22.6 IMAGE PREPROCESSING

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Images are basically a set of pixels that are often less than a perfect image representation. By preprocessing, some unwanted variations/noise can be reduced, and desired features enhanced.

Some sources of image variation/noise,

- electronic noise - this can be reduced by designing for a higher Signal to Noise Ratio (SNR).

- lighting variations cause inconsistent lighting across an image.

- equipment defects - these cause artifacts that are always present, such as stripes, or pixels stuck off or on.