Abstract:
The present invention relates to an apparatus and a method for vector descriptor representation and multimedia data retrieval, which can quantize a plurality of feature values described by a vector descriptor respectively, represent the quantized feature values in the form of bit or orthogonally transform the quantized bector feature values, and rearrange the feature values represented in the form of bit from the highest bit to the lowest bit or rearrange the transformed coefficient from low frequency to high frequency to represent the vector descriptor hierarchically. Moreover, when retrieving multimedia data, the present invention can code in variable length and store the rearranged feature values and the number of feature values which are input, inversely code only the feature values corresponding to the number of the feature values of the stored feature values, inversely arrange the inversely coded feature values to be restored to original feature values, inversely quantize the restored feature values, and compare the feature values restored by the inverse quantization with the feature values stored in a multimedia database to retrieve multimedia data.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and a method for vector descriptor representation and multimedia data retrieval, and more particularly to, an apparatus and a method for vector descriptor representation and multimedia data retrieval, which can hieratically represent and store vector descriptor of multimedia data and retrieve multimedia data using the stored representation information. 
     2. Description of the Related Art 
     Recently, it has brought out the problem to retrieve and store multimedia data because of bulky multimedia data. Moreover, a demand not for text-based retrieval but for content-based retrieval is being increased to retrieve the bulky multimedia data fast and as a user wants. To solve the problems, attempts to represent descriptors of multimedia information and correlation between the descriptors of multimedia information have been continued. 
     For example, multimedia data consists of image and sound, and image consists of various objects: each of them having features of color, shape and texture; and a group of images having a motion feature. If the images are stored only in themselves, there is difficulty to retrieve. 
     To solve the above problem, a method for effectively representing each object or representation unit has been proposed. Especially, in case that several descriptors are represented in the form of vector, stable retrieval result cannot be obtained if the retrieval is performed in the state that several elements of vector are omitted, because vectors have different meanings respectively. 
     Moreover, if vector descriptors are all stored to tremendous multimedia data in construction of database, large storing space may be wasted according to circumstances. Furthermore, several users may want to maintain only small descriptor metafile. 
     However, as described above, because several feature values cannot be omitted from the vector descriptors, there is a problem that data cannot be represented as a flexible amount. 
       FIG. 1  shows a block diagram of a conventional vector descriptor representing apparatus. 
     As shown in  FIG. 1 , the conventional vector descriptor representing apparatus includes a quantization unit  400  for quantizing a great deal of feature values described by vector descriptor and a variable-length coding unit  401  for coding each feature value quantized in the quantization unit  400  in variable length and storing the coded feature values in a feature value storing unit  402 . 
       FIG. 2  shows a block diagram of a multimedia data retrieval device using the conventional vector descriptor representing apparatus. 
     As shown in  FIG. 2 , the multimedia data retrieval device using the conventional vector descriptor representing apparatus includes a variable-length inversely coding unit  502  for inversely coding the coded feature values in variable length, an inverse quantization unit  503  for inversely quantizing the feature values inversely coded in the variable-length inversely coding unit  502  and restoring the inversely coded feature values to original feature value, and a comparing unit  505  for comparing the original feature value restored by the inverse quantization unit  503  with multimedia data stored in a multimedia database  504  and retrieving multimedia data according to the compared result. 
     The operation of the conventional vector descriptor representing apparatus and multimedia data retrieval device using it will be described in more detail as follows. 
     First, the vector descriptor (X) in the conventional vector descriptor representing apparatus shown in  FIG. 1  can be formularized as follows: 
                   〈   MARGIN   〉     ⁢           ⁢     〈   TR   〉     ⁢           ⁢     〈   P   〉     ⁢   X     =       [           X   1                 〈   IP   〉     ⁢     〈   P   〉     ⁢     X   2                   〈   IP   〉     ⁢       〈   P   〉     ·                   〈   IP   〉     ⁢     〈   P   〉     ⁢     X   N             ]     ⁢     〈   IP   〉         ,           Formula 1             
 
     wherein X is the vector descriptor consisting of first to Nth feature values (X 1 , . . . and X N ). 
     To represent the vector descriptor (X), the quantization unit  400  quantizes the first to Nth feature values (X 1 , . . . and X N ) constituting the vector descriptor (X) and provides to the variable-length coding unit  401 . The variable-length coding unit  401  codes the first to Nth feature values (X 1 , . . . and X N ) quantized by the quantization unit  400  in variable length and stores the coded feature values in the storing unit  402 . 
     Next, the operation of the multimedia data retrieval device using the conventional vector descriptor representing apparatus shown in  FIG. 2  will be described in more detail as follows. 
