Methods for transmitting and displaying a still picture image in a still picture video telephone apparatus

Abstract: A still picture video telephone apparatus adapted to transmit and receive, through a telephone line, still picture information put in from a television camera (14) or the like, during a telephone call, comprising a picture memory (20) for storing a plurality of pages of picture information consisting of a camera-taken picture memory portion which rewrites still picture information input therein delivered from the television camera at intervals of a predetermined period, a self-prepared picture memory portion which stores desired still picture information until arrival of a rewrite instruction, and an incoming picture memory portion which sequentially rewrites still picture information therein upon receipt of still picture information when its storage regions are filled up, an input means of memory region information for setting up regions for the self-prepared picture memory portion and the incoming picture memory portion within the picture memory, and picture memory control circuit (21) for controlling still picture information input to and output from the picture memory based on the memory region information, wherein the picture memory is capable of storing a plurality pages of still picture information and allocating memory regions to the self-provided picture memory portion and the incoming picture memory portion in various ways. Further, the present invention is a method for transmitting still picture image capable of extracting, according to the need, only a desired portion of the picture data stored in the picture memory thereby achieving highly efficient time-saving transmission. Furthermore, the present invention is a method for transmitting still picture image whereby clear picture image is displayed even when picture data of a different resolution is received and an accurate display is achieved even when picture data of a different aspect ratio is received at the signal receiver side.

Description: The invention relates to a method for displaying still picture images in video telephone apparatus, in which picture information including header information inserted at the beginning of the picture information for control purposes is transmitted and received through a communication line, and in which picture information to be transmitted or received incoming picture information, is stored in a region of a picture memory and displayed on a display. There are demands for a video telephone system capable of simultaneously transmitting audio and video information through a telecommunication line. By the use of the telecommunication line today, however, it is difficult to continuously transmit and receive a live picture because it requires huge amounts of data. Hence, at present, a still picture video telephone system which transmits a still picture image during a telephone call is being put into practical use. The still picture video telephone is a system capable, in the course of a telephone conversation with an ordinary voice signal, of temporarily stopping the conversation and transmitting, in the meantime, a desired still picture, such as the face of the speaker, photo, picture, and drawing relative to the contents of the conversation. According to such a still picture video telephone system, it is made possible to transmit and receive a picture image through a telephone line, which in the past was impossible, and the processed data quantity is not so large because only a single still picture is transmitted at a time, and therefore, there has been an advantage that the video telephone'system can be easily put into practical use. Such a video telephone system capable of transmitting a still picture is disclosed, for example, in "Overseas Telecommunications Technology", October 1986, in a report by J. Hull, on pages 62-65, about an article in "Telephone Engineer & Management", (Japan), June 15, 1986 pages 140-143. FIG. 1 is a circuit configuration diagram of the simplified still picture video telephone apparatus disclosed therein. Referring to the drawing, reference numeral 1 denotes a hand set, 2 denotes a microphone, 3 denotes a voice input/output circuit, 4 denotes an analog circuit, 5 denotes a matrix switch, 6 denotes a telephone interface circuit, 7 denotes a telephone line connection terminal, 8 denotes a speaker, 9 denotes a key pad, 10 denotes an input/output port, 11 denotes a CPU, 12 denotes a program memory, 13 denotes a modulator/demodulator circuit, 14 denotes a television camera, 15 denotes an image controller, 16 denotes a picture memory, and 17 denotes a display. Operation for transmitting audio and video signals in that prior art video telephone apparatus will be described with reference to FIG. 2. Speech by voice is delivered from the hand set 1 or microphone 2 through the voice input/output circuit 3, the analog circuit 4, the matrix switch 5, and the telephone interface circuit 6 to the telephone line connection terminal 7. The audio signal from the person on the other end of the line is passed through the above signal path in the opposite direction and reproduced by the hand set 1 or speaker 8. When transmitting a picture image signal in this case, the transmitter side sends a header including an ID code such as data on communicating capability to the receiver side for confirming that the set on the receiver side is a video telephone apparatus capable of communicating picture data in the same data format. After confirming that the other party has the same capability upon receipt of a header therefrom, the transmission of the picture data is carried out. More particularly, with reference to FIG. 1, when an instruction