WO2007011136A1

WO2007011136A1 - Electronic program guide method and apparatus using captured still image of digital multimedia broadcasting

Info

Publication number: WO2007011136A1
Application number: PCT/KR2006/002781
Authority: WO
Inventors: Jae-Sung Jang; Seung-Gun Park; Kwang-Pyo Choi
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2005-07-22
Filing date: 2006-07-14
Publication date: 2007-01-25
Also published as: KR20070012058A; KR100703401B1

Abstract

A method and apparatus is provided for displaying Electronic Program Guide (EPG) so as to allow a user to select a desired program in a digital broadcasting system. A still image generator captures a still image from broadcast data of each received broadcasting program, combines the captured still image with EPG data for the each broadcasting program, and stores combined data in a memory. The captured still image is displayed together with the EPG data. The method and apparatus provides the user with the captured image screen currently being transmitted in a broadcast channel rather than the previously generated fixed image, saving transmission resources of the EPG data and helping the user conveniently select channels.

Description

SPECIFICATION

Title of the Invention

ELECTRONIC PROGRAM GUIDE METHOD AND APPARATUS USING CAPTURED STILL IMAGE OF DIGITAL MULTIMEDIA BROADCASTING

Technical Field

The present invention relates generally to Electronic Program Guide (EPG), and in particular, to a method and apparatus for displaying an EPG and a still image together so as to allow a user to select a desired program in a digital broadcasting system.

Background Technology EPG service has been proposed to provide channel information, program titles and broadcast times/dates of the programs that a user can receive, and other detailed information on-line. The user can use the EPG service while viewing a desired program, or to select a desired program.

Data containing program information for EPG service, i.e. EPG data, is transmitted to the user through the same medium as that of broadcast programs, or other media. In the digital broadcasting system like the recently introduced Digital Multimedia Broadcasting (DMB) system, EPG data includes information associated with the programs that can be transmitted in each of broadcast channels for a specific period. For example, the EPG data can include information on the broadcast programs for the next one hour, the next several hours, one day, one week, etc. That is, the EPG data shows titles and simple characteristics of the broadcast programs transmitted by each individual channel by times.

The EPG data can be transmitted in an in-band of the broadcast channel where the corresponding program is transmitted, or can be transmitted in an out- band of the broadcast channel where the corresponding program is transmitted. Otherwise, for the terminal having other communication functions such as Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing (OFDM) as well as a digital broadcast service function, the EPG data can be transmitted using the other communication functions stated above.

The terminal receives the EPG data and stores the received EPG data in a memory thereof or a file system, and the user searches the EPG data and then selects a broadcast program that he/she desires to view. Commonly, the EPG data, as it is based on texts, is configured to merely provide tiles or synopses of the broadcast programs to the user. However, the user cannot simply understand the contents of a particular broadcast program only with the title displayed on the terminal. In addition, the user may want detailed information rather than the simple title before he/she selects the corresponding broadcast program.

In order to solve this problem, research is being conducted on the technologies for including such preview contents as down-sized still image or down-sized moving image of each program in the EPG data before transmission. However, including the video data in the EPG data greatly increases the capacity of the EPG data. Therefore, the conventional technology decreases transmission efficiency of a broadcast channel when the EPG data is transmitted through the same medium as that of the broadcast channel, and unnecessarily occupies a large amount of transmission resources when the EPG data is transmitted through the different medium from that of the broadcast channel.

DETAILED DESCRIPTION OF THE INVENTION

Technical Subject Therefore, to substantially solve the above problems of the conventional technology, the present invention provides a method and apparatus for displaying a captured image of a corresponding broadcast program along with an Electronic Program Guide (EPG) in a digital broadcasting system.

The present invention provides a method and apparatus for capturing images of other programs while receiving a selected program, and displaying the captured images as an EPG in a digital broadcasting system.

Technical Solution According to one aspect of the present invention, there is provided an Electronic Program Guide (EPG) method using a still image of digital multimedia broadcasting. The EPG method comprises the steps of: capturing a still image from broadcast data of each received broadcast program; combining the captured still image with EPG data for each broadcast program, and storing the combined data; and displaying the captured still image together with the EPG data.

According to another aspect of the present invention, there is provided an Electronic Program Guide (EPG) apparatus using a still image of digital multimedia broadcasting. The EPG apparatus comprises a still image generator for capturing a still image from broadcast data of each received broadcast program; a memory for combining the captured still image with EPG data for each broadcast program, and storing the combined data; and a display for displaying the captured still image together with the EPG data.

Effects of the Invention

The typical effects of the present invention will be described below in brief.

