Image analysis – Image compression or coding
Reexamination Certificate
1998-04-02
2002-09-17
Tran, Phuoc (Department: 2621)
Image analysis
Image compression or coding
C382S233000
Reexamination Certificate
active
06453071
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data communication apparatus, method and system, and to programs for a data communication process stored in a computer readable storage medium. More particularly, the invention relates to data communication techniques using communication control buses capable of dealing with mixed control and data signals.
2. Related Background Art
A need for using an apparatus dealing with still or moving images, such as AV (audio visual) apparatuses, as a peripheral apparatus of a personal computer has recently become strong. The AV apparatuses include a digital video tape recorder (D-VTR), a digital video tape recorder with a built-in camera (D-CAM), a digital camera, and the like. For such needs, a system has been developed which can connect such AV apparatuses to PC and can process and edit in various ways digital signals of still and moving images taken with AV apparatuses. Another system has also been developed in which PC can record still and moving image signals from AV apparatuses in a recording medium such as a hard disk, and can print such images with an image printing apparatus such as a printer.
In order to reduce the amount of still and moving image data to be transferred between apparatuses constituting such a system, the image data is converted into compressed data by using various compression encoding techniques. For example, a JPEG (Joint Photographic Experts Group) method is known for still images, and an MPEG (Moving Picture Experts Group) method is known for moving images. These compression encoding methods are realized by a combination of DCT techniques and variable length coding techniques, while taking into consideration the characteristics and features of image data to be compressed.
FIG. 1
is a block diagram showing the structure of a conventional communication system. In
FIG. 1
, reference numeral
101
represents a D-CAM (recording/reproducing device),
102
represents a printer, and
103
represents a PC. PC
103
and the printer
102
are interconnected by communication interfaces of SCSI (small computer system interface) specifications. PC
103
and D-CAM
101
are interconnected by dedicated communication interfaces.
In the communication system shown in
FIG. 1
, for example, the following processes have been executed in printing a still image contained in moving images reproduced with D-CAM
101
.
PC
103
temporarily stores moving image data sequentially output from D-CAM
101
in a storage device such as a hard disk. Next, PC
103
reproduces the moving images by using a predetermined application, and selects a desired still image of one frame from the moving images. In this case, a user performs a special effect process for the selected still image, if necessary, and thereafter instructs to print the still image. In response to this instruction, PC
103
supplies the still image data to the printer
102
connected thereto via a communication interface different from that for D-CAM
101
. Lastly, the printer
102
prints out the still image. As above, the communication system shown in
FIG. 1
prints a still image contained in moving images with the help of PC
102
.
With the communication system described above, however, in order to select a desired still image contained in moving images produced with D-CAM
101
, the moving image is required to be temporarily stored in the storage device such as a hard disk of PC
103
. PC
103
then reproduces moving image data stored in the storage device to select a desired still image.
In the conventional communication system, therefore, a large amount of data such as moving image data is sequentially sent to PC
103
each time in the unit of a predetermined amount of data, so that a load of PC
103
is very large. Depending upon the process performance and condition of PC
103
itself or upon a communication state of each apparatus, PC
103
may become inoperative or adversely affect the communication with other apparatuses. Furthermore, since a desired still image is selected after the moving image data stored in PC
103
is reproduced, it takes a long time to print the still image.
In the communication system shown in
FIG. 1
, in order to reduce the amount of moving image data to be transmitted from D-CAM
101
to PC
103
, the moving image data is compressed at D-CAM
101
by a predetermined compression encoding scheme, and the compressed data is transmitted to PC
103
.
However, even if D-CAM
101
transmits compressed moving image data, a desired still image cannot be selected unless PC
103
itself can expand and decode the compressed moving image data.
In the communication system shown in
FIG. 1
, if moving image data irrelevant to the compression coding scheme used by PC
103
is to be transmitted, D-CAM
101
has conventionally transmitted non-compressed moving data itself to PC
103
.
However, if PC
103
has an expansion decoding scheme corresponding to the compression encoding scheme of D-CAM
101
, a transmission efficiency is lowered unnecessarily and a load on PC
103
is increased.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-described problems.
Another object of the invention is to provide a data communication apparatus in which an encoding process for information data to be transmitted is performed in accordance with a decoding performance at an object node apparatus, to thereby improve the communication efficiency and reduce a capacity of a memory used for communications.
As a preferred embodiment for such objects, the invention discloses a data communication apparatus which comprises: (a) communication means having a first mode of transmitting information data isochronously with a predetermined communication cycle and a second mode of transmitting information data asynchronously with the predetermined communication cycle; (b) encoding means for encoding the information data by a predetermined encoding method; and (c) control means for controlling the communication means so as to transmit encoded information data when the encoding method corresponds to a decoding method at an object node apparatus and to transmit non-encoded information data when the encoding method does not correspond to the decoding method at the object node apparatus.
As another embodiment, the invention discloses a data communication apparatus which comprises: (a) communication means having a first mode of communication isochronous with a predetermined communication cycle and a second mode of communication asynchronous with the communication cycle; (b) encoding means for encoding image information in accordance with a decoding performance at an object node apparatus, the image information including moving image information and still image information; and (c) control means for controlling the communication means so as to transmit the moving image information by using the first mode and to transmit the still image information by using the second mode.
As another embodiment, the invention discloses a data communication apparatus which comprises: (a) input means for inputting moving image information and still image information; (b) encoding means for encoding the moving image information and the still image information; and (c) transmitting means for transmitting the moving image to a number of unidentified apparatuses and transmitting the still image information to a designated apparatus.
As another embodiment, the invention discloses a data communication apparatus which comprises: (a) input means for inputting information data; (b) encoding means for encoding the information data; and (c) transmitting means for transmitting decode information containing program codes realizing the decoding method corresponding to an encoding method to be used by the encoding means and transmitting the information data encoded by the encoding means.
As another embodiment, the invention discloses a data communication apparatus which comprises: (a) input means for inputting encoded information data and decode informatio
Ito Masamichi
Kozuki Susumu
Alavi Amir
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Tran Phuoc
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