| 摘要 |
The invention involves ultrasonic imaging and consists of an ultrasonic holographic B-scan imaging method (UHB imaging). It combines B-scan imaging, which gives good longitudinal resolution and holographic imaging based on wavefront backward propagation, which gives good lateral resolution, to achieve a new imaging method resulting in good resolution in both directions. UHB imaging can be performed in two ways. Firstly, the imaging can be performed so that a conventional B-scan imaging is first produced, whereafter one dimensional holographic imaging based on the numerical wavefront backward propagation is achieved at each depth in the object (3), or at each distance from the transducer (7), and finally the obtained images are combined by multiplying them point by point. Secondly, UHB imaging can be performed so that B-scan imaging and holographic imaging are produced simultaneously by transmitting ultrasound bursts from each element of the transducer (7) on the hologram plane to the object (3) and by measuring the amplitude and phase of the reflected ultrasound as a function of the propagation time. The obtained measurement data is reconstructed to the image in a computer. Additionally, the invention includes image filtering and compensation processing which can be applied to either of these images for the errors caused by propagating of the ultrasound wave in nonhomogeneous media. |
