Method of detecting an anomaly on the surface of a tyre comprising the following steps in the course of which: A - the image of a given anomaly present on the surface of at least one tyre is produced, B - a multivariate image of the said surface, in which each pixel is represented in the form of a pixel vector, is constructed, with the aid of a collection of filters, in a filter space, the components of each pixel vector having a value corresponding to the value of this pixel in the image transformed with the aid of each of the filters of said collection C - with the aid of a linear function, this multivariate image is transformed from the filter space into a spectral space of given dimension whose variables are the filters or combinations of filters of said collection, so as to form a spectral image, D - a classifier is constructed by determining, for this anomaly, those zones, representative of the spectral space, in which the points of the spectral image, of said anomaly transformed into said spectral space, lie in a statistically representative manner.