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CMOS vs CCD image sensors
Due to both design and manufacturing considerations, there are a number of advantages that CMOS Imagers have over CCD:
1. Integration
Because CMOS Imagers are created in the same process as processors, memories and other major components, CMOS Imagers can integrated with these same components onto a single piece of silicon. In contrast, CCDs are made in a specialized process and require multiple clocks and inputs. This feature limits CCDs to discrete systems, which in the long run will put CMOS Imagers at a cost advantage, as well as limit what kinds of portable devices CCDs can be integrated into.
2. Reduced Power Consumption
Because of all the external clocks needed to "bucket brigade" each pixel, CCDs are inherently power hungry. Every clock is essentially charging and discharging large capacitors in the CCD array. In contrast CMOS imagers require only a single voltage input and clock, meaning they consume much less power than CCDs, a feature that is critical for portable, battery operated devices.
3. Pixel Addressability
CCDs use of the bucket brigade to transfer pixel values means that individual pixels in a CCD cannot be read individually. CMOS imagers on the other hand have the pixels in an x-y grid allowing pixels to be read individually. This means that CMOS imagers will be able to do functions such as "windowing", where only a small sample of the imager is read, image stabilization to remove jitters from camcorders, motion tracking and other advanced imaging techniques internally that CCDs cannot do.
4. Manufacturing Cost
Since CMOS imagers are manufactured in the same process as memories, processors and other high-volume devices, CMOS imagers can take advantage of process improvements and cost reductions these devices drive throughout the industry.