The present invention includes previously generated video data in EPG data before transmission. In this way, the present invention saves transmission resources for EPG data, and provides a user with a captured image screen currently being transmitted in a broadcast channel rather than the previously generated fixed image, helping the user conveniently select channels.

Brief Description of Drawings

FIG. 1 is a block diagram illustrating a digital broadcasting system that provides broadcast and EPG data, according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a communication system that transmits/receives broadcast and EPG data, according to another embodiment of the present invention;

FIG. 3 is a diagram illustrating exemplary EPG data according to a preferred embodiment of the present invention;

FIG. 4 is a block diagram illustrating an exemplary structure of a portable terminal capable of receiving digital broadcasting according to a preferred - A -

embodiment of the present invention;

FIG. 5 is a diagram illustrating exemplary display of received EPG data;

FIG. 6 is a block diagram illustrating a structure of an apparatus for generating a still image of broadcast data according to a preferred embodiment of the present invention;

FIG. 7 is a diagram illustrating an exemplary method of storing still images according to a preferred embodiment of the present invention;

FIGs. 8 to 10 are diagrams illustrating exemplary EPG screens according to preferred embodiments of the present invention; FIG. 11 is a flowchart illustrating an EPG operation according to a preferred embodiment of the present invention;

FIG. 12 is a block diagram of a multi-channel image receiver using one video decoder according to a preferred embodiment of the present invention;

FIG. 13 is a flowchart illustrating an operation of outputting a guide of the next broadcast program in the course of receiving a broadcast program according to a preferred embodiment of the present invention;

FIG. 14 is a flowchart illustrating an operation of capturing a still image in the course of receiving a broadcast program according to a preferred embodiment of the present invention.

Best Mode for Implementation of the Invention

Exemplary embodiments of the present invention will now be described in detail with reference to the annexed drawings. In the following description, a detailed description of known functions and configurations incorporated herein has been omitted for clarity and conciseness. The terms used herein are defined taking into account their functions in the present invention, and are subject to change according to user, user's intention, or usual practice. Therefore, the definition should be given based on the overall contents of the specification.

The gist of the present invention is to display a captured still image of a corresponding broadcast program along with an Electronic Program Guide (EPG) in a digital broadcasting system. A terminal having a reception function for digital broadcasting detects one of consecutive image frames constituting a moving image of broadcast data, and stores the detected frame as a still image. The still image is provided to the user along with the EPG received in association with broadcast programs.

The terminal receives EPG data transmitted from a broadcast center for digital broadcasting, in order to allow the user to first receive the broadcast channel that he/she desires to view, or to allow the user to select another broadcast channel. The broadcast center transmits EPG data containing information on a plurality of available broadcast programs, and broadcast program data. The EPG data is transmitted through the same medium as that of the broadcast channel where the broadcast program data is transmitted, or through the different medium from that of the broadcast channel.

FIG. 1 illustrates a digital broadcasting system that provides broadcast and EPG data, according to an embodiment of the present invention. As illustrated, broadcasting stations 110, 120 and 130 each provide broadcast and EPG data 140 to a portable terminal 150 through the same channel or different channels.

The terminal having a reception function for digital broadcasting can communicate with a cellular mobile communication system, using other communication functions, for example, such wireless access technologies as CDMA or OFDM, in addition to the function of receiving digital broadcasting. This means a cellular mobile phone having a digital broadcasting function. Such a terminal can receive EPG data independently of broadcast data from a base station of the cellular mobile communication system.

FIG. 2 illustrates a communication system that transmits/receives broadcast and EPG data, according to another embodiment of the present invention. As illustrated, a portable terminal 220, a cellular communication terminal having, for example, a digital broadcasting reception function, can send a request for EPG data to a mobile communication service provider before receiving digital broadcasting. The mobile communication service provider 230 transmits EPG data generated using information on broadcast programs provided from a broadcast center 210, to the portable terminal 220 via a cellular base station 240. The EPG data includes channel information, program titles, broadcast times/dates, and other detailed information of broadcast programs. If a user previously sets EPG-required broadcast programs, the mobile communication service provider 230 can provide EPG data for the set broadcast programs to the portable terminal 220 via the cellular base station 240 using Multimedia Message Service (MMS) or wireless Internet.

The portable terminal 220 displays an EPG based on the EPG data on its screen, and if the user selects a desired broadcast program, the portable 220 terminal sets a receiver associated with digital broadcasting reception, so as to allow the user to receive a broadcast channel of the selected broadcast program. Then the portable terminal 220 receives broadcast data transmitted from the broadcast center 210, and provides a digital broadcast service to the user. The broadcast data can include EPG data. That is, after starting receipt of digital broadcasting, the portable terminal 220 can acquire EPG data directly from the broadcast center 210.

