Projection image generation apparatus, method and program

A program for causing a computer to function as:

• a first projection means for generating a projection image by projecting, from one viewpoint, a projection target that is present in one set of three-dimensional volume data in a group of sets of three-dimensional volume data that have been obtained by imaging a subject at predetermined time intervals;
• a motion information obtainment means for obtaining, based on the projection target that is present in the one set of three-dimensional volume data and the projection target that is present in a different set of three-dimensional volume data in the group of sets of three-dimensional volume data that was obtained by imaging at a different time from the time of imaging of the one set of three-dimensional volume data, motion information about the motion of the projection target between the two sets of three-dimensional volume data;
• a viewpoint movement means for moving the viewpoint based on the motion information that has been obtained by the motion information obtainment means;
• and
• a second projection means for generating a projection image by projecting, from a viewpoint to which the viewpoint has been moved by the viewpoint movement means, the projection target that is present in the different set of three-dimensional volume data.

A projection image generation method comprising:

• a first projection step for generating a projection image by projecting, from one viewpoint, a projection target that is present in one set of three-dimensional volume data in a group of sets of three-dimensional volume data that have been obtained by imaging a subject at predetermined time intervals;
• a motion information obtainment step for obtaining, based on the projection target that is present in the one set of three-dimensional volume data and the projection target that is present in a different set of three-dimensional volume data in the group of sets of three-dimensional volume data that was obtained by imaging at a different time from the time of imaging of the one set of three-dimensional volume data, motion information about the motion of the projection target between the two sets of three-dimensional volume data;
• a viewpoint movement step for moving the viewpoint based on the motion information that has been obtained in the motion information obtainment step;
• and
• a second projection step for generating a projection image by projecting, from a viewpoint to which the viewpoint has been moved in the viewpoint movement step, the projection target that is present in the different set of three-dimensional volume data.