Università degli Studi di Milano Bicocca                                         Teoria e Tecnologia della Comunicazione  ...
Introduction                      The paper discusses novel image retrieval methods                      based on shape fe...
Content Based Image Retrieval                      keyword search: girasole                      image search:            ...
Edge Detection Masks                      Edge= jump in intensity, a ramp with slope                      The edge is usef...
Edge Detection Masks                      Sobel mask                      integer value in h                       and v d...
Edge Detection Masks                      Sobel mask           Prewitt mask                      integer value in h    mag...
Edge Detection Masks                      Sobel mask           Prewitt mask      Roberts mask                      integer...
Edge Detection Masks                      Sobel mask           Prewitt mask      Roberts mask Canny mask                  ...
Slope Magnitude Method                      Extract the shape features in from of connected boundaries                    ...
Slope Magnitude Method                      Sobel mask   Prewitt mask   Roberts mask Canny maskmartedì 5 giugno 12
CBIR Techiniques                      Mask-Shape CBIR                      Extract feature shape with slope               ...
CBIR Techiniques                      Mask-Shape CBIR                    Mask-Shape BTC CBIR                      Extract ...
Block Truncation Coding                      It’s a lossy image compression that divides the original images into         ...
Implemtentation                      Matlab 7.0 on Interl Core 2 Duo (2.1 GHz) - 2GB RAM                      Database of ...
Result and Discussionmartedì 5 giugno 12
Result and Discussion                      Mask shape BTC have                      higer value of Precision/             ...
Result and Discussion                        Crossover point of avarage precision/recall                                  ...
Conclusion                      The shape features can be extracted using slope magnitude                      method appl...
Finemartedì 5 giugno 12
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Presentazione Corso di Sistemi Informativi Multimediali Slope Magnitude Method

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Presentazione Corso di Sistemi Informativi Multimediali Slope Magnitude Method

  1. 1. Università degli Studi di Milano Bicocca Teoria e Tecnologia della Comunicazione Corso di Sistemi Informativi Multimedial Image Retrieval with Shape Features Extracted using Gradient Operators and Slope Magnitude Technique with Block Truncation Coding Dr.H.B.Kekre, Sudeep Thepade, Priyadarshini Mukherjee, Miti Kakaiya, Shobhit Wadhwa, Satyajit Singh Docenti: Raimondo Schettini Gianluigi Ciocca Presentazione di Michele Pierangeli Matr. 703989martedì 5 giugno 12
  2. 2. Introduction The paper discusses novel image retrieval methods based on shape features extracted using gradient operators and Slope Magnitude Technique with Block Truncation Coding (BTC).martedì 5 giugno 12
  3. 3. Content Based Image Retrieval keyword search: girasole image search: meta tag, color -> histogram texture -> transforms or vector quantization shape -> gradient or morphological operetor and more...martedì 5 giugno 12
  4. 4. Edge Detection Masks Edge= jump in intensity, a ramp with slope The edge is usefull for detecting the shape of object in scene: segmentation, registration, and identificationmartedì 5 giugno 12
  5. 5. Edge Detection Masks Sobel mask integer value in h and v directionmartedì 5 giugno 12
  6. 6. Edge Detection Masks Sobel mask Prewitt mask integer value in h magnitude and and v direction orentation of edgemartedì 5 giugno 12
  7. 7. Edge Detection Masks Sobel mask Prewitt mask Roberts mask integer value in h magnitude and h and v edge in and v direction orentation of sequence then edge slope magnitudemartedì 5 giugno 12
  8. 8. Edge Detection Masks Sobel mask Prewitt mask Roberts mask Canny mask integer value in h magnitude and h and v edge in gaussian gradient and v direction orentation of sequence then derivate, edge slope magnitude susceptible to noisemartedì 5 giugno 12
  9. 9. Slope Magnitude Method Extract the shape features in from of connected boundaries 1 Gx mask to get gradient x 2 Gy mask to get gradient y 3martedì 5 giugno 12
  10. 10. Slope Magnitude Method Sobel mask Prewitt mask Roberts mask Canny maskmartedì 5 giugno 12
  11. 11. CBIR Techiniques Mask-Shape CBIR Extract feature shape with slope magnitude method on gradients of the image in H an V Finding similarity on query with database image Image must have the same dimension of the querymartedì 5 giugno 12
  12. 12. CBIR Techiniques Mask-Shape CBIR Mask-Shape BTC CBIR Extract feature shape with slope Extract feature shape with slope magnitude method on gradients magnitude method on gradients of the image in H an V of the image in H an V Finding similarity on query Resolve the problem of different with database image image size in database Image must have the same BTC applied to have a shape dimension of the query feature vector with consistent sizemartedì 5 giugno 12
  13. 13. Block Truncation Coding It’s a lossy image compression that divides the original images into blocks and then uses a quantiser to reduce the number of grey levels in each block whilst maintaining the same mean and standard deviation. Using sub-blocks of 4x4 pixels gives a compression ratio of 4:1. In the coding phase if a pixel is greater or equal the block mean will have a value of 1 else 0. In the decoding phase pixel are1 repleaced by one mean pixel of the corrisponding value ( 1 or 0).martedì 5 giugno 12
  14. 14. Implemtentation Matlab 7.0 on Interl Core 2 Duo (2.1 GHz) - 2GB RAM Database of 1000 variable sized images witch 11 categories. 55 queries with every method errore quadratico medio Feature similarty:martedì 5 giugno 12
  15. 15. Result and Discussionmartedì 5 giugno 12
  16. 16. Result and Discussion Mask shape BTC have higer value of Precision/ Recall Robert-Shape-BTC outperforms the other methods of image retrieval.martedì 5 giugno 12
  17. 17. Result and Discussion Crossover point of avarage precision/recall 1 3 2 4 Gradientsmartedì 5 giugno 12
  18. 18. Conclusion The shape features can be extracted using slope magnitude method applied on gradient of images taken in both horizontal and vertical directions. The advantage of using BTC is that there would be no need of image resizing for feature vector extraction from image with improvement in performance of image retrieval results. In all the Robert-Mask-Shape-BTC gives the best performance.martedì 5 giugno 12
  19. 19. Finemartedì 5 giugno 12

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