IMAGE PROCESSING APPARATUS, IMAGE PROCESSING METHOD, AND MAGNETIC RESONANCE IMAGING APPARATUS
An image processing apparatus according to an embodiment includes processing circuitry. The processing circuitry obtains, on the basis of a magnetic resonance image, a plurality of shift images resulting from shifting the position of the pixel sampling grid of the magnetic resonance image by a plurality of mutually-different shift amounts. The processing circuitry generates a plurality of ringing-corrected images, by determining, with respect to each of the pixels included in each of the plurality of shift images, a shift amount from the position of the pixel to a position where ringing artifacts will be reduced and further performing a ringing correction to correct the ringing artifacts occurring in the shift images on the basis of the determined shift amounts. The processing circuitry combines, while interleaving, pixels included in each of the plurality of ringing-corrected images.
1 . An image processing apparatus, comprising:
processing circuitry configured to acquire a magnetic resonance image;
obtain, on a basis of the magnetic resonance image, a plurality of shift images resulting from shifting positions of pixels included in the magnetic resonance image by a plurality of mutually-different shift amounts;
generate a plurality of ringing-corrected images, by determining, with respect to each of the pixels included in each of the plurality of shift images, a shift amount from a position of the pixel to a position where ringing artifacts will be reduced and further performing a ringing correction to correct the ringing artifacts occurring in the shift images on the basis of the determined shift amounts; and
generate a combined image in which the plurality of ringing-corrected images are combined, by combining, while interleaving, pixels included in each of the plurality of ringing-corrected images.
2 . The image processing apparatus according to claim 1 , wherein
the processing circuitry is further configured to obtain the plurality of shift images, by using the magnetic resonance image as a first shift image of which the shift amount is 0 and generating a shift image resulting from shifting a position of a pixel sampling grid of the magnetic resonance image by a shift amount different from 0 as a second shift image.
3 . The image processing apparatus according to claim 1 , wherein
the processing circuitry is further configured to obtain the plurality of shift images, by generating a shift image resulting from shifting a position of a pixel sampling grid of the magnetic resonance image by a first shift amount different from 0 as a first shift image and generating another shift image resulting from shifting the position of the pixel sampling grid of the magnetic resonance image by a second shift amount in the direction opposite to the direction used for the first shift image, as a second shift image.
4 . The image processing apparatus according to claim 1 , wherein
the processing circuitry is further configured to obtain the plurality of shift images, by using the magnetic resonance image as a first shift image of which the shift amount is 0, generating a shift image resulting from shifting a position of a pixel sampling grid of the magnetic resonance image by a first shift amount different from 0 as a second shift image, and generating another shift image resulting from shifting the position of the pixel sampling grid of the magnetic resonance image by a second shift amount equal to the first shift amount in the direction opposite to the direction used for the second shift image, as a third shift image.
5 . The image processing apparatus according to claim 1 , wherein
the processing circuitry is further configured to obtain, on the basis of the magnetic resonance image, a plurality of first shift images resulting from shifting a position of a pixel sampling grid of the magnetic resonance image in a first direction,
the processing circuitry is further configured to generate a plurality of first ringing-corrected images by performing the ringing correction on each of the plurality of first shift images,
the processing circuitry is further configured to generate an intermediate combined image by combining, while interleaving, pixels included in each of the plurality of first ringing-corrected images,
the processing circuitry is further configured to obtain, on a basis of the intermediate combined image, a plurality of second shift images resulting from shifting positions of pixels included in the intermediate combined image in a second direction different from the first direction,
the processing circuitry is further configured to generate a plurality of second ringing-corrected images, by performing the ringing correction on each of the plurality of second shift images, and
the processing circuitry is further configured to generate a final combined image by combining, while interleaving, pixels included in each of the plurality of second ringing-corrected images.
