Figure 2. Image segmentation and cell classification.

(a) An image taken at the first time point, immediately before impact, shows characteristic staining pattern. In this mitochondrial assay, red staining highlights polarized mitochondria, green staining highlights all mitochondria regardless of polarity, and blue staining highlights dead cell nuclei. Dashed rectangle indicates region highlighted in (b). Scale bar indicates 100 μm. (b) Images were subsequently analyzed to segment and classify cells as indicated by colored outlines. Cell state, as determined by the color distribution in each cell, is indicated by the color of the segmentation outline. (i) Only cells that had polarized mitochondria (red outlines) before impact were tracked longitudinally. (ii) Observing the same location at 15 minutes after impact, some cells changed from polarized to depolarized (green outline) or dead (blue outline). Scale bar indicates 25 μm.