The market for networked digital IP security cameras is growing rapidly as more companies seek affordable ways to protect their key assets, including personnel, merchandise and real estate. Responding to these needs, IP security camera manufacturers have worked hard to find ways to improve performance while controlling costs.
Together with high-quality optics and advanced image processing, one of the key aspects of digital camera performance is resolution. For various reasons, conventional security cameras have been limited to 640 x 480 pixel VGA resolution and this has caused frustration with many users who require more detailed images for analysis. Fortunately, recent advances in CMOS sensor technology have made it more economical than before to offer “megapixel” IP security cameras, which provide approximately four times the pixel count and twice the linear resolution of conventional VGA cameras. At the same time, advances in compression algorithms have resulted in more efficient data storage with minimal loss of image quality. These new algorithms enable users to manage the increased volume of image data produced by megapixel IP security cameras more effectively.
A good-quality megapixel IP security camera offers multiple resolution and data compression options to suit the needs of various users. In addition to megapixel resolution for detailed image analysis, many users require VGA resolution for low-cost monitor display and QVGA (320 x 240) or even QQVGA (160 x 120) resolution for use on mobile devices such as smartphones.
The two dominant forms of data compression in modern IP security cameras are Motion JPEG and MPEG-4 or its subset, H.264. Motion JPEG is best for applications where there is a need to extract individual video frames for detailed analysis, while MPEG-4 offers superior data compression for video data storage. The better megapixel IP security cameras on the market today provide simultaneous output of Motion JPEG at a variety of resolutions and MPEG-4 or H.264 video.
When it comes to the imaging excellence of high-quality IP security cameras, megapixel resolution and highly efficient image compression are only the beginning. These cameras must also be able to produce crystal-clear, low-distortion images from corner to corner in conditions ranging from extremely low light to extremely high-contrast lighting. This level of performance requires first-rate technology in both optics and digital image processors. Manufacturers that produce these key components in-house are a step ahead of competitors who have to purchase them from outside suppliers. In-house manufacturing ensures better performance because key components such as lenses and image processors can be built to work in total synergy with other camera components.
For most outdoor security applications, a high-power zoom lens is best. The greater the zoom range, the easier it is to obtain close-ups of crucial image details such as license plates, facial features, etc. Conversely, space is at a premium in many indoor applications. This requires a sophisticated compact lens that combines clarity and low distortion with an ultra-wide angle of view.
Good image quality in low light requires many specialized camera features. Among these are a large-aperture lens, a high-sensitivity image sensor and an image processor that’s capable of preserving detail while reducing noise. With these elements in place, the best megapixel IP security cameras can achieve excellent quality in color at light levels as low as .03 lux. For black-and-white images, good quality has been achieved at light levels as low as .001 lux. And for high-contrast lighting conditions, new algorithms such as those employed by Canon’s Smart Shade Control feature allow selective brightening of shadow areas in the image without losing detail in brightly lit areas. This capability is invaluable for many environments that combine outdoor and indoor illumination in a single scene.