Abstract:
A method and apparatus of acquiring program guide information for a digital television receiver. There is provided a digital television signal receiver, including: a tuner to receive a digital television transport stream (TS) which includes audio, video, and program information; an extractor to extract the program information from the received TS; a storage to store the extracted program information; a processor to access the storage to generate a channel list based on the stored program information stored in the storage, where the channel list comprises at least one channel number and the at least one channel number comprises at least one main channel number; and a user interface to allow a user to navigate the channel list to search a channel number, wherein if the at least one main channel number has a corresponding sub-channel number, the sub-channel number can be listed after the at least one main channel number.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of application Ser. No. 09/163,977, filed Sep. 30, 1998 which is now pending. This application claims the benefit of Korean Application No. 98-36628, filed Sep. 5, 1998, in the Korean Industrial Property Office, the disclosures of all of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The present invention relates to a method of acquiring program guide information in an image signal receiving apparatus, and a method and apparatus for guiding a program using the same. 
         [0004]    2. Description of the Related Art 
         [0005]    Generally, program information of a conventional analog TV broadcast is supplied to publications such as newspapers, TVs, magazines, etc. However, in a digital multichannel broadcast, tens to hundreds of channels are provided, so that a selection scope of viewers becomes wider and simultaneously program selection is significantly complicated. 
         [0006]    In such a digital broadcast, an electronic program guide (EPG) providing a program list or information on the content of each program is being introduced as a fundamental data service. 
         [0007]    Current EPG information is transmitted per channel. That is, since the EPG information of a corresponding channel is transmitted per channel, it is difficult to obtain the EPG information of all channels capable of being accessed. 
         [0008]    To be more specific, the EPG information of a current received channel can be obtained by interpreting control information included in a transport packet received. However, in order to acquire EPG information of all channels capable of being accessed, a user must tune all channels individually. 
         [0009]    In the digital broadcast, many more channels are provided than in the analog broadcast, and each channel can include subchannels. Therefore, it is important to swiftly interface the EPG information of each channel to a user. 
       SUMMARY 
       [0010]    An aspect of embodiment, an apparatus of acquiring useful EPG information is provided. 
         [0011]    An aspect of embodiment, there is provided a digital television signal receiver, including: a tuner to receive a digital television transport stream (TS) which includes audio, video, and program information; an extractor to extract the program information from the received TS; a storage to store the extracted program information; a processor to access the storage to generate a channel list based on the stored program information stored in the storage, where the channel list includes at least one channel number and the at least one channel number comprises at least one main channel number; and a user interface to allow a user to navigate the channel list to search a channel number, wherein if the at least one main channel number has a corresponding sub-channel number, the sub-channel number can be listed after the at least one main channel number. 
         [0012]    An embodiment, the channel list can be accessed according to a listing sequence comprising main channel numbers and respective sub-channel numbers. Also, the program information can be navigated using a program specific information. 
         [0013]    According to further embodiment, the listing sequence can be determined based on proximity between main channel numbers to allow the main channel number to be listed with at least one upper close channel number or at least one lower close channel number. 
         [0014]    According to another embodiment, there is provided a converter to convert an IF signal received from the tuner into a baseband signal; and a channel decoder to decode the baseband signal to reconstruct a transport stream (TS). 
         [0015]    An aspect of embodiment, the channel list can be accessed according to a listing sequence comprising main channel numbers and respective sub-channel numbers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above objectives and advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which: 
           [0017]      FIG. 1  is a block diagram illustrating the configuration of a general DTV receiver; 
           [0018]      FIG. 2  is a flowchart illustrating a method of acquiring program guide information, according to the present invention; 
           [0019]      FIG. 3  is a flowchart illustrating a program guide method according to the present invention; 
           [0020]      FIGS. 4A through 4C  show a program list displayed on a screen in the method shown in  FIG. 3 ; 
           [0021]      FIG. 5  is a block diagram illustrating an embodiment of a program guide apparatus according to the present invention; and 
           [0022]      FIG. 6  is a block diagram illustrating another embodiment of a program guide apparatus according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0023]    Channel numbers, channel names, program names, schedules, etc. generally transmitted as data are displayed on a TV screen as a program list having a time axis and a channel axis by EPG software of a receiver. A user can perform operations such as tuning or programming in the program list by manipulating a cursor. 
