Fredrik Nilsson is the general manager for Axis Communications in North America.
The three common operational requirements – detection, recognition and identification – each have a...
The three common operational requirements – detection, recognition and identification – each have a corresponding pixel requirement that refers to the minimum pixel density of an object or person.
What makes a surveillance system successful? You can talk about return on investment or crime reduction statistics, but really, the true success factor is the delivery of imagery that is actionable. Simply put, surveillance video is only valuable if it can actually be used.
Before designing or installing a video surveillance system, it is important to determine what the customer’s needs and expectations are, so in turn the proper cameras are selected. Typically this goal-setting question is answered by one or more of the following operational requirements: detection, recognition and identification.
Being an integrator in the security market is not easy; just think about the hundreds of booths at ISC West all showing the “best” video surveillance solution. Or think of all the hype about the latest and greatest high resolution technology. With the sheer volume of products available, selecting the right camera can be like finding a needle in a haystack. Determining the operational requirements of the solution will help narrow down the haystack so you can find the needle—or in this case, the ideal video surveillance solution—for your customer.
What does your customer really need?
First you must know your customer and what they are trying to accomplish. Does the customer want to identify the person entering a restricted area or simply know an intrusion occurred? The number of “pixels on target” needed to satisfy the operational requirement can be used to shrink the haystack when selecting products.
The three common operational requirements – detection, recognition and identification – each have a corresponding pixel requirement that refers to the minimum pixel density of an object or person. Though there is no industry standard for pixel density requirements, there are references and guidelines from various organizations, including the Swedish National Laboratory of Forensic Science (SKL) reference used for this article.
As you would expect, the most demanding requirement is identification with 12.5 pixels needed per inch or 80 pixels across a person’s face, while detection and recognition come in at 0.5 px/in and 2.5 px/in, respectively. If you install more cameras, you will better meet the pixel density requirements and provide more coverage, right? Often with the proper combination of camera selection, lens pairing and installation location, you can actually cover more with less.
In fact, in most cases a standard definition camera paired with the appropriate lens and camera placement will meet customer requirements. However, standard resolution cameras require either a sacrifice in detail by setting a wide field of view or situational awareness by narrowing it. To deliver both, security practitioners can deploy higher resolution cameras.
The evolution of resolution
This raises the question: HDTV or megapixel? First, it’s important to understand the difference between these two technologies and how each came to be prominent in the security industry.
In the early- to mid-2000s, rapid development in resolution saturated the point-and-shoot digital camera market with inexpensive megapixel models. The most popular camera sellers went from 1MP to 8MP and even up to 12 MP. More was better and further growth was only limited by the lens.
Then something interesting happened: the original iPhone launched in 2007 with a 2MP camera, and the trend of “more megapixels” reversed. Sales were instead dominated by the 2 to 5MP camera phone.
Meanwhile, HDTV came in to the picture with the broadcast of professional sports games about the same time. Within a few short years, it was clear that analog was dead and 720p/1080p HDTV were the preferred new formats among consumers.
With HDTV in their homes and megapixel on their phones, security personnel wondered why they couldn’t have the same superior viewing experience and performance from their surveillance systems. As most people became caught up in the megapixel war of more is better, the HDTV standard gave people a real world point of reference for image quality. Manufacturers were already investing R&D in just that, and in January 2009, the security market launched the first HDTV-compliant surveillance camera, forever changing the industry’s outlook on surveillance.
HDTV vs. megapixel
HDTV is a standards-based format governed by the Society of Motion Picture and Television Engineers (SMPTE), which includes:
- Resolution (720p or 1080p)
- 30 frames per second
- Aspect ratio of 16:9
- Broader palette to render higher color fidelity
Megapixel has its roots in point-and-shoot photography, meaning a megapixel camera refers to the number of pixels produced by the image. In comparison, HDTV provides a better overall video viewing experience. This is why your smartphone takes 8MP snapshots, but records in 720p or 1080p HDTV when you to switch to video recording.
Does HDTV herald the death of the megapixel then? In short, the answer is no. Like any technology, each has its advantages—and it is up to you as the integrator to determine which factors are most important to a customer.
Let’s start with frame rate, which in practical terms relates to situational awareness. At lower frame rates, the video may look choppy, making it difficult to interpret what actually happened in the scene. This can have profound implications in mission-critical surveillance where situational awareness makes a big difference. In casinos, for example, slight-of-hand movements can result in the loss of large sums of money. The HDTV standard of 30 frames per second may be the best fit for an installation requiring situational awareness.
Not all scenes require 30 frames per second though. If high pixel detail is the customer’s priority, then a megapixel camera will meet these needs. For instance, if your customer wants to monitor a well-lit parking lot with slow moving cars, delivering a high level of detail even at a lower frame rate will meet the customer’s needs and deliver a successful solution.
