Super-resolution observation apparatus that changes process contents according to intensity level of noise in digital image data

1. A super-resolution observation apparatus, comprising:

an excitation light irradiation unit for irradiating excitation light intended to excite a sample on the sample;

an excitation light modulation unit for modulating a spatial intensity distribution of the excitation light on the sample;

an enlarged image forming unit for forming an enlarged image of the sample at an image position from observation light generated by irradiating the excitation light on the sample;

an image capturing unit for converting the spatial intensity distribution of the enlarged image into digital image data; and

a super-resolution processing unit for generating a super-resolution image in which a super-resolution frequency component higher than a cutoff frequency of the enlarged image forming unit is made visible from at least one piece of the digital image data,

wherein the super-resolution processing unit comprises a spatial frequency intensity modulation unit that changes process contents according to (i) an intensity level of a noise included in the digital image data and (ii) an observation parameter of the super-resolution observation apparatus, and

wherein the spatial frequency intensity modulation unit (i) comprises a plurality of low-pass filters having mutually different cutoff frequencies, and (ii) cuts off, by low pass filter selected from among the plurality of low-pass filters according to the intensity level of the noise and the observation parameter, a super-resolution frequency component higher than a cutoff frequency of the selected low-pass filter included in the super-resolution image.

2. The super-resolution observation apparatus according to claim 1 , wherein the low-pass filters execute a filter process for a Fourier transform of image data.

3. The super-resolution observation apparatus according to claim 1 , wherein the low-pass filters execute a convolution filter process for image data.

4. The super-resolution observation apparatus according to claim 1 , wherein the observation parameter is an illumination parameter of the excitation light illumination unit.

5. The super-resolution observation apparatus according to claim 1 , wherein the observation parameter is a modulation parameter of the excitation light modulation unit.

6. The super-resolution observation apparatus according to claim 1 , wherein the observation parameter is an image forming parameter of the enlarged image forming unit.

7. The super-resolution observation apparatus according to claim 1 , wherein the observation parameter is an image capturing parameter of the image capturing unit.

8. The super-resolution observation apparatus according to claim 1 , wherein the excitation light is laser light, and the noise is a laser speckle noise.

9. The super-resolution observation apparatus according to claim 1 , wherein the noise is a shot noise caused by the image capturing unit.

10. The super-resolution observation apparatus according to claim 1 , wherein the spatial frequency intensity modulation unit changes process contents according to a brightness value of the digital image data.

11. The super-resolution observation apparatus according to claim 1 , wherein the spatial frequency intensity modulation unit changes process contents according to an exposure time of the image capturing unit.

12. The super-resolution observation apparatus according to claim 1 , wherein the spatial frequency intensity modulation unit changes process contents according to an MTF of the super-resolution image.

13. The super-resolution observation apparatus according to claim 1 , wherein the super-resolution processing unit generates the super-resolution image by using a plurality of pieces of the digital image data obtained in different states of the excitation light modulation unit.

14. The super-resolution observation apparatus according to claim 1 , wherein the super-resolution processing unit generates the super-resolution image by using the digital image data captured while changing an intensity distribution on the sample by the excitation light modulation unit.

15. The super-resolution observation apparatus according to claim 1 , wherein the spatial frequency intensity modulation unit selects, from among the plurality of low-pass filters, a low pass filter having a lower cutoff frequency as the intensity level of the noise increases.