FIG. 3 illustrates exemplary EPG data according to a preferred embodiment of the present invention.

As illustrated, EPG data 310 includes broadcast channel information 320 and text data 330. The broadcast channel information 320 includes such physical information as broadcast channel identifiers and frequencies for receiving brbadciast channels. Herein, information on broadcast programs 01, 02 and 03

(these numerals indicate broadcast program identifiers) of a channel 1 CHl (for example, Korean Broadcasting System (KBS)), a broadcast program 12 of a channel 2 CH2 (for example, Munhwa Broadcasting Center (MBC)), and a broadcast program 25 of a channel 3 CH3 (for example, Education Broadcasting

Center (EBS)) is shown.

The text data 330, as shown in detail by reference numeral 340, includes broadcast times, program titles, and synopses. The text data 330 includes texts 01, 02, 03, 12 and 25 indicating detailed information on their associated broadcast programs 01, 02, 03, 12 and 25.

FIG. 4 illustrates an exemplary structure of a portable terminal capable of receiving digital broadcasting according to a preferred embodiment of the present invention.

Referring to FIG. 4, a portable terminal 400 includes a broadcast receiver

420 and a cellular communication unit 430. The cellular communication unit 430 receives normal call-related signals from a cellular base station via an antenna, and provides the received signals to a controller 410. The cellular communication unit 430 receives EPG data for digital broadcasting via a cellular mobile communication network or wireless Internet, and provides the received EPG data to the controller 410. In another case, the broadcast receiver 420 receives the EPG data and provides the received EPG data to the controller 410 in the same way. A memory 470 includes a storage area for storing the EPG data, and the EPG data is displayed on a display 450 under the control of the controller 410.

A key input unit 440 receives a key input indicating a broadcast program that the user selected for receipt of digital broadcasting depending on the EPG data displayed on the display 450, and provides the received key input to the controller 410. The controller 410 sets the broadcast receiver 420 according to the key input so as to allow it to receive a broadcast channel of the selected broadcast program.

Then the broadcast receiver 420 receives broadcast data of the selected broadcast program, and provides the received broadcast data to the controller 410. The broadcast data includes video data and audio data, and can further include text data and EPG data. The video data and the audio data are provided to the display 450 and an audio input/output unit 460, respectively. The EPG data received by the broadcast receiver 420 is stored in the memory 470 by the controller 410 in the same way.

FIG. 5 illustrates exemplary display of EPG data received by the broadcast receiver 420 or the cellular communication unit 430.

Referring to FIG. 5, reference numeral 510 indicates a status indication area that can be optionally displayed to indicate a communication status and a battery status, reference numeral 520 indicates a program category, for example, movie, drama, comedy, sports, etc., and reference numeral 530 indicates broadcast times and titles of the broadcast programs classified according to the category. The user places a cursor 540 on a desired broadcast program by manipulating the key input unit 440, and selects the broadcast program by pushing a predetermined select key. Then the broadcast receiver 420 receives broadcast data of the selected broadcast program, and video and audio of the received broadcast data are output through the display 450 and the audio input/output unit 460 of the terminal.

In FIG. 4, the controller 410 includes a video/audio processor 480 composed of a video decoder. The video/audio processor 480 restores compressed video data of the broadcast data received by the broadcast receiver 420, such that it can be displayed on the display 450. Particularly, according to a preferred embodiment of the present invention, the video/audio processor 480 captures a single frame of the video data, and generates a still image using the captured frame. The still image is stored in the memory 470 along with EPG data, and when necessary, is displayed on the display 450 together with EPG data of the corresponding broadcast program.

Though will be described later, the EPG data and the captured still image may not be automatically displayed. That is, the EPG data and the still image are stored in the memory 470 of the terminal, selectively read out from the memory 470 according to manipulation of the user, and then displayed on the screen. When EPG display is not selected, the terminal can display a broadcast program currently received through the broadcast channel selected by the user. Upon receipt of a request for EPG display from the user while displaying the broadcast program, the terminal reads the EPG data and the still image from the memory and outputs the read EPG data and still image. The EPG data and the still image are displayed on the full screen instead of the broadcast program, or displayed on a partial area of the screen where the broadcast program is displayed.

FIG. 6 illustrates a structure of an apparatus for generating a still image of broadcast data according to a preferred embodiment of the present invention. The apparatus includes a broadcast channel receiver 610, a video decoder 620, a display 630, a still image detector 640, a still image storage 650, and a channel selector 670. The broadcast channel receiver 610 is included in the broadcast receiver 400 of FIG. 4.