When designing any video surveillance system, storage is an important factor. The frame rate of megapixel video is often dialed back to save on bandwidth and storage. However, if bandwidth and storage are not limiting factors, then megapixel cameras can also record at higher frame rates. Savvy integrators recognize the give and take of frame rate and bandwidth consumption and should be mindful of which factor is of more concern to the customer.
For surveillance of hallways, warehouses and aisle and high-racking shelf environments, HDTV may have the edge. The HDTV standard specifies a widescreen aspect ratio 16:9, which can be turned on its side, known as corridor format, to deliver a 9:16 image. Turning the aspect ratio on its side can provide better coverage of these narrow environments without wasting pixels on the sides. Integrators can set themselves apart from the competition by offering recommendations that are commonly overlooked, such as corridor format, for improved viewing capabilities.
When color rendition is a driving surveillance need, the HDTV standard for high color fidelity can improve image usability. If you compare color images from different manufacturers with similar resolutions, you will often see that color rendition is vastly different. How useable is an image if a black car is rendered as purple or a red coat looks orange?
Today, the majority of high resolution IP surveillance cameras sold in North America are compliant to 720p. Despite the initial race to own the cameras with the most megapixels, savvy security practitioners have learned that more pixels doesn’t always mean better when it comes to usable video.
Where do we grow from here?
While HDTV is the clear choice in the consumer market, the security industry has been slower to adopt. Market research estimates that 35 percent of the surveillance cameras sold in 2012 were IP cameras, and of those IP cameras sold, about half were of higher resolution including HDTV and megapixel. However, industry experts anticipate the adoption of HDTV and megapixel will accelerate in the coming year.
As these technologies continue to be improved and refined, both HDTV and megapixel will continue to meet different and new surveillance challenges. As the haystack of surveillance products grows, it will become even more important for integrators to understand the nuances of new technologies to meet the customer’s specific needs. After all, the goal of a video surveillance system is to produce useable video, and usable video is in the eye of the beholder.
In recent years, camera manufacturers have invested heavily in R&D to widen the array of camera choices available to meet these ever-changing security needs. As the megapixel race warmed up, there was also a considerable push to provide HDTV cameras in all shapes, sizes and price points. Today, security practitioners can choose from fixed, dome, pan/tilt/zoom and even miniature covert all-digital HDTV cameras. We’ve also seen the price of HDTV-compliant cameras come down. The first cameras listed for $1499 MSRP. Today they can be bought for less than $250.
Challenging environmental factors limited video surveillance for years. Lighting conditions are a prime example of an environmental factor that can place restrictions on the operational requirements of a scene. Megapixel cameras perform in well-lit environments, but adding supplemental light to a scene is not always an option, making identification all but impossible at night– and the more pixels on a sensor, the more light that’s needed to activate them.
The market’s first HDTV-compliant cameras were a major feat in itself, but were pretty simple. Each year HDTV cameras feature increased functionality, including a number of image-enhancing features that combat challenging environmental factors such as lowlight.
For instance, utilities substations require surveillance particularly at night when they are most vulnerable to copper theft and potential safety incidents. However, if the substation is located in a residential area, increased illumination is seen more as an annoyance than a security measure. Low light technologies help keep the neighbors happy, while still providing the customer with the surveillance they need. Lightfinder technology even provides color video down to 0.05 lux.
Another challenge has been the surveillance of loading bays, entrances and exits and areas near large windows. Now, cameras equipped with wide dynamic range (WDR) can combat these changing light conditions and provide usable video.
For some customers, it may be less about camera functionality and more about aesthetics. If limiting the number of cameras is a priority, then megapixel cameras may provide the best solution.
Great strides have also been made in providing solutions for all sizes, including small systems. For years, small businesses were limited to analog technology and were saddled with expensive and cumbersome DVR solutions. With small system solutions and hosted video, IP systems have not only become more affordable, but also exceed the capabilities of traditional analog solutions.
A solution for every need
Providing the right solution starts with understanding your customer’s security needs. Knowing and understanding the importance of resolution, pixels on target and the difference between HDTV and megapixel will help you deliver a successful video surveillance system and distinguish you from the competition.
Standard resolution, megapixel and HDTV cameras each meet different requirements for security installations. Knowing when and how each technology is used will help ensure the selected cameras will provide the most usable images—regardless of any hype.
Finding the ideal surveillance solution may be like finding a needle in the haystack, but the advantage to having so many options is the ability to truly provide the “best” surveillance solution. Despite the common belief that more is always better, savvy integrators know when more is better and when less is more.