Patent Publication Number: US-2011055870-A1

Title: Image display apparatus and method for operating the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of Korean Application No. 10-2009-0082006, filed on Sep. 1, 2009 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present invention relates to an image display apparatus and a method for operating the same, and more particularly, to an image display apparatus and a method for operating the same, which enable a user to readily identify broadcast videos of received channels. 
     2. Background 
     An image display apparatus has a function of displaying images to a user. The image display apparatus can display a broadcast program selected by the user on a display from among broadcast programs transmitted from broadcasting stations. The recent trend in broadcasting is a worldwide shift from analog broadcasting to digital broadcasting. 
     As it transmits digital audio and video signals, digital broadcasting offers many advantages over analog broadcasting, such as robustness against noise, less data loss, ease of error correction, and the ability to provide high-definition, clear images. Digital broadcasting also allows interactive viewer services. 
     However, as broadcast channels increase in number to meet various user demands, it becomes more difficult for viewers to determine what programs they are watching as they switch through channels. Therefore, much time is taken to select a channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein: 
         FIG. 1  is a block diagram of an image display system according to an exemplary embodiment of the present invention; 
         FIG. 2  is a block diagram of a channel browsing processor illustrated in  FIG. 1 ; 
         FIGS. 3   a  and  3   b  are diagrams illustrating examples of a remote controller illustrated in  FIG. 1 ; 
         FIG. 4  is a block diagram of a user Input/Output (I/O) unit in an interface illustrated in  FIG. 1  and a pointing device illustrated in  FIG. 3 ; 
         FIG. 5  is a flowchart illustrating a method for operating the image display apparatus according to an exemplary embodiment of the present invention; and 
         FIGS. 6 to 9  illustrate various examples of screens displayed on a display in the method for operating the image display apparatus according to the exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an image display apparatus and a method for operating the same, which enable a user to readily identify broadcast videos of received channels. 
     In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a method for operating an image display apparatus, including displaying a selected screen on a display, and displaying, upon receipt of a number input, a screen including a list of channel numbers each including the input number and thumbnail images of channels having the channel numbers on the display. Or upon receipt of a channel number display command, a channel number list is displayed along with thumbnail images of channels having channel numbers included in the channel number list. 
     In accordance with another aspect of the present invention, there is provided an image display apparatus including a display for displaying a selected screen, a tuner unit for receiving a broadcast signal of a selected channel or broadcast signals of previously stored channels, and a controller for, upon receipt of a number input, controlling display of a screen on the display, the screen including a list of channel numbers each including the input number among channel numbers of the previously stored channels on which the broadcast signals are received, and thumbnail images of channels having the channel numbers. 
     Exemplary embodiments of the present invention will be described below with reference to the attached drawings. 
     The terms “module” and “unit” used to signify components are used herein to help the understanding of the components and thus they should not be considered as having specific meanings or roles. Accordingly, the terms “module” and “unit” may be used interchangeably. 
       FIG. 1  is a block diagram of an image display apparatus according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , an image display apparatus  100  according to an exemplary embodiment of the present invention includes a first tuner  120 , a second tuner  125 , an external signal input unit  128 , a first demodulator  130 , a second demodulator  135 , an Analog-to-Digital (A/D) converter  140 , an interface  150 , a controller  160 , a channel browsing processor  170 , a storage  175 , a display  180 , and an audio output unit  185 . 
     The first tuner  120  selects a Radio Frequency (RF) broadcast signal corresponding to a channel selected by a user from among a plurality of RF broadcast signals received through an antenna and downconverts the selected RF broadcast signal into a digital Intermediate Frequency (IF) signal or an analog baseband Audio/Video (A/V) signal. More specifically, if the selected RF broadcast signal is a digital broadcast signal, the first tuner  120  downconverts the selected RF broadcast signal into a digital IF signal, DIF  1 . On the other hand, if the selected RF broadcast signal is an analog broadcast signal, the first tuner  120  downconverts the selected RF broadcast signal into an analog baseband AN signal, CVBS  1 /SIF. That is, the first tuner  120  may be a hybrid tuner capable of processing not only digital broadcast signals but also analog broadcast signals. The analog baseband AN signal CVBS 1 /SIF may be directly input to the controller  160 . 
     The first tuner  120  may be capable of receiving RF broadcast signals from an Advanced Television Systems Committee (ATSC) single-carrier system or from a Digital Video Broadcasting (DVB) multi-carrier system, as described later. 
     The second tuner  125 , like the first tuner  120 , selects the RF broadcast signal corresponding to the channel selected by the user from among the plurality of RF broadcast signals received through the antenna, and downconverts the selected RF broadcast signal into a second digital IF signal, DIF  2  or an analog baseband AN signal. 
     In addition, the second tuner  125  may sequentially or periodically select a number of RF broadcast signals corresponding to all broadcast channels previously added to the image display apparatus  100  by a channel add function from a plurality of RE signals received through the antenna, and may downconvert the selected RF broadcast signals into IF signals or baseband AN signals. In an exemplary embodiment, one or more video frames acquired from each of the previously-added channels may be displayed on at least a part of the display  180  as a thumbnail image. Thus, it is possible to receive the RF broadcast signals corresponding to all of the previously-added channels sequentially or periodically. 
