1. Fast Retrieval of Old Dropcap Images Mathieu Delalandre, Jean-Marc Ogier and Josep Llados IDoc Meeting Valencia, Spain 22th February 2007

2. Fast Retrieval of Old Dropcap Images Dropcaps in old books of XV° and XVI°Problematics (1) Historian people are interested to retrieve similar printings Wood plug (bottom view) Plug 1 Plug 2 Plug 3 Printing 1 Printing 2 (2) Several large databases are available on the web, a system must retrieve in real-time in order to allow cross queries DB query r 1 r 2 r 3

3. Level 1 : image sizes Level 2 : image density Level 3 : RLE comparison Our system (1/2) Our key ideas (2) To use different level of operator (from more speed to more accurate) query 1 st Level 2 sd Level Speed Depth (1) To use a Run Length Encoding (RLE) of Image 0.75 0.95 0.88 x2x2 x2x2 x2x2 x1x1 x1x1 x1x1 x2x2 line (y) image 1 3 1 24 56 7 line (y+d y ) image 2 while x 1  x 2 handle image 1 while x 2  x 1 handle image 2 Fast Retrieval of Old Dropcap Images

4. Our system (2/2) 11 22 if  1 -  2 < 0 push x, cluster while  1 -  2 < 0 next Fast Retrieval of Old Dropcap Images To switch between levels we use the ‘elbow criteria’ Results 32.89 s903.62 sMax 10.00 s337.06 sMean 05.35 s176.67 sMin Our systemRaster comparison Query times (laptop 1.8GHZ) 250 to 350 dpiResolutions UncompressCompression TiffFormat grayModel 279.7 MoSize 2038Files Test database around 30 times more faster 0.1947 0.2517 0.3485 0.3616 0.3819 0.4064 Same plug Next plug Query 0.4109 0.4209 Example of query result

5. Fast Retrieval of Old Dropcap Images Works in progress … Base Our Retrieve engine control display retrieve Labels driven labelling Bench1Bench2 To produce To use our system like a groundtruthing one to evaluate retrieval results To use a run based signature as additional level to speed up again the process Application perspectives To implement the engine on BVH website in next months http://www.bvh.univ-tours.fr/ Contacts in progress with the EVODIA company to develop a commercial software http://www.evodia.fr/