Facsimile and static presentation processing – Static presentation processing – Communication
Reexamination Certificate
1996-11-27
2001-04-10
Popovici, Dov (Department: 2622)
Facsimile and static presentation processing
Static presentation processing
Communication
C358S001160, C358S001130
Reexamination Certificate
active
06215558
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a print control apparatus and method of compressing/expanding image data and printing it.
2. Related Background Art
A data compression method called a pack bit data compression method is known for compressing image data transmitted from an information processing apparatus such as a host computer to a print control apparatus.
With the pack bit data compression method, image data of each byte is checked whether or not it is formed by the same data elements. As shown in
FIG. 10A
, if the image data of each byte is formed by the same data elements, the number of bytes of the same data elements is written in a one byte control unit
51
, and the same data element byte which occurs that number of times is written in a one byte data unit
52
. If the image data of each byte is formed by different data elements, as shown in
FIG. 10B
, the number of bytes of the different data elements is written in a one byte control unit
53
, and the different data elements of one or more bytes are written in a data unit
54
containing those one or more bytes.
FIG. 11A
shows an example of non-compressed image data transmitted from the host computer, the image data being shown in units of bytes.
FIG. 11B
shows the non-compressed image data shown in
FIG. 11A
, as compressed by the pack bit compression method. With the pack bit compression method, immediately before the two bytes of different data “A” and “B”, control data “command 1” indicating the number (two) of bytes of different data elements is written. Immediately before five consecutive bytes of the same image data “C”, control data “command 2” indicating the number of bytes (five) of the same data elements is written. Similarly, control data indicating the number of bytes of the same or different data elements is written immediately before each such byte or set of bytes.
With the conventional pack bit compression method used with a print control apparatus, however, in order to count the number of bytes of different data elements transmitted from the host computer, it is necessary to temporarily store the bytes of different data elements in a buffer or a memory area different from the data unit
54
, and to transfer the bytes stored in the buffer or the like to the data unit
54
after the control data indicating the number of counted bytes is written in the control unit
53
. Specifically, in the example shown in
FIG. 11B
, in order to generate the control data “command 6” indicating the number of bytes of different data elements “G”, “H”, “I”, and “J”, it is necessary to detect a transition from bytes of the different data elements to bytes of same data elements. Therefore, after the different data elements “G”, “H”, “I”, and “J” are received, it is necessary to receive a plurality of bytes of the same data elements “K” in order to detect the transition and generate the control data “command 6”. A buffer having a capacity sufficient for temporarily storing image data becomes necessary, increasing the load on the apparatus.
In another method of counting the number of bytes of different data elements, the image data is written in the data unit
54
by DMA (direct memory access) without writing the control data in the control unit
53
, and when a transition is detected, the address is returned to the control unit
53
to write the control data therein. With this method, however, to write the control data in the control unit
53
in this fashion (after writing the image data in the data unit
54
), it is necessary to control the write address counter to return to the address of the control unit
53
. This method therefore requires a complicated operation.
SUMMARY OF THE INVENTION
The invention has been made under the above circumstances. It is an object of the present invention to provide a print control apparatus and method capable of simplifying the structure and processes without degrading conventional image processing functions.
According to one aspect of the invention, there is provided a data processing apparatus in which input data is analyzed and the input data is compressed by distinguishing repeat data which repeats same element from nonrepeat data which repeats different element as to the input data, comprising: generating means for generating control data indicating the repeat data if the input data is the repeat data and control data indicating the nonrepeat data if the input data is the nonrepeat data; and compressing means for generating nonrepeat compression data by outputting the input data corresponding to the nonrepeat data sequentially outputting the control data generated by the generating means if the input data is the nonrepeat data, and for generating repeat compression data by outputting the input data corresponding to the repeat data and outputting the control data generated by the generating means if the input data is the repeat data.
According to another aspect of the present invention, there is provided a data processing method in which input data is analyzed and the input data is compressed by distinguishing repeat data which repeats same element from nonrepeat data which repeats different element as to the input data, comprising the steps of: generating control data indicating the repeat data if the input data is the repeat data and control data indicating the nonrepeat data if the input data is the nonrepeat data; and generating nonrepeat compression data by outputting the input data corresponding to the nonrepeat data sequentially outputting the control data generated in the generating step if the input data is the nonrepeat data, and for generating repeat compression data by outputting the input data corresponding to the repeat data outputting the control data generated in the generating step if the input data is the repeat data.
The other objects and advantages of the present invention will become apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings.
REFERENCES:
patent: 3980809 (1976-09-01), Cook
patent: 5434568 (1995-07-01), Moll
patent: 5600316 (1997-02-01), Moll
patent: 5617517 (1997-04-01), Chi
patent: 5649074 (1997-07-01), Welborn
patent: 5778253 (1998-07-01), Blair et al.
patent: 5894544 (1999-04-01), Heydinger
patent: 5963716 (1999-10-01), Welborn et al.
patent: 6124940 (2000-09-01), Heydinger
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Popovici Dov
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