     For example, the first tuner  120  may downconvert a main RF broadcast signal selected by the user into an IF signal or a baseband AN signal, and the second tuner  125  may sequentially or periodically select all RF broadcast signals or all other RF broadcast signals (i.e., sub-RF broadcast signals) except for the main RF broadcast signal and downconvert the selected RF broadcast signals into IF signals or baseband AN signals. 
     The first demodulator  130  receives the first digital IF signal DIF  1  from the first tuner  120  and demodulates the first digital IF signal DIF  1 . 
     For example, if the first digital IF signal DIF  1  is an ATSC signal, the first demodulator  130  may perform 8-Vestigal SideBand (VSB) demodulation on the first digital IF signal DIF  1 . The first demodulator  130  may also perform channel decoding. For channel decoding, the first demodulator  130  may include a Trellis decoder (not shown), a de-interleaver (not shown) and a Reed-Solomon decoder (not shown) so as to perform Trellis decoding, de-interleaving and Reed-Solomon decoding. 
     For example, if the first digital IF signal DIF  1  is a DVB signal, the first demodulator  130  performs Coded Orthogonal Frequency Division Multiple Access (COFDMA) demodulation on the first digital IF signal DIF  1 . The first demodulator  130  may also perform channel decoding. For channel decoding, the first demodulator  130  may include a convolution decoder (not shown), a de-interleaver (not shown), and a Reed-Solomon decoder (not shown) so as to perform convolution decoding, de-interleaving, and Reed-Solomon decoding. 
     The external signal input unit  128  receives signals from an external device. For reception of the external input signals, the external signal input unit  128  may include an AN Input/Output (I/O) unit (not shown) and a wireless communication module (not shown). 
     The external signal input unit  128  is connected to an external device such as a Digital Versatile Disc (DVD) player, a Bluray player, a game console, a camcorder, or a computer (e.g., a laptop computer). Then, the external signal input unit  128  externally receives video, audio, and/or data signals from the external device and transmits the received external input signals to the controller  160 . In addition, the external signal input unit  128  may output video, audio, and data signals processed by the controller  160  to the external device. 
     In order to receive or transmit AN signals from or to the external device, the AN I/O unit of the external signal input unit  128  may include an Ethernet port, a Universal Serial Bus (USB) port, a Composite Video Banking Sync (CVBS) port, a Component port, a Super-video (S-video) (analog) port, a Digital Visual Interface (DVI) port, a High-Definition Multimedia Interface (HDMI) port, a Red-Green-Blue (RGB) port, a D-sub port, an Institute of Electrical and Electronics Engineers (IEEE)-1394 port, a Sony/Philips Digital Interconnect Format (S/PDIF) port, and a LiquidHD port. 
     Various input signals received through the external signal input unit  128  may be input to the channel browsing processor  170  and subjected to a channel browsing operation performed by the channel browsing processor  170  for extracting a number of thumbnail images. For example, analog signals received through the CVBS port and the S-video port may be converted into digital signals by the A/D converter  140  and then input to the channel browsing processor  170 . Digital signals received through the Ethernet port, the USB port, the component port, the DVI port, the HDMI port, the RGB port, the D-sub port, the IEEE-1394 port, the S/PDIF port and the LiquidHD port may be directly input to the channel browsing processor  170  without A/D conversion. A digital signal output from the external signal input unit  128  may be a stream signal, for example, an MPEG-2 Transport Stream (TS) in which an MPEG-2 video signal and a Dolby AC-3 audio signal are multiplexed. 
     The wireless communication module of the external signal input unit  128  may wirelessly access the Internet. For the wireless Internet access, the wireless communication module may use a Wireless Local Area Network (WLAN) (i.e., Wi-Fi), Wireless Broadband (Wibro), World Interoperability for Microwave Access (WiMax), and High Speed Downlink Packet Access (HSDPA). 
     In addition, the wireless communication module may perform short-range wireless communication with other electronic devices. For the short-range wireless communication, the wireless communication module may use Bluetooth, Radio-Frequency IDentification (RFID), Infrared Data Association (IrDA), Ultra WideBand (UWB), and ZigBee. 
     The external signal input unit  128  may be connected to various set-top boxes through at least one of the Ethernet port, the USB port, the CVBS port, the Component port, the S-video port, the DVI port, the HDMI port, the RGB port, the D-sub port, the IEEE-1394 port, the S/PDIF port, and the LiquidHD port and may thus receive data from or transmit data to the various set-top boxes. For example, when connected to an Internet Protocol Television (IPTV) set-top box, the external signal input unit  128  may transmit video, audio and data signals processed by the IPTV set-top box to the controller  160  and may transmit various signals received from the controller  160  to the IPTV set-top box. In addition, video, audio and data signals processed by the IPTV set-top box may be processed by the channel browsing processor  170  and then the controller  160 . 
     The term ‘IPTV’ as used herein covers a broad range of services, depending on transmission networks, such as ADSL-TV, VDSL-TV, FTTH-TV, TV over DSL, Video over DSL, TV over IP (TVIP), Broadband TV (BTV), Internet TV and full- browsing TV, which are capable of providing Internet access services. 
     The first demodulator  130  may perform demodulation and channel decoding on the first digital IF signal DIF  1  received from the first tuner  120 , thereby obtaining a first stream signal TS  1 . The first stream signal TS  1  may be a signal in which a video signal, an audio signal and a data signal are multiplexed. For example, the first stream signal TS  1  may be an MPEG-2 TS signal obtained by multiplexing an MPEG-2 video signal and a Dolby AC-3 audio signal. An MPEG-2 TS may include a 4-byte header and a 184-byte payload. 
