Microarray calibration. (a) Set 1 target intensity as a calibrated function of sample concentration ratio and hybridization temperature. Green and red dots represent the measured target and nontarget values. (b) Set 1 intensity ratio similarly calibrated as a function of sample concentration ratio and hybridization temperature; blue dots are the measured ratio values. (c) Contour map of several intensity (green), ratio (blue), SNR (magenta) and 2SD (red) lines obtained from Set 1 data. (d) Contour map of similar set of lines obtained from Set 2 data. Dashed lines in the contour maps enclose the ± 1 standard deviation range around the 20000 intensity line and the 25× ratio line. See Table 2 for the numerical coordinates of the intersecting points 1--7 on the two contour maps.