PTZs vs 360 / PanoramicsBy John Honovich, Published on Oct 28, 2012
One of the toughest but most important emerging choices is when to use PTZs vs panoramic cameras. It pits one of the most overhyped technologies of the past decade (PTZs) versus one of the most overhyped ones of this decade (panoramics), yet both have significant value as an alternative to fixed cameras.
Covering Larger Areas
Covering large areas with fixed cameras is problematic. Instead of using huge numbers of them, many users turn to PTZs so they can pan, tilt and zoom across such areas. But, clearly, this is not without downsides and misapplication. In the past few years, a new rival solution, panoramics, has emerged for covering them. Instead of mechanical control, these cameras, using multi-megapixel, capture and record a 'panoramic' view at all times. While some vendors hope for the 'death of PTZs', panoramics have many of their own issues.
Contrasting the Options
While PTZ use will decline at the expense of panoramics, both PTZs and panoramics will play an important role in the future of surveillance. Panoramics can help in areas where PTZs have historically been overspecified. However, users need to be careful to not overspecify panoramics which can create problems of their own.
Inside the PRO Member's section, we review the following critical issues:
- Viewing Range / Image Detail
- Recording Range
- Storage and Product Costs
- 180 vs 360 Panoramics (Fisheye vs Panoramic)
- Panoramic Maturity Issues
Finally, we conclude with a dozen real world use cases showing how PTZs and panoramics are best used in operation.
Viewing Range / Image Detail
The biggest downside of using panoramics instead of PTZs is the low level of image detail they deliver in any given direction. While panoramics routinely use 3MP, 5MP or even more, the resolution is typically spread out over 360 degrees. Compared to a traditional fixed camera with a 50 or 60 degree FoV, a 360 camera is covering 8x or more area. While the coverage area of a panoramic may be far greater, the image detail in any given direction is far worse. Think of it like having 8 CIF cameras mounted in a cluster.
This integrator quote nicely sums up the practical problem:
"In terms of Panoramics, the key is setting the expectation. I would say without exception that every client I have ever shown their new live panoramic video stream to is initially ecstatic; they can see the entire area and get 'cool' virtual views. However, they have the 'Oh Sh!*' moment when they try to zoom in and see the lack of detail"
Let's look at a practical example of a PTZ vs a 180 degree panoramic. The first image below is of both cameras in a wide FoV.
Now, a key value of a PTZ is zooming to see small details far away. Let's compare the optical zoom of a PTZ vs the digital zoom of a panoramic (remembering that panoramics do not support optical zoom).
The PTZ delivers dramatically greater detail than the panoramic. It is no contest. This is despite comparing it to the highest resolution, limited FoV panoramic on the market (20MP / 180). Indeed, if a 5MP fisheye was compared to a PTZ, the panoramic would compare even worse.
Panoramics are nowhere close to to the viewing range of PTZs and this is not a gap that will close anytime soon.
Live Monitoring vs Investigations
However, the major constraint on PTZ performance is that to get such high quality details requires the camera being controlled/moved to very specific points. To do this regularly and accurately requires a human being using the PTZ live. Without a live operator, the value of a PTZ drops significantly. While many larger facilities do staff live operators, this is certainly a minority of professional systems.
A tougher gray area is when a PTZ is controlled periodically or infrequently. If this use is valuable enough to the business it may justify the selection of a PTZ. However, often it goes to waste as PTZs are left on pre-programmed tours. As one integrator noted,
"Everyone always states, in the end, that the guard tours are ineffective. They are always in the wrong place at the wrong time. The cameras are are pointing in the direction that is desired. We may be spending a little more money, but I strongly feel that fixed cameras (within schools) are the way to go."
If the primary use of a system is investigations, panoramic may provide better overall coverage than a PTZ over a large area, as one end user explained:
"Since our installations so far have been intended to support after-the-fact investigation about what occurred at the locations that the client deemed to be most critical, the consistent complete record with less detail has still been the preference because someone could figure out what actually happened as the fundamental first step toward taking other appropriate actions."
This leads to the most clear cut benefit of panoramics over PTZs - Panoramics record the entire area at all times while PTZs only record whatever specific spot they are looking at. Regardless of how detailed the image captured in a given spot, 99.9% of the area lacks any recording. With panoramics, while the image detail may be low, at the very least, an overview of the entire scene is available always.
Costs (Product and Storage)
Overall, product and storage costs between the two cancel each other out and should not be a major factor in the decision of one versus the other.
- On the product side, panoramics are certainly less expensive. The purchase cost is routinely hundreds or even one to two thousands USD less than PTZs. Plus, since panoramics are mechanically simpler, their maintenance costs should be lower.
- On the storage and bandwidth side, PTZs are likely less expensive (assuming equal frame rate). This is because panoramics typically require higher resolution to cover large FoVs constantly. Doing so could increase storage costs by hundreds or even a thousand USD per camera.
The biggest cost is operators. While panoramics do not eliminate the need for operators, if operators are not available, panoramics are a useful means to cover wide areas for later review.
180 vs 360 Panoramics (Fisheye vs Multi-Imagers)
Within panoramics, two major groups exist: those using fisheye lenses and those combining multiple imagers in a single housing, pictured below:
Multi-imager panoramics are overall better except for price (higher) and product availability (lower). They can deliver much higher resolutions, over much more focused areas and better overcome WDR problems. The most important practical use is 180 degree cameras which work well mounted to a wall to monitor a large interior area or parking lots.
By contrast, fisheye imagers are better for 360 degree overviews of an area from a central point. Do not expect even moderate amounts of details compared to fixed cameras in traditional setups.
