Patent Number: 
Section: claims

1. A wavefront information obtaining method comprising:receiving intensity information of a first periodic pattern and intensity information of a second periodic pattern having a phase shifted with respect to a phase of the first periodic pattern; andobtaining wavefront information,wherein the obtaining of the wavefront information obtains the wavefront information for one pixel by using:intensity information at a first pixel of the first periodic pattern;intensity information at a second pixel of the first periodic pattern, the second pixel being positioned within three pixels from the first pixel; andintensity information at the first pixel of the second periodic pattern. 2. The wavefront information obtaining method according to claim 1, wherein the obtaining of the wavefront information obtains the wavefront information by applying:the intensity information at the first pixel of the first periodic pattern;the intensity information at the second pixel of the first periodic pattern; andthe intensity information at the first pixel of the second periodic pattern,to a formula based on a phase shifting method on condition that those pieces of intensity information are regarded as pieces of intensity information at the first pixel of different periodic patterns. 3. The wavefront information obtaining method according to claim 1, wherein the obtaining of the wavefront information obtains the wavefront information by applying:the intensity information at the first pixel of the first periodic pattern;the intensity information at the second pixel of the first periodic pattern; andthe intensity information at the first pixel of the second periodic pattern,to a formula based on a phase shifting method on condition that those pieces of intensity information are regarded as pieces of intensity information at the first pixel or the second pixel of different periodic patterns. 4. The wavefront information obtaining method according to claim 3, wherein the obtaining of the wavefront information obtains wavefront information for one pixel by using:the intensity information at the first pixel of the first periodic pattern;the intensity information at the second pixel of the first periodic pattern;the intensity information at the first pixel of the second periodic pattern; andintensity information at the second pixel of the second periodic pattern. 5. The wavefront information obtaining method according to claim 3, wherein the first pixel and the second pixel are adjacent to each other in the first and second periodic pattern. 6. The wavefront information obtaining method according to claim 1, wherein the obtaining of the wavefront information obtains the wavefront information by taking Fourier transform of a composite periodic pattern of an intensity distribution having:an intensity at the first pixel of the first periodic pattern;an intensity at the second pixel of the first periodic pattern; andan intensity at the first pixel of the second periodic pattern. 7. The wavefront information obtaining method according to claim 6, wherein, in the composite periodic pattern,the intensity at the first pixel of the first periodic pattern andthe intensity at the first pixel of the second periodic pattern are positioned within three pixels. 8. The wavefront information obtaining method according to claim 1, wherein the wavefront information is information regarding at least one of a phase, a differential phase, an amplitude, and scattering of a wavefront of light which forms the first and second periodic pattern. 9. The wavefront information obtaining method according to claim 1,wherein the obtaining of the wavefront information obtains wavefront information for a plurality of pixels. 10. The wavefront information obtaining method according to claim 9, further comprisingtransmitting, to a display apparatus, image data of the wavefront information for a plurality of pixels. 11. The wavefront information obtaining method according to claim 1, wherein the periodic pattern is an interference pattern or a moiré. 12. The wavefront information obtaining method according to claim 1, wherein the periodic pattern is an X-ray periodic pattern. 13. A non-transitory computer-readable medium storing a program for causing a computer to execute the wavefront information obtaining method according to claim 1. 14. A wavefront information obtaining method comprising:receiving intensity information of a first periodic pattern, a second periodic pattern having a phase shifted in a first direction with respect to a phase of the first periodic pattern, and a third periodic pattern having a phase shifted in a second direction with respect to the phase of the first periodic pattern, the second direction crossing the first direction;obtaining shearing wavefront information in the first direction; andobtaining shearing wavefront information in the second direction,wherein the obtaining the shearing wavefront information in the first direction obtains the shearing wavefront information in the first direction for one pixel by using:intensity information at a first pixel of the first periodic pattern;intensity information at the first pixel of the second periodic pattern; andintensity information at a second pixel of the first periodic pattern or the second periodic pattern, the second pixel being positioned within three pixels from the first pixel, andwherein the obtaining the shearing wavefront information in the second direction obtains the shearing wavefront information in the second direction for one pixel by using:the intensity information at the first pixel of the first periodic pattern;intensity information at the first pixel of the third periodic pattern; andintensity information at a third pixel of the first periodic pattern or the third periodic pattern, the third pixel being positioned within three pixels from the first pixel. 15. A non-transitory computer-readable medium storing a program for causing a computer to execute the wavefront information obtaining method according to claim 14. 16. A computation apparatus configured to obtain wavefront information comprising:a unit configured to receive intensity information of a first periodic pattern and intensity information of a second periodic pattern having a phase shifted with respect to a phase of the first periodic pattern; anda unit configured to obtain wavefront information for one pixel in wavefront information distribution by using:intensity at a first pixel of the first periodic pattern;intensity at a second pixel of the first periodic pattern, the second pixel being positioned within three pixels from the first pixel; andintensity at the first pixel of the second periodic pattern.