Image processing apparatus, image processing method, and computer product

• US 20050018258A1
• Filed: 07/23/2004
• Published: 01/27/2005
• Est. Priority Date: 07/24/2003
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Miyagi, Noriko, Inamoto, Hirohisa, Shibaki, Hiroyuki
• Application Number:
  US10/898,072
• Publication Number:
  US 20050018258A1
• Time in Patent Office: Days
• US Class Current: 358/521
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: H04N 1/4092 Edge or detail enhancement
• CPC Class Codes: H04N 1/41 Bandwidth or redundancy reduction by scanning H04N1/17 ; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/60 using transform coding

Abstract

An image processing apparatus includes an input unit that inputs an image signal created by optically scanning a document, a first filtering unit that performs a first filtering process on the image signal input to reduce degradation of image quality caused by optical scanning of the document, a compressing unit that irreversibly compresses the image signal filtered, a storage unit that stores the image signal compressed, an expanding unit that expands compressed image signal stored in the storage unit; and a second filtering unit that performs a second filtering process on the image signal expanded to reduce degradation image quality caused by compression of the image signal.

Claims

1. An image processing apparatus comprising;

an input unit to input an image signal created by optically scanning a document;

a first filtering unit to perform a first filtering process on the image signal input by the input unit to reduce degradation of image quality caused by optical scanning of the document;

a compressing unit to irreversibly compress the image signal filtered by the first filtering unit;

a storage unit to store the image signal compressed by the compressing unit;

an expanding unit to expand compressed image signal stored in the storage unit; and

a second filtering unit to perform a second filtering process on the image signal expanded by the expanding unit to reduce degradation image quality caused by compression of the image signal.

2. The image processing apparatus according to claim 1, wherein the first filtering process and the second filtering process includes at least an edge enhancing process.

3. The image processing apparatus according to claim 2, wherein

the first filtering process includes a smoothing process, and

the second filtering process includes the edge enhancing process in a reference area size smaller than that of the edge enhancing process by the first filtering unit.

4. The image processing apparatus according to claim 1, further comprising an edge detector to perform edge detection on the image signal input by the input unit, wherein

at least one of the first filtering unit and the second filtering unit performs a filtering process determined based on a result of detection by the edge detector.

5. The image processing apparatus according to claim 1, wherein the first filtering unit performs a filtering process determined based on a magnification ratio of the image signal input by the input unit.

6. The image processing apparatus according to claim 1, wherein the second filtering unit performs a filtering process determined based on a level of compression of the image signal.

7. An image processing apparatus comprising;

an input unit to input an image signal created by optically scanning a document;

a filtering unit to perform a filtering process on the image signal;

a compressing unit to irreversibly compress the image signal input by the input unit;

a storage unit to store the image signal compressed by the compressing unit;

an expanding unit to expand the image signal stored in the storage unit; and

a determining unit to determine contents of the filtering process, wherein

before compression of the image signal, the filtering process reduces degradation of image quality caused by optical scanning of the document, and

after expanding the compressed image signal, the filtering process reduces degradation of image quality caused by compression of the image signal.

8. The image processing apparatus according to claim 7, wherein the determining unit determines at least an edge enhancing process on both the image signal before the compression and the image signal after the expansion.

9. The image processing apparatus according to claim 8, wherein the determining unit determines a smoothing process on the image signal before the compression, the edge enhancing process on the image signal after the expansion in a reference area size smaller than that of the edge enhancing process performed on the image signal before the compression.

10. The image processing apparatus according to claim 7, further comprising an edge detector to perform edge detection on the image signal input by the input unit, wherein

the determining unit determines the filtering process on at least one of the image signal before the compression and the image signal after the expansion based on a result of detection by the edge detector.

11. The image processing apparatus according to claim 7, wherein the determining unit determines the filtering process on the image signal before the compression based on a magnification ratio of the image signal input by the input unit.

12. The image processing apparatus according to claim 7, wherein the determining unit determines the filtering process on the image signal after the expansion based on a level of the compression of the image signal.

13. An image processing method comprising:

inputting an image signal created by optically scanning a document;

performing a first filtering process on the image signal input by the input unit to reduce degradation of image quality caused by optical scanning of the document;

compressing the image signal filtered by the first filtering unit;

storing the image signal compressed by the compressing unit;

expanding compressed image signal stored in the storage unit; and

performing a second filtering process on the image signal expanded by the expanding unit to reduce degradation image quality caused by compression of the image signal.

14. The image processing method according to claim 13, wherein, the performing a first filtering process and the performing a second filtering process includes at least performing an edge enhancing process.

15. An article of manufacture comprising one or more recordable media having instructions stored thereon, which, when executed by a computer, cause the computer to:

input an image signal created by optically scanning a document;

perform a first filtering process on the image signal input by the input unit to reduce degradation of image quality caused by optical scanning of the document;

compress the image signal filtered by the first filtering unit;

store the image signal compressed by the compressing unit;

expand compressed image signal stored in the storage unit; and

perform a second filtering process on the image signal expanded by the expanding unit to reduce degradation image quality caused by compression of the image signal.