Abstract:
A method of hierarchical image indexing which extracts representative images of a TV program and generates a hierarchical index image guide of the representative images, and an apparatus therefor. Respective images at predetermined times are extracted from a predetermined program. A hierarchical index is allocated to each extracted image and the indexes are mapped to locations of transport stream packets. A tree of images having the allocated indexes is constructed as a hierarchically indexed Image guide (HIIG). When a stored program is to be reproduced, a location desired to be watched is selected in the HIIG, and from the selected location, reproducing and trick plays (FF, rewind) are enabled such that a user easily searches the program and begins viewing the program at the searched for location.

Description:
This application claims the benefit of Korean Application No. 2001-60133 filed Sep. 27, 2001, in the Korean Patent Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a personal video recorder system, and more particularly, to a method of hierarchical image indexing which extracts representative images of a TV program and generates a hierarchical index image guide, and an apparatus therefor. 
     2. Description of the Related Art 
     In general, a digital broadcasting receiving system receives a digital broadcast, and stores and reproduces audio/video data. 
       FIG. 1  is a block diagram of a digital broadcast receiving and/or reproducing system. The digital broadcasting receiving and/or reproducing system of  FIG. 1  has a Transport Stream (TS) demultiplexer (demux) unit  120  which demultiplexes an Audio/Video elementary stream, a storage unit  160  which stores transport packets of a TV program, a digital interface unit  150  which transmits a transport packet to the storage unit  160  or receives a transport packet from the storage unit  160 , an audio decoder  140  which decodes an audio stream output from the TS demux unit  120 , a video decoder  150  which decodes a video stream output from the TS demux unit  120 , and a control unit  110  which controls each unit. 
     Referring to  FIG. 1 , in the TS demux unit  120  a received transport stream packet is demultiplexed into a partial transport stream of a TV program to be stored. The partial transport stream packet is sent through the digital interface unit  150  and stored with time information in the storage unit  160 . When the TV program is reproduced, the partial transport stream packet stored in the storage unit  160  is input to the TS demux unit  120  through the digital interface unit  150 . The partial transport stream packet is output as an audio elementary stream and a video elementary stream from the TS demux unit  120 . The audio and video elementary streams are decoded in the audio decoder  130  and the video decoder  140 , respectively. 
     However, when the TV program is reproduced, the prior art digital broadcasting receiving and/or reproducing system of  FIG. 1  has no information indicating a scene which a TV viewer wants to watch, or a location of the scene. Therefore, the system performs only simple reproduction or a trick play (for example, Fast Forward (FF) or rewind). 
     Accordingly, with the prior art digital broadcasting receiving system, TV viewers must identify each scene, which they want to watch, by using a FF function or a rewind function. 
     SUMMARY OF THE INVENTION 
     To solve the above problems, it is an object of the present invention to provide a method of hierarchical image indexing which, when a user stores a predetermined program or a TV program broadcast for reproduction at an arbitrary time, generates a hierarchical index by extracting representative images of the program that is input and stored. 
     It is another object of the present invention to provide a method of hierarchical index image reproducing which enables a program viewer to reproduce and trick reproduce a program from a location of the program which is selected by referring to a hierarchical image indexing structure of the program. 
     To accomplish the above and other objects of the present invention, a method of image indexing for recording and/or reproducing an image includes extracting an image at each of a plurality of predetermined times from a predetermined program; allocating a hierarchical index to each extracted image and mapping the indexes to corresponding locations of transport stream packets; and constructing a tree of images having the allocated indexes. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     To accomplish the above and other objects of the present invention a method of reproducing a program having a hierarchical image index includes decoding upper layer pictures of the program to be reproduced and displaying the pictures with corresponding upper layer index numbers and if a predetermined picture among the displayed upper layer pictures is selected, decoding the selected picture and displaying the picture with pictures corresponding to a lower layer index number; determining a reproducing time, using the index number of the picture selected among the displayed pictures; detecting a transport stream packet based on the determined reproducing time; and decoding an audio/video signal beginning with the detected transport stream packet. 
