| 摘要 |
An image reading device selectively performs contrast adjustment on edge portions of the image, while suppressing contrast adjustment on noise and roughness of the image, thus obtaining a smooth and modulated image. Light emitted from a light source passes through or is reflected from an original document and is incident on a CCD line sensor, which outputs an electrical signal. This signal is input into an edge contrast unit, e.g., via a gain control amplifier, an A/D converter and a CCD signal processor. The edge contrast unit includes a computation unit by which edge contrast adjustment is accomplished selectively on input signals based on a comparison coefficient input from a comparison coefficient input unit and a contrast coefficient input from a contrast coefficient input unit. The resulting signal is stored in FIFO memory after passing through a normalizing processor, a DPI converter, and a LUT, for example.
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