     The first stream signal TS  1  is input to the controller  160  and is thus subjected to demultiplexing and signal processing. In this exemplary embodiment, the first stream signal TS  1  is input to the channel browsing processor  170  and is thus subjected to a channel browsing operation prior to input to the controller  160 . The channel browsing operation will be described later in great detail. 
     In order to properly handle not only ATSC signals but also DVB signals, the first demodulator  130  may include an ATSC demodulator and a DVB demodulator. 
     The second demodulator  135  receives the second digital IF signal DIF  2  from the second tuner  125  and demodulates the second digital IF signal DIF  2 , thereby generating a second stream signal TS  2 . The operation of the second demodulator  135  is almost the same as the operation of the first demodulator  130 . 
     An analog baseband video signal CVBS  2  output from the second tuner  125  needs to be converted into a digital signal by the ND converter  140 . 
     The A/D converter  140  converts a received analog signal into a digital signal. If the received analog signal is a video signal, the A/D converter  140  performs sampling and quantization on the analog signal, thereby obtaining the digital video signal DV. The digital video signal DV may be a signal that has yet to be encoded. The digital video signal DV is provided to the channel browsing processor  170 , for processing. 
     The interface  150  transmits a signal received from the user to the controller  160  or transmits a signal received from the controller  160  to the user. For example, the interface  150  may receive various user input signals such as a power-on/off signal, a channel selection signal, and a screen setting signal from a remote controller  200  or may transmit a signal received from the controller  160  to the remote controller  200 . 
     The controller  160  may demultiplex an input stream signal into a number of signals and process the demultiplexed signals so that the processed signals can be output as AN data. The controller  160  may provide overall control to the image display apparatus  100 . 
     The controller  160  may include a demultiplexer (not shown), a video processor (not shown), an audio processor (not shown), and a user input processor (not shown). 
     The controller  160  may demultiplex an input stream signal, e.g. an MPEG-2 TS signal, into a video signal, an audio signal and a data signal. 
     Thereafter, the controller  160  may process the video signal. For example, if the video signal is an encoded signal, the controller  160  may decode the video signal. More specifically, if the video signal is an MPEG-2 encoded signal, the controller  160  may decode the video signal by MPEG-2 decoding. On the other hand, if the video signal is an H.264-encoded DMB or DVB-handheld (DVB-H) signal, the controller  160  may decode the video signal by H.264 decoding. 
     In addition, the controller  160  may adjust the brightness, tint and color of the video signal. 
     The video signal processed by the controller  160  is displayed on the display  180 . Alternatively or additionally, the video signal processed by the controller  160  may be output to an external output port connected to an external output device. 
     The controller  160  may process the audio signal obtained by demultiplexing the input stream signal. For example, if the audio signal is an encoded signal, the controller  160  may decode the audio signal. More specifically, if the audio signal is an MPEG-2 encoded signal, the controller  160  may decode the audio signal by MPEG-2 decoding. On the other hand, if the audio signal is an MPEG-4 Bit Sliced Arithmetic Coding (BSAC)-encoded terrestrial DMB signal, the controller  160  may decode the audio signal by MPEG-4 decoding. If the audio signal is an MPEG-2 Advanced Audio Coding (AAC)-encoded DMB or DVB-H signal, the controller  180  may decode the audio signal by AAC decoding. 
     In addition, the controller  160  may adjust the bass, treble or volume of the audio signal. 
     The audio signal processed by the controller  160  is output to the audio output unit  185 , e.g., a speaker. Alternatively or additionally, the audio signal processed by the controller  160  may be output to an external output port connected to an external output device. 
     The controller  160  may process the data signal obtained by demultiplexing the input stream signal. For example, if the data signal is an encoded signal such as an Electronic Program Guide (EPG), which provides broadcast information (e.g. start time and end time) about programs played on each channel, the controller  160  may decode the data signal. Examples of an EPG include ATSC-Program and System Information Protocol (ATSC-PSIP) information and DVB-Service Information (DVB-SI). ATSC-PSIP information or DVB-SI may be included in the header of a TS, i.e., the 4-byte header of an MPEG-2 TS. 
     The controller  160  may perform On-Screen Display (OSD) processing. More specifically, the controller  160  may generate an OSD signal for displaying various information on the display  180  as graphic or text data based on a user input signal received from the remote controller  200  and at least one of a processed video signal and a processed data signal. The OSD signal may be input to the display  180  along with the processed video and data signals. 
     The OSD signal may include various data such as a User-Interface (UI) screen, various menu screens, widgets, and icons for the image display apparatus  100 . 
     The channel browsing processor  170  enables channel browsing of at least one of a plurality of broadcast signals corresponding to a plurality of received channels, various input image signals received from the external signal input unit  128 , or both. More specifically, the channel browsing processor  170  may receive the first or second stream signal TS  1  or TS  2  from the first or second demodulator  130  or  135 , a stream signal from the external signal input unit  128 , or the digital signal DV from the A/D converter  140 , demultiplex the first or second stream signal TS  1  or TS  2 , and extract some of the frames of a video signal obtained through demultiplexing. Thereafter, the channel browsing processor  170  may generate a new TS signal, i.e., a sub-stream signal TSa, by multiplexing a video signal including the extracted video frames. For example, the sub-stream signal TSa and a main-stream signal TSb may both be MPEG-2 TS signals. 
