1. A method for operating an ultrasound machine to produce an ultrasound image including an image of an interventional instrument, comprising: establishing a first ultrasound imaging signature having one or more imaging parameters including a transmit waveform, ratio of transmit to receive beamformed lines, imaging steering angle, receive line density, number of focal zones, quadrature bypass filter type and coefficients, compression curve and speckle reduction parameters selected to produce a high quality image of tissue within a volume to be imaged; establishing a second ultrasound imaging signature having one or more imaging parameters including a transmit waveform, ratio of transmit to receive beamformed lines, imaging steering angle, receive line density, number of focal zones, quadrature bypass filter type and coefficients, compression curve and speckle reduction parameters selected to produce a high quality image of an instrument within the volume to be imaged; generating a first frame using the image data resulting from application of the first ultrasound imaging signature; and generating a second frame using the image data resulting from application of the second ultrasound imaging signature; detecting pixels in the second frame that correspond to the interventional instrument; automatically determining a mask of pixels that correspond to the location of the interventional instrument; blending pixels from the first frame and the second frame in a region that is inside the mask and using pixels from the first frame in a region that is outside the mask to form a blended final ultrasound image; and producing a graphic indication on the blended final ultrasound image that indicates the boundaries of a coverage area in the blended final ultrasound image where one or more of the imaging parameters of the second ultrasound imaging signature is selected to produce a high quality image of the interventional instrument.