for transmitting a picture image is issued with the use of the key pad 9, the CPU 11 detects this through the input/output port 10, and delivers a header in accordance with a program previously stored in the program memory 12 to the modulator/demodulator circuit 13. Therein, the header is converted into an analog signal and this signal is then transmitted through the matrix switch 5 from the telephone line connection terminal 7. The header from the other end is passed through the same path in the opposite direction and subjected to confirmation by the CPU 11 as to its code or the like. In the meantime, picture images picked up by the television camera 14 are quantized in the image controller 15 and stored in the picture memory 16, and then led out to the display 17 to be displayed thereon in succession, and the stored picture data are read out from the picture memory 16 under the instruction of the CPU 11 and delivered to the telephone line connection terminal 7. Incidentally, the picture data has a header added thereto indicating the data length or the like. When the header from the other end of the line is received, it is acknowledged that reception of picture data will be started, and the matrix switch 5, based on a received carrier signal, switches, from the analog circuit 4 to the modulator/demodulator circuit 13, the delivering path of the incoming signal from the telephone interface circuit 6. After the received signal is demodulated in the modulator/demodulator circuit 13, the CPU 11 sends back a header or stores the data in the picture memory 16. Thereafter, the image controller 15 leads out the picture data prepared in its own system and the picture data received from the system on the other end from the picture memory 16 in succession to be displayed on the display 17. Also to the front of ordinary picture data is attached a simple header including an indication that picture data will follow. When the transmission and reception of image data have been finished and there is no more carrier signal from the modulator/demodulator circuit 13, the matrix switch 5 connects the telephone interface circuit 6 with the analog circuit 4 and thereby resumes voice communication. In the case where the answerback from the receiver side is to be omitted, the information that it can be omitted is put in the header and picture data is transmitted in succession to the header. Even in this case, the receiver side, upon receipt of the header, prepares the arrangement for receiving the picture data in the same manner as described above. Incidentally, the picture memory 16 of the prior art is composed of a camera-taken picture memory portion which stores picture information input from its own television camera 14, rewriting it at intervals of a predetermined period (e.g., 1/30 second), and an incoming picture memory portion for storing picture information obtained by demodulating still picture information received from the system on the other end of the line during the telephone call, and the memory portions of the picture memory 16 each have storage capacity for one page of picture information. Further prior art video telephone systems are described in: 1) ELECTRONICS, vol. 58, No. 33, August 1985, pages 34-36, New York, USA; "Picture phone cuts time and cost in teleconferencing". 2) PROCEEDINGS OF THE INTERNATIONAL ZURICH SEMINAR ON DIGITAL COMMUNICATIONS, Zurich 9th-11th March 1976, pages B7.1-B7.6, IEEE, Long Beach, USA; W. FAWER: "The picture memory and its influence on some functions of a display telephone". 3) PROCEEDINGS ON COMMMUNICATIONS OF EUROCON '77, EUROPEAN CONFERENCE ON ELECTRONICS, Venice, 3rd-7th May 1977, pages 2.12.2.1-2.12.2.10; L.J.W: VAN LOON et al.: "On some aspects of video telephony and video conferencing". 4) BRITISH TELECOMMUNICATIONS ENGINEERING, vol. 5, No. 3, October 1986, pages 197-199, London, GB; J.T. LING et al.: "IMTRAN image transfer system". In the third article as listed above, on page 2.12.2.4 it is mentioned that as far as compatibility of video telephone and TV standards are concerned, the selection of the system parameters has been made such that a simple method for converting video telephone signals into signals used in existing communication networks is ensured. In this connection it is mentioned that the aspect ratio of video telephone systems is 4:3, whereas the aspect ratio of European TV system is the same. Moreover, in the first and fourth articles, different image resolutions are supported. However, the first article does not specify how the receiver is informed of the resolution. The fourth article achieves this by using "end-to-end" signalling, as discussed with respect to Figure 2. Neither article discusses details of how to convert resolution. However, there is still a problem in the prior art still picture video telephone transmission systems that, when picture data is transmitted from a still picture video telephone apparatus having a different aspect ratio of horizontal width to vertical height of the picture plane, it cannot be displayed on a receiving system having a different aspect ratio. It is therefore an object of the present invention to provide a method for transmitting still picture image information whereby an accurate display can be performed at the signal receiver side even if picture data of a different aspect ratio is received. According to the invention, a method for displaying still picture images in video telephone apparatus, as defined at the beginning, is characterized by the step of inserting aspect ratio data into the header information of the picture information to be transmitted, the aspect ratio defining the ratio of width to height in a picture; and is further characterized by the steps on