Referring to FIG. 6, the broadcast channel receiver 610 receives broadcast data of a broadcast program that a user desires to view, by the channel selector 670, and provides the received broadcast data to the video decoder 620. The video decoder 620 restores compressed video data and audio data of the broadcast data.

The video decoder 620, supporting H.263, Moving Picture Experts Group

(MPEG)-4 part-2 or MPEG-4 part-10/H.264, decodes a series of image frames constituting compressed video data, and generates image signals corresponding to each of the image frames. Although not illustrated, if the user desires to receive a broadcast program, the generated image signals will be projected on the screen through the display 630.

On the contrary, if there is an intention to generate a still image, the still image detector 640 detects an image signal of one point among the image signals decoded by the video decoder 620. In this case, the still image can be generated as a down-sized image compared to a size of the original image signal. This is to save the storage space necessary for storing the still image, and display as many still images of the broadcast channels as possible on the size-limited screen of the portable terminal. The generated still image is stored in the still image storage 650 under the control of the channel selector 670 such that it is mapped to EPG data of the corresponding broadcast program.

After a still image is previously stored for a particular broadcast program, if a new still image is extracted for the broadcast program, the previously stored still image is cleared and the new still image is stored, replacing the previous still image. Therefore, a still image storage 716 always stores the last still image for each broadcast program. The stored still image is displayed on the display 630 together with EIP data (for example, texts), at the user's request or automatically.

The still image is combined with EPG data of the corresponding broadcast program, and then stored. There are several possible combining methods. For example, the still image and the EPG data are recorded in separate storage areas, and then associated with a corresponding broadcast program of the EPG data by an identifier. As another example, the still image and the EPG data are stored in the same storage area. FIG. 7 illustrates an exemplary method of storing still images according to a preferred embodiment of the present invention.

Referring to FIG. 7, an EPG storage 710 includes a broadcast channel information storage area 712, a text data storage area 714, and an image storage area 716. The broadcast channel information storage area 712 and the text data storage area 714 are filled with broadcast channel information and text data of

EPG data received from a broadcast center or a cellular base station, and the image storage area 716 is composed of empty address areas predetermined according to broadcast channel information corresponding to the time at which the EPG data is stored. According to an example of the EPG data 310, the image storage area 716 having address areas corresponding to broadcast programs 01,

02, 03, 12 and 25 is formed.

The still images extracted for each broadcast channel are stored in the image storage area 716 such that they are mapped to corresponding broadcast channel information, at the user's image search request or automatically. Herein, only the images 01, 02, 03 and 12 corresponding to the broadcast programs 01, 02, 03 and 12 are captured and stored in the image storage area 716, and the still image for the broadcast program 25 is not generated.

An EPG storage 720 and a still image storage 730 are provided to separately store the still images and the EPG. The EPG storage 720 consists of a broadcast channel information storage area 712 and a text data storage area 714 for storing broadcast channel information and text data of EPG data. The still image storage 730 is composed of a broadcast program identifier area 732 and an image storage area 734. The image storage area 734 stores still images captured from a broadcast program directly received by the portable terminal. The broadcast program identifier area 732 stores broadcast program identifiers for indicating from which broadcast program the stored still images were captured.

* According to a preferred embodiment of the present invention, the still images captured from the broadcast programs are used for displaying a list of the currently available broadcast programs, in response to the user's manipulation or automatically. If there is a request for EPG service, the previously stored and stored EPG data and the captured still images are displayed together on the screen of the portable terminal. FIGs. 8 and 9 illustrate exemplary EPG screens according to an embodiment of the present invention.

Referring to FIG. 8, reference numeral 810 indicates a program category, and reference numeral 812 indicates detailed information (broadcast times and titles) of broadcast programs classified by the category, and still images, which are shown in the form of a lattice. The user places a cursor 814 on a desired broadcast program, and selects the broadcast program by pushing a predetermined select key. Then the received broadcast data of the selected broadcast program is output through a screen of the terminal.

Referring to FIG. 9, similarly, reference numeral 820 indicates a program category, and reference numeral 822 indicates detailed information (broadcast times, titles and synopses) of broadcast programs classified by the category, and still images, which are listed longitudinally. The user places a cursor 824 on a desired broadcast program, and selects the broadcast program by pushing a predetermined select key. Then the received broadcast data of the selected broadcast program is output through a screen of the terminal.

FIG. 11 is a flowchart illustrating an EPG operation according to a preferred embodiment of the present invention.