     The variable-length inversely coding unit  502  inversely codes the coded feature values in variable length and provides to the inverse quantization unit  503 . 
     The inverse quantization unit  503  inversely quantizes the feature values provided from the variable-length inversely coding unit  502  and provides to the comparing unit  505 . 
     The comparing unit  505  compares the feature values provided from the inverse quantization unit  503  with multimedia data stored in the multimedia database  504  and outputs retrieval data according to the compared result. 
     As previously described, the conventional multimedia data retrieval device retrieves multimedia data using the feature values of the vector descriptor represented by the vector descriptor representing device. 
     However, as previously described, in the conventional vector descriptor representing device, when data is represented, because it is difficult to determine importance of the first to Nth feature values (X 1 , . . . and X N ) of the vector descriptor (X), there is a problem that cannot represent multimedia data by a small amount of data. 
     Furthermore, also in the multimedia data retrieval device using the conventional vector descriptor representing apparatus, because it is difficult to determine importance of the first to Nth feature values (X 1 , . . . and X N ) of the vector descriptor (X), there is a problem that cannot represent multimedia data by a small amount of data. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an apparatus and a method for vector descriptor representation and multimedia data retrieval, which can represent and rearrange a plurality of feature values constituting vector descriptor of multimedia data in the form of bit, represent and store the vector descriptor hierarchically according to the number of the feature values, and retrieve multimedia data using the stored representation information. 
     It is another object of the present invention to provide an apparatus and a method for vector descriptor representation and multimedia data retrieval, which can orthogonally transform a plurality of feature values constituting vector descriptor of multimedia data, represent and store the vector descriptor hierarchically according to the number of the feature values, and retrieve multimedia data using the stored representation information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a block diagram of a conventional vector descriptor representing apparatus; 
         FIG. 2  is a block diagram of a multimedia data retrieval device using the conventional vector descriptor representing apparatus; 
         FIG. 3  is a block diagram of a preferred embodiment of a vector descriptor representing apparatus according to the present invention; 
         FIG. 4  is a block diagram of a preferred embodiment of a multimedia data retrieval device using the vector descriptor representing apparatus according to the present invention; 
         FIG. 5  is a block diagram of another embodiment of the vector descriptor representing apparatus according to the present invention; 
         FIG. 6  is a block diagram of another embodiment of the multimedia data retrieval device using the vector descriptor representing apparatus according to the present invention; 
         FIG. 7  is a flow chart showing a preferred embodiment of a method for representing vector descriptor according to the present invention; 
         FIG. 8  is a flow chart showing a preferred embodiment of a method for retrieving multimedia data using the vector descriptor representing method according to the present invention; 
         FIG. 9  is a flow chart showing another preferred embodiment of a method for representing vector descriptor according to the present invention; and 
         FIG. 10  is a flow chart showing another preferred embodiment of a method for retrieving multimedia data using the vector descriptor representing method according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings. For reference, like reference characters designate corresponding parts throughout several views. 
       FIG. 3  shows a structure of a vector descriptor representing apparatus according to a preferred embodiment of the present invention. 
     As shown in  FIG. 3 , the vector descriptor representing apparatus according to a preferred embodiment of the present invention includes a quantization unit  1  for quantizing a great deal of feature values of the vector descriptor respectively, a bit representing unit  2  for representing each feature value quantized in the quantization unit  1  in the form of bit, a bit rearranging unit  3  for rearranging each feature value represented in the bit representing unit  2 , and a variable-length coding unit  4  for coding the feature values rearranged in the bit rearranging unit  3  in variable-length and storing the coded feature values in a feature value storing unit  5  or for coding the feature values rearranged in the bit rearranging unit  3  and the number of feature values which are input and storing the coded feature values in the feature value storing unit  5 . 
     Referring to  FIG. 7 , the operation of the vector descriptor representing apparatus according to the present invention will be described in more detail as follows. 
     First, in a step S 1 , if the vector descriptor consisting of first to Nth feature values (X 1 , . . . and X N ) is input in the quantization unit  1 , the quantization unit  1  quantizes the first to Nth feature values (X 1 , . . . and X N ) in a step S 2 . 
