The present disclosure relates to a method of determining that a finger is in stable contact with a surface covering a sensor area of a fingerprint sensor. The method comprises, by means of the fingerprint sensor, acquiring a time-sequence of images of the fingerprint of the received finger. The method also comprises, for each image of the time-sequence, dividing an image area of the image, corresponding to the sensor area of the fingerprint sensor, into a plurality of image regions (r), said regions partly overlapping each other and covering the whole image area. The method also comprises, based on image analysis of each of the plurality of image regions of each image of the time-sequence, determining that the finger is in stable contact with the surface covering the sensor area.