Referring to FIG. 11, in step 910, a portable terminal receives EPG data from a broadcast center or a cellular base station, and stores the received EPG data. The EPG data includes a list of broadcast programs that the portable terminal can receive at the current position. In step 912, the portable terminal determines whether there is an image search request. The portable terminal receives the image search request either automatically at the reception time of the EPG data or depending on the user's manipulation. If it is determined in step 912 that there is an image search request, the portable terminal proceeds to step 914.

Otherwise, the portable terminal proceeds to step 924.

In step 924, the portable terminal determines whether an EPG display request is received from the user or it will automatically display the EPG. If there is no need to display the EPG, the portable terminal ends the operation. On the contrary, if there is a need to display the EPG, the portable terminal displays text information of each broadcast program included in the EPG data in step 926. An exemplary display of step 926 can be equal to that of FIG. 5.

In step 914, the portable terminal sets a broadcast channel of a broadcast program to be searched, among the broadcast programs included in the EPG data. The broadcast channels can be sorted in order of broadcast program identifiers included in the EPG data. In step 916, the portable terminal, as described above, captures a still image for a broadcast program of the set broadcast channel, and stores the captured still image such that it should be mapped to the broadcast program. In step 918, the portable terminal determines whether it will continuously search images of the next broadcast channel. If still images for all broadcast programs are stored or the image search is stopped by the user, the portable terminal proceeds to step 920. Otherwise, the portable terminal returns to step 914 to search the next broadcast channel.

In step 920, the portable terminal determines whether EPG display is requested by the user or the EPG will be automatically displayed as still images fό'r all broadcast programs are acquired. If there is a need to display the EPG, the portable terminal displays the text information of each broadcast program included in the EPG data and its associated captured still image together in step 922. An exemplary display of step 922 can be equal to that of FIG. 8 or 9. If there is no need to display the EPG, the portable terminal ends the operation.

If the EPG is displayed in step 922 or step 926, the user places a cursor on a desired broadcast program, and then selects the broadcast program to receive the broadcast program.

Meanwhile, in the course of receiving a selected main broadcast program and displaying the received main broadcast program on the full screen of the portable terminal, an improved embodiment of the present invention searches still images of other broadcast programs, or searches images being displayed on a small screen area. The small screen area can overlap with a partial area of the full screen. That is, in the communication scheme capable of receiving two or more broadcast channels like CDMA or OFDM, the portable terminal captures a still image of another broadcast program while receiving one broadcast program.

An exemplary EPG screen according to the improved embodiment is shown in FIG. 10.

Referring to FIG. 10, reference numeral 830 indicates a screen of the broadcast program that the portable terminal is now receiving, and reference numeral 832 means text information of the next broadcast program in order of a broadcast program identifier based on the EPG data. Reference numeral 834 indicates a screen on which a still image captured for the next broadcast program is displayed. The still image displayed in a Picture-in-Picture (PiP) fashion can be captured by the same or separate video decoder as/from the video decoder for the currently received broadcast program while the current broadcast program is being received.

However, using a separate video decoder to simply detect a still image, though it contributes to maximization of video decoding performance, is inappropriate for a portable digital multimedia broadcast receiver due to the high system complexity. Therefore, a multi-channel image decoder that efficiently simultaneously decodes video images received from more than two broadcast channels with one video decoder is used.

Specifically, the current broadcast channel that the user desires to view becomes a main channel, and another broadcast channel from which the user desires to capture a still image, or the next broadcast channel that the user desires to search becomes a sub channel. One video decoder that can be connected to both the main channel and the sub channel decodes a key frame of the sub channel at a possible time, while decoding the image frames of the main channel. The "possible time" refers to the time at which a key frame is generated in the main channel.

FIG. 12 illustrates a block diagram of a multi-channel image receiver for generating a still image of a sub channel using one video decoder according to a preferred embodiment of the present invention. There are shown two channel receivers 1002 and 1012 for a main channel 1000 and a sub channel 1010, a key frame discriminator 1003 for the main channel 1000, a key frame discriminator 1014 for the sub channel 1010, a channel selector 1004, a video decoder 1006, an image selector 1008, a display 1016, and a still image detector 1018. The channel receivers 1002 and 1012 are included in the broadcast receiver 420 of FIG. 4.

Referring to FIG. 12, a broadcast channel that a user desires to view is mapped to the main channel 1000, and another broadcast channel from which the user desires to capture a still image is mapped to the sub channel 1010. This channel mapping can be performed by an undepicted channel selector. A received signal including video data of the main channel 1000 undergoes demultiplexing/demodulation by the channel receiver A 1002. Similarly, a received signal including video data of the sub channel 1010 undergoes demultiplexing/demodulation by the channel receiver B 1012.