     In a step S 3 , the bit representing unit  2  represents the first to Nth feature values (X 1 , . . . and X N ) quantized in the quantization unit  1  in the form of bit as shown in the following formula 2: 
                       〈   MARGIN   〉     ⁢           ⁢     〈   TR   〉     ⁢           ⁢     〈   P   〉     ⁢   X     =       [           X   1                 〈   IP   〉     ⁢     〈   P   〉     ⁢     X   2                   〈   IP   〉     ⁢       〈   P   〉     ·                   〈   IP   〉     ⁢     〈   P   〉     ⁢     X   N             ]     ⁢     〈   IP   〉     ⁢     〈   P   〉     ⁢     〈   IP   〉                     =     P   ≥       [             X   1     M1   -   1       ,     X   1     M1   -   2       ,           ⁢     …   ⁢           ⁢     X   1   0                       〈   IP   〉     ⁢     〈   P   〉     ⁢     X   2     M2   -   1         ,       X   2     M2   -   2       ⁢           ⁢   …   ⁢           ⁢     X   2   0                       〈   IP   〉     ⁢     〈   P   〉     ⁢           ⁢   …     ⁢                           〈   IP   〉     ⁢     〈   P   〉     ⁢     X   N     MN   -   1         ,       X   N     MN   -   2       ⁢           ⁢   …   ⁢           ⁢     X   N   0               ]     ⁢     〈   IP   〉           ,                 Formula 2             
 
     wherein X is the vector descriptor consisting of the first to Nth feature values (X 1 , . . . and X N ), and X N   K  is Kth bit when Nth feature value (X N ) is represented by binary number. 
     Next, in a step S 4 , the bit rearranging unit  3  rearranges the first to Nth feature values (X 1 , . . . and X N ) represented like the above formula 2 in the bit representing unit  2  as hierarchical or progressive vector descriptor (Y) as shown in the following formula 3: 
                       〈   MARGIN   〉     ⁢           ⁢     〈   TR   〉     ⁢           ⁢     〈   P   〉     ⁢   Y     =       [           Y   1                 〈   IP   〉     ⁢     〈   P   〉     ⁢     Y   2                   〈   IP   〉     ⁢       〈   P   〉     ·                   〈   IP   〉     ⁢     〈   P   〉     ⁢     Y       max   ⁡     (     M1   ,   …   ⁢           ,   MN     )       -   1               ]     ⁢     〈   IP   〉     ⁢     〈   P   〉     ⁢     〈   IP   〉                   =     P   ≥       [             X   1     M1   -   1       ,     X   1     M1   -   2       ,     …   ⁢           ⁢     X   1   0                       〈   IP   〉     ⁢     〈   P   〉     ⁢     X   2     M2   -   1         ,       X   2     M2   -   2       ⁢           ⁢   …   ⁢           ⁢     X   2   0                       〈   IP   〉     ⁢     〈   P   〉     ⁢   …     ⁢                           〈   IP   〉     ⁢     〈   P   〉     ⁢     X   N     MN   -   1         ,       X   N     MN   -   2       ⁢           ⁢   …   ⁢           ⁢     X   N   0               ]     ⁢     〈   IP   〉                       Formula 3             
 
     By being rearranged by the bit rearranging unit  3 , the first feature value (Y 1 ) in the hierarchical vector descriptor (Y) is a representative feature value of the vector descriptor (X). 
     Like the above, the number of the feature values (Y 1 , Y 2 , . . . ) in the hierarchical vector descriptor (Y) is increased to become similar with the vector descriptor (X). 
     To store the plural feature values (Y 1 , Y 2 , . . . ) of the hierarchical vector descriptor (Y) rearranged by the bit rearranging unit  3 , in steps S 6  and S 7 , the variable-length coding unit  4  codes each of the feature values (Y 1 , Y 2 , . . . ) in variable length and stores the coded feature values in the feature value storing unit  5 . 
     Moreover, in the steps of S 6  and S 7 , the variable-length coding unit  4  codes each feature values rearranged in the bit rearranging unit  3  and the number of feature values input in the step S 5  and stores the coded feature values in the storing unit  5 . 
       FIG. 4  shows a block diagram of a device for vector descriptor representation and multimedia data retrieval according to the present invention. 
     As shown in  FIG. 4 , the device for vector descriptor representation and multimedia data retrieval according to the present invention includes a variable-length inversely coding unit  11  inversely coding the coded feature values in variable length, a bit inversely arranging unit  12  for rearranging the feature value inversely coded in the variable-length inversely coding unit  11  to original vector descriptor, an inverse quantization unit  13  for inversely quantizing feature values inversely arranged in the bit inversely arranging unit  12 , and a comparing unit  15  for comparing the feature values inversely quantized in the inverse quantization unit  13  with multimedia data stored in the multimedia database  14  and outputting retrieval data according to the compared result. 
     Referring to  FIG. 8 , the operation of the device for vector descriptor representation and multimedia data retrieval according to the present invention having the above structure will be described in more detail as follows. 
     First, in a step S 10 , if the coded feature values are input in the variable-length inversely coding unit  11 , the variable-length inversely coding unit  11  inversely codes the input feature values and restores the hierarchical vector descriptor (Y). 
