The Differences Between MultiSensor and Fisheye Panoramic Cameras
Since video surveillance is a 24/7/365 high-stakes application, it’s important to select the right video camera for each specific viewing location.
It used to be that selecting a video surveillance camera was relegated to choosing a fixed camera or a p/t/z camera based upon its specific placement and coverage requirements.
Today’s vast selection of analog, IP and HD cameras in box, dome and bullet form factors with numerous accessory choices further complicates this process.
The good news is that this allows integrators to specify cameras for specific locations based on predetermined surveillance performance and coverage requirements for each camera location.
Over the last few years, the emergence and popularity of panoramic cameras has continued to rise for mainstream applications as an efficient cost and performance complement, and sometimes alternative, to traditional surveillance camera form factors.
As end user demand for panoramic cameras increases, it is important that integrators know the differences between the two types of devices available — fisheye panoramic cameras and multisensor panoramic cameras.
Fundamentally, fisheye cameras are single-sensor devices, and multisensor panoramic cameras incorporate multiple image sensors in a single housing. Both deliver the unique ability to provide up to 360° wide area coverage with great situational awareness, along with detailed viewing of specific areas within the panoramic coverage area.
Both are dramatically different in terms of performance, capabilities and the applications for which they are best suited.
These distinctly different types of panoramic cameras require different planning and implementation processes to be most effective, often requiring the integrator to adapt a new perspective on how to approach surveillance system design and installation altogether.
First, it’s important to understand core technology behind fisheye and multisensor panoramic cameras. This will help better clarify the most appropriate applications and installation needs for each.
A single-sensor camera employs a fisheye or panomorphic lens to capture a panoramic field of view of up to 360°. They produce circular video images of a scene which inherently appeared warped as a result of the fisheye lens.
This technique allows a single fisheye camera to provide coverage of areas below the camera to above the horizon of their mounting point. For detailed surveillance applications, fisheye cameras require dewarping software to correct the lens image distortion in the video stream to produce useable surveillance images.
Multisensor cameras offer 180°, 270° and 360° fields of view using multiple sensors in a single camera housing. Individual video streams of video from each image sensor are combined and stitched together, creating a single video stream image.
The better the stitching technique – the more seamless the panoramic image will be. They are designed so that each individual sensor can be electronically zoomed in on specific areas of interest within the 360° range. This flexibility allows a single multisensor camera to provide the same detailed coverage as multiple conventional fixed cameras at a fraction of the cost.
Single-sensor, fisheye panoramic cameras are most commonly used in retail, interior office and mixed residential environments. They take up little space, are relatively unobtrusive, offer good wide area coverage to improve overall situational awareness and are highly cost-efficient.
Their drawbacks include adequate but otherwise average performance in low and variable lighting conditions. Since a single image sensor is used to cover an entire scene, the maximum number of pixels on a specific target is greatly limited versus a multisensor panoramic camera.
This makes single-sensor fisheye cameras more suited to internal applications with smaller areas of coverage. They also require dewarping software which needs to be compatible with the video management system (VMS) to produce better images.
Multisensor cameras can typically be configured for three different viewing applications: The 180° viewing to provide surveillance along an expansive horizontal viewing field such as streets, parking lots, piers and platforms when mounted on a flat wall surface.
The 270° panoramic cameras are ideal for situations where it is necessary to see out across the horizon and also below the camera; the perfect application is to corner-mount a 270° panoramic camera on the corner of a building with one sensor pointed down at the entrance, and three other sensors providing a sweeping view of the surrounding streets and intersection.
The 360° panoramic cameras provide a comprehensive panoramic view ideal for pole mounts in parking lots, seaports, airports, railway yards, street intersections, anywhere there are wide open spaces that demand high quality surveillance.
Multisensor cameras also offer advanced electronic pan, tilt and zoom functionality that allows operators to view specific areas of interest in great detail while still viewing and recording the complete panoramic scene.
In addition to providing improved overall situational awareness panoramic cameras in general offer a multitude of advantages:
- Lower Cost – Fewer cameras are needed per site for equivalent coverage compared to conventional fixed cameras, lowering product acquisition, installation and maintenance costs.
- Integration – Using a single VMS license, the data captured from these wide area imaging solutions can be integrated with access control, building management, fire control and intruder detection systems which elevates overall security.
- Intelligence – Multi-sensor cameras are designed with a wide range of feature-rich analytics including, but not limited to, abandoned object detection, adaptive motion detection, camera sabotage, directional motion, loitering detection, object counting, removed object detection and stopped vehicle detection – all of which improve overall security by alerting system operators to abnormal activity that requires further investigation.
- Detection/Recording – Using the camera’s analytic capabilities across wide panoramic viewing areas alerts to site incidents in real time. In effect, this reduces operator fatigue by allowing them to view those areas of interest that demand their attention, as opposed to monitoring dozens or more cameras to detect incidents. Once alerted, operators can digitally zoom in to specific regions of interest within the larger overall view for a more immediate and appropriate response and recorded incidents can be easily located and reviewed.
Video surveillance is a 24/7/365 high stakes application, and selecting the right video camera for each specific viewing location can mean the difference between the success and failure of a system.
Knowing and understanding how panoramic cameras contribute to overall surveillance system operations can create higher levels of situational awareness and ultimately a safer and more secure environment.
Kevin Saldanha is Director, Product Management at Pelco by Schneider Electric.
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