Object information acquiring apparatus

Patent metadata

Field	Value
Publication number	US-9664782-B2
Application number	US-201214114308-A
Country	US
Kind code	B2
Filing date	Apr 26, 2012
Priority date	May 10, 2011
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

The present invention employs an object information acquiring apparatus comprising a plurality of receiving elements which receive acoustic waves emitted from an object and convert the acoustic waves into received signals, a delay unit which matches phases of the received signals, a complex converter which converts the received signals into complex signals, a complex covariance matrix calculator which periodically obtains a complex covariance matrix by using a complex signal group configured from a plurality of phase-matched complex signals, an eliminator which eliminates the number of bits of input data configured from at least either the complex signal group or matrix elements, and an electric power calculator which calculates a power of target positions, wherein the eliminator eliminates the number of bits by performing common level conversion processing on all input data relating to one complex covariance matrix.

First claim

The invention claimed is:

1. An object information acquiring apparatus, comprising:
a delay unit which matches phases of received signals output from a plurality of receiving elements that has received acoustic waves emitted from an object;
a complex converter which converts the received signals output from said delay unit into complex signals;
a complex covariance matrix calculator which periodically obtains a complex covariance matrix by using a complex signal group configured from a plurality of phase-matched complex signals;
an eliminator which uses, as input data, at least either the complex signal group or matrix elements contained in the complex covariance matrix, and reduces a number of bits of the input data; and
an electric power calculator which calculates a power value of each target position based on the complex covariance matrix,
wherein said eliminator reduces the number of bits by performing common level conversion processing on a plurality of input data relating to one complex covariance matrix.

2. The object information acquiring apparatus according to claim 1 , wherein said eliminator performs a bit shift on signals contained in the input data in a higher direction by a number of bits that is common to the signals for each input data related to the one complex covariance matrix to an extent that a maximum value of the input data does not overflow, and deletes lower bits in the plurality of input data by a number of bits that is common to the all input data.

3. The object information acquiring apparatus according to claim 2 , further comprising:
a corrector which corrects the power value calculated by said electric power calculator according to the number of bits shifted by said eliminator.

4. The object information acquiring apparatus according to claim 2 , wherein said eliminator determines the number of bits to be shifted based on the results of performing OR processing per bit on the signals contained in the input data converted into a positive value and represented as a binary number.

5. The object information acquiring apparatus according to claim 1 , wherein the acoustic waves emitted from the object result from the acoustic waves transmitted from the receiving elements being reflected inside the object.

6. 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 by said light source.

7. The object information acquiring apparatus according to claim 1 , wherein said electric power calculator calculates the power value using an adaptive signal processing method.

8. The object information acquiring apparatus according to claim 7 , wherein the adaptive signal processing method includes Constrained Minimization of Power method.

9. The object information acquiring apparatus according to claim 1 , wherein said electric power calculator includes a QR-decomposition circuit.

10. The object information acquiring apparatus according to claim 1 , further comprising the plurality of receiving elements.

11. An object information acquiring method, comprising the steps of:
matching, using a processor, phases of received signals output from a plurality of receiving elements that has received acoustic waves emitted from an object;
converting, using the processor, the received signals processed by the matching step into complex signals;
obtaining, using the processor, a complex covariance matrix periodically by using a complex signal group configured from a plurality of phase-matched complex signals;
reducing, using the processor, a number of bits of the input data using at least either the complex signal group or matrix elements contained in the complex covariance matrix as input data, and
calculating, using the processor, a power value of each target position based on the complex covariance matrix,
wherein the number of bits are reduced by performing common level conversion processing on a plurality of input data relating to one complex covariance matrix.

12. The object information acquiring method according to claim 11 , wherein said reducing step includes performing a bit shift on signals contained in the input data in a higher direction by a number of bits that is common to the signals for each input data related to the one complex covariance matrix to an extent that a maximum value of the input data does not overflow, and deleting lower bits in the plurality of input data by a number of bits that is common to the all input data.

13. The object information acquiring method according to claim 12 , further comprising:
correcting, using the processor, the power value calculated in said calculating step according to the number of bits shifted in said reducing step.

14. The object information acquiring method according to claim 12 , wherein said reducing step includes determining the number of bits to be shifted based on the results of performing OR processing per bit on the signals contained in the input data converted into a positive value and represented as a binary number.

15. The object information acquiring method according to claim 11 , wherein the acoustic waves emitted from the object result from the acoustic waves transmitted from the receiving elements being reflected inside the object.

16. The object information acquiring method according to claim 11 , further comprising:
irradiating, using a light source, 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.

17. The object information acquiring method according to claim 11 , wherein said calculating step includes calculating the power value using an adaptive signal processing method.

18. The object information acquiring method according to claim 17 , wherein the adaptive signal processing method includes Constrained Minimization of Power method.

19. The object information acquiring method according to claim 11 , wherein said calculating step is performed using the processor, and wherein the processor includes a QR-decomposition circuit.

Assignees

• Yoda Haruo
• Canon Kk

Inventors

• Yoda Haruo

Classifications

• G01S7/52017 Primary

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

• G01S7/52047 Primary

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