Photomicroscopy system, image input device, and automatic exposure method

1. A photomicroscopy system, comprising:

a microscope unit which outputs an enlarged image of a subject as a light flux;

an image capturing unit which forms an image of the light flux output by the microscope unit, and converts the formed image into digital data;

a sensitivity changing unit which changes a sensitivity of the image capturing unit; and

a computing unit which obtains an exposure time by using the digital data captured by the image capturing unit in a state where the sensitivity is increased to a maximum sensitivity after instructing the sensitivity changing unit to increase the sensitivity of the image capturing unit from an initial sensitivity to the maximum sensitivity while calculating the exposure time for obtaining a suitable brightness by the image capturing unit, and sets the sensitivity of the image capturing unit back to the initial sensitivity after the exposure time is set in the image capturing unit;

wherein the computing unit is configured to calculate an intermediate exposure time on the basis of a ratio of brightness of the digital data, which is captured at the maximum sensitivity, to a suitable brightness until a brightness obtained on the basis of the digital data reaches the suitable brightness while calculating the exposure time, and adjust the intermediate exposure time using an exposure time correction coefficient which is determined from the maximum sensitivity and the initial sensitivity.

2. The photomicroscopy system according to claim 1 , further comprising a display unit which displays the image on the basis of the digital data captured by the image capturing unit.

3. The photomicroscopy system according to claim 1 , further comprising a storage unit which stores the digital data converted by the image capturing unit.

4. The photomicroscopy system according to claim 1 , wherein the microscope unit irradiates the subject with a same amount of illumination light in a state where the sensitivity of the image capturing unit is increased to a high sensitivity and a state where the sensitivity of the image capturing unit is set to a low sensitivity.

5. An image input device for converting a light flux of an image observed with a microscope into a digital image, and for holding the digital image, comprising:

an image capturing unit which forms an image of the light flux output by a microscope unit, and converts the formed image into digital data;

a sensitivity changing unit which changes a sensitivity of the image capturing unit; and

a computing unit which obtains an exposure time by using the digital data captured by the image capturing unit in a state where the sensitivity is increased to a maximum sensitivity after instructing the sensitivity changing unit to increase the sensitivity of the image capturing unit from an initial sensitivity to the maximum sensitivity while calculating the exposure time for obtaining a suitable brightness by the image capturing unit, and sets the sensitivity of the image capturing unit back to the initial sensitivity after the exposure time is set in the image capturing unit;

wherein the computing unit is configured to calculate an intermediate exposure time on the basis of a ratio of brightness of the digital data, which is captured at the maximum sensitivity, to a suitable brightness until a brightness obtained on the basis of the digital data reaches the suitable brightness while calculating the exposure time, and adjust the intermediate exposure time using an exposure time correction coefficient which is determined from the maximum sensitivity and the initial sensitivity.

6. The image input device according to claim 5 , wherein the sensitivity is a maximum sensitivity of the image capturing unit.

7. The image input device according to claim 5 , wherein the exposure time is obtained by using, for the intermediate exposure time when the exposure time is obtained, a ratio of a sensitivity before being changed to the high sensitivity to a sensitivity after being changed.

8. The image input device according to claim 5 , wherein

the image capturing unit includes a CCD, and

the sensitivity is an amplification ratio of an output of the CCD.

9. The image input device according to claim 5 , wherein

the sensitivity is a binning of the image capturing unit.

10. The image input device according to claim 5 , further comprising

an operation detecting unit which detects an operation performed for the microscope, wherein

the computing unit instructs the sensitivity changing unit to set a sensitivity of the image capturing unit to a high sensitivity also when the operation unit detects the operation performed for the microscope.

11. A photomicroscopy system, comprising:

microscope means for outputting an enlarged image of a subject as a light flux;

image capturing means for forming an image of the light flux output by the microscope means, and for converting the formed image into digital data;

sensitivity changing means for changing a sensitivity of the image capturing means; and

computing means for obtaining an exposure time by using the digital data captured by the image capturing unit in a state where the sensitivity is increased to a maximum sensitivity after instructing the sensitivity changing unit to increase the sensitivity of the image capturing unit from an initial sensitivity to the maximum sensitivity while calculating the exposure time for obtaining a suitable brightness by the image capturing unit, and sets the sensitivity of the image capturing unit back to the initial sensitivity after the exposure time is set in the image capturing unit;

wherein the computing means is configured to calculate an intermediate exposure time on the basis of a ratio of brightness of the digital data, which is captured at the maximum sensitivity, to a suitable brightness until a brightness obtained on the basis of the digital data reaches the suitable brightness while calculating the exposure time, and adjust the intermediate exposure time using an exposure time correction coefficient which is determined from the maximum sensitivity and the initial sensitivity.

12. An image input device for converting a light flux of an image observed with a microscope into a digital image, and for holding the digital image, comprising:

image capturing means for forming an image of the light flux output by microscope means, and for converting the formed image into digital data;

sensitivity changing means for changing a sensitivity of the image capturing means;

computing means for obtaining an exposure time by using the digital data captured by the image capturing unit in a state where the sensitivity is increased to a maximum sensitivity after instructing the sensitivity changing unit to increase the sensitivity of the image capturing unit from an initial sensitivity to the maximum sensitivity while calculating the exposure time for obtaining a suitable brightness by the image capturing unit, and sets the sensitivity of the image capturing unit back to the initial sensitivity after the exposure time is set in the image capturing unit;

wherein the computing means is configured to calculate an intermediate exposure time on the basis of a ratio of brightness of the digital data, which is captured at the maximum sensitivity, to a suitable brightness until a brightness obtained on the basis of the digital data reaches the suitable brightness while calculating the exposure time, and adjust the intermediate exposure time using an exposure time correction coefficient which is determined from the maximum sensitivity and the initial sensitivity.

13. An automatic exposure method used when an image is captured with a microscope, comprising:

obtaining an exposure time by using digital data captured by an image capturing unit in a state where a sensitivity of the image capturing unit is increased from an initial sensitivity to a maximum sensitivity while calculating the exposure time for obtaining a suitable brightness at the maximum sensitivity;

setting the sensitivity of the image capturing unit back to the initial sensitivity after setting the exposure time in the image capturing unit; and

wherein the calculating of the exposure time comprises calculating an intermediate exposure time on the basis of a ratio of brightness of the digital data, which is captured at the maximum sensitivity, to a suitable brightness until a brightness obtained on the basis of the digital data reaches the suitable brightness while calculating the exposure time, and adjust the intermediate exposure time using an exposure time correction coefficient which is determined from the maximum sensitivity and the initial sensitivity.

14. The automatic exposure method according to claim 13 , wherein the exposure time is obtained by using, for the intermediate exposure time when the exposure time is obtained, a ratio of a sensitivity before being changed to the high sensitivity to a sensitivity after being changed.