Demand for higher-resolution images propels the development in technology, and vendors are actively improving lowlight performance. Recent spikes in megapixel camera sales reveal that there is more than meets the eye.
The global market for megapixel cameras was estimated, by IMS Research, to be worth of US$150 million in 2008. "The economy has affected the surveillance industry, and growth is lower than previously forecasted," said Alastair Hayfield, Senior Market Research Analyst, Security and Fire Group, IMS Research. However, the improved resolution from megapixel cameras is one key driver for IP-based solutions, and has helped maintain some of the strong growth seen previously, added Hayfield. "By 2012, approximately 6 percent of surveillance camera shipments will be of megapixel resolution."
"The Americas and EMEA are more aggressive in adoption of megapixel cameras; however, significant growth in the number of projects has been noted in APAC," said Chalon Dilber, Global Business Development Manager, Pelco (a Schneider Electric company). This market breakdown was seconded by Basler, with the Americas and EMEA taking the lion's share at 40 percent each.
Government, education, transportation, commercial and retail are the primary users, and according to Panasonic, railway and education applications enjoy solid growths of about 47 percent and 43 percent from 2010 to 2012. The ability to provide greater details has proven useful in aiding city surveillance and protecting critical infrastructure. "Public venues with heavy traffic flow and high population density show substantial needs," said Yoshikazu Hirano, GM, Head of Security Solutions, Business and Professional Products APAC Company (a division of Sony Electronics APAC).
With limited capital available, businesses are increasingly looking for value-added installations that deliver both ROI and performance, noted Dave Tynan, VP of Global Sales at Avigilon.
Aside from protecting valuable assets, preserving forensic evidence is equally important. Megapixel cameras, traditionally used to detect theft in production and warehouse facilities, have now been applied to identify incidents of sabotage and insurance fraud, in which employees deliberately injure themselves to seek liability compensation, explained James Ionson, CEO of Oncam Global. Megapixel images not only validate the integrity of claims, protect patrons and venue management, but also save investigation time and litigation costs, said Tynan.
"Commercial viability is driving the uptake of megapixel cameras, as one of them can achieve the same coverage of at least three to four standard cameras," said Ralf Hinkel, CEO of Mobotix. "The same trend is now taking place at the low end of the market where budget-conscious buyers are attracted to the value proposition."
Technology
The latest technology development includes onboard intelligence, which involves H.264 compression plus multistreaming capability, motion detection, alarm handling, and storage management. The idea is to allow for a total security solution, where nonstop surveillance, acquisition of multiple targets, automatic tracking, video analytics interrogation and onsite verification are carried out by a single megapixel camera, said Ionson.
Developing end-to-end megapixel and HD surveillance systems, including management software designed for high-resolution surveillance, has gained popularity, added Tynan.
"Despite advancements, the real-world demand for higher resolution seems to 
stop at 5 megapixels," said Paul Bodell, CMO at IQinVision. "There are bandwidth challenges and low-light issues that will still take some time to address."
To stream megapixel images for live monitoring at 25 to 30 fps can hardly be handled by regular networks. The advent of H.264 emerges as the latest rescue; however, "many people specify it without knowing what it is or when it should be used," added Bodell. In the meantime, acquiring sufficient processing power for H.264 and built-in analytics is where the rubber meets the road, making power planning difficult.
"Many manufacturers are still working on an acceptable compromise between high resolution, real-time frame rate and compression algorithms," said Ely Maspero, Director of Marketing and Communication for EMEA, March Networks. Some, like IQinVision, have refined their firmware to improve processing efficiency, while others, like Basler, have taken advantage of the flexible stream functionality where the areas of interest can be transmitted in high resolution. On the other hand, some manufacturers have developed proprietary compression technologies, catering to save as much processing power as possible and allow full megapixel resolution to be streamed at higher frame rates.
Requiring 90 percent less computing power than MPEG-4, Mobotix's compression format maintains image integrity and low CPU overhead. It transmits what has 
moved within the scene in high quality at low bandwidth, allowing users to extract high-resolution, still images for positive identification, explained Hinkel. "The codec enables a standard P4 computer to handle up to 40 streams simultaneously, with viewing and recording at 25 fps." Based on distributed intelligence, users are allowed to access raw megapixel images stored in the camera with no bandwidth consumption when recording.
Furthermore, megapixel cameras with built-in analytics could function as the brain of a security system that identifies an event and instructs high-frame-rate PTZ cameras to zoom in for further interrogation, said Ionson. Megapixel recording could also be set to begin after an alarm has been triggered, saving bandwidth and storage space, said Hirano.
At the moment, installers are relying on mixed solutions of standard cameras and megapixel cameras, said Maspero. "D1-resolution cameras with analytics take on live monitoring and alarm management, and megapixel cameras handle post-event reconstruction."
Low-light Performance
There is an ongoing debate that megapixel cameras generally underperform in challenging lighting conditions. To render a more desirable low-light performance, manufacturers start from the fundamentals. On top of the basic automatic iris 
control and true day/night functionality (with removable IR cut filter), efforts in lens selection, sensor adjustment and DSP development have been made to improve image clarity.
Pelco recommends using megapixel lenses with megapixel cameras, as they play a critical role in transmitting and refracting light. Oncam's lens is tailor-made to allow for the entry of longer-wavelength light, which delivers a fine black/white image during the day and promises quality video at night. Sony has developed an exclusive complementary color filter technology that allows two times more light to be captured in a dim environment.
