Motion-compensated processing

Abstract

An echo processor (117) for an ultrasound imaging device (102) includes a frame processor (118) that aligns a plurality (N) of sequentially received frames of echoes based on a set of motion displacement fields for the plurality of frames and combines the aligned plurality of sequentially received frames, thereby forming a compounded frame. A method includes obtaining a set of frames of echoes acquired at different times, determining a motion displacement field based on at least two of the frames of the set, motion-compensating all of the frames of the set based on the displacement field and previously determined displacement fields, and generating a compounded frame based on the motion-compensated frames.

What is claimed is: 
     
         1 . An echo processor for an ultrasound imaging device, comprising:
 a frame processor that aligns a plurality (N) of sequentially received frames of echoes based on a set of motion displacement fields for the plurality of frames and combines the aligned plurality of sequentially received frames, thereby forming a compounded frame, and   a compounded frame processor that combines a compounded frame and either a previous compounded frame or a previous combined compounded frame based on the displacement field.   
     
     
         2 . The echo processor of  claim 1 , wherein each displacement field is based on a displacement between a most recently acquired frame of the plurality of frames corresponding to a latest angle of insonation and another of the plurality of frames acquired at the latest angle of insonation. 
     
     
         3 . The echo processor of  claim 2 , the frame processor, comprising:
 a motion-compensator that motion-compensates samples of each of the N−1 oldest frames of the plurality of frames based on N−1 latest displacement fields, thereby aligning the frames to the latest frame of the plurality of frames.   
     
     
         4 . The echo processor of  claim 3 , wherein the displacement for each image sample is equal to the displacement field divided by a number of frames in the plurality of frames. 
     
     
         5 . The echo processor of  claim 2 , the frame processor, comprising:
 a displacement field determiner that determines the displacement field based on displacements between corresponding samples between the two frames.   
     
     
         6 . The echo processor of  claim 5 , wherein the displacement field is a summation of the displacements between the corresponding samples between the two frames. 
     
     
         7 . The echo processor of  claim 2 , wherein the displacement field estimates motion between the two frames. 
     
     
         8 . The echo processor of  claim 2 , wherein the displacement field aligns the plurality of frames at an acquisition time of the frame acquired at the latest angle of insonation. 
     
     
         9 . The echo processor of  claim 1 , the compounded frame processor, comprising:
 an inter predictor that predicts the compounded frame based on the displacement field and either the previous compounded frame or the previous combined compounded frame;   an intra predictor that predicts the compounded frame from the compounded frame;   a matching component that matches that compounded frame and the predicted compounded frame using both the inter and the intra prediction; and   a soft-decision component that determines to which degree the compounded frame and the inter-predicted frame are to be combined based on the matching.   
     
     
         10 . The echo processor of  claim 9 , wherein the compounded frame and the previous compounded frame are combined when the matching indicates that combining the frames is likely to improve image quality. 
     
     
         11 . The echo processor of  claim 10 , wherein the compounded frame and the previous compounded frame are not combined when the matching indicates that combining the frames is likely to degrade image quality. 
     
     
         12 . A method, comprising:
 obtaining a set of frames of echoes acquired at different times;   determining a motion displacement field based on at least two of the frames of the set;   motion-compensating all of the frames of the set based on the displacement field and previously determined displacement fields;   generating a compounded frame based on the motion-compensated frames;   motion-compensating a previously received compounded frame based on a motion displacement field for a currently received compounded frame; and   generating a combined compounded frame by combining the currently received compounded frame and the motion-compensated previously received compounded frame or a motion-compensated previously generated combined compounded frame.   
     
     
         13 . The method of  claim 12 , wherein the displacement field is determined based on the most recently acquired frame and a previously acquired frame, wherein both frames have a same angle of insonation. 
     
     
         14 . The method of  claim 13 , wherein the frames are motion-compensated by the same displacement. 
     
     
         15 . The method of  claim 14 , wherein the displacement is uniformly spread across the frames. 
     
     
         16 . The method of  claim 14 , wherein at least two of the frames are motion-compensated by a different displacement. 
     
     
         17 . The method of  claim 14 , wherein the displacement field is a summation of displacements between corresponding samples between the two frames. 
     
     
         18 . A computer readable medium encoded with computer readable instructions, which when executed by a processor cause the processor to:
 obtain a set of frames of echoes acquired at different times;   determine a motion displacement field based on at least two of the frames of the set;   motion-compensate all of the frames of the set based on the displacement field and previously determined displacement fields;   generate a compounded frame based on the motion-compensated frames;   motion-compensate a previously received compounded frame based on a motion displacement field for a currently received compounded frame; and   generate a combined compounded frame by combining the currently received compounded frame and the motion-compensated previously received compounded frame or a motion-compensated previously generated combined compounded frame.   
     
     
         19 . The computer readable medium of  claim 18 , wherein the displacement field is determined based on the most recently acquired frame and a previously acquired frame, wherein both frames have a same angle of insonation. 
     
     
         20 . The computer readable medium of  claim 19 , wherein the frames are motion-compensated by the same displacement.