Imaging apparatus and imaging method

1. An imaging apparatus, comprising:

a holder that holds a specimen holding plate substantially in a horizontal state, the specimen holding plate being formed with a well capable of holding liquid;

a light illuminator that irradiates light from above the specimen holding plate held by the holder to a surface of a specimen obtained by injecting fluid into the well;

a controller that controls a light quantity distribution of light to be incident on the surface of the specimen from the light illuminator based on a luminance distribution preliminarily measured at the well with the fluid; and

an imager for obtaining an image of the specimen by imaging the specimen under light illumination at the light quantity distribution set by the controller;

wherein the controller sets the light quantity distribution of the light to be incident on the surface of the specimen based on a luminance distribution in a preliminary image obtained by imaging the well by the imager under a predetermined standard light quantity distribution; and

wherein the controller sets a larger incident light quantity for a position with lower luminance in a background image obtained by removing high frequency components higher than a predetermined spatial frequency from the preliminary image.

2. The imaging apparatus according to claim 1 , wherein the light illuminator includes:

a light source; and

a transmission light quantity adjuster arranged between the light source and the specimen and capable of setting a light transmission quantity for each position, and

the controller controls the transmission light quantity adjuster.

3. The imaging apparatus according to claim 2 , wherein the transmission light quantity adjuster is capable of setting different transmission quantities for a plurality of wavelength components included in light from the light source.

4. The imaging apparatus according to claim 2 , wherein the transmission light quantity adjuster is a liquid crystal shutter.

5. The imaging apparatus according to claim 1 , wherein:

the light illuminator includes a light source in which a plurality of light emission modules are arranged; and

the controller individually controls light emission quantities of the light emission modules.

6. The imaging apparatus according to claim 1 , wherein:

the light illuminator includes a light source and a plurality of reflecting mirrors configured to reflect light from the light source and cause the light to be incident on the surface of the specimen and capable of changing a reflection direction independently of each other; and

the controller controls the reflection direction of each of the reflecting mirrors.

7. The imaging apparatus according to claim 1 , wherein the imager includes a line sensor which obtains an image of the specimen by being moved relative to the specimen holding plate.

8. The imaging apparatus according to claim 7 , wherein the light illuminator is moved relative to the specimen holding plate integrally with the line sensor as the line sensor is moved relative to the specimen holding plate.

9. The imaging apparatus according to claim 8 , wherein the controller changes the light quantity distribution of the light to be incident on the surface of the specimen in synchronization with a movement of the light illuminator relative to the specimen holding plate.

10. An imaging method for imaging a specimen obtained by injecting fluid into a well provided in a specimen holding plate, comprising:

a preliminary imaging step of imaging the specimen and obtaining a preliminary image by irradiating light having a predetermined standard light quantity distribution toward a surface of the specimen from above the substantially horizontally held specimen holding plate;

a detecting step of detecting a luminance distribution of the preliminary image;

a setting step of setting a light quantity distribution of light to be incident on the specimen based on a detection result in the detecting step; and

an image obtaining step of obtaining an image of the specimen under light illumination at the light quantity distribution set in the setting step;

wherein a luminance distribution in a background image obtained by removing high frequency components higher than a predetermined spatial frequency from the preliminary image is obtained in the detecting step; and

a larger incident light quantity is set for a position with lower luminance in the background image in the setting step.

11. The imaging method according to claim 10 , wherein the specimen is imaged by moving a line sensor relative to the specimen holding plate in the preliminary imaging step and the image obtaining step.

12. The imaging method according to claim 11 , a light illuminator for irradiating light to the specimen is moved relative to the specimen holding plate integrally with the line sensor as the line sensor is moved relative to the specimen holding plate.

13. The imaging method according to claim 12 , wherein imaging is performed while the light quantity distribution of the light to be incident on the surface of the specimen from the light illuminator is changed in synchronization with a movement of the light illuminator relative to the specimen holding plate based on the setting in the setting step.

14. The imaging method according to claim 10 , wherein the preliminary imaging step, the detecting step, the setting step and the image obtaining step are performed for each of specimens respectively held in a plurality of wells provided in the specimen holding plate.