Abstract: A method of determining components present in a sample from spectral data obtained from the sample including resolving each of a plurality of models of the spectral data, the plurality of models including models having a different number of component reference spectra selected from a set of predetermined component reference spectra; selecting a one of the plurality of models based upon a model selection criterion and determining one or more components present in the sample based upon the selected model. The model selection criterion includes a measure for each model, which balances improvements in fit quality of the model to the spectral data against a complexity penalty determined from the number of component reference spectrum used in the model.

Abstract: Spectroscopy including a source generating light profile on the sample. The light profile is movable relative to the sample. An optical input for receiving light from sample interaction with light from the source, a detector including two-dimensional array of photodetector elements, a dispersive device between the optical input and detector to spectrally disperse light from the optical input in spectral direction across the detector, an optical splitter in optical path between the optical input and detector to split light based upon wavenumber so, for a spectrum generated by a point on the sample, the spectrum first and second portions are dispersed across photodetector elements of different array row/column.

Abstract: This invention concerns a spectroscopic method, apparatus for determining whether a component is present in a sample. In one aspect, the method includes resolving a model of the spectral data separately for candidates from a set of predetermined component reference spectra, and determining whether a component is present in the sample based upon a figure of merit quantifying an effect of including the candidate reference spectrum corresponding to that component in the model.

Abstract: The invention relates to a method and apparatus for focusing structured image such as a laser spot. A method for determining the degree of focus of such a structured image are disclosed whereby: an image is provided at a photosensitive array formed from a plurality of elements; the position of the image is determined; for an element of the array a weighting is assigned according to the position of that element relative to the position of the image; the intensity of the image at the element is determined; a value is produced for the element dependent on its weighting and the intensity of the image thereat. In addition the values of the plurality of elements are summed and one overall focus value is found which is indicative of the degree of focus of the image. This value is used to search for and maintain best focus and methods for achieving this are disclosed also. Apparatus is shown in which a microprocessor and a controller are used to perform the methods disclosed.