Image generating apparatus, image generating method, and program

1. A method of generating a motion contrast image using optical coherence tomography, comprising:

a data obtaining step of obtaining a plurality of pieces of tomographic image data each indicating a tomogram at substantially the same portion of an object;

a removing step of removing an outlier from the plurality of pieces of tomographic image data;

a computation step of computing a motion contrast value based on the plurality of pieces of tomographic image data from which the outlier is removed; and

a generation step of generating a motion contrast image of the object based on the motion contrast value.

2. The image generating method according to claim 1 , wherein the plurality of pieces of tomographic image data is data obtained by performing frequency analysis for an output of a sensor which has received interfering light.

3. The image generating method according to claim 2 , wherein performing the frequency analysis includes applying Fast Fourier Transform (FFT) to the interfering light.

4. The image generating method according to claim 3 , further comprising:

a positioning step of positioning the plurality of pieces of tomographic image data, wherein

the removing step is performed after the positioning step is performed.

5. The image generating method according to claim 3 , wherein, at the removing step, when outliers are detected at a fixed percentage or higher in an A-scan line or a frame, the outliers are removed in a unit of the A-scan line or a unit of the frame.

6. The image generating method according to claim 2 , further comprising:

a positioning step of positioning the plurality of pieces of tomographic image data, wherein

the removing step is performed after the positioning step is performed.

7. The image generating method according to claim 6 , wherein, at the removing step, when outliers are detected at a fixed percentage or higher in an A-scan line or a frame, the outliers are removed in a unit of the A-scan line or a unit of the frame.

8. The image generating method according to claim 2 , wherein, at the removing step, when outliers are detected at a fixed percentage or higher in an A-scan line or a frame, the outliers are removed in a unit of the A-scan line or a unit of the frame.

9. The image generating method according to claim 1 , further comprising:

a positioning step of positioning the plurality of pieces of tomographic image data, wherein

the removing step is performed after the positioning step is performed.

10. The image generating method according to claim 9 , wherein, at the removing step, when outliers are detected at a fixed percentage or higher in an A-scan line or a frame, the outliers are removed in a unit of the A-scan line or a unit of the frame.

11. The image generating method according to claim 1 , wherein, at the removing step, a signal intensity deviated by a predetermined value or more from an average value of signal intensities indicated by the plurality of pieces of tomographic image data is removed as the outlier.

12. The image generating method according to claim 1 , wherein, at the removing step, a phase deviated by a predetermined value or more from an average value of phases indicated by the plurality of pieces of tomographic image data is removed as the outlier.

13. The image generating method according to claim 1 , wherein, at the removing step, a signal intensity deviated by a predetermined value or more from an approximation straight line or an approximation curve computed from an average value of signal intensities indicated by the plurality of pieces of tomographic image data is removed as the outlier.

14. The image generating method according to claim 1 , wherein, at the removing step, a phase deviated by a predetermined value or more from an approximation straight line or an approximation curve computed from an average value of phases indicated by the plurality of pieces of tomographic image data is removed as the outlier.

15. The image generating method according to claim 1 , wherein, at the computation step, variation of signal intensities or phases between the plurality of pieces of tomographic image data is computed as a motion contrast feature quantity.

16. The image generating method according to claim 1 , wherein, at the removing step, when outliers are detected at a fixed percentage or higher in an A-scan line or a frame, the outliers are removed in a unit of the A-scan line or a unit of the frame.

17. The image generating method according to claim 1 , further comprising:

a display control step of causing a display unit to display a motion contrast image generated at the generation step, wherein

at the display control step, a portion at which the outlier is generated is displayed on the motion contrast image.

18. The image generating method according to claim 1 , wherein

at the removing step, a pixel of a region in which a predetermined number of outliers are generated is stored as an erroneous region, and

at the computation step, the erroneous region is interpolated with a motion contrast value of an adjacent non-erroneous pixel.

19. An image generating apparatus, comprising:

a data obtaining unit configured to obtain a plurality of pieces of tomographic image data each indicating a tomogram at substantially the same position of an object;

a removing unit configured to remove an outlier from the plurality of pieces of tomographic image data;

a computation unit configured to compute a motion contrast value based on the plurality of pieces of tomographic image data from which the outlier is removed; and

a generation unit configured to generate a motion contrast image of the object based on the motion contrast value.

20. A recording medium non-transitory storing therein a program for causing a computer to execute the steps of the image generating method according to claim 1 .