Image Data

The manner in which an image is converted into data and the way the data is sent to the computer is predetermined. The following sections describe this process.

Image data format

The smallest element of image data is called a pixel (short for picture element). A pixel is an individual dot; combining these dots, or pixels, forms an image.

If you represent each pixel by one bit of data, you can determine whether that pixel is light or dark (1 or 0). This is called bi-level conversion, and produces bilevel data.

However, most images contain a nearly infinite number of color shades. By increasing the number of data bits per pixel, you can increase the possible number of pixel shades you can represent. As you can see from the following illustration, 1 bit per pixel allows you to show only two shades; 2 bits per pixel allows you to represent up to 4 shades.

The image data format is what determines the amount of data necessary for each pixel. The amount of data determines how many shades you can express. Normally, you can select from 1 to 8 bits per pixel. For monochrome scanning, this data determines the shade of gray. For color scanning, you can differentiate the same number of shades for each of three colors (green, red, and blue).

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