the receiving side of recognizing the aspect ratio data from the header data of the received picture information, and following receipt of still picture information with a larger aspect ratio than that of the display of the receiving apparatus: deleting part of the picture image data thereof corresponding to horizontal peripheral regions of said image, or adding, to the stored picture information, data of a specific pattern to memory areas corresponding to the top and bottom of the display of the receiving apparatus. These methods are defined in the independent claims 1 and 2. Thus, according to the method for transmitting still picture for use in a still picture video telephone apparatus according to the present invention, since the header of the picture data includes data on number of pixels of picture image signal and of the aspect ratio of the picture plane, the system on the receiver side can acknowledge what aspect ratio of the picture plane the incoming data has. Hence, when the picture data received has a different aspect ratio from that of its own picture plane, the data corresponding to portions of the peripheral region of the picture data received is deleted, or the specific pattern is added to the portions corresponding to the peripheral region of its own picture plane, therefrom so that a display adapted for its own picture plane can be performed. Thus, this invention makes it possible to communicate each other between still picture video telephone apparatus with different picture configuration. FIG. 1 is a block diagram showing a prior art still picture video telephone apparatus; FIG. 2 is an explanatory diagram of communicating procedures in a prior art still picture video telephone apparatus; FIG. 3 is an explanatory diagram showing picture data processing to which an embodiment of a method for transmitting still picture for an object of the present invention is applied; FIG. 4 is an explanatory diagram showing an example of a display on a still picture video telephone apparatus in the above embodiment; FIG. 5 is an explanatory diagram showing another example of a display on a still picture video telephone apparatus in the above embodiment; FIG. 6 is an explanatory diagram showing picture data processing to which another embodiment is applied; FIG. 7 is a flow chart for explaining overall operations in the above mentioned method for transmitting still picture; FIG. 8 is a flow chart showing an example to delete a portion of picture data in the case of transmission of a signal with a different aspect ratio of picture plane; and FIG. 9 is a flow chart showing an example to add partial picture data in similar case to above. The method for still picture transmission according to the present invention is characterized in the procedures carried out within the CPU 11. The component parts 1 to 17 of the apparatus are the same as those in the prior art example as shown in FIG. 1 and hence explanation thereof will be omitted. What is characteristic of the present embodiment is firstly that the header preceding the picture data to be transmitted and received is provided with data representative of the aspect ratio horizontal width to vertical height of the picture plane of the system of the transmitter. Such data may be put in the header normally used for exchange of the ID codes to be performed prior to transmission and reception of the picture data, as in the prior art example, or it may be put in the header provided at the front portion of the picture data. The CPU 11, according to the program previously stored in the program memory 12, prepares the header including the data representative of the aspect ratio of its own display 17. In this case, in the header for the ID code as aforesaid or the header to be provided at the front portion of the picture data, there are generally included such data on the picture data as number of lines, number of data, extension bits, and FCS (frame check sequence) and the like, other than the pixel data frame representative of the aspect ratio of its own. In receiving picture data, the CPU 11, in the present embodiment, first receives the header. It recognizes the aspect ratio included in the header and determines whether or not the aspect ratio is in agreement with that of its own picture plane. If it is in agreement therewith, the CPU 11 performs ordinary Processes as heretofore. FIG. 7 is a flow chart describing such ordinarily performed processes. If the aspect ratio of the incoming picture data is different from the aspect ratio of its own picture plane, the following processes are performed. For example, in the case where the number of pixels of its own picture plane is 96 x 96 and its aspect ratio is 4 Wide : 5 High as shown in FIG. 4 and its received picture data has 96 x 96 pixels and an aspect ratio of 4 Wide : 3 High as shown in FIG. 5, if the apparatus would display the picture data as it is, a vertically elongated, strange picture would be displayed. Hence, in the present embodiment, the CPU 11 deletes the data corresponding to specific pixels from the received picture data. More particularly, from 96 picture data each on the first line to the 96th line, the first to 20th and 77th to 96th data corresponding to both sides of its own picture plane are deleted. Thereby, in the display on the display 17, the data in the area indicated by oblique lines in FIG. 3 are deleted and only the central portion in FIG. 3 is displayed. Thus, a picture plane virtually equal to that shown in FIG. 4 is obtained. Here, since the picture image at both side portions in FIG. 5 are deleted, what were displayed there on the transmitter side are not displayed on the receiver side. However, in many cases with still picture video