Abstract: A method calibrates a microscope using a test pattern by capturing a plurality of images of the test pattern with the microscope. The test pattern has a plurality of uniquely identifiable positions across a plurality of repeating and overlapping 2D sub-patterns. The method determines an image contrast metric from the captured image in a selected patch of the test pattern and a reference contrast metric in the corresponding region; and (iii) determines a normalised contrast metric using the reference contrast metric and the image contrast metric. The method estimates depths of the two captured images at the plurality of positions using the normalised contrast metrics and a set of predetermined calibration data for a stack of images captured using the test pattern at a range of depths, and calibrates the microscope using a comparison of the determined depth estimates for the at least two images.

Abstract: A method of demodulating an image captured from an imaging system having at least one two-dimensional grating. The captured image comprises a phase modulated fringe pattern comprising cross-term phase components resulting from presence of the at least one two-dimensional grating. The method determines parameters of at least a first non-linear transformation for attenuating the cross-term phase components. The parameters of the first non-linear transformation are determined for the imaging system to reduce artefacts in a demodulated image introduced by the cross-term phase components. The method demodulates the captured image by applying at least the first non-linear transformation with the determined parameters to the captured image to attenuate the cross-term phase components.

Abstract: A method determining a retinal pigment epithelium identifies a plurality of regions using captured image data of the eye and fits a curve into at least some of the regions. A curve score is determined associated with the fitted curve using at least a distance between the fitted curve and at least some of the regions in which a contribution of the regions to the curve score is biased towards (asymmetric) regions below the fitted curve. These steps are repeated whereupon one of the fitted curves is selected, using the corresponding associated curve score, for classifying some of the regions as forming at least a part of a retinal pigment epithelium.

Abstract: A method of determining a coordinate transform between a first image and a second image, said method comprising the steps of: determining a rate of change of pixel values for locations on the first image to identify candidate alignment patches in the first image; specifying subsets of patches from the set of candidate alignment patches based on an error metric, selecting a subset of candidate alignment patches from said plurality of subsets of candidate alignment patches based upon a predetermined criterion; estimating, for each patch in the selected subset, a shift between the patch and a corresponding patch in the second image, the location of the corresponding patch in the second image being determined from the location of the patch in the first image; and determining the coordinate transform between the first image and second image based on the estimated shifts.