AU592940B2

AU592940B2 - Video encoding apparatus

Info

Publication number: AU592940B2
Application number: AU22817/88A
Authority: AU
Inventors: Kenichi Asano; Hiroaki Kikuchi; Tsutomo Kubo; Mitsuyoshi Suzuki
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1985-01-16
Filing date: 1988-09-26
Publication date: 1990-01-25
Anticipated expiration: 2006-01-15
Also published as: AU2281788A; AU2282188A; AU2281988A; AU2282388A; AU2282088A; AU2281888A; AU588743B2; AU588746B2; AU579441B2; AU588514B2; AU588744B2; AU588745B2; AU589070B2; AU5240786A; AU2282288A

Description

A

AUSTRALIA

PATENTS ACT 1952 COMPLETE SPECIFICATION 592940 Form

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: 0 6 o *Q 0 60 0. P 0 S a0 a 0 00 00 4 It o l op 4 II Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: This documenit c01 ans the amendments made un.r Section 49 and is correct toi printinlg.- DIVISIONAL OF 52407/86 TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2 CHOME

CHIYODA-KU

TOKYO 100

JAPAN

Actual Inventor: A I Address for Service: GRIFFITH HACK CO., 601 St. Kilda Road, Melbourne, Victoria 3094, Australia.

Complete Specification for the invention entitled: VIDEO ENCODING APPARATUS The following statement is a full description of this invention including the best method of performing it known to me:- 2 4.

0 0 9*6 4 *e 9 o oo e 4 40 i 90t a o 6a «n a 4 *9 09 a 0 I *9 a 94 9 90r VIDEO ENCODING APPARATUS 5 Background of the Invention Field of the Invention The present invention relates to a video encoding apparatus which is applied, for example, to a video communication system.

This patent application is a divisional of Patent Application No. 52407/86, the contents of which are incorporated herein by reference. There are a number of further divisional applications divided from Patent Application No. 52407/86, and the contents of these are also incorporated herein by reference.

-rr I~ I~ C 3 *a 4 4O 4 44 *s 4 44 4 4 44 4, 4 4 4r 4 'U.rr Summary of the Invention An object of an embodiment of the invention is to provide a video encoding apparatus wherein, even if signals from a plurality of cameras being not synchronously coupled are suitably changed and inputted, the irregularity of the picture image can be suppressed and made minimum.

A further object of an embodiment of the invention is to provide a video encoding apparatus wherein the irregularity of the picture image can be suppressed and made minimum and more-over the original picture image can be restored rapidly.

Therefore, according to one aspect of the invention there is provided a video encoding apparatus wherein an interframe difference signal between an inputted video signal and a video signal being one frame before the existing video signal is converted in quantization encoding by a quantization encoder and then outputted, and the quantization encoding output is 20 converted in quantization decoding by a quantization decoder and then written on a frame memory, characterized in that said video encoding apparatus is provided with a fluctuation detecting means which detects time fluctuation of a synchronizing signal contained in the inputted video signal, and said quantization encoder stops operation while fluctuation is detected based on the output of the fluctuation detecting means.

According to a further aspect of the invention there is provided a video encoding apparatus wherein an 30 interframe difference signal between an inputted video signal and a video signal being one frame before the existing video signal is *converted in quantization encoding by a quantization encoder and then outputted, and the quantization encoding output is converted in quantization decoding by a quantization decoder and then j 4 written on a frame memory, said video encoding apparatus comprising a fluctuation detecting means for detecting time fluctuation of a synchronizing signal contained in the inputted video signal, and a signal changing means for changing input to the quantization encoder from an interframe difference signal into an input video signal based on the output of the fluctuation detecting means, characterized in that said quantization encoder stops operation while fluctuation is detected based on the output of the fluctuation detecting means, and said signal changing means changes the input from the input o video signal into said interframe difference signal at a 6 delay corresponding to one frame of the input video oooa °0 signal after the fluctuation is no longer detected.

0* Brief Description of the Drawings In order that the invention can be more clearly 0M ascertained, an example of a preferred embodiment will now be described with reference to the accompanying drawings, wherein: 20 Fig. 1 is a diagram illustrating constitution go 04 a Ce of a video encoding apparatus as background art of an 0 00 embodiment of the invention; and Fig. 2 is a diagram illustrating constitution *444 of a video encoding apparatus in the embodiment.

o 25 Description of Preferred Embodiments 0.0 0 :Fig. 1 shows a video encoding apparatus in 0 0background art. In Fig. 1 numeral 8 designates a i plurality of cameras for inputting picture images, and numeral 200 designates a changing device for changing the plural video signals. Numeral 100 designates a video encoding apparatus comprising an A/D converter 1 for converting the inputted video signals in A/D conversion, a pre-processor 40 for performing pre-processing to encode the video signals in digital form, a frame memory

WIA

0 CE Ilk-~- 3 for storing the video signal being one frame before the existing frame, a subtractor 6 for estimating difference between output of the pre-processor 40 and output of the frame memory 3, a quantization encoding member 7 for performing quantization encoding of the difference signal between frames, a quantization decoding member 9 for performing the reverse processing to the quantization encoding member 7, and an adder Among the video signals outputted from the plural cameras 8, only one sort is selected by the selecting device 200 and outputted. If the output signal is inputted to the video encoding apparatus 100, the 4^ signal is converted in the A/D conversion by the A/D converter 1 and processed in pre-processing for encoding 15 by the pre-processor 40 and then inputted to the

S

t subtractor 6 so as to estimate the difference signal 4 between frames. The difference signal between frames is subjected to the quantization encoding in the quantization encoding member 7, and then outputted to the t 20 outside and also subjected to the quantization decoding in the quantization decoding member 9. For processing of next frame, the decoded signal is added through the adder to output of the frame memory 3 and then stored in the frame memory 3.