telephone apparatus, the transmitted picture images are those for pictures of a person on the transmitter side, and therefore, the deletion of both the side portions is not a problem in most cases. Since, however, the display on the receiver side in this example must be of 96 x 96 pixels, the CPU 11 gives some treatment, such as interpolation of the same data as adjoining data, to the data so that a display corresponding to 96 x 96 is obtained. In this way, an accurate display can be obtained even when picture data of a different aspect ratio is received. Further, even when the received picture data is also different in number of pixels, a matching treatment for number of pixels may first be given to the received picture data and then the data corresponding to the pixels at both sides may be deleted, and thereby, the same effect as described above will be obtained. FIG. 8 is a flow chart describing in a concrete manner the processes performed in deleting both sides of the picture data. Also a specific pattern may be added to the received oblong picture data as shown in FIG. 6 to convert the data into picture data adapted for its own picture plane thereby to obtain a proper display. For example, in the case similar to the above where the number of pixels of the picture plane of an apparatus is 96 x 96 and its aspect ratio is 4 Wide : 5 High as shown in FIG. 4 and its received picture data has 96 x 96 pixels and an aspect ratio of 4 Wide : 3 High as shown in FIG. 5, the CPU 11 compresses the 96-line picture data to the 58-line data. For compensating for 19 lines in each of the upper and lower picture data, it adds data of specific patterns in white, black, or the like to the picture memory (see step ST 14 or ST 22 in Fig. 9). Thereby, the picture image displayed on the display 17 becomes similar to that displayed on the picture plane on the transmitter side. Thus, also by the method used in this example, picture data of a different aspect ratio can be received and displayed. FIG. 9 is a flow chart describing in a concrete manner the processes performed in adding picture data as described above. Conversion between picture data of different aspect ratios is also possible for other ratios than those used in the above examples. It is further practicable to provide both the method to delete data (Fig. 8) and the method to add specific patterns (Fig. 9) as described above and to arrange such that either of these treatments is selectable by operating the key pad 9 or the like, or the treatments may be given in combination. According to the method for still picture transmission according to the present invention as described above, communication between still picture video telephone apparatuses of different aspect ratios can be performed smoothly.

Claims: A method for displaying still picture images in video telephone apparatus, in which picture information including header information inserted at the beginning of the picture information for control purposes is transmitted and received through a communication line, and in which picture information to be transmitted or received incoming picture information, is stored in a region of a picture memory and displayed on a display; a) characterized by the step of inserting aspect ratio data into the header information of the picture information to be transmitted, the aspect ratio defining the ratio of width to height of a picture; b) further characterized by the steps on the receiving side of: recognizing the aspect ratio data from the header data of the received picture information; and following receipt of still picture information with a larger aspect ratio than that of the display of the receiving apparatus, deleting part of the picture image data thereof corresponding to horizontal peripheral regions of said image. A method for displaying still picture images in video telephone apparatus, in which picture information including header information inserted at the beginning of the picture information for control purposes is transmitted and received through a communication line, and in which picture information to be transmitted or received incoming picture information, is stored in a region of a picture memory and displayed on a display; a) characterized by the step of inserting aspect ratio data into the header information of the picture information to be transmitted, the aspect ratio defining the ratio of width to height of a picture; b) further characterized by the steps on the receiving side of: recognizing the aspect ratio data from the header data of the received picture information; and following receipt of still picture information with a larger aspect ratio than that of the display of the receiving apparatus, compressing the picture information into fewer lines, and then adding, to the stored picture information, data of a specific pattern to memory areas corresponding to the top and bottom of the display of the receiving apparatus.

Inventors: FUJIMOTO HITOSHI MITSUBISHI DE, KABASAWA AKIFUMI MITSUBISHI DE, KASHIWAGI KENICHI MITSUBISHI D, KOMATSU FUMIAKI MITSUBISHI DEN, OHTSUKA HIROSHI MITSUBISHI DEN, SAIGUSA KAZUYUKI MITSUBISHI DE, SAKAMOTO JUNICHI MITSUBISHI DE, YOKODATE SHINYA MITSUBISHI DEN, FUJIMOTO, HITOSHI MITSUBISHI DENKI KABUSHIKI K., KABASAWA, AKIFUMI MITSUBISHI DENKI KABUSHIKI K., KASHIWAGI, KENICHI MITSUBISHI DENKI KABUSHIKI K., KOMATSU, FUMIAKI MITSUBISHI DENKI KABUSHIKI K., OHTSUKA, HIROSHI MITSUBISHI DENKI KABUSHIKI K., SAIGUSA, KAZUYUKI MITSUBISHI DENKI KABUSHIKI K., SAKAMOTO, JUNICHI MITSUBISHI DENKI KABUSHIKI K., YOKODATE, SHINYA MITSUBISHI DENKI KABUSHIKI KAISHA
Applicants: MITSUBISHI ELECTRIC CORP, MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1988
Main classification: H04N7
IPC codes: H04N7