     The channel browsing processor  170  may output the main-stream signal TSb, which corresponds to a main video signal to be displayed in a main region of the display  180 , without any processing. On the other hand, the channel browsing processor  170  may perform channel browsing on a sub-video signal, which is to be displayed in a sub-region of the display  180 , thereby obtaining the sub-stream signal TSa. 
     In this exemplary embodiment, the channel browsing processor  170  may extract some of the video frames of each of a plurality of broadcast signals received through a plurality of channels and re-encode the extracted video frames into a TS, thereby displaying a list of the channels on the display  180 . Since the extracted video frames are displayed on the display  180  as thumbnail images, the user can readily identify the contents of broadcast programs received through the plurality of channels. 
     Likewise, the channel browsing processor  170  may extract some of the video frames of each of various external input signals received from the external signal input unit  128  and re-encode the extracted video frames into a stream, thereby displaying an external input image list on the display  180 . In this manner, a list of a plurality of external input image signals received from a plurality of external input devices may be displayed on the display  180  as thumbnail images. Therefore, the user can readily identify the external input signals received from the external input devices based on the external input image list. 
     Also, the channel browsing processor  170  may extract some of the video frames of each of a plurality of broadcast signals received through a plurality of channels and some of the video frames of each of various external input signals received from the external signal input unit  128  and re-encode the extracted video frames into TSs, thereby displaying a channel list and an external input image list on the display  180 . Since the extracted video frames are displayed on the display  180  as thumbnail images, the user can readily identify the contents of broadcast programs received through the plurality of channels and the external input signals received from the external input devices. 
     The structure and operation of the channel browsing processor  170  will be described later in further detail with reference to  FIG. 2 . 
     The storage  175  may store various programs for processing and controlling signals of the controller  160 , and may also store processed video, audio and data signals. 
     The storage  175  may temporarily store a video, audio or data signal received from the external signal input unit  128 . 
     The storage  175  may store broadcast channels identified through the channel add function. 
     The storage  175  may include, for example, at least one of a flash memory-type storage medium, a hard disk-type storage medium, a multimedia card micro-type storage medium, a card-type memory, a Random Access Memory (RAM), or a Read-Only Memory (ROM) such as an Electrically Erasable Programmable ROM (EEPROM). 
     While the storage  175  is shown in  FIG. 1  as configured separately from the controller  160 , to which the present invention is not limited, the storage  175  may be incorporated into the controller  160 , for example. 
     The image display apparatus  100  may play a file (such as a moving picture file, a still image file, a music file, or a text file) stored in the storage  175  to the user. 
     The display  180  may convert a processed video signal, a processed data signal, and an OSD signal received from the controller  160  or a video signal and a data signal received from the external signal input unit  128  into RGB signals, thereby generating driving signals. The display  180  may be various types of displays such as a Plasma Display Panel (PDP), a Liquid Crystal Display (LCD), an Organic Light-Emitting Diode (OLED) display, a flexible display, and a three-dimensional (3D) display. The display  180  may also be a touch screen that can be used not only as an output device but also as an input device. 
     The audio output unit  185  may receive a processed audio signal (e.g., a stereo signal, a 3.1-channel signal or a 5.1-channel signal) from the controller  160  and output the received audio signal as voice. The audio output unit  185  may be various types of speakers. 
     The remote controller  200  transmits a user input to the interface  150 . For the transmission of a user input, the remote controller  200  may use various communication techniques such as Bluetooth, RF, IR, UWB and ZigBee. 
     In addition, the remote controller  200  may receive a video signal, an audio signal and a data signal from the interface  150  and output the received signals. 
     The remote controller  200  may be a pointing device. A pointing device will be described in greater detail with reference to  FIG. 3 . 
     While two tuners are shown in  FIG. 1  to display a channel list with thumbnail images according to the exemplary embodiment of the present invention, to which the present invention is not limited, the exemplary embodiment of the present invention may be implemented by use of a single tuner. 
     For example, when a channel list display command is issued while a broadcast channel is being received on a selected channel, the single tuner may sequentially or periodically receive broadcast signals on all broadcast channels preliminarily stored in the storage  175  by the channel add function. The channel list may be displayed in a full-view mode. 
     The image display apparatus  100  may be a fixed digital broadcast receiver capable of receiving at least one of ATSC (8-VSB) broadcast programs, DVB-T (COFDM) broadcast programs, and ISDB-T (BST-OFDM) broadcast programs or may be a mobile digital broadcast receiver capable of receiving at least one of terrestrial DMB broadcast programs, satellite DMB broadcast programs, ATSC-M/H broadcast programs, DVB-H (COFDM) broadcast programs, and Media Forward Link Only (MediaFLO) broadcast programs. Alternatively or additionally, the image display apparatus  100  may be a digital broadcast receiver capable of receiving cable broadcast programs, satellite broadcast programs or IPTV programs. 
     Examples of the image display apparatus  100  include a TV receiver, a mobile phone, a smart phone, a laptop computer, a digital broadcasting receiver, a Personal Digital Assistant (PDA) and a Portable Multimedia Player (PMP). 
       FIG. 2  is a block diagram of the channel browsing processor  170  illustrated in  FIG. 1 . 