The channel receiver A 1002 outputs consecutive frames containing compressed video information of the main channel 1000. The key frame discriminator 1003 discriminates a key frame by analyzing frame headers of the main channel, and provides a control signal to the channel selector 1004 and the image selector 1008 upon detecting the key frame of the main channel.

The channel receiver B 1012 outputs consecutive frames containing compressed video information of the sub channel 1010. The key frame extractor 1014 attempts to detect a key frame by analyzing frames of the sub channel, and upon detecting the key frame of the sub channel, stores the key frame of the sub channel in a buffer thereof (not shown). If the next key frame of the sub channel is detected before the stored key frame of the sub channel is output, the key frame extractor 1014 removes the previously stored key frame of the sub channel by clearing the buffer, and stores again the next key frame. In this way, the key frame extractor 1014 always stores the last key frame of the sub channel. In this case, differential frames of the sub channel are disregarded.

If a control signal indicating generation of the key frame of the sub channel is not generated by the key frame discriminator 1003, the channel selector 1004 simply bypasses the frames of the main channel received through the key frame discriminator 1003, to the video decoder 1006. When the control signal is generated, the channel selector 1004 reads the key frame of the sub channel, buffered in the key frame extractor 1014, and delivers the read key frame to the video decoder 1006. After delivering the key frame of the sub channel, the channel selector 1004 delivers frames of the main channel to the video decoder 1006, restarting from the key frame of the main channel.

That is, when the control signal is generated, decoding on the key frame of the main channel is temporarily interrupted, and the key frame of the sub channel is input to the video decoder 1006 by the channel selector 1004. In other words, the key frame of the sub channel is input to the video decoder 1006 before the key frame of the main channel is input to the video decoder 1006. In this case, the key frame of the main channel and non-key frames to be input later can be temporarily stored together in the buffer of the channel receiver A 1002. In another case, if the video decoder 1006 has a capability of operating at a sufficiently high speed, the video decoder 1006 decodes the key frame of the sub channel while the decoding on the main channel is temporarily interrupted, and decodes the key frame of the main channel before succeeding frames of the main channel are received.

The video decoder 1006 decodes image frames received through the channel selector 1004, and outputs image signals corresponding to each frame. If the received frame is a differential frame rather than the key frame, the video decoder 1006 restores the image signal of the corresponding channel by combining the received differential frame with the previously processed frame. On the contrary, if the received frame is the key frame, the video decoder 1006 refreshes the existing image processing, and restores the image signal of the corresponding channel simply with the key frame. Herein, the procedure in which the video decoder 1006 restores the image signal follows the image compression technology, and this is not related to the gist of the present invention, so a detailed description thereof will be omitted.

The image signals output from the video decoder 1006 are input to the image selector 1008. When the control signal indicating generation of the key frame of the main channel is not generated by the key frame discriminator 1003, the image selector 1008 waits for a one-frame processing time of the video decoder 1006, and then outputs the image signals output from the video decoder 1006 to a larger screen (i.e. the full screen) of the display 1016 as a main channel image.

When the control signal is generated, the image selector 1008 waits for a one-frame processing time of the video decoder 1006, and then outputs the image signal output from the video decoder 1006 to the still image detector 1018 as a sub channel mage. The still image detector 1018 generates a captured still image of the sub channel from the sub channel image. The still image becomes an image down-sized to a predetermined size compared with the original image signal.

The captured still image of the sub channel is output to a smaller screen of the display 1016. In this case, the smaller screen can be displayed together with text information for the sub channel of the EPG data. That is, the text information of the sub channel, read out from the EPG data, is displayed along with the still image. The exemplary display of the main channel and the sub channel can be equal to that of FIG. 10. In addition, the captured still image of the sub channel can be stored together with the EPG data of the sub channel in an image storage (not shown) such that they can be displayed at the user's request.

FIG. 13 is a flowchart illustrating an operation of outputting a guide of the next broadcast program in the course of receiving a broadcast program according to a preferred embodiment of the present invention. The "next broadcast program" refers to a broadcast program arranged after the currently received broadcast program according to the order where the related information is arranged in the EPG data.

Referring to FIG 13, after a broadcast program that a user desires to view is selected by the user's manipulation in step 1110, a portable terminal sets a broadcast channel of the selected broadcast program as a main channel, and receives broadcasting of the main channel in step 1112. In step 1114, the portable terminal checks channel information for the next broadcast program of the selected broadcast program according to a broadcast program list of EPG data. In step 1116, the portable terminal sets the checked next broadcast program as a sub channel, and receives broadcasting of the sub channel. In step 1118, a still image for the sub channel is captured in the foregoing manner. The captured still image is mapped to the corresponding EPG data and then stored, so that it can be used in response to an EPG display request.

