SUPPORTING LANDMARK
IMAGE RETRIEVAL WITH
SKYLINE EXTRACTION
TECHNIQUES
Date : 2012 / 04 / 12
資訊碩一 10077034 蔡勇儀 @ LAB603
Outline
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Introduction
Preliminaries
Method
Experimental result
Conclusions
Introduction
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Image retrieval have more challenge than text
retrieval.
Use low-level feature to identify objects is nontrivial.
Skyline is a good feature to identify landmark
contour.
Outline
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Introduction
Preliminaries
Method
Experimental result
Conclusions
Traditional image retrieval
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Traditional techniques for image retrieval rely on
some metadata (i.e., keywords or captions of image)
It isn’t a good method for practical applications
since it is labor intensive and need more space.
Content-based image retrieval
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Content-based image retrieval(CBIR) is using
image’s feature for retrieval.
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Query-by-example
Query-by-sketch
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Relevance feedback technique
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Identifying landmarks with skylines
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Region-growing-based
 Using
same color region extend find the skylines
 Weak robustness on the sky with cloud or complex
background
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Edge-based
 Edge
detection
 Retaining the points which are luminous intensity change
sharply
 Using other method to find clear skyline.
Outline
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Introduction
Preliminaries
Method
Experimental result
Conclusions
Method(1/4) - Difficulties
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Small portion of edge points constitute the proper
skyline.
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Skyline may not fully-connected.
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Steep or tortuous.
Method(2/4) - RON
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RON(radius of neighborhood)
 Defining
the search region
(ex. RON = 2 -> grid zone = 5*5)
 Solving the difficulties.
Method(3/4) – Direction priority
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Using clockwise
 Good
direction for traversal skyline.
Method(4/4) – Find the skyline
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Using Sobel Filter for edge detection
Using DFS for search. (Need decide the start point?)
Outline
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Introduction
Preliminaries
Method
Experimental result
Conclusions
Experimental Result
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DP VS This method ( O(n2) & O(n) )
Outline
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Introduction
Preliminaries
Method
Experimental result
Conclusions
Conclusions
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This is a feasible for landmark image retrieval.
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If there are more line cross the image?
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If sky have complex object(ex. Light or cloud…)?
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If the beginning point is not in skyline?
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More problem need to solving…
Thank for your listening!
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Q&A