Abstract: A method for classifying image pixels comprises obtaining (210) of a plurality of pixel vectors of an image. Each said pixel vector has n intensity elements associated with a same respective imaged position, n?2. Each of the n intensity elements is a digital value representing a discretized intensity measure of light, within a respective predetermined wavelength interval, coming from the imaged position. The method further comprises creating (220) of an angle histogram of angles of the pixel vectors, in a space spanned by unity vectors of the n intensity elements. At least one angle interval is defined (230), corresponding to a respective pixel class, based on statistics of the angle histogram. Pixel vectors are classified based on the defined angle intervals. Co-localization classification insensitive to cross-talk can thereby be obtained. A fluorescence microscopy device having an image analyser according to the method is presented.