This document presents a method for improving image classification using crowdsourcing and global visual features. It calculates worker reliability to weight crowd votes and uses these weighted votes to label images. Visual classifiers are then trained on the newly labeled data. Experimental results show that combining crowdsourcing with visual features leads to good classification performance, even with small labeled datasets. Worker reliability measures perform well, and transfer learning is effective. However, some concepts are better detected visually than others.
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Frame the Crowd: Global Visual Features Labeling boosted with Crowdsourcing Information
1. Frame the Crowd:
Global Visual Features
Labeling boosted with
Crowdsourcing Information
Presentation: Michael Riegler, AAU
Mathias Lux, AAU
Christoph Kofler, TU Delft
5. Idea
Solve the problem with a Global Visual Features
approach based on the framing theory
Always available and for free (beside computation time)
Workers Reliability for Crowdsourcing Information
Transfer learning
6. Visual Classifier
Modification of LIRE framework
Search based
12 Global features
Feature selection
Feature combination
late fusion
7. Workers Reliability
Calculate the reliability of a Worker:
#(agrees with majority vote) /
#(total votes by worker)
Used as weight for the votes
Together with self report familiarity as
feature vector
8. Runs
1. Reliability measure for workers
2. Visual information with MMSys model
3. Visual information with low fidelity worker
votes of Fashion10000 dataset model
4. Visual information with new, by the method
of run#1, labeled Fashion10000 dataset
5. Visual information based decision for not
clear results of run#1
11. Weighted F1 score (WF1)
Weighted metric of each F1 score per
class
Can help to interpret the results better
Can compensate differences between
biased classes
13. Conclusion
Calculating the workers reliability performs well
Well known that metadata leads to better results
Transfer learning works well
Crowdsourcing can boost visual classification
With visual features, even small amount of labeled data leads
to good results
Usefulness of Framing is reflected by the results
Label 1 very good detectable with global visual features,
but label 2 not (concept detection)
Weighted F1 score can help to understand the results better