Unsupervised classification of cell imaging data using the quantization error in a Self Organizing Map

TL;DR

This paper demonstrates that the quantization error in Self Organizing Maps can rapidly and precisely detect subtle spatial variations in cell viability imaging data, with potential clinical significance.

Contribution

It introduces a novel application of SOM quantization error for unsupervised classification of cell imaging data, highlighting its sensitivity and speed.

Findings

SOM QE detects small spatial changes in cell viability images.

SOM QE shows color sensitivity, especially to RED pixel variations.

The method is fast, taking only a few seconds per image.

Abstract

This study exploits previously demonstrated properties such as sensitivity to the spatial extent and the intensity of local image contrast of the quantization error in the output of a Self Organizing Map (SOM QE). Here, the SOM QE is applied to double color staining based cell viability data in 96 image simulations. The results show that the SOM QE consistently and in only a few seconds detects fine regular spatial increases in relative amounts of RED or GREEN pixel staining across the test images, reflecting small, systematic increases or decreases in the percentage of theoretical cell viability below the critical threshold. Such small changes may carry clinical significance, but are almost impossible to detect by human vision. Moreover, we demonstrate a clear sensitivity of the SOM QE to differences in the relative physical luminance (Y) of the colors, which here translates into a RED GREEN color selectivity. Across differences in relative luminance, the SOM QE exhibits consistently greater sensitivity to the smallest spatial increases in RED image pixels compared with smallest increases of identical spatial extents in GREEN image pixels. Further selective color contrast studies on simulations of biological imaging data will allow generating increasingly larger benchmark datasets and, ultimately, unravel the full potential of fast, economic, and unprecedentedly precise biological data analysis using the SOM QE.