         [0024]      FIG. 1  is a block diagram showing the configuration of a conventional digital multichannel TV (hereinafter, called “DTV”) receiver. In  FIG. 1 , a tuner  102  tunes a radio frequency (RF) channel from received broadcast signals via an antenna  100  under the control of a microprocessor  124 . The tuner  102  outputs an intermediate frequency (IF) signal of the tuned channel, and an IF module  104  outputs a baseband signal of the tuned channel to a channel decoder  106 . 
         [0025]    The channel decoder  106  channel decodes the baseband signal received from the IF module  104  and reproduces data bit lines. Each of the reproduced data bit lines is divided into audio data, video data, and additional data by a transport stream (TS) decoder  108 . 
         [0026]    The audio data is applied to an audio decoder  110  and decoded according to an MPEG standard or dolby AC-3 standard by the audio decoder  110 . The audio data is processed by an audio processing and output unit  112  and output as sound through a speaker  114 . 
         [0027]    The video data is applied to a video decoder  116 , decoded according to the MPEG standard, applied to an on-screen-display (OSD) mixer  118 , mixed with OSD data generated by the microprocessor  124 , processed by a video processing and outputting unit  120 , and output on the screen of a picture tube  122 . Here, the OSD data is used for the microprocessor  124  to display various information as graphics or text on a screen. 
         [0028]    The additional data is applied to the microprocessor  124 . The microprocessor  124  extracts program guide information or other information and stores the extracted information in a memory unit  126 . Typical EPG information is stored in a nonvolatile memory such as an EEPROM or a flash ROM. 
         [0029]    A key pad  130  and an infra red (IF) receiving unit  134  are connected to the microprocessor  124  which is a control unit of a DTV receiver, via a user interface  128 . The microprocessor  124  performs operations depending on various operation commands received from an IR remote controller  132  via the keypad  130  and the IR receiving unit  134 , according to a program stored in the memory  126 . Here, the IR remote controller  132  can be a wireless mouse such as an air mouse, a remote controller, etc. 
         [0030]    A command from the IR remote controller is received as an IR signal by the IR receiving unit  134 , and applied to the microprocessor  124  via the user interface  128 . Also, the additional data from the TS decoder  108  is applied to the microprocessor  124 . Here, the additional data includes program specific information (PSI) as a table with respect to program associated information prescribed in MPEG-2, and the aforementioned EPG information. 
         [0031]    The memory unit  126  includes a ROM for storing the program of the microprocessor  124 , a RAM for temporarily storing data created during the program execution in the microprocessor  124 , and an electrically erasable and programmable ROM (EEPROM) for storing various reference data. 
         [0032]    The microprocessor  124  is connected via a bus  136  to the tuner  102 , the IF module  104 , the channel decoder  106 , the TS decoder  108 , the audio decoder  110 , the audio processing and outputting unit  112 , the video decoder  116 , the OSD mixer  118 , the video process and output unit  120 , and the memory unit  126 . 
         [0033]    In the apparatus shown in  FIG. 1 , while a user selects and receives a channel, the microprocessor  124  detects EPG information from the additional data provided by the TS decoder  108 . EPG information of a corresponding channel is stored in the memory unit  126 , and provided to a user in a program guide mode. 
         [0034]    Since the EPG information is transmitted separately for each channel, EPG information of a corresponding channel cannot be acquired if that channel is not tuned. 
         [0035]    Thus, a program list for all channels cannot be provided in the program guise mode for guiding a program list for each channel to a user. 
         [0036]    In the present invention, while a program of a channel tuned by the tuner  102  is not displayed, for example, while a user selects or programs a program with reference to EPG information displayed on a screen or views line input, an accessible channel is scanned in a background operation, to obtain the EPG information. 
         [0037]      FIG. 2  is a flowchart showing a method of obtaining program guide information according to the present invention, which shows an example of obtaining EPG information in a program guide mode 
         [0038]    When a program guide command is input from a user via the keypad  130 , the apparatus shown in  FIG. 1  enters into a program guide mode. In the program guide mode, first, all channels capable of being accessed by the tuner  102  are scanned to obtain program guide information for each channel, in step S 200 . The microprocessor  124  controls the tuner  102  to scan as many channels as possible, and detects the program guide information for each channel from additional data introduced via the tuner  102 . Here, the accessible channels include not only the channels capable of being accessed by the tuner  102  but also line input. 
