Fig. 1
From: Unsupervised image segmentation for microarray spots with irregular contours and inner holes
a The microarray image was taken from SMD database (ID 20385). The image shows the intensity of fluorescent light emitted from dye cyanine Cy3. The spots of high intensity indicate sequence-specific hybridisation of labelled DNA extracted from Arabidopsis thaliana. The experiment has been designed to study global transcriptional factors of hormone treatment. The detection of groups of co-localized spots is shown by the grid of the global addressing. The groups of spots are separated by the horizontal and vertical lines of the grid. b A sub-image of the microarray image shown in a). The sub-image depicts a group of 324 co-localized spots. The size of a sub-image is in round numbers 460×480 pixels. Spots of high intensity are separated by lines of a grid. Inflection points of intensity profiles were computed to align the grid, see Section Grid alignment. The horizontal and vertical lines of the griding separate rows and columns of spots. The two horizontal broken lines and the two vertical broken lines cut out a slice of the 14th row and of the 6th column of spots, respectively. c The procedure of grid alignment yields a stable separation even for spots with non-spherical profiles, low intensities or high background signal