Information processing apparatus and information processing method
An information processing apparatus according to an embodiment includes a processing circuit. The processing circuit acquires a measurement field corresponding to a spatial distribution of a predetermined physical quantity in a subject of measurement. The processing circuit calculates an unknown quantity in the subject of measurement based on a first equation between the measurement field and the unknown quantity having spatial dependence, and on the acquired measurement field. The first equation is one that is acquired based on a second equation expressing a dual field divergence of which can be expressed using the measurement field, by using the measurement field and the unknown quantity, and on the Helmholtz decomposition of the dual field.
1. An information processing apparatus comprising
a processing circuit configured to acquire a measurement field corresponding to a spatial distribution of a predetermined physical quantity in a subject of measurement, and calculate an unknown quantity in the subject of measurement based on a first equation between the measurement field and the unknown quantity having spatial dependence, and on the acquired measurement field, wherein
the first equation is one that is acquired based on a second equation expressing a dual field divergence of which is capable of being expressed using the measurement field by using the measurement field and the unknown quantity, and on the Helmholtz decomposition of the dual field.
2. The information processing apparatus according to claim 1 , wherein the first equation is an integral equation from which a spatial derivative term of the unknown quantity is removed.
3. The information processing apparatus according to claim 1 , wherein
the measurement field is an RF (high frequency) magnetic field, and the unknown quantity includes at least one of a conductivity and a permittivity.
4. The information processing apparatus according to claim 3 , wherein
the measurement field is an amplitude and a phase of the RF magnetic field.
5. The information processing apparatus according to claim 4 , wherein
magnetic resonance electrical property tomography (MREPT) is performed based on the unknown quantity calculated by the processing circuit.
6. The information processing apparatus according to claim 3 , wherein
the measurement field is a phase of the RF magnetic field, and
Quantitative conductivity mapping (QCM) is performed based on the unknown quantity calculated by the processing circuit.
7. The information processing apparatus according to claim 1 , wherein
the measurement field is a displacement, and the unknown quantity includes at least one of a coefficient of elasticity and a coefficient of viscosity.
8. The information processing apparatus according to claim 1 , wherein
the measurement field is a displacement, and the dual field is a stress tensor.
9. The information processing apparatus according to claim 1 , wherein
magnetic resonance elastography (MRE) is performed based on the unknown quantity calculated by the processing circuit.
10. The information processing apparatus according to claim 1 , wherein
the first equation is one that is derived from Ampere's law and Faraday's law.
11. The information processing apparatus according to claim 1 , wherein
the first equation is one that is derived from an equation of motion of an elastic body and Hooke's law.
12. The information processing apparatus according to claim 1 , wherein
the processing circuit is configured to acquire a structural image of a subject of measurement, identify a measurement subject region in which the measurement field is acquired from the subject of measurement by performing segmentation processing with respect to the subject of measurement included in the structural image, and calculate the unknown quantity based on the measurement field in the measurement subject region.
13. The information processing apparatus according to claim 12 , wherein
the subject of measurement is a brain,
the processing circuit is configured to acquire the structural image of a region of the brain by magnetic resonance imaging, identify a region of a substantial part of the brain as the measurement subject region based on the structural image by the segmentation processing, and calculate the unknown quantity based on the measurement field in the region of the substantial part.
14. The information processing apparatus according to claim 1 , wherein
the processing circuit is configured to calculate the unknown quantity based on an evaluation function including a term acquired from the first equation and a regularization term.
15. An information processing method comprising:
acquiring a measurement field corresponding to a spatial distribution of a predetermined physical quantity in a subject of measurement; and
calculating an unknown quantity in the subject of measurement based on a first equation between the measurement field and the unknown quantity having spatial dependence, and on the acquired measurement field, wherein
the first equation is one that is acquired based on a second equation expressing a dual field divergence of which is capable of being expressed using the measurement field, by using the measurement field and the unknown quantity, and on the Helmholtz decomposition of the dual field.