CAPTCHA-based image labeling on the Soylent Grid

We introduce an open labeling platform for Computer Vision researchers based on Captchas, creating as a byproduct labeled image data sets while supporting web security. For the two different tasks of annotation and detection, we explore usability issues. We present the interfaces used by researchers and users and experimental results obtained using the platform. Finally, we discuss system sustainability issues in the context of a broader "ecosystem" for the platform.