     Referring to  FIG. 2 , the channel browsing processor  170  may include a TS switch  205 , a demultiplexer  210 , a picture decoder  215 , a DV decoder  217 , a format converter  220 , an image encoder  230  and a stream encoder  240 . 
     The TS switch  205  selects one of the first and second stream signals TS  1  and TS  2 , outputs the selected stream signal as the main-stream signal TSb without processing, and transmits the other stream signal to the demultiplexer  210  as a sub-stream signal. The main-stream signal, which corresponds to a main video signal, may be displayed on almost the entirety of the display  180 . The sub-stream signal, which corresponds to a sub-video signal, may be displayed only on a certain part of the display  180 . 
     In this manner, a channel list, an external input image list, or both may be displayed in a compact-view mode in a certain area on the display  180 . 
     The demultiplexer  210  may demultiplex the first or second stream signal TS  1  or TS  2  into a video signal, an audio signal and a data signal, output the video signal to the picture decoder  215 , and output the audio signal and the data signal to the stream encoder  240  in order for the stream encoder  240  to generate a new stream signal. 
     The picture decoder  215  decodes at least some of the frames of the received video signal by MPEG-2 decoding, MPEG-4 decoding or H.264 decoding. The decoded frames may be still images or moving pictures. For example, the picture decoder  215  may decode an Intra-coded (I) frame or some section of the received video signal. 
     The DV decoder  217  receives the digital signal DV from the A/D converter  140  and acquires a digital image from the digital signal DV. 
     The format converter  220  converts the format of a video signal received from the picture decoder  215  or the DV decoder  217 . For example, the format converter  220  may change the size (or resolution) of the input image signal. The size change depends on the number of thumbnail images in a thumbnail list displayed on the display  180 . For example, as the number of thumbnail images increases, the size of the thumbnail images may be decreased. 
     The format converter  220  may scale the input image signal to a different size according to whether the input image signal is to be displayed in a compact-view mode or in a full-view mode. The size of thumbnail images displayed in the full-view mode may be greater than the size of thumbnail images displayed in the compact-view mode. A channel list, an external input image list, or both may be displayed on the display  180  either in the compact-view mode or in the full-view mode. 
     The image encoder  230  may encode the image signal received from the format converter  220  by JPEG coding or MPEG-2 coding. Still images or moving pictures encoded by the image encoder  230  may be displayed on the display  180  as thumbnail images. 
     The stream encoder  230  may re-encode or multiplex an encoded video signal received from the image encoder  230  and the audio and data signals obtained by the demultiplexing performed in the demultiplexer  210  into a stream, for example, an MPEG-2 TS. 
     In this exemplary embodiment, the channel browsing processor  170  extracts some of the video frames of each of a plurality of broadcast signals and a plurality of external input signals and re-encodes the extracted video frames. Then, the re-encoded images may be displayed on the display  180  as thumbnail images in response to a user input requesting the display of a channel list or an external input image list. In this manner, the user can readily identify the contents of broadcast programs received from various channels or external input signals provided by various external input devices. 
       FIGS. 3   a  and  3   b  illustrate examples of the remote controller  200  illustrated in  FIG. 1 . 
     Referring to  FIGS. 3   a  and  3   b , the remote controller  200  may be a pointing device  301  for inputting commands to the image display apparatus  100 . In operation, the pointing device  301  transmits or receives RF signals to or from the image display apparatus  100  according to an RF communication standard. As illustrated in  FIG. 3   a , a pointer  302  representing the movement of the pointing device  301  may be displayed on the image display apparatus  100 . 
     A user may move the pointing device  301  up and down, back and forth, and side to side or may rotate the pointing device  301 . The pointer  302  moves in accordance with the movement of the pointing device  301 , as illustrated in  FIG. 3B . 
     Referring to  FIG. 3   a , if the user moves the pointing device  301  to the left, the pointer  302  moves to the left accordingly. The pointing device  301  includes a sensor capable of detecting motion. The sensor of the pointing device  301  detects the movement of the pointing device  301  and transmits motion information corresponding to the result of the detection to the image display apparatus  100 . Then, the image display apparatus  100  determines the movement of the pointing device  301  based on the motion information received from the pointing device  301 , and calculates the coordinates of a target point to which the pointer  302  should be shifted in accordance with the movement of the pointing device  301  based on the result of the determination. 
     Referring to  FIGS. 3   a  and  3   b , the pointer  302  moves according to whether the pointing device  301  moves vertically or horizontally or rotates. The moving speed and direction of the pointer  302  may correspond to the moving speed and direction of the pointing device  301 . 
     In this exemplary embodiment, the pointer  302  moves in accordance with the movement of the pointing device  301 . Alternatively or additionally, an operation command may be input to the image display apparatus  100  in response to the movement of the pointing device  301 . That is, as the pointing device  301  moves back and forth, an image displayed on the image display apparatus  100  may be enlarged or reduced. Accordingly, this exemplary embodiment of the present invention does not limit the scope and spirit of the present invention. 
       FIG. 4  is a detailed block diagram of the pointing device  301  illustrated in  FIG. 3  and the interface  150  illustrated in  FIG. 1 . 
     Referring to  FIG. 4 , the pointing device  301  may include a wireless communication module  320 , a user input unit  330 , a sensor unit  340 , an output unit  350 , a power supply  360 , a memory  370 , and a controller  380 . 