     Also, to accomplish the above and other objectives of the present invention, an image indexing apparatus in a system for recording and/or reproducing an image having a storage unit which stores a program in units of transport stream packets is provided. In the image indexing apparatus, a Transport Stream (TS) demultiplexing unit demultiplexes the transport stream packets into audio streams and video streams; a decoder unit decodes the audio streams and video streams that are demultiplexed in the TS demultiplexing unit into audio data and video data; a picture codec unit encodes predetermined picture data among pictures decoded in the decoder unit if an operation mode is a store mode, and decodes the picture data stored in the storage unit if the operation mode is a reproducing mode; and a microprocessor unit stores picture data encoded in the picture codes unit and hierarchically indexes the picture data at each predetermined time if the operation mode is a store mode, and hierarchically displays the picture data stored in the storage unit on a screen and a outputs transport stream packet based on the selected picture data to the TS demultiplexing unit if the operation mode is a reproducing mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the accompanying drawings in which: 
         FIG. 1  is a block diagram of a conventional digital broadcast receiving and/or reproducing system; 
         FIG. 2  is a block diagram of a digital broadcasting receiving and/or reproducing system according to an embodiment of the present invention; 
         FIG. 3  is a flowchart for showing a method of hierarchical image indexing in the digital broadcasting receiving and/or reproducing system of  FIG. 2 ; 
         FIG. 4  is a flowchart of an image indexing process of  FIG. 3 ; 
         FIG. 5  is a flowchart for showing a method of hierarchical image indexing in the digital broadcasting receiving and/or reproducing system of  FIG. 2 ; 
         FIG. 6  shows an example of a hierarchical image guide displayed on a screen according to the present invention using symbolic representative images; and 
         FIG. 7  shows an example of a hierarchical image guide displayed on a screen according to the present invention using realistic representative images. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
     Referring to  FIG. 2 , a broadcasting receiving and/or reproducing system according to an embodiment of the present invention will be described. A memory is formed with a TS packet memory  214  and a picture memory  212 . The TS packet memory  214  temporarily stores a stream which is demultiplexed in the TS demux unit  230 , and the picture memory  212  temporarily stores picture data encoded in a picture encoder  262 . 
     The TS demux unit  230  demultiplexes a TS stream into audio and video elementary streams. An audio decoder  240  and a video decoder  250  decode the audio stream and the video stream, respectively. 
     An Integrated Development Environment (IDE) control unit  270  controls an interface between a data bus of a microprocessor  220  and a Hard Disc Driver (HDD)  280 . 
     A picture codec unit  260  is formed with a picture encoder  262  and a picture decoder  264 . The picture codec unit  260  encodes or decodes picture data in order to store the picture data in the HDD  280  or display the picture data on a screen. That is, the picture encoder  262  encodes given picture data among picture data decoded in a video decoder  250  to store the given picture data in the HDD  280 , and the picture decoder  264  decodes compressed picture data which is stored in the picture memory  212  through the HDD  264 . A display unit  290  includes the screen to display an image decoded in the video decoder  250  and the picture decoder  264 . 
     The microprocessor  220  stores the program and hierarchical index images in the HDD  280 , and using the hierarchical index images, controls reproduction and trick reproduction. The microprocessor  220  controls the TS demux unit  230 , the audio decoder  240 , the video decoder  250 , the IDE control unit  270 , and the picture codec unit  260 . In particular, the microprocessor  220  provides Direct Memory Access (DMA) to store TS packets and picture data stored in the memory  210 , in the HDD  280 . 
       FIG. 3  is a flowchart for showing a method of hierarchical image indexing in the digital broadcasting receiving and/or reproducing system of  FIG. 2 . 
     A Packet IDentifier (PID) of the program to be stored is set in operation  314 . Then, the TS packet of the program is stored in the TS packet memory  210  through the TS demux unit  230  in operation  316 . Input TS packets are searched for an Intra-picture (I-picture) and an index number is given to the I-picture in operation  318 . It is determined whether it is a time to store the I-picture in operation  320 . If it is not time to store a picture, the method advances to operation  328  as described below. If it is time to store the I-picture, a video stream of the selected program, the video stream corresponding to the I-picture, is input to the video decoder  250  and decoded into frame data in operation  322 . 
     Next, the decoded frame data is encoded into a still image in the picture encoder  262  in operation  324 . Picture data corresponding to the encoded still image is stored in the picture memory  212  in operation  326 . A number of TS packets stored in the TS packet memory  214  is compared with a predetermined size in operation  328 . If the two numbers are the same, the TS packets stored in the TS packet memory  214  are stored in the HDD  280  in operation  330 . If the number of TS packets is not the predetermined size, the method advances to operation  332  as described below. 
