What is a CCD Camera?
Originally developed nearly fifty years ago, the charged-coupled device (CCD) is essentially the eye inside any CCTV system. It processes individual light elements and converts each one into the signal displayed on a monitor. The CCD CCTV camera has been a mainstay for decades, providing the best possible resolution in a wide array of environments and conditions.
Since television has always demanded an abundance of light for a clear display, a solution was needed to address the problem of low light, typical of obscure areas requiring surveillance coverage. In response to this need, the CCD chipset has performed well in low and no-light situations, and various improvements in CCD CCTV camera technology have made coverage even better over the last decade.
What is a CMOS Camera?
Developed during the same period as CCD, the complementary metal-oxide-semiconductor (CMOS) is a separate digital imaging technology whose function is more concentrated than CCD. Meaning, CMOS amplifies and moves the pixel information individually, while CCD image processing occurs on a larger part of the chipset.
Although CMOS technology consumes less power, the image resolution has historically not been as strong. Since CMOS sensors are more closely configured, light capturing has a tendency to merge, compromising the camera’s ability to capture detail in dark settings.
For many years the need for a high-quality surveillance system was grounded in image quality and low light capability, and CCD-based systems had the advantage. Additionally, a CMOS light capturing function known as ‘rolling shutter’ has produced artifacts that in turn lead to occasional image blurs, making freeze frames difficult to isolate when needed. In contrast however, CMOS’s high frame rate compensates for its lack of the CCD’s global shutter by capturing quick movement in the video.
Though CCD-based security systems require more energy, larger-scale operations often include redundant power supplies, eliminating the problem of electrical drain associated with an older CCD camera. And at 1/3 inch or less, CCD imagers are smaller, allowing equipment configuration in confined spaces. Recent developments have minimized the distinction between the two imaging technologies, with CMOS making notable gains on the CCD camera during recent years.
CCD vs CMOS Sensor Image Quality and Cost
When cost is a concern, CMOS-based systems provide an advantage with many multi-camera home packages fitting tight budgets. New CCTV systems using the CMOS chip maintain a higher resolution than ever before, and though low-light capability may not always match their CCD counterparts, a side-by-side comparison shows fewer differences than just a few years ago. In addition, the signals delivered by CMOS-based cameras typically use less bandwidth, which is an important distinction when prolonged streaming is required.
In considering CCD vs CMOS sensor image quality, the lines are closer than ever before and ultimately depends on the budget, coverage environment, and eventual signal distribution. Larger industrial settings with a redundant power supply and wide coverage requirements would do well with cameras based on the latest CCD technology.
Other environments might benefit from battery-backed power, vandal-proof camera casings, and confined equipment placement, and as a result, may be better suited to CMOS-based cameras. Ultimately a CCTV purchase decision may rest with cost, setting size, low-light need, and the manner with which the signal is finally delivered.