A QuadtreeBased Representation Technique for Indexing and Retrieval

A Quadtree-Based Representation Technique for Indexing and Retrieval of Image Databases Source：Journal of Visual Communication and Image Representation Volume: 14, Issue: 3, September, 2003, pp. 340 -357 Authors：El-Qawasmeh, Eyas Speaker：Chuen-Ko Tsai Date： 2004/06/09 9/14/2021 1

Outline n n n Quadtrees Database Design Search Process The Centroid Algorithm Experimental Results 9/14/2021 2

Quadtree 1 st 3 nd 2 nd First three levels of an image decomposition with its quadtree presentation 9/14/2021 3

An Example-Use quadtree method to represents an image(1/4) 9/14/2021 4

An Example-Use quadtree method to represents an image(2/4) 9/14/2021 5

An Example-Use quadtree method to represents an image(3/4) 9/14/2021 6

An Example-Use quadtree method to represents an image(4/4) 9/14/2021 7

Use Morton Order for encoding(1/2) 9/14/2021 8

Use Morton Order for encoding(2/2) 9/14/2021 9

An Example-Use Morton Order for encoding(1/2) [4 W 4 W 4 W 1 W 2 B 1 W] [2 W 2 B 1 W 1 B 2 W 2 W 1 B 1 W] [1 W 3 B 4 W 1 W 1 B] [4 W 1 W 1 B 2 W 2 B 1 W 1 B] 9/14/2021 [13 W 2 B 1 W] [2 W 2 B 1 W 1 B 4 W 1 B 1 W] [1 W 3 B 5 W 1 B 1 W 1 B 3 W 1 B] [5 W 1 B 1 W 1 B 2 W 2 B 1 W 1 B] 10

An Example-Use Morton Order for encoding(2/2) 9/14/2021 11

Database Design. Number of Subsets(NS=1) F 1=1 F 1=0 NS=1 9/14/2021 12

Database Design. Number of Subsets(NS=2) F 1=1, F 2=10 F 1=1, F 2=01 F 1=0, F 2=11 F 1=0, F 2=00 NS=2 9/14/2021 13

Number of subsets for the database Possible combinations of the database organization 9/14/2021 14

Search Process The process of obtaining the graded-key for a quadtree 9/14/2021 15

The centroid algorithm The order of the visited pixels in the image 9/14/2021 16

Point-Differences 9/14/2021 17

Result(1/2) Average recall and average precision for 50 different queries in B/W database 9/14/2021 18

Result(2/2) Average recall and average precision for 50 different queries in colored database 9/14/2021 19