Most low-light cameras with a fixed focus are optimized for daylight (visible light), so the focus is tailored specifically for shorter light wavelength. When the filter is removed to allow for the entry of near IR light at night, the camera slightly loses focus due to longer wavelength, explained Ionson. Pelco and Panasonic have developed auto-backfocus technology that adjusts the sensor position mechanically to maintain megapixel resolution after the shift of focus.
Arecont Vision goes for the dual-sensor solution, where a 3-megapixel color sensor and a 1.3-megapixel monochrome sensor are used for day and night applications, respectively. Arecont insists on using a 1/2 inch sensor as it gathers twice as much light as a 1/3 inch sensor. To capture more light, Mobotix's solution 
allocates extra exposure to the areas of interest for increased visibility. With onboard software, users are allowed to define the exposure zones in an image to ensure the right amount of exposure to capture the most important details, said Hinkel.
In terms of image processing, Sony's 1.3-megapixel cameras automatically switch to 640x480 VGA mode in low-light conditions. "By combining 4 pixels into 1, the camera is four times more sensitive at a normal shutter speed and delivers focused images without distortion in low-light environments," said Hirano. Another technology, adaptive black stretch developed by Panasonic, analyzes the illumination map and adjusts gamma correction to dark areas, explained Takahiro Ike, Team Leader, Camera Design Team 2, Camera Group, Panasonic System Solutions Company.
There are, still, other options, Avigilon, for example, integrates IR illuminators to its compact megapixel dome camera where the supplementary illumination provides extra light.
To determine low-light performance, there are two more factors to consider: application and rating standard. In low-light gaming rooms, when the priority is to detect criminal activity with high-resolution images, color is not a necessity, said Ionson.
With lux being a common rating standard, Ionson added, one has to take heed of 
whether it has been measured under low visible light or high IR light. "If a 5-megapixel sensor can detect invisible light between 700 and 1,100 nm (near IR), it is not applicable to rate luminosity with lux."
Selection Criteria
With more intelligent features to choose from, differentiating between the needs and the wants is the first, difficult step. High resolution does not guarantee better images, said Hirano, as it is crucial to select appropriate pixels to fit specific applications.
Display panels, storage capacity and network infrastructure are other things to consider. One obvious example is that megapixel images require high-resolution monitors for optimized display, explained Hirano.
With higher-resolution cameras come larger storage and bandwidth requirements. As such, TCO should be taken into account. Combining megapixel cameras with standard cameras to suit various surveillance needs — powerful optical zoom and extreme light sensitivity, for example — creates a cost-effective security system, said Nafis Jasmani, Regional Sales Manager for ASEAN, Axis Communications. Users could also compare the overall cost between centralized and decentralized megapixel cameras systems, said Hinkel.
As real-world installations usually bring up unexpected challenges, Bodell 
recommended asking for references on similar applications. "Users should demand field tests and evaluate technical support."
HD or Megapixel
Another buzzword in the security field right now is HD. When to use HD has become an issue. A different tool from megapixel, HD complies with industry standards to ensure quality color video in 16:9 format at full frame rate, said Jasmani.
Actual applications are a deciding factor. "When it comes to typical video surveillance applications, while frame rate is an important factor; for postevent viewing, quality and integrity of the image are what matters," said Hinkel. The current HD solution provides no higher than 2.1-megapixel resolution.
HD also requires 16:9 displays, and 4:3 cameras will not produce a full-screen image. "While the market is moving toward higher resolution, analog systems with 4:3 footage continue to be mainstream," said Ike. Unlike megapixel cameras demanding dedicated networks for resolution above 1.3 megapixels, regular bandwidth will be sufficient to stream HD video, noted Hirano. In addition, "HD cameras save production cost, as no tailor-made lens is required."
For camera manufacturers, suggested Dilber, "it is crucial to list the horizontal and 
vertical pixels, aspect ratios, frame rates and scan methods before resorting to HD as an all-around marketing tactic."
Challenges and Outlook
Assumptions have been held that with higher-resolution cameras come greater cost. In financially difficult times, people are forced to examine all aspects of an installation. On the other hands, far fewer cameras will be required to cover a greater area, so the overall cost ends up less, explained Tynan.
The rise of higher-resolution cameras means that traditional analog installers and users have to be educated on the value and functions of megapixel solutions. "One major challenge is to assist users to determine where to use megapixel cameras and for what purposes," said Hirano.
As more megapixel cameras are being integrated into surveillance systems, they bring interoperability challenges. "Every technological leap should be combined with continual updates on management platforms, but aggressive marketing has led to some unrealistic performance expectations and poorly designed systems," said Dilber. "Falling short on interoperability results in underperformance of megapixel cameras and missed opportunities to exploit their full potential."
The technology has currently reached its limit in terms of camera and sensor size, noted Ionson. "The typical resolution on the market is 5 megapixels, which is likely the optimal limit for daylight applications." For more pixels, a larger sensor would be required; however, that would take more time to read the information and a need for better compression.
Growth is driven by IP in combination with improvements in compression techniques that make larger numbers of pixels handy, said Hardy Mehl, Director of 
Marketing at Basler Vision Technologies. Advancements in storage technology also make megapixel solutions more affordable, said Bodell.
By integrating storage, alarm management and plug-and-play features, intelligent megapixel cameras present significant opportunities in the home and small business markets, emphasized Hinkel.
The market continues to move toward distributed intelligence, with manufacturers maintaining the current megapixel level and adding more onboard features, said Ionson. "At the high end, the feature set of the camera is not likely to improve much, but costs will come down to increase value."