Method and apparatus for determining a focal position of an imaging device adapted to image a biologic sample

An apparatus for imaging a biologic sample disposed within a chamber, which sample has a refractive index, and wherein a plurality of lenslets are disposed and positionally fixed within the chamber, and which lenslets have a height and a refractive index, which refractive index is different from that of the sample, the apparatus comprising:

• a field illuminator for selectively illuminating at least a field of the sample and the lenslets;
• an image dissector for producing an electronic image of light passing through the field of the sample and the lenslets;
• a positioner operable to selectively change the relative position of one or more of the chamber, the field illuminator, and the image dissector to selectively change a focal position of the apparatus along the height of the lenslets;
• and
• a programmable analyzer adapted to cooperate with the field illuminator and the image dissector to image at least the field of the sample and a plurality of the lenslets using transmittance, and to determine a representative light transmittance intensity of the sample field, and to determine a representative light transmittance intensity of at least one region of the lenslets, and to determine the focal position of the apparatus using the representative light transmittance intensity of the sample field and the representative light transmittance intensity of the region of the lenslets.