Image capturing apparatus and focusing method thereof

A method of capturing an image of a sample, the method comprising:

• by an objective lens, acquiring an optical image of at least a portion of a sample supported on a stage;
• dividing the optical image into a first optical image and a second optical image
• giving a continuous optical path difference to the second optical image;
• capturing at least a portion of the first optical image;
• setting a first imaging region and a second imaging region to capture the at least the portion of the second optical image, the second imaging region being captured after a predetermined time from capture of the first imaging region;
• controlling at least one of a position of the first imaging region and a position of the second imaging region;
• changing both the position of the first imaging region and the position of the second imaging region so that an interval between the first imaging region and the second imaging region changes;
• by the first imaging region and the second imaging region, capturing the at least the portion of the second optical image and providing image data;
• and
• analyzing the image data to control a focus position of the objective lens based on the analysis result in an analysis period.

A method of capturing an image of a sample, the method comprising:

• by an objective lens, acquiring an optical image of at least a portion of the sample supported on a stage;
• dividing the optical image into a first optical image and a second optical image;
• giving a continuous optical path difference to the second optical image;
• capturing at least a portion of the first optical image;
• capturing at least a portion of the second optical image and providing image data, the at least the portion of the second optical image being captured a predetermined time from the at least the portion of the second optical image;
• controlling at least one of a position of the first imaging region and a position of the second imaging region;
• changing both the position of the first imaging region and the position of the second imaging region so that an interval between the first imaging region and the second imaging region changes;
• analyzing the image data to control a focus position of the objective lens based on the analysis result in an analysis period;
• and
• keeping a position of the objective lens relatively with respect to the sample in the analysis period.

An apparatus for capturing an image of a sample, comprising:

• an objective lens that faces a sample;
• a beam splitter optically coupled to the objective lens and that divides an optical image of at least a portion of the sample through the objective lens into a first optical image and a second optical image;
• a first camera that captures at least a portion of the first optical image;
• a second camera that captures at least a portion of the second optical image given a continuous optical path difference and provides image data, the at least the portion of the second optical image being captured a predetermined time from the at least the portion of the second optical image;
• and
• one or more hardware processors having instructions stored in a memory device that when executed cause the apparatus to perform operations comprising:
• analyzing the image data to control a focus position of the objective lens based on the analysis result in an analysis period;
• controlling a position of the objective lens relatively with respect to the sample, wherein the position of the objective lens is not actuated during the analysis period;
• controlling at least one of a position of a first imaging region and a position of a second imaging region on the imaging area along an in-plane direction;
• and
• changing both the position of the first imaging region and the position of the second imaging region along the in-plane direction so that an interval between the first imaging region and the second imaging region changes.