In step 1120, the portable terminal determines whether there is a search request for the next broadcast channel corresponding to the next broadcast program, from the user. If there is no search request for the next broadcast channel, the portable terminal returns to step 1110 to continuously receive the main channel, or to set another broadcast channel selected by the user as a main channel and receive the channel. On the contrary, if there is a search request for the next broadcast channel, the portable terminal outputs, in step 1122, the text information of the next broadcast channel based on the EPG data and the captured still image to a part of the screen where the image of the main channel is output.

If the user checks the text information and the still image of the next broadcast channel and then selects the next broadcast channel using a cursor, the selected broadcast channel is switched as a main channel, and then starts to be output through the full area of the screen. The portable terminal performs the procedure of FIG. 13 while receiving the new main channel to receive the corresponding next broadcast channel, and detects/stores a still image of the next broadcast channel.

The multi-channel image receiver of FIG. 12 can be used not only for detecting a still image of the next broadcast channel while receiving one broadcast channel, but also for detecting still images of several broadcast channels. That is, the multi-channel image receiver sets the broadcast channel that the user desires to view as a main channel, and receives/displays an image of the main channel. At the same time, the multi-channel image receiver sequentially captures/stores still images of other several broadcast channels as sub channels.

The stored still images are used for displaying a broadcast program list as shown in FIG. 8 or 9, in response to the user's manipulation or automatically.

Referring to FIG. 14, if a broadcast program that a user desires to view is selected by the user's manipulation in step 1210, a portable terminal sets a broadcast channel of the selected broadcast program as a main channel and receives broadcasting of the main channel in step 1212. In step 1214, the portable terminal checks channel information for another broadcast program that the user desires to search, sets the broadcast program desired to be searched as a sub channel, and receives broadcasting of the sub channel. Initially, the broadcast program desired to be searched can be the next broadcast program of the main channel based on the broadcast program list of the EPG data. In step 1216, a still image for the sub channel is captured in the foregoing manner. The captured still image is stored so that it can be used in response to an EPG display request.

In step 1218, the portable terminal determines whether it will continuously search images of the next broadcast channel. If still images for all broadcast programs are stored or the image search is stopped by the user, the portable terminal proceeds to step 1220. Otherwise, the portable terminal returns to step 1214 to search the next broadcast channel.

In step 1220, the portable terminal determines whether EPG display is requested by the user. If there is a need to display the EPG, the portable terminal displays, in step 1222, the text information of each broadcast program included in the EPG data and its associated captured still image together, or displays only the text information and the still image for the next broadcast program of the currently received broadcast program (i.e. main channel). If there is no need to display the EPG, the portable terminal returns to step 1210 to continuously receive the currently received broadcast program or to receive another broadcast channel selected by the user.

In step 1222, if the portable terminal displays the EPG and the captured still images, the user can place a cursor on a desired broadcast program, and then select/receive the broadcast program.

As another example, the multi-channel image receiver alternately sets the broadcast channels desired to be searched, to a main channel and a sub channel, and rapidly captures still images of the broadcast channels at double speed. In this case, still images are detected from both the main channel and the sub channel. The detected still images are stored in a memory, and displayed together with EPG data in the form of a list.

Industrial Utility

While the invention has been shown and described with reference to a certain preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Although the preferred embodiment captures a still image of the currently received broadcast program and stores/displays the captured still image together with EPG data, an alternative embodiment can capture a moving image of the currently received broadcast program, and store/display the captured moving image together with EPG data.

Claims

WHAT IS CLAIMED IS:

1. An Electronic Program Guide (EPG) method using a still image of digital multimedia broadcasting, the method comprising the steps of: capturing a still image from broadcast data of each received broadcast program; combining the captured still image with EPG data for each broadcast program, and storing the combined data; and displaying the captured still image together with the EPG data.

2. The EPG method of claim 1, wherein the step of capturing a still image comprises the steps of: receiving a frame indicating a compressed image of a main channel, determining whether the frame of the main channel is a key frame; if the received frame of the main channel is not a key frame, decoding a non-key frame of the main channel and outputting the decoded non-key frame as an image signal of the main channel; if the received frame of the main channel is a key frame, decoding a previously-stored last key frame of a sub channel, and outputting the decoded last key frame as an image signal of the sub channel; generating the still image using the image signal of the sub channel; and after decoding the key frame of the sub channel, decoding a key frame of the main channel and outputting the decoded key frame of the main channel as an image signal of the main channel.

