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Data Hiding Approach for Efficient Image Indexing. J. Jiang and A. Armstrong, IEE ELECTRONICS LETTERS , Vol. 38, No. 23, November 2002, pp.1424-1425. Advisor : Dr. Chang, Chin-Chen Reporter: Lee, Jiau-Yun Date : 2003/3/4. Outline. Introduction Overall System Algorithm Design
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Data Hiding Approach for Efficient Image Indexing J. Jiang and A. Armstrong, IEE ELECTRONICS LETTERS, Vol. 38, No. 23, November 2002, pp.1424-1425 Advisor :Dr. Chang, Chin-Chen Reporter:Lee, Jiau-Yun Date :2003/3/4
Outline • Introduction • Overall System • Algorithm Design • Experimental Results • Conclusions
Introduction • Content based image indexing and retrieval has attracted. • Those indexing keys are often ignored(negligible). • When millions of images are stored, the storage space becomes significant.
Overall System Texture extraction Store to DB Indexing key hiding Entropy coding DCT transform Quantize Input image
Algorithm Design • Extract LBP-based texture key. • DCT transformation. • Quantize the DCT coefficients. • Alone the zigzag scanning route • To choose the embedding position. • Hiding procedure.
Local Bit Partition(LBP) • Step 1: (11110100)=244 • Step 2:
Step 3: Local Bit Partition(count.) Texture key (00001011) (00100011) ………. (01001000) ………. ……….
LBP-based texture key • For each pixel p in the image, the eight neighbors are examined to see if their intensity is greater than that of p • x is the pixel being examined • yi is the surrounding pixels(b7b6…b0)
LBP-based texture key(count.) • A histogram of these numbers is used to represent the texture of the image. : the elements of the histogram : the counting operator, which records the number of times that has occurred.
Hiding procedure • If we want hide four bits(message) inside the four coefficients of each blocks. • X={x0,x1,x2,x3} • D={d0,d1,d2,d3} • For(I=0 to 3){ If (di is odd and xi=0) di=di+1; else (di is even and xi=1) di=di+1;}
Experimental Results • A small database of around 10000 images in BMP format was tested.
Experimental Results(count.) • The storage cost for indexing key is 2.5mb for 10000 images.
Conclusions • The storage space of our method is reduced to the region of 7-21%. • The quality of reconstruction remains almost unchanged. • The data hiding approach could affect efficiency.