     The wireless communication module  320  may transmit signals to and/or receive signals from the image display apparatus  100 . The wireless communication module  320  may include an RF module  321  for transmitting RF signals to and/or receiving RF signals from the interface  310  of the image display apparatus  100  according to an RF communication standard. The wireless communication module  320  may also include an InfraRed (IR) module  323  for transmitting IR signals to and/or receiving IR signals from the interface  310  of the image display apparatus  100  according to an IR communication standard. 
     The pointing device  301  transmits motion information regarding the movement of the pointing device  301  to the image display apparatus  100  through the RF module  321  in this exemplary embodiment. The pointing device  301  may also receive signals from the image display apparatus  100  through the RF module  321 . The pointing device  301  may transmit commands, such as a power on/off command, a channel switching command, or a sound volume change command, to the image display apparatus  100  through the IR module  323 , as needed. 
     The user input unit  330  may include a keypad and/or a plurality of buttons. The user may enter commands to the image display apparatus  100  by manipulating the user input unit  330 . If the user input unit  330  includes a plurality of hard-key buttons, the user may input various commands to the image display apparatus  100  by pressing the hard-key buttons. Alternatively or additionally, if the user input unit  330  includes a touch screen displaying a plurality of soft keys, the user may input various commands to the image display apparatus  100  by touching the soft keys. The user input unit  330  may also include various input tools other than those set forth herein, such as a scroll key and/or a jog key, which should not be construed as limiting the present invention. 
     The sensor unit  340  may include a gyro sensor  341  and/or an acceleration sensor  343 . The gyro sensor  341  may sense the movement of the pointing device  301 , for example, in X-, Y-, and Z-axis directions, and the acceleration sensor  343  may sense the moving speed of the pointing device  301 . 
     The output unit  350  may output a video and/or audio signal corresponding to a manipulation of the user input unit  330  or a signal transmitted by the image display apparatus  100 . The user may easily identify whether the user input unit  330  has been manipulated or whether the image display apparatus  100  has been controlled based on the video and/or audio signal output by the output unit  350 . 
     The output unit  350  may include a Light Emitting Diode (LED) module  351  which is turned on or off whenever the user input unit  330  is manipulated or whenever a signal is received from or transmitted to the image display apparatus  100  through the wireless communication module  320 , a vibration module  353  which generates vibrations, an audio output module  355  which outputs audio data, and a display module  357  which outputs video data. 
     The power supply  360  supplies power to the pointing device  301 . If the pointing device  301  is kept stationary for a predetermined time or longer, the power supply  360  may, for example, reduce or cut off supply of power to the pointing device  301  in order to save power. The power supply  360  may resume supply of power if a specific key on the pointing device  301  is manipulated. 
     The memory  370  may store various application data for controlling or operating the pointing device  301 . The pointing device  301  may wirelessly transmit signals to and/or receive signals from the image display apparatus  100  in a predetermined frequency band through the RF module  321 . The controller  380  of the pointing device  301  may store information regarding the frequency band used for the pointing device  301  to wirelessly transmit signals to and/or wirelessly receive signals from the paired image display apparatus  100  in the memory  370  and may then refer to this information for use at a later time. 
     The controller  380  provides overall control to the pointing device  301 . For example, the controller  380  may transmit a signal corresponding to a key manipulation detected from the user input unit  330  or a signal corresponding to motion of the pointing device  301 , as sensed by the sensor unit  340 , to the interface  310  of the image display apparatus  100 . 
     The interface  310  may include a wireless communication module  311  which wirelessly transmits signals to and/or wirelessly receives signals from the pointing device  301 , and a coordinate calculator  315  which calculates a pair of coordinates representing the position of the pointer  302  on the display screen, which is to be moved in accordance with the movement of the pointing device  301 . 
     The wireless communication module  311  includes an RF module  312  and an IR module  313 . The RF module  312  may wirelessly transmit RF signals to and/or wirelessly receive RF signals from the RF module  321  of the pointing device  301 . The IR module  313  may wirelessly receive IR signals from the IR module  321  of the pointing device  301  according to the IR communication standard. 
     The coordinate calculator  315  may receive motion information regarding the movement of the pointing device  301  from the wireless communication module  320  of the pointing device  301  and may calculate a pair of coordinates (x, y) representing the position of the pointer  302  on a screen of the display  180  by correcting the motion information for possible errors such as user hand tremor. 
     A signal received in the image display apparatus  100  from the pointing device  301  through the interface  310  may be transmitted to the controller  160 . Then, the controller  160  may acquire information regarding the movement of the pointing device  301  and information regarding a key manipulation detected from the pointing device  301  from the signal received from the interface  150 , and may control the image display apparatus  100  based on the acquired information. 
     The image display apparatus  100 , the remote controller  200 , and the pointing device  301  being a kind of the remote controller  200  are shown in  FIGS. 1 to 4  as having a number of components in a given configuration. However, the image display apparatus  100 , the remote controller  200 , and/or the pointing device  301  may include fewer components or more components than those shown in  FIGS. 1 ,  2  and  3  in alternative embodiments. Also, two or more components of the image display apparatus  100 , the remote controller  200 , and/or the pointing device  301  may be combined into a single component or a single component thereof may be separated into two more components in alternative embodiments. The functions of the components of the image display apparatus  100 , the remote controller  200 , and the pointing device  301  as set forth herein are illustrative in nature and may be modified, for example, to meet the requirements of a given application. 
