There are provided embodiments for providing a compound image of Doppler spectrum images corresponding to at least two sample volumes. In one embodiment, by way of non-limiting example, an ultrasound system comprises: a processing unit configured to form at least two Doppler spectrum images corresponding to at least two sample volumes based on ultrasound data corresponding to the at least two sample volume, the processing unit being further configured to perform an image process for forming a compound image upon the at least two Doppler spectrum images to form the compound image.