If you were to ask the security dealers, systems integrators or even end-users of video surveillance to identify the variables that most significantly impact the ability of HD and megapixel IP cameras to deliver high-quality images, there is a good chance that lighting would be near the top of the list. Traditionally, this has been an area where these cameras have faced challenges — chiefly due to the laws of physics.
Each pixel that makes up an image captures the available light in its specific area of the scene. The combination of light captured by all pixels determines the quality of the video in any given lighting situation. With insufficient or no light, the result is low-quality video — if images can be captured at all.
While the perception that IP cameras underperform in challenging lighting may continue to exist, the reality is that IP camera manufacturers have long recognized these potential hurdles and have worked hard to deliver products that offer ever-improving low-light performance using a number of new or improving technologies. As with many of today’s more complex imaging problems, lighting challenges are most typically addressed using software-based technologies designed to either maximize available light or generate light to allow cameras to capture higher-quality video images in low-light situations.
For the most part, low-light conditions can be resolved by using a number of these technologies, including cameras with advanced day/night operation, by combining a number of prevalent imaging technologies so they work better together. That’s why many of today’s more innovative and effective low-light imaging devices apply advanced algorithms to alter the properties of a video signal with the intent of enhancing available light.
Perhaps most recognizable among these is the H.264 compression algorithm that has become the de facto industry standard for reducing file size for more efficient bandwidth and storage. H.264 compression, and now H.265, allow cameras to send video only when there is motion within the frames. However, in low-light applications, video can be fuzzy and/or contain noise, both of which are interpreted as motion. This results in a much larger video stream. When combined with Digital Noise Reduction (DNR) and/or video analytics, however, video quality increases while file sizes decrease but this only partially solves the problem.
Highly contrasted lighting within a single field of view — such as car headlights moving across a dark parking lot — presents a whole different set of challenges. Conventional cameras balance the overall lighting in a scene, providing a low-quality image. On the other hand, wide dynamic range (WDR) technology — measured in decibels — is designed to overcome this specific problem by processing bright and dim light sources separately within a scene to deliver high-quality images regardless of the lighting in different areas of the scene. It is another fantastic solution, but one still plagued by the ability to clearly capture clean video images at great distances, or of moving objects.
From Low Light to No Light
H.264 and H.265 compression and WDR are the most prevalent DSP-based technologies used to provide quality video in low-light environments; however, “low-light” and “no light” are entirely different concepts, with each presenting its own unique set of challenges. The ability to capture usable images in areas with no light normally requires hardware-based solutions such as adding illumination from conventional lighting sources, using cameras with IR illuminators, deploying thermal cameras, or a combination. Each of these approaches comes with its own potential drawbacks, which are related to high cost, limited coverage capabilities and/or compromised performance.
One example is thermal imaging. Because thermal cameras rely on temperature rather than visible light, they are capable of “seeing” in any challenging lighting condition — bright light, low-light and complete darkness. For the most part, they are also unaffected by weather and other elements that can be challenging with traditional surveillance cameras. When critical infrastructure surveillance and/or wide area perimeter protection are the main objectives, there are thermal camera solutions that deliver excellent results, but they are typically not ideal for general surveillance applications.
While these factors may make thermal imaging seem like an attractive option for outdoor surveillance, cost could make them unrealistic for many end-users. Price points for thermal cameras have dropped recently but they are still out of reach for many. Some manufacturers have introduced low-cost models, but these are typically entry-level cameras that lack the features and functionality of their more expensive counterparts — making them unsuitable for a number of critical applications.
Another technology commonly implemented to overcome lighting challenges is IR illumination. Traditionally, this has come in the form of external IR sources aimed at a scene to allow cameras equipped with an IR cut filter to see in low light or total darkness. This can be an effective solution, but distance limitations and the need to provide power to additional devices can complicate things. Additionally, unless the camera is equipped with an IR lens, performance and accuracy will be diminished. Cameras with built-in IR illumination can be deployed to overcome these challenges and are increasingly being deployed in place of external IR sources but often lack long distance imaging and tracking capabilities.
Adding conventional lighting is another tactic employed for capturing video in dark areas, but like traditional IR lighting, its ability to throw light over wide areas is limited if not expensive. Another drawback is that different types of lighting — such as fluorescent, incandescent and high-pressure sodium — have different effects on video and can make it difficult to identify objects or people in the field of view.
Combining Features
Recognizing these realities, a new approach has been developed that plays on the core strengths of existing low-light technologies by combining advancements in software and mechanical engineering. This confluence of technology and best practices has resulted in new imaging devices such as Samsung’s SNP-6320 Spider Camera, which can capture high-quality images at distances up to 500 feet in total darkness.
The secret in accomplishing this level of low light performance lies in the combining of specific features on-board the camera. These features include: a high-quality 32X optical zoom, advanced digital signal processing (DSP), auto tracking software, and adjustable high-powered IR lighting. What makes this truly unique is that the adjustable IR lights built into the camera are engineered to physically change position behind a zoom lens on each illuminator. The camera’s software coordinates the movement of the IR lights to match the lens’s zoom ratio as it tracks a subject. This allows the camera to illuminate the area in focus with extreme accuracy even when objects are moving at long distances. Cameras with IR lighting simply cannot accomplish this enhanced level of coverage.
The ability to capture high-quality video while tracking objects over long distances can be difficult if not impossible for traditional HD and megapixel cameras in low light or complete darkness. When combined on the camera level, advanced software, hardware and mechanical engineering hold the key to overcoming this challenge with extreme efficiency. Creative design and engineering accomplishments such as this will continue to drive new innovations, and lead to even more powerful and effective solutions for longstanding security and surveillance challenges.
Tom Cook is Vice President, Sales, North America, for Samsung Techwin America. Request more info about the company at www.securityinfowatch.com/10215711.