         [0039]    Obtained EPG information is stored, in step S 202 . 
         [0040]    The obtained EPG information is stored in the memory unit  126 . The EPG information is transmitted for each channel, so that the microprocessor  124  acquires EPG information of a corresponding channel whenever a channel is changed and stores the acquired EPG information to the memory unit  126 . 
         [0041]    According to the method of  FIG. 2 , when the program guide mode begins, program guide information with respect to all the accessible channels is acquired all at once in an initial stage. Thus, it takes a lot of time to display the program guide information. 
         [0042]    An increase in the number of accessible channels requires a longer time to display the program guide information, and causes the user inconvenience. In particular, a digital broadcast provides tens or hundreds of channels, thus requiring a lot of time to acquire the EPG information of all channels. 
         [0043]    To solve this problem, in the present invention, the EPG information of a prior channel among prioritized channels is obtained first of all, and the EPG information of a channel having the lowest priority is then obtained, thereby accomplishing smooth user interface. 
         [0044]    The priority of channel search is determined by the distance (interval) between channels tuned before a program guide command is applied, or by a probability distribution of channels, i.e., the accumulation of the number of times which channels are selected. 
         [0045]    A typical user searches using a channel up/down command, so it is natural for the user to search from channels included in a currently-displayed program list and their close channels. 
         [0046]    Here, the close channels include upper close channels and lower close channels, and it is preferable to determine by default which channel among the above close channels is to be accessed first. 
         [0047]    Also, it is necessary to change the direction of search according to the characteristics of a user, even if the search direction is determined by default. For example, even if the default search direction is set to be upward, once the user designates a channel down button, lower channels must be preferentially searched. It is preferable that in preparation for when a user changes the search direction in the middle, a channel search direction is determined referring to a channel up/down command or page up/down command received just before determining a search channel. 
         [0048]      FIG. 3  is a flowchart illustrating a program guide method according to a preferred embodiment of the present invention. Response must be preferentially considered in the interface with a user. It is considered that good response is provided if a system quickly responds to a command input by a user. The response is not considered good if a user must wait until program guide information for all channels is obtained after inputting the program guide command. 
         [0049]    However, the user immediately needs a channel viewed before the program guide command is applied, and program guide information of several channels adjacent to the channel viewed, not the program guide information for all channels. 
         [0050]    In the present invention, the channel viewed before the program guide command is applied, and the program guide information of several channels adjacent to the above channel are acquired first of all and displayed to the user, thereby improving the response. 
         [0051]    Also, channels adjacent to channels displayed in preparation for the channel search by a user are first searched, and far channels are then gradually searched, thus obtaining the program guide information on accessible channels. 
         [0052]    First, it is detected whether program guide information of a channel tuned before a program guide command is applied is effective, in step S 300 . 
         [0053]    Generally, a user applies a program guide command while receiving the program of a channel. The EPG information of a channel is automatically obtained while that channel is tuned, so that at least the program guide information of the channel tuned before the program guide command is applied can be considered effective. 
         [0054]    In a display step S 310 , at least a program list of channels tuned before the program guide command is applied among stored EPG information is displayed. The microprocessor  124  writes a program list including channels tuned before the program guide command is applied among EPG information stored in the memory unit  126 , and provides the program list to the OSG mixer  118 . The OSG mixer  118  converts the program list provided by the microprocessor  124  into a character signal, and displays the character signal on a screen. 
         [0055]      FIG. 4A  shows the contents displayed on a screen as the result of the step S 310 . In  FIG. 4A , reference numeral  400  is a screen, reference numeral  410  is a program list, reference numeral  420  is a cursor, reference numeral  430  is an up/down button, reference numeral  432  is a page up/down button, and reference numeral  440  is a left/right scan button. 
         [0056]    The program list  410  lists a program for each channel on channel and time axes. Channels listed in the program list  410  are controlled by the up/down button  430 , and time is controlled by the left/right scan button  440 . 
         [0057]    A user can search for a channel and time of a desired program, using the up/down button  430  and the left/right scan button  440 . 
         [0058]    Whenever the up/down button  430  is pressed, a selection bar  460  moves between the listed channels. When the selection bar  460  departs from a screen boundary, the content of the program list  410  is renewed so that the next adjacent channel can be displayed. 
