Final answer:
Power Doppler is the imaging technique that is not dependent on the angle of incidence of the sound beam because it measures the amplitude rather than the frequency shift of the Doppler signal.
Step-by-step explanation:
The imaging technique that is not dependent on the angle of incidence of the sound beam is Power Doppler. Power Doppler, which focuses on the amplitude of the Doppler signal rather than its frequency shift, is less dependent on the angle between the sound beam and the blood flow direction. This makes it a useful tool for depicting blood flow, especially in areas where the angle cannot be corrected, unlike CW Doppler, Color Doppler, and Speckle tracking which are affected by the angle of incidence to varying degrees.