| 摘要 |
A method for optimizing the beam distribution to obtain the highest frame rate together with the least amount of acoustic noise while limiting the spatial aliasing to an acceptable level. The beam distribution is adjusted according to the scan format and as a function of the beam width, which is proportional to the product of the F number and the operating wavelength. As the F number changes in going from the shallow depth to a deeper depth, the number of beams fired to construct an image would change correspondingly. In addition, if the F number is changing in going from the center of image to the edge of the image, the separation of the fired beams would change. Alternatively, if the operating frequency is being changed in going from shallower depths to deeper depths or in going from the center of image to the edge of the image, the beam spacing is changed in order to fire the optimum number of beams at all times, and thereby obtain the highest frame rate. Another variation is to have a beam distribution which depends on the spatial resolution of the display unit. For a sector scan, the number of beams which are fired at the shallower depths can be made smaller than the number of beams fired at the deeper depths. Once the beam distribution has been defined, the sequencing of beam firings must be determined to maximize the frame rate.
|
