Image reading with color shift correction

• US 8,824,030 B2
• Filed: 04/11/2012
• Issued: 09/02/2014
• Est. Priority Date: 06/15/2011
• Status: Active Grant

• Current Assignee: PFU Limited (Fujitsu Limited)
• Original Assignee: PFU Limited (Fujitsu Limited)
• Inventors: Kanaya, Shingo
• Primary Examiner(s): Lee, Thomas D
• Application Number:
  US13/444,567
• Publication Number:
  US 20120320437A1
• Time in Patent Office: 874 Days
• Field of Search: 358/1.1, 358/1.9, 358/3.23, 358/3.26, 358/500, 358/501, 358/518, 358/523
• US Class Current: 358/518
• CPC Class Codes: H04N 1/19594 using a television camera or a still video camera
• CPC Class Codes: H04N 1/401 Compensating positionally unequal response of the pick-up or reproducing head H04N1/403 takes precedence
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 2201/0436 Scanning a picture-bearing surface lying face up on a support H04N2201/0434 takes precedence; using cylindrical picture bearing surfaces H04N1/06; with manual scanning H04N1/107

Abstract

An image-reading apparatus, includes a variation acquiring unit that acquires a variation of a distance or an angle between a medium to be read and an imaging unit or a light source, and a color shift correcting unit that calculates a color shift between the medium and the imaging unit or the light source based on the variation acquired by the variation acquiring unit and corrects the color shift.

Claims

1. An overhead scanner comprising:

a light source configured to irradiate a medium to be read with light;

an imager configured to rotate together with the light source to scan the medium;

a controller configured to, when the imager scans the medium, obtain a variation of a distance or an angle between the medium and the imager or the light source, calculate a color shift between the medium and the imager or the light source based on the variation, and correct the color shift.

2. The overhead scanner according to claim 1, wherein the controller is configured to correct the color shift by using a correction table that stores the variation and a correction value associated with the variation.

3. The overhead scanner according to claim 2, wherein the controller is further configured to set the correction table.

4. An image processing method executed by an overhead scanner comprising a light source configured to irradiate a medium to be read with light;

and an imager configured to rotate together with the light source to scan the medium, the image method comprising;

obtaining a variation of a distance or an angle between the medium and the imager or the light source;

calculating a color shift between the medium and the imager or the light source based on the variation; and

correcting the color shift.

5. A non-transitory tangible machine-readable medium having instructions for a controller of an overhead scanner comprising a light source configured to irradiate a medium to be read with light;

and an imager configured to rotate together with the light source to scan the medium, the instructions, when the imager scans the medium, causing the controller to perform the steps of;

obtaining a variation of a distance or an angle between the medium and the imager or the light source;

calculating a color shift between the medium and the imager or the light source based on the variation; and

correcting the color shift.