Digital Basic Page 5

Analog to digital is the core of the digital imaging. Visual images and photographic images are a kind of analog signals. To convert these signals into data, a special device is required. CCD (Charge-coupled Device), which developed from CMOS (Complementary Metal Oxide Semiconductor) is the most common design for its low noise and stability. Due to its high cost, nowadays we have other simular designs, e.g. CMOS-CCD. That is the work of those manufacturers, we need not bother about. What concerns us is the quality and price.

For simplicity, we shall use CCD as a common name for all these devices, else we are wasting our time for the names without benefits. Of course, when such kind of technology is covered, all devices and difference will be mentioned.

Digital cameras and film scanners are built with CCD. The resolution is fixed by the CCD, and the output is controlled by individual Color Table etc. That is what remains the major difference among brands and designs.

We must understand that the image quality is based on the optical resolution because the output resolution may be interpolated.

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