Tracking of objects with known color signature - ELITECH 20


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My presentation on conference ELITECH 2011. It is on tracking colored objects. Presentation and paper won the award for best contribution in area of computer science from Slovak IT SAV society.

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Tracking of objects with known color signature - ELITECH 20

  1. 1. Tracking of objects with known color signature Lukáš Tencer [email_address]
  2. 2. Content <ul><li>Overview of existing approaches </li></ul><ul><li>Motivation </li></ul><ul><li>Basic apparatus </li></ul><ul><li>Our approach: </li></ul><ul><ul><li>Preprocessing </li></ul></ul><ul><ul><li>Image segmentation </li></ul></ul><ul><ul><li>Object identification </li></ul></ul><ul><ul><li>Object tracking </li></ul></ul><ul><li>Testing and Results </li></ul><ul><li>Future work </li></ul>
  3. 3. Previous work <ul><li>ACM Survey [Yilmaz et al., 2004], after this emphasis on accuracy, speed, robustness </li></ul><ul><li>Kernel based tracking </li></ul><ul><li>tracking kernel of image region </li></ul><ul><li>Point Based Tracking </li></ul>
  4. 4. Previous work 2 <ul><li>Structure Based Tracking </li></ul><ul><li>uses skeleton/silhouette </li></ul><ul><li>Our previous work </li></ul><ul><li>Gesture-based </li></ul><ul><li>mouse control </li></ul>
  5. 5. Basic apparatus <ul><li>Color signature: </li></ul><ul><ul><li>artificial representation of objects projection into digital space, based on its color values </li></ul></ul><ul><ul><li>for our method, it is ranged values in HSV color model </li></ul></ul><ul><li>Convex hull of set of points: </li></ul><ul><ul><li>Polygon, for which every point from input set lies “inside” the polygon </li></ul></ul><ul><ul><li>minimal convex set containing input set </li></ul></ul>
  6. 6. Our approach <ul><li>Preprocessing </li></ul><ul><ul><li>Background subtraction </li></ul></ul><ul><li>Image Segmentation </li></ul><ul><ul><li>Image histogramization </li></ul></ul><ul><li>Object Identification </li></ul><ul><ul><li>Color contribution condition, border conditions </li></ul></ul><ul><li>Object Tracking </li></ul><ul><ul><li>Bumper-region based tracking </li></ul></ul>
  7. 7. Preprocessing <ul><li>Background subtraction </li></ul><ul><li>Color difference between trained background and input image </li></ul><ul><li>Could cause loss of image information </li></ul>
  8. 8. Image segmantation <ul><li>Image Histogramization </li></ul><ul><ul><li>Segment image into sub-regions (fixed/adaptive) </li></ul></ul><ul><ul><li>Extract descriptive channel of the image </li></ul></ul><ul><ul><li>In our case, HUE channel of HSV image model </li></ul></ul><ul><ul><li>Create histogram with n dimensions for each sub-region </li></ul></ul>
  9. 9. Object Identification <ul><li>Select regions corresponding to object’s projection into image plane </li></ul><ul><li>For one colored object, we select minimal level of dominant dimension </li></ul><ul><li>For two colored object, minimal level of contribution of other color </li></ul><ul><li>Border regions, maximal contribution of other colors and minimal connectivity condition </li></ul>
  10. 10. Object tracking <ul><li>Pick center of the convex hull of identified regions </li></ul><ul><li>Place tracking object inside the convex hull </li></ul><ul><li>Once object is moved, we identify regions, which are no longer covered by object </li></ul><ul><li>Create convex hull of uncovered regions, connect it’s center and center of tracking object to identify movement vector </li></ul><ul><li>Move tracking object in direction of movement vector, until all regions are covered by object regions </li></ul>
  11. 11. Testing and Results <ul><li>Improved tracking speed </li></ul><ul><li>Robustness against disruptive elements in scene </li></ul><ul><li>Unique color signature </li></ul><ul><li>Approach of image histogramization </li></ul><ul><li>Bumper-region based object tracking </li></ul><ul><li>Method could be used for tracking of colored object, HCI, surveillance … </li></ul>
  12. 12. Future Work <ul><li>Use of more adaptive object representation structures, to improve computational speed </li></ul><ul><ul><li>Quad-tree? </li></ul></ul><ul><li>Remove requirement to have prior information about color signature </li></ul><ul><ul><li>Use training algorithm, to create model from identified foreground </li></ul></ul>
  13. 13. Thank you for you attention
  14. 14. Questions ?