6 . The image processing apparatus according claim 1 , wherein
the processing circuitry is further configured to obtain, on the basis of the magnetic resonance image, a plurality of first shift images resulting from shifting a position of a pixel sampling grid of the magnetic resonance image in a first direction,
the processing circuitry is further configured to generate a first intermediate combined image, by combining, while interleaving, the pixels included in each of the plurality of first shift images,
the processing circuitry is further configured to obtain, on a basis of the first intermediate combined image, a plurality of second shift images resulting from shifting positions of pixels included in the first intermediate combined image in a second direction different from the first direction,
the processing circuitry is further configured to generate a plurality of first ringing-corrected images by performing the ringing correction on each of the plurality of second shift images,
the processing circuitry is further configured to generate a second intermediate combined image by combining, while interleaving, pixels included in each of the plurality of first ringing-corrected images,
the processing circuitry is further configured to obtain, on the basis of the magnetic resonance image, a plurality of third shift images resulting from shifting the position of the pixel sampling grid of the magnetic resonance image in the second direction,
the processing circuitry is further configured to generate a third intermediate combined image by combining, while interleaving, the pixels included in each of the plurality of third shift images,
the processing circuitry is further configured, on the basis of the third intermediate combined image, to obtain a plurality of fourth shift images resulting from shifting positions of pixels included in the third intermediate combined image in the first direction,
the processing circuitry is further configured to generate a plurality of second ringing-corrected images by performing the ringing correction on each of the plurality of fourth shift images,
the processing circuitry is further configured to generate a fourth intermediate combined image, by combining, while interleaving, pixels included in each of the plurality of second ringing-corrected images, and
the processing circuitry is further configured to generate a final combined image by adding together the second intermediate combined image and the fourth intermediate combined image.
7 . The image processing apparatus according to claim 6 , wherein
the processing circuitry is further configured to generate k-space data of a first ringing image in which a ringing artifact remain along the second direction only by applying a filter that suppresses higher spatial frequency components in the first direction to k-space data of the magnetic resonance image and configured to obtain the plurality of first shift images on a basis of the k-space data of the first ringing image, and
the processing circuitry is further configured to generate k-space data of a second ringing image in which a ringing artifact remain along the first direction only by applying a filter that suppresses higher spatial frequency components in the second direction to the k-space data of the magnetic resonance image and configured to obtain the plurality of second shift images on a basis of the k-space data of the second ringing image.
8 . The image processing apparatus according to claim 1 , wherein
the processing circuitry is further configured to generate the combined image, by sorting the pixels included in the plurality of ringing-corrected images according to an order of positions thereof within the magnetic resonance image and subsequently combining, while interleaving, the pixels in the sorted order.
9 . An image processing method, comprising:
acquiring a magnetic resonance image;
obtaining, on a basis of the magnetic resonance image, a plurality of shift images resulting from shifting positions of pixels included in the magnetic resonance image by a plurality of mutually-different shift amounts;
generating a plurality of ringing-corrected images, by determining, with respect to each of the pixels included in each of the plurality of shift images, a shift amount from a position of the pixel to a position where ringing artifacts will be reduced and further performing a ringing correction to correct the ringing artifacts occurring in the shift images on the basis of the determined shift amounts; and
generating a combined image in which the plurality of ringing-corrected images are combined, by combining, while interleaving, pixels included in each of the plurality of ringing-corrected images.
10 . A magnetic resonance imaging apparatus comprising:
processing circuitry configured to
generate a magnetic resonance image;
obtain, on a basis of the magnetic resonance image, a plurality of shift images resulting from shifting positions of pixels included in the magnetic resonance image by a plurality of mutually-different shift amounts;
generate a plurality of ringing-corrected images, by determining, with respect to each of the pixels included in each of the plurality of shift images, a shift amount from a position of the pixel to a position where ringing artifacts will be reduced and further performing a ringing correction to correct the ringing artifacts occurring in the shift images on the basis of the determined shift amounts; and
generate a combined image in which the plurality of ringing-corrected images are combined, by combining, while interleaving, pixels included in each of the plurality of ringing-corrected images.