DeviParikh WACV 2008

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Slide1: 

Localization and Segmentation of 2D High Capacity Color Barcodes Gavin Jancke Microsoft Research, Redmond Devi Parikh Carnegie Mellon University

Motivation: 

Motivation UPC Barcode QR Code Datamatrix

HCCB: 

HCCB Microsoft’s High Capacity Color Barcode

Application: 

Application Uniquely identifying commercial audiovisual works such as motion pictures, video games, broadcasts, digital video recordings and other media

Goal: 

Goal Locate and Segment the barcode from consumer images

Overview: 

Overview Design specifications of Microsoft’s HCCB Approach Localization Segmentation Progressive Strategy Results Conclusions

Microsoft’s HCCB: 

Microsoft’s HCCB 4 or 8 colors Triangles String of colors palette

Microsoft’s HCCB: 

Microsoft’s HCCB

Microsoft’s HCCB: 

Microsoft’s HCCB

Microsoft’s HCCB: 

Microsoft’s HCCB

Microsoft’s HCCB: 

Microsoft’s HCCB R rows S symbols per row S = (r+1)*R Aspect ratio: r

Approach: 

Approach Thresholding Orientation prediction Corner localization Row localization Symbol localization Color assignments Barcode localization Barcode segmentation point inside the barcode is known

Localization: Thresholding: 

Localization: Thresholding Identify thick white band and row separators Normalization Adaptive

Localization: Orientation: 

Localization: Orientation orientation orientation distance -90 90 0 summation

Localization: Corners: 

Localization: Corners Rough estimates whiteness mask non-texture mask combined mask

Localization: Corners: 

Localization: Corners Gradient based refinement

Localization: Corners: 

Localization: Corners Line based refinement

Segmentation: Rows: 

Segmentation: Rows Summation Flip?

Segmentation: Symbols: 

Segmentation: Symbols Local search Number of symbols per row q(S,E) = Sq(samples|S,E)

Segmentation: Colors: 

Segmentation: Colors Palette

Observations: 

Segmentation results given accurate localization Satisfactory Corner localization Unsatisfactory No one strategy works well on all images However (1) Errors of different strategies are complementary (2) Results are verifiable with decoder in the loop! Observations

Progressive strategy: 

Progressive strategy Hence – progressive strategy! Similar to ensemble of weak classifiers Or hypothesize-and-test Multiple strategies: Rough + gradient + line, or rough + line, or rough + gradient, or rough alone Different values of threshold during rough corner detection Total 12 Order of strategies

Results: 

Results Dataset of 500 images Performance metric: % barcodes successfully decoded Decoder model: Barcode successfully decoded if 80% of symbols are correctly identified

Results: 

Results Allows for explicit trade-off between accuracy and computational time

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Results: 

Results

Conclusions: 

Conclusions 2D High Capacity Color Barcode (HCCB) Successful localization and segmentation of HCCB from consumer images Varying densities, aspect ratios, lighting, color balance, image quality, etc. Simple computer vision and image processing techniques Progressive strategy

Acknowledgements: 

Acknowledgements Microsoft Research Larry Zitnick Andy Wilson Zhengyou Zhang Carnegie Mellon University Advisor: Tsuhan Chen

Slide37: 

Thank you!