Autofocus system for a computational microscope

An autofocus microscope, comprising:

• at least one image capture device configured to capture images of a sample located on a stage, wherein the at least one image capture device includes a lens;
• a focus actuator configured to adjust a distance between the sample and a focal plane of the at least one image capture device;
• an illumination assembly including a plurality of light sources to illuminate the sample from any of a plurality of illumination angles;
• and
• at least one controller programmed to:
• cause the illumination assembly to concurrently illuminate the sample from a first illumination angle and from a second illumination angle different from the first illumination angle;
• acquire, from the at least one image capture device, a single image of the sample illuminated from the first illumination angle and the second illumination angle;
• determine an amount of shift in the image of the sample between one or more image features associated with the first illumination angle and a corresponding one or more image features associated with the second illumination angle;
• and
• where the amount of determined shift is non-zero, cause the focus actuator to change the distance between the sample and the focal plane.

A method for focusing an image using image information acquired under a plurality of different illumination conditions, the method comprising:

• illuminating a sample at a first illumination condition;
• acquiring, from at least one image capture device, a first image of the sample illuminated from the first illumination condition;
• illuminating a sample at a second illumination condition;
• acquiring, from the at least one image capture device, a second image of the sample illuminated from the second illumination condition;
• and
• determining an amount of shift between one or more image features present in the first image of the sample and a corresponding one or more image features present in the second image of the sample.