Color standardization in whole slide imaging using a color calibration slide

BACKGROUND: Color consistency in histology images is still an issue in digital pathology. Different imaging systems reproduced the colors of a histological slide differently. MATERIALS AND METHODS: Color correction was implemented using the color information of the nine color patches of a color calibration slide. The inherent spectral colors of these patches along with their scanned colors were used to derive a color correction matrix whose coefficients were used to convert the pixels’ colors to their target colors. RESULTS: There was a significant reduction in the CIELAB color difference, between images of the same H & E histological slide produced by two different whole slide scanners by 3.42 units, P < 0.001 at 95% confidence level. CONCLUSION: Color variations in histological images brought about by whole slide scanning can be effectively normalized with the use of the color calibration slide.