Fig. 1: Overview of the Loon Visualization Tool. (a) The Condition Selector visualizes cell growth rates for different drugs at different concentrations using small multiple line charts in a matrix. Analysts can pick conditions that show interesting behavior for detailed analysis. (b) The Image Selection View is used to navigate images and visualizes aggregate cell and track (cells tracked over time) properties. (c) The Image View shows a selected microscopy image and the segmentation of cells. (d) The Cell and Track Attributes View shows distributions of and correlations between attributes of cells and tracks and serves as the primary means to define selections and filters. (e) The Exemplar Cells View shows cells extracted from the images and samples from a user-specified distribution. It also shows the growth curves for the condition and the selected cells.

Which drug is most promising for a cancer patient? This is a question a new microscopy-based approach for measuring the mass of individual cancer cells treated with different drugs promises to answer in only a few hours. However, the analysis pipeline for extracting data from these images is still far from complete automation: human intervention is necessary for quality control for preprocessing steps such as segmentation, to adjust filters, and remove noise, and for the analysis of the result. To address this workflow, we developed Loon, a visualization tool for analyzing drug screening data based on quantitative phase microscopy imaging. Loon visualizes both, derived data such as growth rates, and imaging data. Since the images are collected automatically at a large scale, manual inspection of images and segmentations is infeasible. However, reviewing representative samples of cells is essential, both for quality control and for data analysis. We introduce a new approach of choosing and visualizing representative exemplar cells that retain a close connection to the low-level data. By tightly integrating the derived data visualization capabilities with the novel exemplar visualization and providing selection and filtering capabilities, Loon is well suited for making decisions about which drugs are suitable for a specific patient.