UnProjection: Leveraging Inverse-Projections for Visual Analytics of High-Dimensional Data
This addresses the challenge of mapping projected data back to original high-dimensional spaces for users in visual analytics, though it appears incremental as it builds on existing projection methods.
The paper tackles the problem of inverse-projection for visualizing high-dimensional data by introducing NNInv, a deep learning technique that approximates the inverse of any projection to reconstruct high-dimensional data from 2D points, enabling interactive visual analytics tasks like instance interpolation and classifier agreement.
Projection techniques are often used to visualize high-dimensional data, allowing users to better understand the overall structure of multi-dimensional spaces on a 2D screen. Although many such methods exist, comparably little work has been done on generalizable methods of inverse-projection -- the process of mapping the projected points, or more generally, the projection space back to the original high-dimensional space. In this paper we present NNInv, a deep learning technique with the ability to approximate the inverse of any projection or mapping. NNInv learns to reconstruct high-dimensional data from any arbitrary point on a 2D projection space, giving users the ability to interact with the learned high-dimensional representation in a visual analytics system. We provide an analysis of the parameter space of NNInv, and offer guidance in selecting these parameters. We extend validation of the effectiveness of NNInv through a series of quantitative and qualitative analyses. We then demonstrate the method's utility by applying it to three visualization tasks: interactive instance interpolation, classifier agreement, and gradient visualization.