Panoramic Maturity Issues and Limitations
Even if you like the concept of panoramic cameras, you must factor in certain issues and limitations of them:
- VMS Support: The first step is to check what panoramic cameras your VMS supports and how deeply they are integrated. Most VMS system only support a few panoramic cameras fully.
- Mounting Height: If the panoramic camera need to be mounted far away from the subjects, image quality will suffer as these cameras are fixed focal length and cannot be 'zoomed' out. You may need to mount them with a pendant mount to get the cameras closer to the subject.
- Limited Frame Rate: Since panoramics are usually multi-megapixel cameras, the frame rate is routinely 10fps or lower. Make sure to check this and any impact it might have.
- Low Light Issues: Panoramics typically have high f numbers, high resolution and lack mechanical cut filters. All of these combine for fairly poor low light performance (e.g., the 20MP Arecont, featured above, was terrible in low light). If you have a moderately dark scene or worse, make sure to test panoramic performance before deploying.
- Not All Camera Manufacturers Make Panoramics: While many camera manufacturers offer panoramics, the overall product availability and model options remain far lower than what is available for PTZs.
See our panoramic camera criteria / selection guide for more details.
Panoramic Real World Uses
Successes of panoramics most frequently come in smaller to mid sized indoor areas:
Art Museum: "One Panoramic 360 located in the centre of each room provided coverage of the entire room
Panoramic 360’s were far more discreet than having multiple fixed cameras that would be required to provide the same coverage. Each room was small enough for a Panoramic 360 to provide sufficient level of detail"
- Low Heights: "I typically see panoramic fisheye cameras in very low height mounts. Convenient stores, liquor stores needing a short but wide panoramic field of view."
- Basketball court: "A good example is a new middle school I recently bid, I chose to use the panamorphic lens on a basketball court installed in the center hung scoreboard. I've done this before and will do it again, it works well. However, this application doesn't work on the football stadium or the soccer fields. In this case, I specified multiple fixed, but in the future I will use multimagers."
- Apartment Building Inside: "I recently did a Housing Authority job in which they wanted to view both the elevators and laundry room equipment in one view (x20 floors elevator corridor area). The idea was to save money and not buy 2 cameras (2 cams x 20 floors = 40cams) for this very wide view (approx 160 degrees only 10ft away). The GHA ended up being happy with the Panoramic solution as they got to see what they wanted and cut costs by 20 cameras at $650 each + labor. A PTZ was not the solution as nothing is attended and the cost too great."
- Covered Parking Lot: "Fisheye panoramics to cover the floors on a multi-storey car park and to cover service yard areas. In both cases this was to pick up incidents which might happen anywhere. Typically the incidents were minor collisions. The problem was that the PTZs were never covering the correct area at the time and it was too expensive to provide full area coverage with fixed cameras. The panoramics meant that we knew we would have the incident recorded, even though the image detail would be poor. The incident image would be sufficient to go back to the entrance cameras and identify the vehicle(s) involved. This worked OK."
- Classroom: "Customer loved it. It was designed to monitor a proctored testing environment with cubicles. When the proctor left the room, it was easy to see when someone looked around the wall or 'groundhogged' their head up over the cubes....which immediately earned them a zero."
- Warehouse Internal: "Warehouse with good lighting; they had several megapixel cameras initially implemented and could monitor their chokepoints and assets effectively; however they subsequently made a request for an "overall" view of areas so they could easily track movement of materials, forklifts, etc from an overhead view. The fisheye view was great for them, it was demoed and accepted (they understood the lack of detail) and several cameras were then implemented to give a "master" view where warehouse managers could see the movement in the area and investigate with individual cameras after examining overhead footage"
PTZs Use Cases
PTZs find their most support in larger outdoor areas of bigger systems:
- Highways: "There has been some play with panoramics, but for the most part they have fallen flat on highways. PTZ's are vital to this industry for a few reasons....one, being able to zoom far lengths (1 - 2 miles) without the image digitizing. Two, the ability to pan and tilt multiple cameras to face one incident and get different views of the incident."
- City Monitoring: "We have the experience of using PTZ cameras for metropolitan monitoring, where there are one or more control rooms with pepople dedicated specially to control and view PTZ cameras 24 hours a day. However, these PTZ cameras regularly are complemented with several fixed cameras that always will be recording video on main point of interest. In this case Panoramic cameras are no the best option, because of light, quality and distance conditions that could be captured with this kind of camera."
Additionally, casinos and big box retailers remain major users of PTZ cameras. While those are indoor areas, they are also high loss use cases that are well staffed with security monitors tracking suspects in real time.
Beyond that, a number of advanced use cases deliver value:
- Monitoring + LPC Capture: "The PTZ can be used for normal surveillance, then when (for example) a vehicle approaches a gate, the perimeter sensor could trigger a preset on the PTZ to zoom in for LPR and run it through our program. Panoramics so far can't do what we need."
- Monitoring + Door Entrance: "One of the coolest deployments I've seen of a PTZ with no live observer, was a large lobby with two entrances and two PTZ cameras. The cameras were set to a continuous auto-pan, and each was paired with a door sensor. When the door contact tripped, the camera paired to it would jump to a preset that was zoomed in to get a close shot of the face of the person walking in the door; then after the door closed returned to the auto-pan."
- Autotracking: "Autotracking (mainly of vehicles of people) is another key reason for PTZ specifications in tenders."
Mixing PTZs and Panoramics
An end user of a large convention center summed up a good rationale for using both in certain areas: "We have quite a few of fixed cameras and a few PTZ's but unfortunately no Panoramics currently. Seems to me they will be for more useful in our lobbies and in the meeting room area's. PTZ's will still serve their function for parking lots as well as in parts of the exhibit halls."
PTZs and panoramics will live side by side for many years to come. Think carefully about the pros and cons of both for deciding on what to use.