Electrical computers and digital processing systems: multicomput – Computer-to-computer protocol implementing – Computer-to-computer data framing
Reexamination Certificate
1999-12-01
2004-03-09
Vu, Viet D. (Department: 2154)
Electrical computers and digital processing systems: multicomput
Computer-to-computer protocol implementing
Computer-to-computer data framing
C709S231000, C709S246000, C710S030000
Reexamination Certificate
active
06704793
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image communication device, and more particularly, to a data transmission protocol in an image communication device.
2. Discussion of Related Art
An image communication device based on a conventional technique is described referring to the accompanied drawings, as follows.
FIG. 1
represents a block diagram of an image communication device. The image communication device is composed of a semiconductor optical element such as a CCD(Charge Coupled Device)
1
for converting light inputted from the outside through a lens
1
a
into an electric image signal, a CCD driving part
2
for transferring the image signal inputted through the CCD
1
to a digital signal processor(DSP)
3
, the digital signal processor
3
for performing a digital signal process on the image signal inputted from the CCD driving part
2
, displaying and outputting the processed signal through a monitor
4
, and outputting the processed signal as a format of a luminance signal and a color signal for the sake of a compression of the image, an image compression/decompression part
5
for compressing and decompressing the inputted image signals, a communication control and interface part
6
for executing a communication with a communication circuit and sound input/output part
8
in order to transmit the compressed image signal and receive the transmitted image signal, and a controlling part
7
for controlling the respective parts of the system to perform a process, a compression and decompression, a transmission, etc. of the image signals.
FIG. 2
sets forth a frame structure showing a data communication method which uses an HDLC(High-Level Data Link Control) way. This frame structure is made up of a start flag for informing of a start of a file, data information, e.g., audio/video/control/etc., a CRC(Cycle Redundancy Check) code as an error search code, and a stop flag for informing of a completion of the file.
FIG. 3
shows a frame structure of the data information based on a conventional non-protocol method.
Describing the image communication device based on the conventional technique with such construction in detail, referring to the accompanied drawings, outside light inputted through the lens
1
a
is converted into an electric image signal through the CCD
1
, and is inputted to the CCD driving part
2
. The CCD driving part
2
performs an analog signal correction for the image signal to make the signal a constant level, and outputs it to the DSP
3
.
The DSP
3
executes a clamp, an RGB color control, a lightness control etc., for the inputted image signal, and then, displays the inputted image on the monitor
4
.
At this time, the DSP
3
converts the inputted image into a constant format of a luminance signal and a color signal to gain an image compression in order for its transmission to the outside, and outputs it to the image compression/decompression part
5
.
The image compression/decompression part
5
performs the image compression by the JPEG(Joint Photographic Coding Experts Group) and the MPEG(Moving Picture Experts Group) according to a kind of the inputted image signals, and such compressed image signal is transmitted to the communication circuit and sound input/output part
8
through the communication control and interface part
6
.
A flow of this signal is controlled by the controlling part
7
.
As the data communication method using a MODEM as the communication control and interface part
6
in such image communication device, there are an HDLC(High-Level Data Link Control) method and a non-protocol method, and the HDLC method is mainly used.
FIG. 2
provides a frame structure showing a data communication method which uses the HDLC way, and this frame structure includes a start flag for informing of a start of a file, data information, e.g., audio/video/control/etc., a CRC code as an error search code, and a stop flag for informing of a completion. In the HDLC structure, a flag pattern of the start and stop flags, ‘01111110(7E
HEC
)’, has a writing by a combination of 8 bit, wherein the start and stop flags are to inform of a start and a completion of a file for the sake of a synchronization of the frame.
That is, the flag synchronizing system is to send a code of a constant pattern and always attain a synchronization between the transmission and the reception even though there is no transmission data, and this constant pattern is as the flag pattern ‘01111110(7E
HEC
)’, the 7E
HEC
being a hexadecimal.
The MODEM of a receiving side which receives this flag, transfers the flag to the controlling part, CPU, under a removal state of the start and stop flags.
Data information sent, next to the start flag, contains optional bytes such as audio/video/control/etc. and is sent. Data 1 byte is herewith provided by a structure of 8 bit, and both ends of this 8 bit have each additional 1 bit as a start bit and a stop bit, thus 10 bit is transmitted.
The data information itself contains a CRC code in order to search the respective data such as the audio/video/control etc.
Six Data ‘1s’ in the above data stream are limited to the flag (01111110). Therefore, when one data information to be sent needs over six consecutive ‘1s’, ‘0’ is compulsorily added next to fifth ‘1’ as a zero insert, so that it is definitely divided with the start and stop flags. Then, the receiving side removes ‘0’ positioned next to the fifth ‘1’ of the consecutive ‘1s’.
The CRC code, namely an error searching code, is provided next to this data stream, and this is as a combination of 16 bit and checks an existence or non-existence of an error for a part excepting the start and stop flags.
In such HDLC method, however, it is the state that the CRC code for a search of an error is already made in the data information such as the audio/video/control/etc., and that the repeated CRC code is then provided by using a MODEM line, to accordingly cause an overhead by an extent of a CRC code.
Further, a large overhead by data 1 byte, namely 10 bit, is transmitted to transmit the data 1 byte though data 1 byte is 8 bit, since each 1 bit as the start and stop bit is added in a data transmission. Consequently, a loss of a data quantity per communication second becomes large and its size also becomes increase.
Furthermore, when over six ‘1s’ among data of the data information are consecutive, ‘0’ is compulsively added next to a fifth ‘1’ to prevent a restriction to the flag. In other words, ‘0’ is inserted in order to prevent an existence of data same as the start and stop flags. Thus, an overhead of the data information owing to an insertion of ‘0’ and a complication to again eliminate ‘0’ by the receiving side are increased.
In the non-protocol method, meantime, as shown in
FIG. 3
, its structure is to directly transmit and receive sending data with only a data stream.
Then, the receiving side previously decides with a transmitting side a mutual protocol for a file division of an audio, a video, a control, etc. among the transmitted data information, and after that, a transmission from its protocol is performed, namely the protocol transmission for a ‘video:control=3:2’ etc. is executed. The receiving side has a difficulty in distinguishing it, and also, in a case of changing the transmission protocol and transmitting it within a given quantity, a newly dividing work is required every its each case.
Additionally, in the HDLC method mainly used as the conventional transmission method, several search codes of the data information and error search codes added in the MODEM transmission are repeated, thus an overhead by its added quantity occurs. Further, the overhead for the 1 byte data, the data loss and the size increase are caused, since the start and stop bits are added to the data 1 byte by each 1 bit. In addition, there are complicated problems such as the overhead caused due to a compulsive addition of ‘0’ to the data information restricted to the flag, and its data removal performed by the receiving side, and there is a difficulty f
Chang Sung June
Kim Jun Seon
Oh Byong Khi
Oh Hyung Hoon
LG Electronics Inc.
Vu Viet D.
LandOfFree
Data transmission protocol in image communication device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Data transmission protocol in image communication device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data transmission protocol in image communication device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3261240