Reliable Aggregation Method for Vector Regression Tasks in Crowdsourcing

Crowdsourcing platforms are widely used for collecting large amount of labeled data. Due to low-paid workers and inherent noise, the quality of acquired data could be easily degraded. To solve this, most previous studies have sought to infer the true answer from noisy labels in discrete multiple-choice tasks that ask workers to select one of several answer candidates. However, recent crowdsourcing tasks have become more complicated and usually consist of real-valued vectors. In this paper, we propose a novel inference algorithm for vector regression tasks which ask workers to provide accurate vectors such as image object localization and human posture estimation. Our algorithm can estimate the true answer of each task and a reliability of each worker by updating two types of messages iteratively. We also prove its performance bound which depends on the number of queries per task and the average quality of workers. Under a certain condition, we prove that its average performance becomes close to an oracle estimator which knows the reliability of every worker. Through extensive experiments with both real-world and synthetic datasets, we verify that our algorithm are superior to other state-of-the-art algorithms.