In a preferred embodiment, a fluctuation 0- 5' r'ov detecting means detects fluctuation oflsA eH@©s signal due to changing of input video signals and stops operation of a quantization encoding member so as to prevent the fluctuation of the picture image due to encoding of the significant difference signal between *frames.

In Fig. 2, parts similar to those in Fig. 1 O$<j NUT

CE

L. 6 are designated by the same reference numerals. Numeral 7 designates a quantization encoding member which can be ON/OFF controlled by external signals, numeral 9 a quantization decoding member which performs the reverse processing to the quantization encoding member 7, numeral 110 a detector which separates4 a-1cro signal from the inputted video signals and detects the time variation and controls the quantization encoding member t "7 and changing means as hereinafter described, numeral t t 120 a changing device which changes output of the preprocessor 40 and output of the subtractor 6 according to output of the detector 110, and numeral 130 a changing device which changes ON/OFF state of output of the frame memory 3 inputted to the adder 10. The changing devices 120, 130 are set to restore the output of the detector 110 after being lost to the original state with delay corresponding to one frame of the video signal. In this case, the detector 110 constitutes a fluctuation detecting means and the changing device 120 constitutes a signal changing means.

Operation of the embodiment will be 'I described.

The plural cameras 8 are not synchronously coupled but individually transmit the video signals to i the changing device 200. The video signals inputted through the changing device 200 to the video encoding device 100 are converted in A/D conversion by the A/D converter i, and then processed in pre-processing by the pre-processor 40 and also inputted to the detector 110 so as to perform Qzrs ,ono signal separation and phase difference detection. The video signal after finishing ,the pre-processing is converted into the difference r signal between frames to that being one frame before the frame memory 3 by the subtractor 5, and the difference signal is inputted to the changing device 120. Both the difference signal between frames and the original video signal are inputted to the changing device 120, but the difference signal between frames is usually outputted from the changing device 120 as shown in Fig. 8.

The difference signal between frames outputted from the changing device 120 is subjected to the quantization encoding by the quantization encoding member 7, and then outputted to the outside and also subjected to the quantization decoding by the quantization decoding member 9.

On the other hand, in the changing device 130, since output of the frame memory 3 is usually outputted without changing, the difference signal between frames subjected to the quantization decoding and outputted by the sbmee *4 s 8 quantization decoding member 9 is added in the adder to the frame memory output outputted from the changing device 130, and the added output is written to the frame memory 3 and ready to processing of next frame.

Studying the operation when the changing device 200 for changing the cameras 8 is changed, since the Sfit output video signal becomes discontinuous just after the changing, the detector 110 detects the significant phase I shift in nynnhEt-~li signal. If the detector 110 detects the phase shift, the quantization encoding member 7 stops the encoding of the picture image and prevents the fluctuation of the picture image. At the same time, the changing device 120 for input of the quantization encoder 7 is changed to output the original-video signal, and also the changing device 130 for input of the adder is changed so that output of the frame memory 3 is not supplied to the adder 10. If the apparatusN i ihes Jl Oc tSe Sor\Yc N\-C\Yz i dawinge fi~f=ynr-hou signal, output of the detector 110 is lost and the quantization encoding member 7 starts encoding of the original video signal. Then, output of the quantization decoding member 9 is written without changing to the frame memory 3. When encoding of the original video signal corresponding to one frame is finished, the changing devices 120, 130 are reset to t r

OP

2 111 :Ilit f P -9 the normal state and the original encoding of the difference signal between frames is started.

Above-mentioned operation of the embodiment is compared with that of Fig. 1 as follows: *A-e sychrov z'\ Since time fluctuation of yhrn_ signal is detected just after changing of the changing device 200 and operation of the quantization encoding member 7 is stopped, irregularity of the picture image due to encoding of the insignificant difference signal between frames is eliminated.

(ii) Only just after detecting the finishing cf rn drrain; of 4 signal, not the difference signal between frames but the original video signal is encoded. Consequently, restoring to the original picture image is rapid in comparison to the case that the difference signal between frames is used without changing.

Although the picture image becomes irregular at changing the changing device 200 and is restored slowly in the prior art, the picture image stands still just after the changing and is restored rapidly in the embodiment.

Claims

3. A video encoding apparatus as claimed in either of Claim 1 or Claim 2, and as substantially described herein with reference to the example shown in Figure 2. Dated this 18th Day of September, 1989. MITSUBISHI DENKI KABUSHIKI KAISHA By Its Patent Attorneys GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia 4 a., Cr 0. 0 9 9C 0 0r 99 9I 0 L 0 k 0 C-