Sample observation apparatus

1 . A sample observation apparatus comprising:

a light source;

an illumination optical system including at least one first lens, light from the light source exits the at least one first lens and is incident on a sample as a light spot;

an observation optical system including at least one second lens, light from the sample is incident on the at least one second lens;

a holding member that holds the sample;

an image sensor that is located at a pupil of the observation optical system or at a position which is conjugate to a pupil of the observation optical system, wherein the pupil of the observation optical system is located at a conjugate position to a pupil of the illumination optical system, and the image sensor is configured to output first image data of the pupil of the observation optical system formed by light emitted from the light spot;

a scanning mechanism that changes a relative position between the light spot on the sample and the holding member such that the image sensor obtains a plurality of the first image data corresponding to a plurality of positions of the sample; and

a processor comprising hardware, the processor having a filter image in which a value indicating brightness is set for each pixel;

wherein the filter image includes a first region and a second region, and pixel values indicating brightness in the first region are greater than pixel values indicating brightness in the second region;

each pixel of the filter image corresponds to each pixel of the first image data;

the processor being configured to generate a plurality of second image data by calculating, for each of the plurality of first image data, a product of pixel values of the first image data and the corresponding pixel values of the filter image and to generate image data of the sample based on the plurality of second image data.

2 . The sample observation apparatus according to claim 1 , wherein

the first region is a circular region, and

the second region is positioned outside the first region.

3 . The sample observation apparatus according to claim 1 , wherein

the first region is a semi-circular region, and

the second region is positioned outside the first region.

4 . The sample observation apparatus according to claim 1 , wherein

the filter includes a third region,

the first region is an annular region,

the second region is positioned outside the first region, and

the third region is positioned inside the first region.

5 . The sample observation apparatus according to claim 1 , wherein

the first region is positioned outside the second region, and

the second region is a circular region.

6 . The sample observation apparatus according to claim 1 , further comprising a phase film disposed at the pupil position of the illumination optical system,

wherein the first region corresponds to a region of an image of the phase film at the pupil position of the observation optical system,

the second region is a region positioned inside the first region, and

a region positioned outside the first region is a third region.

7 . The sample observation apparatus according to claim 6 , wherein

the first region is determined by a brightness in a range of 3% or more and 30% or less of a maximum brightness,

the maximum brightness is a maximum brightness in an image of the pupil of the illumination optical system, and

the image of the pupil of the illumination optical system is formed at the pupil position of the observation optical system.

8 . The sample observation apparatus according to claim 1 , wherein the processor changes a filter for producing the filter image in accordance with the relative position between the light spot and the holding member.

9 . The sample observation apparatus according to claim 1 ,

wherein the processor has a plurality of filters for producing the filter image, and

a filter is selected from among the plurality of filters in accordance with an observation method.

10 . The sample observation apparatus according to claim 1 , wherein the scanning mechanism is selected from a group consisting of a stage, a galvano scanner, a polygon mirror, and an acousto-optic deflector.

11 . The sample observation apparatus according to claim 1 , wherein the processor is configured to

calculate a total value obtained by summing pixel values of each of the plurality of second image data,

and to generate the image data of the sample based on the total value.