1. A method of converting raw multidimensional digital data (xk) corresponding to points (k) making up a 2D or 3D image of unknown size, the method comprising: a step of sizing a multidimensional window for traversing of the said image, the said sizing depending on the size of a buffer; a step of traversing the said image comprising the movement of the said window in the image along the axes of the image; at each position of the said window in the image: a step of acquiring and loading, in the said buffer, raw data (x k ) of the part of the said image defined by the window; a conversion step comprising a step of calculating the multidimensional wavelet transform of the said loaded part by means of at least one compact support filter for generating low-frequency (s k ) and high-frequency (d k ) coefficients; a step of saving the said coefficients generated.