Object information acquiring apparatus and object information acquiring method

Patent metadata

Field	Value
Publication number	US-10088560-B2
Application number	US-201214114322-A
Country	US
Kind code	B2
Filing date	Apr 26, 2012
Priority date	May 10, 2011
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

The present invention employs an object information acquiring apparatus comprising a plurality of conversion elements which receive acoustic waves emitted from an object and convert the acoustic waves into electrical signals, a correlation calculator which calculates correlation data by using the plurality of electrical signals output from the plurality of conversion elements, an average correlation calculator which calculates an average correlation matrix by extracting a plurality of submatrices from the correlation data and averaging the submatrices, and an adaptive signal processor which generates power distribution by performing adaptive signal processing by using the average correlation matrix and calculating the power of each target position, wherein the correlation calculator calculates the correlation data by obtaining the correlation of input signals that are separated by at least one input signal among the input signals.

First claim

The invention claimed is:

1. An object information acquiring apparatus, comprising:
a plurality of conversion elements which receive acoustic waves emitted from an object and convert the acoustic waves into electrical signals;
a correlation calculator which calculates correlation data by using the plurality of electrical signals output from said plurality of conversion elements;
an average correlation calculator which calculates an average correlation matrix by extracting a plurality of submatrices from the correlation data and averaging the submatrices; and
an adaptive signal processor which generates power distribution by performing adaptive signal processing by using the average correlation matrix and calculating the power of each target position,
wherein said correlation calculator calculates the correlation data by obtaining the correlation of input signals that are separated by at least one input signal among the input signals input to said correlation calculator and without obtaining the correlation of input signals that are not separated by at least one input signal among the input signals input to said correlation calculator, and
wherein the correlation data calculated with said correlation calculator contains only elements of diagonal components of the correlation matrix, and elements at positions that are separated at intervals of one or more columns from the elements of the diagonal components.

2. The object information acquiring apparatus according to claim 1 , wherein said adaptive signal processor obtains the power by obtaining an inverse matrix of the average correlation matrix, or performing QR decomposition and back substitution processing on the average correlation matrix.

3. The object information acquiring apparatus according to claim 1 , wherein said average correlation calculator performs averaging only on elements contained in the plurality of submatrices, among the elements of the correlation data.

4. The object information acquiring apparatus according to claim 1 , further comprising:
a delay processor which performs delay processing on the plurality of electrical signals according to a target position in the object,
wherein said correlation calculator calculates the correlation matrix with the electrical signals output from said delay processor as the input signals.

5. The object information acquiring apparatus according to claim 1 , further comprising:
a moving average processor which performs moving average processing on the plurality of electrical signals and calculates moving average signals,
wherein said correlation calculator calculates the correlation matrix with the moving average signals as the input signals.

6. The object information acquiring apparatus according to claim 4 , further comprising:
a moving average processor which performs moving average processing on the electrical signals output from said delay processor and calculates moving average signals,
wherein said correlation calculator calculates the correlation matrix with the moving average signals as the input signals.

7. The object information acquiring apparatus according to claim 5 , wherein, if an aperture size when said moving average processor performs the moving average processing is A (wherein A is an integer equal to or greater than 2), said correlation calculator obtains the correlation of the input signals that are separated by (A−1) input signals.

8. The object information acquiring apparatus according to claim 1 , further comprising:
a signal adder which performs addition processing on the plurality of electrical signals, wherein said correlation calculator calculates the correlation matrix with the electrical signals output from said signal adder as the input signals.

9. The object information acquiring apparatus according to claim 4 , further comprising:
a signal adder which performs addition processing on the electrical signals output from said delay processor,
wherein said correlation calculator calculates the correlation matrix with the electrical signals output from said signal adder as the input signals.

10. The object information acquiring apparatus according to claim 1 , wherein the acoustic waves emitted from the object result from the acoustic waves output from said conversion elements being reflected inside the object.

11. The object information acquiring apparatus according to claim 1 , further comprising:
a light source which irradiates the object with electromagnetic waves,
wherein the acoustic waves emitted from the object are photoacoustic waves emitted from the object irradiated with the electromagnetic waves.

12. An object information acquiring method, comprising:
a correlation calculation step of calculating correlation data by using a plurality of electrical signals output from a plurality of conversion elements which receive acoustic waves emitted from an object;
an average correlation calculation step of calculating an average correlation matrix by extracting a plurality of submatrices from the correlation data and averaging the submatrices; and
an adaptive signal processing step of generating power distribution by performing adaptive signal processing by using the average correlation matrix and calculating the power of each target position,
wherein, in said correlation calculation step, the correlation data is calculated by obtaining the correlation of input signals that are separated by at least one input signal among the input signals input in said correlation calculation step and without obtaining the correlation of input signals that are not separated by at least one input signal among the input signals input in said correlation calculation step, and
wherein the correlation data calculated in said correlation calculation step contains only elements of diagonal components of the correlation matrix, and elements at positions that are separated at intervals of one or more columns from the elements of the diagonal components.

13. The object information acquiring method according to claim 12 , wherein, in said adaptive signal processing step, the power is obtained by obtaining an inverse matrix of the average correlation matrix, or performing QR decomposition and back substitution processing on the average correlation matrix.

14. The object information acquiring method according to claim 12 , wherein, in said average correlation calculation step, averaging is performed only on elements contained in the plurality of submatrices, among the elements of the correlation data.

15. The object information acquiring method according to claim 12 , further comprising:
a delay processing step of performing delay processing on the plurality of electrical signals according to a target position in the object,
wherein, in said correlation calculation step, the correlation matrix is calculated with the electrical signals output in said delay processing step as the input signals.

16. The object information acquiring method according to claim 12 , further comprising:
a moving average processing step of performing moving average processing on the plurality of electrical signals and calculating moving average signals,
wherein, in said correlation calculation step, the correlation matrix is calculated with the moving average signals as the input signals.

17. The object information acquiring method according to claim 15 , further comprising:
a moving average processing step of performing moving average processing on the electrical signals output in said delay processing step and calculating moving average signals,
wherein, in said c

Assignees

• Nagae Kenichi
• Sato Toru
• Canon Kk

Inventors

• Nagae Kenichi
• Sato Toru

Classifications

• G01N21/1702

  with opto-acoustic detection, e.g. for gases or analysing solids · CPC title

• G01S7/52047 Primary

  for elimination of side lobes or of grating lobes; for increasing resolving power · CPC title

• G01S7/52017 Primary

  particularly adapted to short-range imaging (G01S7/53 takes precedence) · CPC title