The basic technology for IR cameras has performed ably for years. While the technology is mature, breakthroughs in camera design and intelligent analysis enable increased uptake. A&S takes a look at current technology developments for IR cameras in the Asian industry.
Surveillance for low-light areas protects human safety and valuable assets. The market for IR cameras continues to grow, as poorly lit areas have a higher incidence of crime. While IR cameras are a niche application, annual market growth can be estimated at 25 to 35 percent. Demand continues for more user friendly cameras with powerful functions.
To satisfy different needs, customized chipsets or DSP designs enable clear images in dark or low-light environments. Achieving image clarity with the least power and longest camera life span are shared goals.
Seeing in Low-Light
Despite the importance of IR LEDs for IR cameras, other components for low-light surveillance cannot be overlooked. "AVTECH uses a large aperture camera lens to allow the camera to see clear color images in low-lux environments without having to turn on the IR LEDs," said Andy Lee, Product Manager at AVTECH. "If the LED is on, our IR shifter will automatically ensure a well-focused image." In case an object is too close to the camera, the company's smart light control prevents excessive light exposure to ensure a clear image by making image adjustments.
Also focusing on low-light vision is GKB Security. In dimly lit places like night clubs or restaurants, color images are needed. "We developed a patented day/night smart timer technology. With this technology, users can set the camera to switch to IR mode only at an exact time range," said Anderson Chen, Product Manage at GKB Security.
To determine if a removable IR cut filter (ICR) or LEDs are needed, GKB Security uses a triple night sensor technology which combines both traditional analog light sensors and digital light sensor. "If a camera that looks over a bright area is installed at a dark corner, the digital sensor can determine whether to switch on or off the IR mode based on the image taken from the camera's field of view," Chen said. "Our customized DSP further delays the reaction time of the IR switch, preventing false switching."
In low-light vision, ensuring image clarity is key for video surveillance. LSVT couples IR LEDs with a specially programmed DSP. An IR camera requires sufficient LEDs to effectively light the camera's view. The coverage for the IR LEDs and camera lens must be the same. "Most camera lenses zoom automatically but their LED coverage is fixed. If the lens zooms out of the LEDs' coverage, low-light images are lost," said Yi Ying Wang, GM at LSVT. "We program our DSP so the LEDs digitally zoom at angles that match the lens. Since users need to see objects at various distances, we customized the camera board to enable the LEDs to light up depending on coverage — far or wide — to allow zooming."
Image clarity is ensured by several component technologies. "By programming the DSP and using 3-D noise reduction with IR LEDs, our cameras can provide high-resolution images at 600 TVL," said Wang. "Other than using the 1/3-inch Sony CCD image sensors, the 1/4-inch Sharp 3C CCD chipset is also available."
Quality IR cameras must have good mechanical design, particularly for power, to achieve image quality. "IR LEDs should maintain the same lighting power despite electrical input changes," said Bob Zhang, R&D Technical Director at Sunell Technology. "We designed our circuit board so the electrical input to the camera does not affect the lighting power for the LEDs."
Even if a camera had all the latest technologies built inside, it would not be good unless all the parts worked together. "For us, the key to a quality IR camera is how to incorporate each feature successfully and produce the best image quality," Zhang said. "More efficient IR LEDs, intelligent IR LED control and energy saving are our future R&D directions."
Overall camera design is key for Relong. Heat ventilation is an important camera consideration as well as defogging and defrosting. Relong designs the electrical circuit board to allow the camera to work under all weather conditions. "Adding fans or heaters to the camera cannot truly solve the issue with overheating or frosting," said Jerry Lin, VP of Engineering at Relong. "Outdoor cameras cannot have vents for heat dissipation to protect the intricate camera components inside, so each company's R&D capability is key to building a quality and long-lasting IR camera."
"Apart from using starlight, auto zoom lenses and apertures to achieve long radiant distances of 100 meters, adjusting the IR LED angle can increase LED efficiency up to 95 percent," Lin said. "For user convenience, the camera adopts a mixture of LEDs at different angles to cover a wider range and extend the viewing distance."
Changing light conditions still affect image quality, but current IR technology is quite mature. Users are looking for cameras that can view longer distances at wider lighting ranges, with less energy consumption and extended product life span. Manufacturers are developing functions for auto adjustment of IR LED coverage and zooming. Intelligent features are becoming a trend, such as motion detection, object tracking and alarm notification through mobile devices.