Figure 8From: caCORRECT2: Improving the accuracy and reliability of microarray data in the presence of artifactsExamples of artifacts present for biomarker identification analysis. Images are heat maps of residuals for two pairs of arrays, with red color indicating higher-than-expected probe intensity, and blue color indicating lower-than-expected probe intensity. Heat maps such as these reveal the intensity and type of artifacts after caCORRECT normalization and artifact identification, but before removal. Panels A and B show naturally occurring artifacts on two chips from the Schuetz et al. dataset. Blue color in the upper right quadrant of panel A indicates data in this region is artificially low. Multiple small compact artifacts, both red and blue, can also be seen. Panel B shows more examples of naturally occurring artifacts, including a large artifact on the right edge of the chip. In panels C and D respectively, synthetic circle-shaped hot-spot and black-hole type artifacts have been applied to the same chips from panels A and B. The artifact in C appears red due to its artificially high probe intensity values. In panel D, the synthetic black-hole artifact is visible as a blue circle.Back to article page