3. The EPG method of claim 2, wherein the decoded image signals are distinguished as a main channel or a sub channel according to whether the key frame of the main channel is detected.

4. The EPG method of claim 1, wherein the step of capturing a still image comprises the step of, in the course of setting a broadcast program that a user desires to view, as a main channel, and receiving the main channel, sequentially setting other broadcast programs as a sub channel and capturing still images for the other broadcast programs.

5. The EPG method of claim 1, wherein the step of capturing a still image comprises the step of, in the course of setting broadcast data of a broadcast program that a user desires to view, as a main channel, and displaying the main channel, setting a next broadcast program of the currently received broadcast program as a sub channel and capturing a still image for the next broadcast program.

6. The EPG method of claim 5, wherein the still image for the next broadcast program is displayed on a part of a screen area where the broadcast data of the main channel is displayed, in an overlapping fashion.

7. The EPG method of claim 1, wherein the storing step comprises the step of storing the still image in the same or different storage area as/from that of the EPG data.

8. The EPG method of claim 1, wherein the still image is generated in a reduced size compared with an original size of the broadcast data.

9. The EPG method of claim 1, wherein the EPG data includes broadcast time and title of the broadcast program.

10. The EPG method of claim 1, wherein the EPG data includes broadcast time and title, and synopsis of the broadcast program.

11. The EPG method of claim 1, wherein the displaying step comprises the step of, in the course of displaying a broadcast program that a user desires to view on a screen of a terminal receiving the digital multimedia broadcasting, displaying the still image and the EPG data together on a smaller screen area.

12. The EPG method of claim 1, wherein the displaying step comprises the step of displaying the still image and the EPG data in the form of a list, if there is an EPG display request from a user.

13. An Electronic Program Guide (EPG) apparatus using a still image of digital multimedia broadcasting, the apparatus comprising: a still image generator for capturing a still image from broadcast data of each received broadcast program; a memory for combining the captured still image with EPG data for each broadcast program, and storing the combined data; and a display for displaying the captured still image together with the EPG data.

14. The EPG apparatus of claim 13, wherein the still image generator comprises: a key frame extractor for receiving frames indicating a compressed image of a sub channel, extracting a key frame among the frames of the sub channel, and storing the extracted key frame; a key frame discriminator for receiving a frame indicating a compressed image of a main channel, and determining whether the frame of the main channel is a key frame; a channel selector for, upon failure to detect a key frame of the main channel, outputting frames of the main channel, and upon detecting a key frame of the main channel, outputting the stored key frame of the sub channel, and after outputting the key frame of the sub channel, outputting the key frame of the main channel and its succeeding frames; a video decoder for decoding frames of the main channel or the sub channel, output from the channel selector, and outputting image signals; an image selector for distinguishing the decoded image signals as a main channel or a sub channel, and outputting an image signal of the main channel to the display; and a still image detector for generating the still image using the image signal of the sub channel, distinguished by the image selector.

15. The EPG apparatus of claim 14, wherein the decoded image signals are distinguished as a main channel or a sub channel according to whether the key frame of the main channel is detected.

16. The EPG apparatus of claim 13, wherein in the course of setting a broadcast program that a user desires to view, as a main channel, and receiving the main channel, the still image generator sequentially sets other broadcast programs as a sub channel and captures still images for the other broadcast programs.

17. The EPG apparatus of claim 13, wherein in the course of setting broadcast data of a broadcast program that a user desires to view, as a main channel, and displaying the main channel, the still image generator sets a next broadcast program of the currently received broadcast program as a sub channel and captures a still image for the next broadcast program.

18. The EPG apparatus of claim 17, wherein the display displays the still image for the next broadcast program on a part of a screen area where the broadcast data of the main channel is displayed, in an overlapping fashion.

19. The EPG apparatus of claim 13, wherein the memory stores the still image in the same or different storage area as/from that of the EPG data.

20. The EPG apparatus of claim 13, wherein the still image is generated in a reduced size compared with an original size of the broadcast data.

21. The EPG apparatus of claim 13, wherein the EPG data includes broadcast time and title of the broadcast program.

22. The EPG apparatus of claim 13, wherein the EPG data includes broadcast time and title, and synopsis of the broadcast program.

23. The EPG apparatus of claim 13, wherein in the course of displaying a broadcast program that a user desires to view on a screen of a terminal receiving the digital multimedia broadcasting, the display displays the still image and the EPG data together on a smaller screen area.

24. The EPG apparatus of claim 13, wherein the display displays the still image and the EPG data in the form of a list, if there is an EPG display request from a user.