         [0059]    If program guide information of channels tuned before the program guide command is applied is not effective or not stored, a screen display message like “please wait” or “obtaining program guide information” is displayed to the user, in step S 360 . If it takes a short time to obtain the program guide information of the tuned channel, this message display step may be omitted. 
         [0060]    Then, program guide information of channels tuned before a program guide command is applied is obtained, in step S 360 . A program list including this program guide information is displayed, in step  310 . 
         [0061]    In a program guide information acquiring step S 320 , program guide information for each channel is obtained by scanning accessible channels via the tuner  102  while a user views displayed EPG information. 
         [0062]    To be more specific, in the program list shown in  FIG. 4A , an inverted channel number in a program list  360  of a channel No. 53 indicates that channel No. 53 was viewed before a program guide mode. 
         [0063]    In the circumstances where the program list as shown in  FIG. 4A  is displayed, channels are searched to obtain EPG information, in the following sequence. 
         [0064]    If a channel No. 52 and a channel No. 54 are channels listed closest to a channel No. 53, i.e., channels most adjacent, they have the highest preference. 
         [0065]    If a channel No. 51 and a channel No. 56 are channels listed next closest to the channel No. 53, they have the next highest preferences after the channels No. 52 and No. 54. 
         [0066]    If an upward search direction is determined by default, channels are searched for in the sequence of No. 53, to No. 52, to No. 54, No. 51, and No. 56. 
         [0067]    EPG information for each channel is stored in the memory unit  126  as soon as it is obtained, and the microprocessor  124  writes a new program list referring to this information and provides the new program to the OSG mixer  118 , in steps S 330  and S 340 . As a result, new program lists as shown in  FIGS. 4B and 4C  are sequentially displayed. 
         [0068]    The sequence in which the EPG information is listed in the memory unit  126  is determined by a typical channel number. Also, when a channel has subchannels, the subchannels are listed after the main channel. 
         [0069]    Accordingly, the microprocessor  124  already knows the listing sequence of the EPG information stored in the memory unit  126 , and also knows the channel viewed before the program guide mode, to determine the search sequence. 
         [0070]    The sequence for searching for channels may not be determined according to adjacency. For example, channels may be searched for upward or downward based on the channel viewed before the program guide mode. However, considering response to the user, it is more proper that the channel search sequence be determined according to the adjacency between channels. 
         [0071]    The channel search sequence may be changed by the search inclination of a user. For example, if a user manipulates the channel up/down button  430  referring to a screen shown in  FIG. 4C , continuous search in a direction to be indicated later can be expected. Thus, when a channel up operation is indicated, the channel search operation may be limited to upper channels. 
         [0072]    The channel search sequence can be determined referring to past viewing tendencies of users This determines the probability that a channel is to be tuned based on the accumulated frequency of channels tuned by a user. A channel having a higher probability is searched for earlier. 
         [0073]    In a storing step S 330 , the obtained EPG information is stored in the memory unit  126 . Here, the obtained program guide information can be renewed only when there is a difference between the obtained program guide information and program guide information stored in the memory unit  126 . 
         [0074]    The obtained EPG information is stored in the memory unit  126 . Since the EPG information is transmitted by channels, the microprocessor  124  acquires EPG information of a corresponding channel whenever a channel is changed, and stores the acquired EPG information in the memory unit  126 . 
         [0075]    A program list is displayed, in step S 340 . 
         [0076]    The microprocessor  124  accesses the program guide information stored in the memory unit  126  to generate the program list as shown in  FIGS. 4A through 4C . The program list generated by the microprocessor  124  is displayed on a screen via the OSG mixer  118 . 
         [0077]    The program list is controlled according to a channel up/down command or page up/down command from a user, and when a channel selection command is applied by the user, the program of a selected channel is displayed, in step S 350 . 
         [0078]    According to the program guiding method of the present invention, the longer it takes for a user to refer to the program list, the program guide information of more channels can be obtained. However, the program guide information of channels immediately required by a user can be sufficiently acquired even in a short searching time. 
         [0079]    According to the method shown in  FIG. 3 , while a program is selected referring to the EPG information displayed by a user, accessible channels are scanned in a background operation unnoticeable to a user, thereby obtaining the EPG information. Also, the EPG information is obtained referring to the search direction of a user, thus accomplishing a smooth interface with the user. 
