Image analysis – Image transformation or preprocessing – Changing the image coordinates
Reexamination Certificate
1999-01-26
2003-11-04
Patel, Jayanti K. (Department: 2625)
Image analysis
Image transformation or preprocessing
Changing the image coordinates
C358S002100, C358S445000, C345S502000, C345S659000
Reexamination Certificate
active
06643415
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for rotating image data, and, more particularly, to a method and apparatus for rotating image data used in a facsimile device, a digital copying machine, or a printer.
2. Description of the Prior Art
In a conventional facsimile device, when it has been loaded with recording paper with a lateral length different from that of an image being read for transmission or received, the image has been recorded at the center of recording paper in the size as is if the recording paper has had larger width. The image has been recorded after it has been reduced in its lateral size if the recording paper has had narrower width.
In addition, if the image has the same longitudinal size as the width of recording paper, for example, if the image size is B5 (182 mm×257 mm), while the width of recording paper is B4 (257 mm), there has been a device which has recorded the image on the recording paper after it is rotated by 90 degrees. This image rotating method has used two page memories each storing image data of one sheet. First, after image data for the first sheet before it has been rotated (original image data) has been written in one page memory, the original image data is rotated by reading from that page memory, and the rotated image data is written into the other page memory. Then, while original image data for second sheet has been being written in one page memory, the rotated image data for the first sheet has been read from the other page memory. However, this method has a disadvantage that it requires two page memories, so that the device becomes expensive.
Then, as an approach to solve this disadvantage, Japanese Patent Application Laid-Open No. 6-105118 discloses an image data rotating method which rotates original image data using a line buffer capable of storing image data of several lines, and writes the rotated image data in one page memory. This image data rotating method is outlined in the following. As shown in
FIG. 32
, after several lines of original image data is once stored in an n-line buffer memory
31
, it is read and rotated in a rotating section
32
, and the rotated image data is written in a predetermined address of a page memory
33
. After the above process is performed until all image data for one sheet is written in the page memory
33
, the rotated image data for one sheet is read from the page memory
33
and recorded on recording paper at a recording section
34
.
According to this image data rotating method, since it is sufficient to provide one page memory and several line memories, capacity of memory can be reduced when compared to the above-mentioned image rotating method.
In
FIG. 32
, since a code storage section and other components are not directly related to the present invention, description of them is omitted. Refer to the published specification for detail.
In addition, Japanese Patent Application Laid-Open No. 7-320053 discloses an image data rotating method described below. This image data rotating method uses one page memory, and two buffer memories which have storage capacity capable of storing image data for n pixels×n lines (n being a positive integer) out of image data stored in the page memory. Then, image data of n pixels×n lines is read from the page memory, and written in one of the buffer memories. After the image data of n pixels×n lines is rotated by using the other buffer memory, the rotated image data of n pixels×n lines is written in the same area in the page memory where the image data of n pixels×n lines before rotation has been stored.
The conventional image data rotating method disclosed in Japanese Patent Application Laid-Open No. 6-105118 or 7-320053 requires the n-line buffer
31
capable of storing image data of several lines or two buffer memories capable of storing image data of n pixels×n lines, both of which are used only for rotation of image data, in addition to the page memory for storing image data for one sheet.
Therefore, there is a disadvantage that provision of the n-line buffer
31
or two buffer memories dedicated for rotation of image data makes the device expensive, and they are wasteful if image data is not frequently rotated.
In addition, since the conventional image data rotating method requires a process for writing image data in the n-line buffer
31
or the buffer memories, a process for rotating the image data, and a process for writing the rotated image data for one sheet in the page memory, in addition to processes when the rotation is not performed such as a process for writing the image data for one sheet in the page memory, and a process for reading the image data for one sheet from the page memory, it has a disadvantage that time in rotating and recording the image data for one sheet is about twice than a case where rotation is not performed.
Furthermore, the conventional image data rotating method has the following disadvantages since, after it once writes image data for one sheet in the page memory, it reads and rotates the image data, and then writes the rotated image data for one sheet in the page memory. That is, if, after image data is rotated, the image data cannot be recorded in the form after the rotation, for example, when original image data of A4 size (210 mm×297 mm) with its longitudinal direction as the vertical direction is rotated by 90 degrees, and recorded on recording paper with width of the longitudinal length of A4 size (297 mm), the recording paper is exhausted, and recording paper with width of the lateral length of A4 size (210 mm, but actual width of recording paper being 216 mm) is loaded on the device, it becomes necessary to perform a process for returning the rotated image data to the image data before rotation, and a process for reading original image data, whereby recording the image data on the recording paper takes much time by such amount.
SUMMARY OF THE INVENTION
The present invention is made in view of the above circumstances, and intended to provide a method and apparatus for rotating image data which can reduce capacity of memory used for rotation of image data, and shorten processing time.
To solve the above problems, an image data rotating method according to a first aspect of the present invention comprises the steps of:
using an image memory capable of storing pixels in same number as square of a maximum number among number of pixels per one line of each of image data with a plurality of sizes to be rotated and number of lines to be rotated;
number of pixels and number of lines in the same number as one of common divisors of the number of pixels per line and the number of lines being unit number of pixels and unit number of lines in the process writing or reading the image data in or from said image memory;
for consecutive two pages in image data with the same size of a plurality of pages to be rotated, reading all pixels of image data in a former page written in the image memory from each storage area at each address of the image memory in a predetermined order of reading according to an angle to be rotated by the unit number of pixels for one line and by the unit number of lines for all lines; and
writing all pixels of image data in the latter page in the same storage area at the same address of the image memory in said predetermined order by the unit number of pixels for one line and by the unit number of lines for all lines.
The image data rotating method according to a second aspect of the present invention comprises: a first process comprising the steps of:
using an image memory capable of storing pixels in same number as square of a maximum number among number of pixels per one line of each of image data with a plurality of sizes to be rotated and number of lines to be rotated;
number of pixels and number of lines in the same number as one of common divisors of the number of pixels per line and the number of lines being unit number of pixels and unit number of lines in the process writing
Fukai Toshiaki
Ogawa Shigetaka
Foley & Lardner
NEC Corporation
Patel Jayanti K.
Tabatabai Abolfazl
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