Organisation internationale de normalisation

Conformance testing and reference software

1.1.1.1.1.1.1.1.29m36390 A proposal for CDVS conformance testing [Massimo Balestri, Gianluca Francini, Skjalg Lepsoy]

Preliminary conformance dataset used: 1000 images with six reference CDVS descriptors each.

Conditions to pass conformance:

100% of descriptors shall be syntactically correct and 99% of descriptors shall satisfy the conditions below.

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  Interest points: The number of interest points in a test descriptor shall not differ by more than 10% of the number of interest points in the corresponding reference descriptor.
  
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  Global descriptor: Al least 90% of the 32-bit words composing the global descriptor in the test descriptor must have a bitwise distance (Hamming distance) not exceeding 4 bits from the corresponding words in the reference descriptor.
  
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  Local descriptors:
  
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    Compute p1 = min(number of intest points in test and reference descriptors).
    
  • 
    Establish one-to-one correspondence between the interest points of the test and reference local descriptors according to the following conditions:
    
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      The L1 distance between the quantized elements of each interest point of the two descriptors must be below or equal to 20% of their theoretic maximum distance;
      
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      The L2 distance between the X,Y coordinates of the test and reference interest points must be below 6.5 pixels;
      
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    Compute p2 = number of interest point pairs for which one-tp-one correspondence was established.
    
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    For the test descriptor to pass this part of the conformance testing, the ratio p2 / p1 shall be greater than 90%.
    

SW for conformance testing was provided.

Conformance tested using the "main" CDVS implementation versus BFLoG and LowMem versions. All passed conformance.

The proposal was accepted. The group selected 1000 cleared images for conformance during the 112^th MPEG meeting.

The software license under which the software was originally provided was still the “old” MPEG header. About 10 companies have contributed to the software in the meantime using the same, and it seems hardly possible to come to any agreement on changing the header.

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