Single step multi-section exposure scanning method

Abstract

A single step multi-section exposure scanning method for a scanner. The scanner includes a photo-sensor and a stepper motor. The photo-sensor has N rows of sensor cells that correspond to each primary color. The scanning device is driven forward an exposure distance for each revolution of the stepper motor. The single step multi-section exposure scanning method includes the following steps. First, the photo-sensor moves forward one exposure distance. One row of sensor cells is exposed after moving every 1 / Nth of the exposure distance. Thereafter, analogue voltages obtained through the exposed row of sensor cells are transmitted to an analogue / digital converter. The above process is repeated until the entire document is scanned.

Description

[0001]Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,608,301 filed as application Ser. No. 09 / 920,388 on Jul. 31, 2001.[0002]the present application is a reissue of U.S. Pat. No. 6,608,301 files as application Ser. no. 09 / 920,388 on Jul. 31, 2001, and a parent of the divisional U.S. reissue application Ser. No. 12 / 412,207 filed on Apr. 13, 2009.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention relates to a scanning method. More particularly, the present invention relates to a single step multi-section exposure scanning method.[0005]2. Description of Related Art[0006]In general, a charge-coupled device (CCD) is used as the photosensitive element inside most color scanners. The color CCD is constructed using a large number of sensor cells each capable of sensing light intensity of one of the three primary colors including red (R), green (G) and blue (B). FIG. 1 is a schematic diagram of a conventional cha...

AI Technical Summary

Benefits of technology

[0009]Accordingly, one object of the present invention is to provide a single step multi-section exposure scanning method capable of reducing compensation memory and video memory capacity and does not rely on lamp-adjusting techniques to solve sensor saturation problem. Ultimately, hardware production and engineering cost is reduced and fewer compensation counters are used. Furthermore, a larger area scanning to support a high image resolution is possible and the scanner can have a higher scanning speed.

Problems solved by technology

However, the production of a high-resolution scanner often causes some critical problems including: (1) lamp-adjusting techniques have to be deployed to resolve sensor saturation problem because long exposure will lead to saturation of the CCD while short exposure will lead to insufficient time for outputting voltage signal; (2) using a run-stop-scan scanning method to scan a document not only leads a repetition of start, rotate and stop motion for the stepper motor, but also leads to a slow down of scanning speed; (3) the CCD generates a large quantity of voltage signal data so that storage capacity of the compensation memory has to increase, thereby restricting large area scanning for obtaining a higher resolution; (4) the generation of large quantity of voltage signal data by the CCD also necessarily increases the storage capacity of the video RAM unit.

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