X-ray imaging apparatus

1. An X-ray imaging apparatus comprising:

an X-ray source;

a detector configured to detect X-rays radiated from the X-ray source at a plurality of detection positions translated by a movement amount smaller than a pixel size of the detector from each other; and

an image processor configured to generate a plurality of acquired images based on the X-rays detected at the plurality of detection positions, respectively, the image processor being configured to generate a high-resolved image having higher resolution than the plurality of acquired images by performing a super-resolution process to increase resolution based on the plurality of acquired images; wherein

the image processor is configured to apply the super-resolution process to a first region in each of the acquired images, the first region including a subject, and to increase a number of pixels according to an increase in resolution in the first region by application of the super-resolution process thereto by a simpler process than the super-resolution process with respect to a second region other than the first region in each of the acquired images.

2. The X-ray imaging apparatus according to claim 1 , wherein the image processor is configured to increase the number of pixels by an increase rate equal to an increase rate of the number of pixels due to the increase in the resolution in the first region by the application of the super-resolution process thereto with respect to the second region in each of the acquired images to which the super-resolution process is not applied.

3. The X-ray imaging apparatus according to claim 2 , wherein the image processor is configured to increase the number of pixels by the increase rate by interpolating between the pixels in the second region by an image process.

4. The X-ray imaging apparatus according to claim 1 , wherein the image processor is configured to apply the super-resolution process using successive approximation calculation to the first region.

5. The X-ray imaging apparatus according to claim 1 , wherein the image processor is configured to acquire the first region by an image process based on image data of the acquired images.

6. The X-ray imaging apparatus according to claim 5 , wherein the image processor is configured to acquire the first region based on magnitude of a luminance value or magnitude of a spatial frequency in each of the acquired images.

7. The X-ray imaging apparatus according to claim 1 , wherein

the detector is configured to detect, from a plurality of directions, the X-rays radiated from the X-ray source while rotating about a rotation axis;

the image processor is configured to generate a plurality of two-dimensional acquired images based on the X-rays detected from the plurality of directions, respectively, and to generate a three-dimensional reconstructed image obtained by reconstructing the plurality of two-dimensional acquired images; and

the first region is set by a user based on data of the three-dimensional reconstructed image.

8. The X-ray imaging apparatus according to claim 7 , wherein the image processor is configured to set, as the first region, a region in the three-dimensional reconstructed image corresponding to regions set by the user in at least two two-dimensional sectional images viewed in different directions, the at least two two-dimensional sectional images being obtained by cutting out arbitrary cross-sections from the three-dimensional reconstructed image, and to set the first region in the plurality of two-dimensional acquired images by converting the three-dimensional reconstructed image in which the first region has been set into the plurality of two-dimensional acquired images.