Subject information acquisition apparatus, subject information acquisition method, and program

Abstract

A subject information acquisition apparatus of the present invention includes a transmission/reception unit including a plurality conversion elements which transmit an elastic wave to the subject and receive a reflected wave that is reflected at each position in the subject, a scan line signal acquisition unit which acquires a plurality of signals corresponding to the reflected waves from each position in the subject as scan line signals by using a plurality of reception signals outputted from the conversion elements, and a processing unit which acquires moving information of the object by using the plurality of scan line signals. The processing unit acquires the moving information of the object on the basis of a distribution of cross-correlation values on a plane represented by two axes including an axis of time difference and an axis of distance difference by using a plurality of cross-correlation values between scan line signals at different positions.

1 . A subject information acquisition apparatus for acquiring moving information of an object in a subject, the subject information acquisition apparatus comprising:
 a transmission/reception unit including a plurality conversion elements configured to transmit an elastic wave to the subject and receive a reflected wave that is reflected at each position in the subject;   a scan line signal acquisition unit configured to acquire a plurality of signals corresponding to the reflected waves from each position in the subject as scan line signals by using a plurality of reception signals outputted from the plurality of conversion elements; and   a processing unit configured to acquire the moving information of the object by using the plurality of scan line signals,   wherein the processing unit acquires the moving information of the object, where a decrease of cross-correlation values due to a temporal change of the object is considered, by using a plurality of cross-correlation values between scan line signals at different positions.   
     
     
         2 . The subject information acquisition apparatus according to  claim 1 , wherein the processing unit acquires the moving information of the object on the basis of information related to a maximum value of cross-correlation value at a certain time difference among acquisition time differences of scan line signals by using a plurality of cross-correlation values between scan line signals at different positions. 
     
     
         3 . The subject information acquisition apparatus according to  claim 1 , wherein, the processing unit acquires the moving information by further using a cross-correlation value between scan line signals at the same position. 
     
     
         4 . The subject information acquisition apparatus according to  claim 1 , wherein,
 the plurality of conversion elements perform electronic scanning, in which a beam of the elastic wave is sequentially transmitted to a plurality of positions, twice or more,   the scan line signal acquisition unit acquires a plurality of scan line signals by performing the electronic scanning twice or more, and   the processing unit acquires the moving information by using   cross-correlation values between scan line signals acquired by the second and the following electronic scanning and a scan line signal at a datum point acquired by the first electronic scanning, and   cross-correlation values between the scan line signal at the datum point acquired by the first electronic scanning and scan line signals other than the scan line signal.   
     
     
         5 . The subject information acquisition apparatus according to  claim 1 , wherein, the processing unit acquires the moving information by using cross-correlation values between scan line signals that are randomly combined. 
     
     
         6 . The subject information acquisition apparatus according to  claim 1 , wherein
 the plurality of conversion elements perform a process, which transmits an elastic wave to a plurality of positions at the same time, twice or more, and   the processing unit acquires the moving information by using a cross-correlation value between scan line signals which are based on elastic waves transmitted at different times and which are located at different positions.   
     
     
         7 . The subject information acquisition apparatus according to  claim 1 , further comprising:
 a target range specification unit configured to specify a target range where the moving information of the object is acquired,   wherein the moving information in the target range is acquired by using only scan line signals in the target range specified by the target range specification unit.   
     
     
         8 . The subject information acquisition apparatus according to  claim 1 , wherein the processing unit acquires a velocity distribution of the object as the moving information. 
     
     
         9 . A subject information acquisition method for acquiring moving information of an object in a subject, the subject information acquisition method comprising:
 a step of receiving a plurality of reception signals outputted from a plurality of conversion elements by transmitting an elastic wave to the subject and receiving a reflected wave that is reflected at each position in the subject;   a step of acquiring a plurality of signals corresponding to the reflected waves from each position in the subject as scan line signals by using the plurality of reception signals; and   a step of acquiring the moving information of the object by using the plurality of scan line signals,   wherein in the step of acquiring the moving information, the moving information of the object, where a decrease of cross-correlation values due to a temporal change of the object is considered, is acquired by using a plurality of cross-correlation values between scan line signals at different positions.   
     
     
         10 . A computer-readable storage medium storing a program for causing a computer to execute the steps of the subject information acquisition method according to  claim 9 .