Image processor

Details Image processor Image processor

1998-01-20

2003-03-25

Rogers, Scott (Department: 2624)

Facsimile and static presentation processing

Static presentation processing

Attribute control

C358S003060, C358S003080, C358S003130, C382S235000, C382S237000

Reexamination Certificate

active

06538771

ABSTRACT:

This application claims priority under 35 U.S.C. §§119 and/or 365 to Patent Applications 9-8383 and 9-8386 filed in Japan on Jan. 21, 1997; the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image processor such as a digital copying machine.
2. Description of Prior Art
This application is based on applications Nos. 9-8383 and 9-8386 filed in Japan, the content of which is incorporated hereinto by reference.
Multi-level image data are obtained by reading a document image in an image processor. For an image processor such as a digital copying machine using an electrophotographic process, it is known to convert such multi-level image data to bi-level image data so as to form an image on a paper according to the bi-level image data. For an image processor which transmits the bi-level image data to a monochromatic printer, it is also known that an image processor converts multi-level image data to bi-level image data.
In the above-mentioned image processing for binarizing multi-level image data, it is known that image data are sampled while multi-level image data of a document is read, and real time dither pattern process or error dispersion process is performed by using high speed calculation. However, this technique has a limit on the sampling number of image data according to the calculation speed. It is also known that after all the multi-level image data read on a document is stored in a memory, features used for binarization are extracted from the multi-level image data to be binarized.
However, this technique needs a memory of large storage capacity. Further, it takes a long calculation time because a large amount of data have to be processed at one time.
SUMMARY OF THE INVENTION
An object of this invention is to provide an image processor which converts a multi-level image data to a bi-level image fast with a simple structure.
Another object of this invention is to provide an image processor which converts a bi-level image to a multi-level image fast with a simple structure.
In one aspect of the invention of an image processor, multi-level image data are divided into blocks, and compressed in the unit of block. The compressed multi-level image data of a block are converted to compressed bi-level image data without expanding the multi-level image data. For example, the compressed multi-level image data on an image of uniform density are converted to compressed bi-level image data expressed with area gradation.
In a second aspect of the invention of an image processor, the compressed multi-level image data of a block are converted to compressed multi-level image data, without expanding the multi-level image data. For example, the compressed multi-level image data on an image of bi-level image expressed with area gradation are converted to compressed multi-level image data of a half-tone image.
An advantage of the present invention is that conversion from compressed multi-level image data to compressed bi-level image data can be performed in a short time with a memory of a smaller capacity.
Another advantage of the present invention is that conversion from compressed bi-level image data to compressed multi-level image data can be performed in a short time with a memory of a smaller capacity.


REFERENCES:
patent: 4972502 (1990-11-01), Katsuta et al.
patent: 5282059 (1994-01-01), Fukushima et al.
patent: 5319471 (1994-06-01), Takei et al.
patent: 5416606 (1995-05-01), Katayama et al.
patent: 5524067 (1996-06-01), Miyake et al.
patent: 5673116 (1997-09-01), Fukushima
patent: 5701364 (1997-12-01), Kanno
patent: 5742704 (1998-04-01), Suzuki et al.
patent: 5801841 (1998-09-01), Susuki
patent: 5838455 (1998-11-01), Imaizumi et al.
patent: 5867612 (1999-02-01), Roboson
patent: 5872874 (1999-02-01), Natarajan
patent: 6047087 (2000-04-01), Imaizumi et al.
R. C. Gonzales et al, “Digital Image Processing”, Addison-Wesley Publishing Company, Mar. 24, 1992, pp. 309-322.*
Gray, R.M., Lecture Notes for EE372: Quantization and Data Compression [online], Spring 2000-2001, Stanford University, Stanford, CA [retrieved on May 16, 2002]. Retrieved from the Internet: <http://www.stanford.edu/class/ee372/intro4.pdf> Topic 1, Introduction, frames 1-43.
Gray, R.M., Lecture Notes for EE372: Quantization and Data Compression [online], Spring 2000-2001, Stanford University, Stanford, CA [retrieved on May 16, 2002]. Retrieved from the Internet: <http://www.stanford.edu/class/ee372/scalar4.pdf> Topic 2, Scalar Quantization, frames 44-225.

Affiliated with

Also associated with

Rating

Image processor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Image processor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image processor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3023982