In the first part of this series, we covered the differences between fisheye cameras and multi-sensor cameras. In this guide, we’ll go over choosing a fisheye camera to suit your needs. From ensuring great image quality to what to look for to ensure a high-quality camera design, you’ll know everything you need to know about using these innovative imaging solutions to protect your home or property.
The Megapixel Debate
One of the first things to consider will be video quality. When looking for a fisheye lens, it’s important to remember that the megapixel rating on the camera will likely be higher than the megapixels of the video captured. This is because the shape of fisheye lenses creates a round video while camera sensors are square or rectangular. Pixel loss can reach as high as 50%. After dewarping the image, select regions of the field of view might limit megapixels further still.
For this reason, we highly recommend going to at least 5 megapixels. If you’re using it as primary camera source instead of an overview in support of additional cameras, higher megapixels will help to ensure that you can pull identifying information and convictable evidence from all corners of the feed without issues.
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On-camera vs Client-based Dewarping
One of the most important features for any fisheye camera is a good way of dewarping images. This helps to correct perspective and make video from your fisheye camera easier to scan. It will also help to pick out details should you need to create copies of footage after an incident. It does this by using software to account for the circular video as well as rotating portions of the video as needed to maintain proper alignment on your video monitors.
You’ll find two different types of dewarping with most fisheye camera models:
- On-camera Dewarping: These cameras will apply the dewarping before streaming the video to your video management system (VMS) or network video recorder (NVR). Dewarping at the camera often results in the best quality as dewarping is performed before the video is compressed and streamed over the network. However, many on-camera models require you to set your field of view and dewarp regions prior to recording. This limits the flexibility of coverage.
- Client-based Dewarping: Client-based dewarping takes the standard stream from the fisheye camera and does the adjustments to the stream on your VMS or NVR. While this allows greater pan-tilt-zoom flexibility and ensures that your capturing the most amount of data possible, it also comes with increased hardware and storage costs.
As both options are popular, many major camera makers offer models with either functionality to ensure you’ll find the perfect equipment for your needs.
Ensuring Proper Field of View
Fisheye cameras come in two varieties—panomorph and full-frame. While they are interchangeable in some instances, they are not the same.
- Panomorph—or 360-degree—fisheye cameras capture a full 360-degree view and create a circular image with dark corners. These are often best for covering large open areas or obtaining an overview of a region.
- Full-frame fisheye cameras only have a 180-degree field of view. The sensor and lens are adjusted so that the top and bottom regions of the 360-degree view are not captured. This creates a full-frame video—though you might still notice image warping without on-camera or client-based dewarping. These cameras are best suited for hallways, intersections or other areas where you want to capture video on a horizontal plane instead of a vertical one.
In many cases, simply attaching a panomorph camera to a tilting mount and a vertical surface will create much the same effect as a 180-degree camera. However, most 180-degree cameras are not capable of 360-degree video capture.
Beware of Framerates
One last thing to consider is the framerate at which your camera captures video. While you might find cheaper models touting high megapixel capture and advanced features, many of these are doing so at the cost of framerate.
Low framerate cameras product jittery video and might even drop seconds of footage entirely. When it comes to monitoring a situation or obtaining convictable evidence, fluid, complete coverage of an event from start to finish is critical. Having exceptional coverage doesn’t mean anything if the quality of the video is subpar.
Be sure to check that framerates don’t drop below acceptable levels in low-light conditions if you plan to monitor darker areas as well. Cameras that use heavy image processing to improve images might produce great video in optimal lighting but quickly degrade in both detail and smooth movement as lights dim.
In most cases, you’ll want a framerate or frames-per-second (FPS) measurement of at least 15. However, as you near 30, the ability for the camera to capture fluid video and fast movements improves greatly.
In the last section of this fisheye camera guide, we’ll be covering the do’s and don’ts of integrating fisheye cameras into your surveillance system. You should now have a thorough understanding of the advantages of fisheye cameras and what to look for. If you’re ready to start planning your surveillance system, Mammoth Surveillance is available 24/7 to assist! Starting the process only takes a quick phone call!