       FIG. 5  is a flowchart illustrating a method for operating the image display apparatus according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 5 , a selected screen is displayed on the display  180  in step S 510 . The selected screen may be a menu screen, a broadcast screen, a screen displaying played multimedia, an external input screen, a Webpage screen, etc. 
     If a number input is received while the selected screen is displayed in step S 520 , a thumbnail image screen is displayed on the display  180 , including a list of channel numbers each including the input number and thumbnail images of channels having the channel numbers in step S 530 . 
     In terrestrial digital broadcasting, for example, if a major number of 9 and a minor number of 1 are assigned to a channel, channel ‘9-1’ is displayed to a user. For example, analog and digital terrestrial channel numbers for Korean Broadcasting System (KBS) are 9 and 9-1, respectively. Considering even analog and digital cable channels for KBS, KBS may be represented by a plurality of channel numbers each including ‘9’. As the number of channels increases, such channel numbers as 91 may be detected as similar to channels having channel numbers each including 9. In this case, the user may have difficulty in switching to a channel by inputting a channel number because the user cannot easily identify digital broadcast channels or analog broadcast channels and remember channel numbers. 
     In this context, upon receipt of a number input, a list of similar channel numbers and thumbnail images of channels having the similar channel numbers are provided to the user, thus increasing convenience. 
     For example, if the user enters ‘1’, a list of channel numbers each including ‘1’ such as 10-0, 10-1, 11-1, etc. and thumbnail images of channels having the channel numbers are displayed. Therefore, the user can identify the contents of broadcast programs readily. 
     Even when the user does not know the number of a channel that he or she wishes to view, the user can select the channel conveniently because broadcast information such as the contents of broadcast programs is provided to the user. If the user wants to view channel 11-1, the user has only to input one digit ‘1’ without the need for inputting the entire number ‘11-1’. Then a list of channel numbers each including ‘1’ is displayed and the user selects one of the channel numbers. Hence, the number of key inputs of the user is decreased. 
     A thumbnail image screen including a channel number list and thumbnail images of channels having channel numbers included in the channel number list may be displayed on a part of the display  180 . 
     In addition, the thumbnail image screen may be designed to include a scroll bar and display only a part of the channel number list, such that the remaining part of the channel number list is displayed by moving the scroll bar. The user may set the number of channel numbers to be displayed on a screen. 
     Thumbnail images based on broadcast video signals of received channels may be thumbnail images based on broadcast video signals of pre-stored channels. That is, broadcast channels previously stored by the channel add function may be received through the second tuner  125 , thumbnail images may be generated based on broadcast signals of the stored broadcast channels, and then displayed on the display  180 . Therefore, thumbnail images of channels with channel numbers including an input number may be selected out of the thumbnail images of the previously stored channels and displayed along with a list of the channel numbers each including the input number. 
     In addition, while the thumbnail image screen is displayed on the display  180 , a screen including an updated thumbnail image of at least one of the displayed thumbnail images may be displayed on the display  180  or at least one of the displayed thumbnail images may be updated in the displayed thumbnail image screen. The update may be periodic or random, and the thumbnail images may be updated wholly or partially. The updated thumbnail images are based on images updated by the afore-described channel browsing processor  170 . 
     The displayed thumbnail images may be still images or moving pictures. Currently received images or pre-stored images may be displayed as the thumbnail images. 
     The thumbnail images may be images that have been processed and extracted by the channel browsing processor  170 . 
     In the thumbnail image screen, the channel number list and the thumbnail images may be displayed separately, or overlapped with each other. 
     Thereafter, upon input of a selection command to select one of a plurality of channel numbers displayed on the display  180 , an input image of a channel having the selected channel number is displayed on the display  180 . 
     Before the selection command is generated, one of the channel numbers and the thumbnail images may be focused upon. For example, when a focus command to focus on one of the channel numbers and the thumbnail images is input, a channel number or a thumbnail image corresponding to the focus command may be focused upon. The focus command may be generated through manipulation of a directional key of the remote controller or a pointer input of the pointing device. A thumbnail image may be focused upon by at least one of indicating the thumbnail image with a cursor, highlighting the thumbnail image, or zooming in on the thumbnail image. When the focused thumbnail image is moved by a directional key input or a pointer input, the thumbnail image may be continuously displayed during the movement. 
     Upon input of an edit command while the thumbnail image screen is displayed on the display  180 , the displayed thumbnail images may be edited. 
     For example, upon input of an edit command while one of the displayed thumbnail images is being focused upon, the focused thumbnail image may be edited. The editing of the focused thumbnail image may include ‘save as favorite’, ‘delete setting’, ‘lock setting’, etc. 
     If an information view command is received for a channel number in the channel number list, detailed program information about a channel having the channel number may be displayed. The program information may include at least one of the channel number, a program title, program time information, or thumbnail images extracted at a plurality of different times. 
     The above-described method for operating an image display apparatus may be performed in a similar manner when any other type of channel number list is displayed. In accordance with an exemplary embodiment of the present invention, the method for operating an image display apparatus includes displaying a selected screen on a display and, upon input of a command to view favorite channel numbers, previous channel numbers, or an EPG, displaying a screen including a channel number list and thumbnail images of channels having channel numbers listed in the channel number list. 