     In a step S 12 , the bit inversely arranging unit  12  inversely arranges the hierarchical vector descriptor (Y) restored in the variable-length inversely coding unit  11  and generates feature values, which are represented in the form of bit, of the vector descriptor (X). 
     In a step S 13 , the inverse quantization unit  13  inversely quantizes the plural feature values, which are represented in the form of bit, generated in the bit inversely arranging unit  12  and generates original feature values. 
     In a step S 14 , the comparing unit  15  compares the feature values generated in the inverse quantization unit  13  with feature values stored in the multimedia database  14  and outputs retrieval data according to the compared result. 
     Like the above, multimedia data is retrieved by the feature values restored according to the number of the feature values stored in the feature value storing unit  10 , and thereby progressive multimedia data retrieval becomes possible. 
       FIG. 5  shows a block diagram of the vector descriptor representing apparatus according to the present invention. 
     As shown in  FIG. 5 , the vector descriptor representing apparatus according to the present invention includes an orthogonal transformation unit  100  for orthogonally transforming feature vectors constituting the vector descriptor and for representing feature vectors from low frequency feature to high frequency feature, a quantization unit  101  for quantizing the feature values represented in the orthogonal transformation unit  100 , and a variable-length coding unit  102  for coding the number of feature values input and feature vectors quantized in the quantization unit  101  and storing the coded feature values in the feature value storing unit  103 . 
     The orthogonal transformation in the orthogonal transformation unit  100  uses DCT (Descrete Cosine Transform), DST (Discrete Sine Transform), DFT (Discrete Fourier Transform), Haar or Wavelet. 
     Referring to  FIG. 9 , the operation of the vector descriptor representing apparatus according to the present invention will be described in more detail as follows. 
     First, in a step S 100 , if the vector descriptor is input in the orthogonal transformation unit  100 , the orthogonal transformation unit  100  performs orthogonal transformation such as DCT, DST, DFT, Haar or Wavelet to the input vector descriptor and represents feature values from low frequency feature to high frequency feature. 
     In a step S 102 , the quantization unit  101  quantizes feature values represented by the orthogonal transformation unit  100 . 
     In a step S 104 , the variable-length coding unit  102  performs variable-length coding to feature values represented in the quantization unit  101  with the number of feature values input in the step S 103  and stores the coded feature values in the feature value storing unit  103 . 
       FIG. 6  shows a block diagram of another embodiment of the device for vector descriptor representation and multimedia data retrieval according to the present invention. 
     As shown in  FIG. 6 , the device for vector descriptor representation and multimedia data retrieval according to the second embodiment of the present invention includes a variable-length inversely coding unit  200  for inversely coding coded feature values in variable length, an inverse quantization unit  201  for inversely quantizing the feature values inversely coded in the variable-length inversely coding unit  200 , an inversely orthogonal transformation unit  202  for inversely and orthogonally transforming the inversely quantized feature values and restoring to original feature values, and a comparing unit  204  for comparing the feature values restored in the inversely orthogonal transformation unit  202  with feature values stored in the multimedia database  203  and outputting retrieval data according to the compared result. 
     The inversely orthogonal transformation in the inversely orthogonal transformation unit  202  uses inverse DCT, inverse DST, inverse DFT, inverse Haar or inverse Wavelet. 
     Referring to  FIG. 10 , the operation of the device for vector descriptor representation and multimedia data retrieval according to the second embodiment of the present invention will be described in more detail as follows. 
     First, in a step S 200 , if the coded feature values are input in the variable-length inversely coding unit  200 , the variable-length inversely coding unit  200  inversely codes the coded feature values in a step S 201 . Here, the coded feature value includes feature values and the number of the feature values. 
     In a step S 202 , the inverse quantization unit  201  inversely quantizes the feature values inversely coded in the variable-length inversely coding unit  200 . 
     In a step S 203 , the inversely orthogonal transformation unit  202  performs inversely orthogonal transformation to the feature values inversely quantized in the inverse quantization unit  201  using inverse DCT, inverse DST, inverse DFT, inverse Haar or inverse Wavelet to restore feature values of original vector descriptor. 
     In a step S 204 , the comparing unit  204  compares the feature values restored in the inversely orthogonal transformation unit  202  with feature values stored in the multimedia database  203  and outputs retrieval data according to the compared result. 
     Like the above, multimedia data is retrieved by the feature values restored according to the number of the coded feature values, and thereby progressive multimedia data retrieval becomes possible. 
     As previously described, according to the preferred embodiments of the present invention, importance of each feature value can be determined to represent multimedia data using a small amount of data. 
     Furthermore, the vector descriptor of multimedia data can be represented in multi-stage to retrieve important data progressively. 
     While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.