TITLE: Towards Good Practices for Efficiently Annotating Large-Scale Image Classification Datasets 

ABSTRACT: Data is the engine of modern computer vision, which necessitates collecting
large-scale datasets. This is expensive, and guaranteeing the quality of the
labels is a major challenge. In this paper, we investigate efficient annotation
strategies for collecting multi-class classification labels for a large
collection of images. While methods that exploit learnt models for labeling
exist, a surprisingly prevalent approach is to query humans for a fixed number
of labels per datum and aggregate them, which is expensive. Building on prior
work on online joint probabilistic modeling of human annotations and
machine-generated beliefs, we propose modifications and best practices aimed at
minimizing human labeling effort. Specifically, we make use of advances in
self-supervised learning, view annotation as a semi-supervised learning
problem, identify and mitigate pitfalls and ablate several key design choices
to propose effective guidelines for labeling. Our analysis is done in a more
realistic simulation that involves querying human labelers, which uncovers
issues with evaluation using existing worker simulation methods. Simulated
experiments on a 125k image subset of the ImageNet100 show that it can be
annotated to 80% top-1 accuracy with 0.35 annotations per image on average, a
2.7x and 6.7x improvement over prior work and manual annotation, respectively.
Project page: https://fidler-lab.github.io/efficient-annotation-cookbook
Data is the engine of modern computer vision, which necessitates collecting
large-scale datasets. This is expensive, and guaranteeing the quality of the
labels is a major challenge. In this paper, we investigate efficient annotation
strategies for collecting multi-class classification labels for a large
collection of images. While methods that exploit learnt models for labeling
exist, a surprisingly prevalent approach is to query humans for a fixed number
of labels per datum and aggregate them, which is expensive. Building on prior
work on online joint probabilistic modeling of human annotations and
machine-generated beliefs, we propose modifications and best practices aimed at
minimizing human labeling effort. Specifically, we make use of advances in
self-supervised learning, view annotation as a semi-supervised learning
problem, identify and mitigate pitfalls and ablate several key design choices
to propose effective guidelines for labeling. Our analysis is done in a more
realistic simulation that involves querying human labelers, which uncovers
issues with evaluation using existing worker simulation methods. Simulated
experiments on a 125k image subset of the ImageNet100 show that it can be
annotated to 80% top-1 accuracy with 0.35 annotations per image on average, a
2.7x and 6.7x improvement over prior work and manual annotation, respectively.
Project page: https://fidler-lab.github.io/efficient-annotation-cookbook
Towards Good Practices for Efficiently Annotating Large-Scale Image Classification Datasets
http://arxiv.org/abs/2104.12690v1