     It takes considerable time for a user to switch to a channel that he or she wishes to view from among broadcast channels, which have been greatly increased in number due to the transition to digital broadcasting. Therefore, image display apparatuses provide a favorite channel view function and a previous (previously viewed) channel view function. The favorite channel number view function or the previous channel number view function facilitates rapid selection of a desired channel from among favorite channels or previously viewed channels. As thumbnail images of the favorite channels or the previously viewed channels are displayed along with the list of favorite channel numbers or previously viewed channel numbers, the user can switch to a broadcast program that he or she wishes to view more accurately and more easily. 
     More specifically, when a command requesting a list of channel numbers or information including the channel number list is received, such as a favorite channel view command, a previous channel number view command or an EPG view command, a thumbnail image screen including the requested channel number list and thumbnail images of channels having channel numbers included in the channel number list is displayed on the display. Therefore, the user can readily identify images played on broadcast channels. 
     In the thumbnail image screen, the channel number list and the thumbnail images may be displayed separately, or overlapped with each other. Upon receipt of an information view command for a channel number in the channel number list, program information may further be displayed, inclusive of at least one of the channel number, a program title, program time information, or thumbnail images extracted at a plurality of times. 
       FIGS. 6 to 9  illustrate various examples of screens displayed on a display in the method for operating an image display apparatus according to the exemplary embodiment of the present invention. 
     Referring to  FIG. 6 , upon receipt of a number input while a selected screen  600 , for example, an over-the-air broadcast video screen is displayed on the display, the controller controls display of a thumbnail image screen including channel numbers  620  and thumbnail images  630  of channels having the channel numbers  620  on the display. A number input window  610  may further be displayed to allow a user to enter a number. 
     While the size of each of the thumbnail images  630  may vary depending on settings, it is preferable to display the thumbnail images  630  at a small size at first and, upon input of a selection command or a focus command for a thumbnail image, to enlarge the thumbnail image, in order to accommodate an increased number of channels and prevent the user from being distracted from a broadcast program that he or she is watching. 
     An exemplary embodiment illustrated in  FIG. 7  is similar to that illustrated in  FIG. 6 , except that a number is input by moving a pointing device. 
     Referring to  FIG. 7 , a screen  700  and a pointer  302  corresponding to a pointing signal received from the remote controller  301  are displayed on the display of the image display apparatus. When a directional pointing signal is received, a trajectory  710  of the pointing signal is displayed at coordinates calculated from the pointing signal. The pointer  302  may be displayed together with the trajectory  701 . 
     If the trajectory  701  is recognized as representing number ‘1’ according to a number recognition rule, channel numbers each including ‘1’ are included in a channel number list  720 . Thumbnail images of channels having the channel numbers are also displayed. Thus, the user can readily identify the contents of broadcast programs played on the channels. 
     If the trajectory  710  is recognized as representing a full channel number ‘ 14 - 1 ’ within a predetermined time, a channel having the channel number ‘ 14 - 1 ’ may be immediately switched to and thus an image played on channel ‘ 14 - 1 ’ may be displayed on the display. 
       FIG. 8  illustrates detailed program information about a channel, when an information view command is received for the channel number of the channel in a channel number list. Referring to  FIG. 8 , program information  800  may include at least one of the channel number, a program title, program time information, or a plurality of thumbnail images  810  and  820  extracted at different times. 
     As illustrated in  FIG. 8 , the thumbnail images  810  and  820  of the channel may be displayed separately or partially overlapped. The thumbnail images  810  and  820  may have information about the times at which they were extracted or may be arranged in a time order. A progress bar  830  may indicate the progress of an on-going program. 
       FIG. 9  illustrates a screen displayed on the display, including a channel number list and thumbnail images of channels having channel numbers listed in the channel number list, when an EPG view command is received. 
     As a thumbnail image is displayed in the background of each channel number, the user can readily identify the contents of a broadcast program currently airing on a channel corresponding to the channel number. The thumbnail image may be updated repeatedly so as to provide the user with up-to-date broadcast information about the channel. 
     As is apparent from the above description of the present invention, since a channel number list is displayed along with thumbnail images of channels having channel numbers included in the channel list on a screen, a user can readily identify broadcast videos played on the channels and thus easily select a desired broadcast program and video. In addition, the thumbnail images are repeatedly updated to thereby provide up-to-date information about the channels to the user. If the thumbnail images are updated sufficiently frequently the user can identify contents of the channels in almost real time. Therefore, the user can look over the channels before selecting one of the channels. 
     Upon receipt of a number input, a list of similar channel numbers each including the input number is displayed along with thumbnail images of channels having the similar channel numbers. Accordingly, the user can identify programs airing on the channels easily and various user interfaces can be used. 
     The image display apparatus and the operation method therefor according to the foregoing exemplary embodiments are not restricted to the exemplary embodiments set forth herein. Therefore, variations and combinations of the exemplary embodiments set forth herein may fall within the scope of the present invention. 
     The method for operating an image display apparatus according to the foregoing exemplary embodiments may be implemented as code that can be written to a computer-readable recording medium and can thus be read by a processor. The computer-readable recording medium may be any type of recording device in which data can be stored in a computer-readable manner. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, an optical data storage, and a carrier wave (e.g., data transmission through the Internet). The computer-readable recording medium can be distributed over a plurality of computer systems connected to a network so that computer-readable code is written thereto and executed therefrom in a decentralized manner. Functional programs, code, and code segments needed for realizing the embodiments herein can be construed by one of ordinary skill in the art. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.