Abstract: A three-dimensional image of flowing fluid or moving tissue using velocity or power Doppler data is displayed by using an ultrasound scanner that collects velocity or power data in a cine memory to form a volume of pixel data. Average or median pixel values are projected on an image plane by casting rays through the data volume. As the ray passes through each scan plane, a data value is assigned to the ray at that point. At each scan plane, the assigned pixel data value is tested to see if it exceeds a noise threshold. For a given ray, pixel data values above the detection threshold are accumulated until a pixel data value falls below the detection threshold. A minimum number of pixel data values exceeding the threshold are required for each ray before the average of the accumulated values is processed and/or the median value is selected. When all pixels along a given ray have been tested, the projection is complete and the average or median projection is then displayed.