premises and sensitive assets. The level of effectiveness provided by security cameras is closely proportional to their proper installation. The field of view of a security camera is one consideration when installing one (FOV).
FOV has a vertical component (Vertical Field of View) and a horizontal component (Horizontal Field of View). In layman’s terms, this refers to the image displayed by the camera in either live or recorded mode.
Here are a few suggestions to help guarantee your camera’s field of view is successful.
Take into account all of the relevant variables.
One of the first things to understand is that field of view is not an independent factor. Camera setup can be an expensive process, and it becomes even more costly when done incorrectly.
Pole location, detecting scene, blind zones, and FOV are all dependent elements to consider. Changing one has an effect on the others.
Because of the variable focus lens, emphasis on that aspect has often been disregarded, with the assumption that camera misalignments or scene difficulties can be fixed by subsequent adjustment of the adjustable focus feature of the lens. This is a blunder and a potentially costly bet.
You should approach your design with each component in mind, including a fixed FOV and how it’s affected by the other setup variables.
You should approach your design with each aspect in mind, including a fixed FOV and its reliance the other set-up factors.
Brush up on your geometry, then research and involve a FOV calculator as well as a solid camera setup tool.
Check your detection scenes, extend your camera footage for blind zones, and establish your FOV parameters so you have some flexibility after the equipment is deployed.
There will be flaws in pole positioning and unforeseeable scene concerns, but a multifocal lens modification will not be sufficient to compensate.
Ignore the Rule of Thirds.
We all remember the rule of thirds from high school photography class: The floor and object should take up two-thirds of the scene, while the sky should take up one-third.
We never manage to get a perfect shot while photographing aunt Eunice or shooting vacation shots in Hawaii, but it’s remarkable how often we get it right when installing security cameras.
Although the “rule of thirds” is appealing to the sight, it is rarely considered in the security field.
Viewing the sky has almost no use in security applications. There are, however, numerous reasons why you can not gaze towards the sky. These include things like glare and blinding the camera at sunrise and dusk. Another thing to consider is that you are virtually burning 33% of your video storage space and network bandwidth.
The only need to having sky in your FOV is to provide a point of comparison and to ensure you have just enough space for any vertical calibration zones.
As a general guideline, 10% of the scenery is more than adequate to provide context. When considering vertical imaging scenes, such as ensuring you can monitor for intruders that come over a fence, a view of the sky is much less relevant.
Consider Nighttime Scenarios
Worksite inspections are a crucial aspect of the security design process. Good contractors and experienced property owners make these available to possible security vendors so that all of the site’s unique qualities are understood during the early planning stages of a security design.
I’m certain you or your firm have actually participated in several of these, but I’m interested in how many of us have gone on a nocturnal site walk? Most people believe that these are unneeded because a security design would usually incorporate some form of priority for poor light viewing: infrared illuminators, thermal cameras, and so on.
When determining a field of view, several current light sources must be considered: existing facility lights, intermittent headlights, lights from neighbouring facilities, sunrise/sunset, reflected light (water/windows), and so on.
Light sources may wreak havoc on cameras in a number of ways, so it’s critical to be aware of their location and, if feasible, arrange your FOV around them.
However, if you do not intend to remain up for the night duty, you will not have the chance to explore where such illumination concerns may exist.
Align the coverage of the camera and the infrared lighting.
It may seem strange to consider anything other than the camera while setting up a range of view of the camera, but one big mistake in setting up the field field of view of the camera is not factoring the field of view of the light source.
Whether employing infrared illumination or even white light illumination, the most significant feature for nighttime monitoring is not the FOV of the camera, but instead the FOV of the Infrared illuminator or visible light source.
If you’ve ever looked at a camera at nighttime with no or little illumination, you’ll understand why it’s vital; otherwise, you’ll get a dark camera feed.
If you want your late-night FOV to match your daylight FOV, make sure your illuminator beam has the same distance and width as your camera FOV. Some illuminators allow you to alter the beam so that it is thin and lengthy, or broad and brief. Others have a predetermined light pattern.
In virtually all circumstances, the illuminator’s capability will be far shorter than the camera’s, which will impact the overall perimeter design. As a result, failing to consider your illuminant’s field of view throughout the planning stages might be costly, creating gaps in nighttime coverage.
Understand Pixel-Dilution Before Extending Your View
Pixel-Dilution refers to the concept that the more detail that is attempted to be represented by a single pixel, the more diluted that feedback becomes. This problem usually occurs while setting up the parameters and adjusting the camera’s field of vision to be as wide as the lens allows.
Because the information is readily available, why not broaden the focus to capture it? The short answer is…it depends.
The key concept to grasp would be that a camera is designed to provide you with a specific amount of pixels, which is essentially video feedback. Adjusting the lens or magnification level of a lens results in a different FOV but no more pixels.
The pixels do not change. Increasing the size of the scene essentially erodes the video frames of any given pixel.
“Consider the number of pixels you want from a particular camera as an elastic cargo net,” A pixel is represented by each square in the net. By enlarging the camera’s field of view, you effectively lengthen the net.
You’ve broadened the pixels, but keep in mind that a pixel is only a single value, therefore you’ve now extended that single value across more of your picture.” In practice, this means that you will have less data on a specific item at a fixed distance.
A narrow FOV, for example, may give sufficient image data to allow you to read a person’s face. At 100m, a person’s baseball cap can be read, yet a wide FOV of the same person may not have enough data in the diluted pixels to tell if the individual is even wearing a hat.
As a result, it is a planning decision to choose if it is better to accommodate a larger region at the expense of more detailed video information or to limit the extent of the FOV and get that detailed coverage. The error is in failing to recognize the compromise being made.
Restrict the View to the Subject of Interest
We all like to be amused, but it isn’t always the ideal strategy when it comes to determining the FOV of a surveillance camera.
A common blunder is including “interesting places” in the FOV in contrast to “areas of interest”
Consider the following scenario: a high-traffic sidewalk runs alongside a facility’s outer fence. The camera’s field of view is frequently adjusted to include this high-traffic area.
Unfortunately, if the area of focus is not the sidewalk itself, but rather the space between the sidewalk and the fence, the question is why the sidewalk should be included in the camera’s field of view. Every event on the sidewalk is now the watching guard’s or security software’s job to identify and assess as a potential threat.
The same can be true of roads or bodies of water in the background. If the location is not of interest in terms of security, then caution should be exercised.
The choice of the camera’s field of view is frequently overlooked. The idea appears simple at first, but when you examine its link to other components of the perimeter layout, security objectives, and even the camera on its own, it rapidly becomes clear that it is a critical aspect of the whole design.
Fortunately, the adequate field of view and a good video surveillance system may be ensured with early planning and thorough consideration of the criteria, such as those described in this article.