         [0080]    Furthermore, in order to obtain the program guide information, the program guide information of a preferential channel is obtained first and provided to a user. Therefore, a user does not need to wait until the program guide information of all the channels is obtained, increasing convenience. 
         [0081]    In the program guide method shown in  FIG. 3 , the program list as shown in  FIG. 4C  may be displayed in the display step S 310 . This is the case when a program list including a channel viewed before and channels adjacent to the channel is displayed in the initial stage of a program guiding operation. 
         [0082]    According to an advanced television standard committee (ATSC) standard, the EPG information is recommended to be transmitted in a quantity of at least 8 hours to a maximum of 384 hours, at time intervals of 3 hours. Thus, erroneous program guide information is less likely to be displayed if a program guide command is performed within 384 hours at maximum. 
         [0083]    Accordingly, it is all right to display the program list including a channel viewed before the program guide mode and several channels adjacent to the channel. 
         [0084]    However, a program may be changed by the circumstances of a broadcasting station, or unstored program guide information may be requested. Thus, it is preferable that channels are searched for by the above-described searching method even after the program list including the channel viewed before the program guide mode and several channels adjacent to the channel is displayed, to again obtain a program guide. 
         [0085]    Meanwhile, when the program list including the channel viewed before the program guide mode and several channels adjacent to that channel is displayed in the initial stage of the program guide operation, possible erroneous information of some channels can be replaced with correct information by searching for channels using the aforementioned search method. 
         [0086]      FIG. 5  is a block diagram illustrating the configuration of a program guide apparatus according to the present invention. As shown in  FIG. 5 , the apparatus includes a tuner  50 , a ROM  52 , a program guide information detector  54 , a memory  56 , a key input unit  58 , a microprocessor  60 , and an OSD generator  62 . 
         [0087]    The tuner  50  is tuned to a broadcast signal of a tuned channel. The program guide information detector  54  detects EPG information from the broadcast signal of a channel tuned by the tuner  50 . The detected EPG information is stored in the memory  56 . 
         [0088]    The microprocessor  60  writes a program list from the EPG information stored in the memory  56  according to a program stored in the ROM  52 , and provides the program list to the OSD generator  62 . The OSD generator  62  converts the program list written from the EPG information stored in the memory  56  into a character signal to display the program list to a CRT  64 . 
         [0089]    The microprocessor  60  controls tuning of the tuner  60  in the background operation while the program list is displayed on the CRT  64 , i.e., while the viewer does not watch any broadcast program via the tuner, to obtain EPG information of accessible channels. 
         [0090]    The microprocessor  60  searches for channels in a programmed channel searching sequence. This channel searching sequence depends on the sequence of channels which are displayed in the program guide mode. 
         [0091]    When the channel up/down command is input via the key input unit  58  during channel search, the microprocessor  60  changes the channel searching sequence referring to the input channel up/down command. 
         [0092]    When the EPG information is not stored in the memory  56 , the microprocessor  60  generates a message of “please wait” or “acquiring guide information”. When at least a current channel and current program guide information are obtained, the microprocessor  60  generates a program list corresponding to the stored program guide information. 
         [0093]      FIG. 6  is a block diagram illustrating another embodiment of a program guide apparatus according to the present invention. Units shown in  FIG. 6  performing the same operations as those in  FIG. 5  are referred to by the same reference numerals, and will not be described again. The apparatus of  FIG. 6  further comprises a probability estimator  64  in addition to the components of the apparatus of  FIG. 5 . 
         [0094]    The probability estimator  64  accumulates the number of times channels are tuned by a user, and calculates the probability that each channel will be tuned, according to the accumulated value. It can be estimated that the probability of tuning is high as a channel is tuned more often. 
         [0095]    The microprocessor  124  determines the order of priority of channel search according to the probability calculated by the probability estimator  64 . 
         [0096]    In the program guide information acquiring method according to the present invention as described above, while a viewer does not watch the program of any channel tuned in a tuner, program guide information of accessible channels is obtained in a background operation. Therefore, the program guide information of the accessible channels can be obtained by only a single tuner. 
         [0097]    Furthermore, in the program guide method and apparatus according to the present invention, information immediately required by a user is obtained first, and information of less preferential channels is obtained next, thus smoothing the interface with the user.