IMAGE SCANNING APPARATUS AND IMAGE SCANNING METHOD

• US 20100231989A1
• Filed: 02/24/2010
• Published: 09/16/2010
• Est. Priority Date: 12/26/2008
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: INADOME, Takanori
• Granted Patent: US 8,390,902 B2
• Time in Patent Office: Days
• US Class Current: 358/474
• CPC Class Codes: H04N 1/02845 using an elongated light source, e.g. tubular lamp, LED array
• CPC Class Codes: H04N 1/02885 Means for compensating spatially uneven illumination, e.g. an aperture arrangement
• CPC Class Codes: H04N 1/0303 with the scanned line and the photodetector array lying in non-parallel planes
• CPC Class Codes: H04N 1/1013 with sub-scanning by translatory movement of at least a part of the main-scanning components H04N1/107 takes precedence
• 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 2201/0081 Image reader H04N2201/0091 - H04N2201/0094 take precedence

Abstract

An image scanning apparatus, including a contact glass having an original to be scanned on; a light source including plural dotted light-emitting elements linearly arrayed in a main scanning direction and emitting scanning light to the original; a photoelectric converter photoelectrically converting reflected scanning light from the original to produce line-image data in the main scanning direction; a halation detector receiving the line-image data from the photoelectric converter and detecting whether the line-image data has halation; and a corrector receiving information whether the line-image data has halation and correcting pixel values of all pixels of the line-image data having halation into a predetermined pixel value.

Claims

1. An image scanning apparatus, comprising:

a contact glass configured to have an original to be scanned on;

a light source, comprising plural dotted light-emitting elements linearly arrayed in a main scanning direction, configured to emit scanning light to the original;

a photoelectric converter configured to photoelectrically convert the scanning light reflected from the original to produce line-image data in the main scanning direction;

a halation detector configured to receive the line-image data and detect whether the line-image data has halation; and

a corrector configured to receive information from the halation detector whether the line-image data has halation and correct pixel values of all pixels of the line-image data having halation into a predetermined pixel value.

2. The image scanning apparatus of claim 1, wherein the halation detector comprises:

a comparator configured to compare a pixel value of each pixel of the line-image data with a predetermined threshold; and

a determiner configured to determine whether halation occurs depending on whether a pixel position having a pixel value greater than the threshold corresponds to a position of the dotted light-emitting elements in the main scanning direction.

3. The image scanning apparatus of claim 1, wherein the dotted light-emitting element is an LED.

4. The image scanning apparatus of claim 1, wherein the corrector computes brightness of all pixels of the line-image data having halation and corrects only the brightness of all pixels of the line-image data into a predetermined brightness based on the computed result.

5. The image scanning apparatus of claim 1, wherein the corrector computes brightness of all pixels of the line-image data having halation to detect a maximum brightness and corrects only the brightness of all pixels of the line-image data having halation into the maximum brightness.

6. The image scanning apparatus of claim 1, wherein the corrector computes brightness of pixels having no halation in the line having halation to determine an average brightness of the pixels having no halation, and corrects only brightness of all pixels of the line-image data having halation into the average brightness.

7. The image scanning apparatus of claim 1, further comprising:

an abnormality detector configured to detect abnormality of the dotted light-emitting elements.

8. The image scanning apparatus of claim 7, wherein the abnormality detector comprises:

a comparator configured to compare a pixel value of each pixel of the line-image data with a predetermined threshold; and

an abnormality determiner configured to determine whether the dotted light-emitting elements have abnormality depending on whether all or apart of a pixel position having a pixel value greater than the threshold corresponds to a position of the dotted light-emitting elements in the main scanning direction.

9. An image scanning method, comprising:

emitting scanning light to an original through a transparent table from plural dotted light-emitting elements linearly arrayed in a main scanning direction;

photoelectrically converting reflected scanning light from the original to produce line-image data in the main scanning direction;

detecting halation of the line-image data; and

correcting pixel values of all pixels of the line-image data having halation into a predetermined pixel value.

10. The image scanning method of claim 9, wherein the detecting halation comprises:

comparing a pixel value of each pixel of the line-image data with a predetermined threshold; and

determining whether halation occurs depending on whether all or a part of a pixel position having a pixel value greater than the threshold corresponds to a position of the dotted light-emitting elements in the main scanning direction.

11. The image scanning method of claim 9, wherein the correcting pixel values comprises:

computing brightness of all pixels of the line-image data having halation; and

correcting only the brightness of all pixels of the line-image data into a predetermined brightness based on the computed result.

12. The image scanning method of claim 9, wherein the correcting pixel values comprises:

computing brightness of all pixels of the line-image data having halation to detect a maximum brightness; and

correcting only the brightness of all pixels of the line-image data having halation into the maximum brightness.

13. The image scanning method of claim 9, wherein the correcting pixel values comprises:

computing brightness of pixels having no halation in the line having halation to determine an average brightness of the pixels having no halation; and

correcting only brightness of all pixels of the line-image data having halation into the average brightness.

14. An image scanning apparatus, comprising:

a contact glass configured to have an original to be scanned on;

means for emitting scanning light to the original, comprising plural dotted light-emitting elements linearly arrayed in a main scanning direction;

means for photoelectrically converting reflected scanning light from the original to produce line-image data in the main scanning direction;

means for detecting halation of the line-image data; and

means for correcting pixel values of all pixels of the line-image data having halation into a predetermined pixel value.