Method for computer-aided
processing of
spatially resolved mass spectrometry data with a multitude of spectra assigned to respective measurement positions (x), wherein a spectrum (s x (m / z)) for several image channels (m / z) comprises respective intensities (I) which represent a
physical quantity detected for the corresponding image channel (m / z), wherein the image channels (m / z) represent
mass-to-charge ratios and the
physical quantity detected for the corresponding image channel (m / z) represents the number of molecules detected for the corresponding
mass-to-charge ratio, where: - the
mass spectrometry data are decomposed using a non-negative matrix factorization, according to which a
data matrix (X) is generated, which for each measurement position (x) represents the intensities (I) for the image channels (m / z) of the spectrum (s) assigned to the respective measurement position (x). x(m / z)) is represented as a matrix product of a component matrix (S) and a
coefficient matrix (C), where the component matrix (S) contains, for a predetermined number of components (k), intensities of a spectrum (ψ) assigned to the respective component (k). k (m / z)) for the image channels (m / z) and wherein the
coefficient matrix (C) for the predetermined number of components (k) includes coefficients for the measurement positions (x), wherein the non-negative matrix factorization is designed such that the decomposed
mass spectrometry data have a smaller amount of data compared to the
mass spectrometry data before
decomposition; - based on the non-negative matrix factorization, an optimization of a cost function is carried out in the form of a maximization or minimization of the cost function depending on the component matrix (S) and the
coefficient matrix (C) as variables, where the cost function comprises a functional (f(X, S, C)) that depends on the
data matrix (X), the component matrix (S) and the coefficient matrix (C); - when optimizing the cost function, a first and a second constraint are applied, whereby according to the first constraint, the cost function is optimized towards the smallest possible number of non-zero entries in the component matrix (S), and according to the second constraint, the cost function is optimized towards the smallest possible number of non-zero entries in the coefficient matrix (C); - the entries of the component matrix (S) and the coefficient matrix (C) generated by the non-negative matrix factorization are stored.