     It is determined whether it is time to store the encoded still image picture data in the HDD  280  in operation  332 . If it is time to store the encoded still image picture data in the HDD  280 , the encoded still image picture data stored in the picture memory  212  is stored in the HDD  280  in operation  334 . If it is not time to store the still image picture data in the HDD  280 , the method advances to operation  336  as described below. 
     It is determined whether recording of the program unit is completed in operation  336 . If the recording is completed, an image indexing routine is performed and a Hierarchically Indexed Image Guide (HIIG) is generated in operation  338 , and otherwise operations  316  through  336  are repeated until the recording is completed. 
       FIG. 4  is a detailed flowchart of an image indexing process of  FIG. 3 . 
     First, using a number (M) of index images at each level defined by a user and a hierarchical level (N), an image is extracted from the HDD  280  in operation  410 . The extracted image is mapped to a location (a disc packet number) of the TS packet stored in the HDD  280  in operation  420 . M upper layer images are defined in the extracted image, and upper layer index numbers are allocated in the M upper layer images and mapped to the location stored in the HDD  280  in operation  430 . 
     Then M images are defined in the sub-upper layer index image and lower layer index numbers are allocated and mapped to the location of the TS packet stored in the HDD  280  in operation  432 . This process is repeated to the lowest level in operation  440 . Then an image signal having an upper layer index number and a lower layer index number is constructed to have a tree structure in operation  450 . 
     Next, the HIIG formed with an index image is displayed on the screen of the display unit  290 . 
       FIG. 5  is a flowchart for showing a method of hierarchical image indexing in the digital broadcasting receiving and/or reproducing system of  FIG. 2 . 
     First, a program to be reproduced is selected in a program list in operation  512 . Upper layer index picture data of the program to be reproduced is extracted from the HDD  280 , input and temporarily stored in the picture memory in operation  514 . The picture data stored in the picture memory  212  is decoded in the picture decoder  264  in operation  516 . The picture data with the upper index number is output on the screen of display unit  290  in operation  518 . It is determined whether the upper layer picture is selected in operation  520 . If the upper layer picture is selected, the lower layer index picture data of the picture is extracted from the HDD  280 , input and temporarily stored in the picture memory  212  in operation  522 . 
     The picture data stored in the picture memory  212  is decoded in the picture decoder  264  in operation  524 . The decoded picture with the lower layer index number is displayed on the screen of the display unit  290  in operation  526 . It is determined whether the lower layer picture is selected in operation  528 . If the lower layer picture is selected, it is determined whether an operation mode is a trick mode in operation  530 . If the operation mode is not the trick mode, using the selected lower layer picture data, corresponding TS packets stored in the HDD  280  are extracted, input and temporarily stored in the TS packet memory  214  in operation  532 . 
     A packet stream, comprising the extracted TS packets which are stored in the TS packet memory  214 , is demultiplexed into an audio stream and a video stream in the TS demux unit  230 , and the audio stream is decoded into audio data in the audio decoder  240  and the video stream is decoded into video data in the video decoder  250  in operation  534 . The decoded audio and video data are provided to the screen of the display unit  290  and to a speaker, respectively, in operation  536 . 
     If it is determined that the operation mode is the trick mode, a track operation corresponding to FF or rewind is performed according to a user selection. That is, if FF is selected in operation  540 , TS packets of the I-picture are sequentially TS multiplexed into a packet stream at operation  532  and decoded into audio/video in operation  534 . If rewind is selected in operation  550 , TS packets of the I-picture are TS multiplexed at operation  552  in order of decreasing disc packet number and decoded into audio/video in operation  534 . 
       FIGS. 6 and 7  show examples of hierarchical image guide displayed on a screen according to the present invention. 
     Referring to  FIGS. 6 and 7 , a tree structure of images having upper layer index numbers and lower layer index numbers is displayed on the screen. That is, images having upper layer index numbers (1st picture˜6th picture) are first displayed on the screen. If an image of which the index number is 1 is selected, images having lower layer index numbers (1-1st picture˜1-6th picture) according to the selected upper layer image are displayed first on the screen. A text  610  and/or a graph  620  which indicate a location and time of the selected image in the entire program are displayed. 
     Although the present invention has been described and explained with respect to a Personal Video Recorder, the present invention is applicable to other systems for recording and reproducing images, in addition to the Personal Video Recorder (PVR) system. 
     According to the present invention as described above, when a stored program is reproduced, a location desired to watch is selected in the HIIG, and from the location, reproducing and trick plays (FF, rewind) are enabled such that the user easily searches the program and reproduces the program at the desired location. 
     Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.