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, which sample has a refractive index, comprising:

• a chamber formed between a first panel and a second panel, which panels are transparent, and which chamber is operable to quiescently hold the sample;
• a plurality of lenslets disposed within the chamber, which lenslets have a height and a refractive index, which refractive index is different from that of the sample;
• a field illuminator for selectively illuminating at least a field of the sample and the lenslets;
• an image dissector for convening an image of light passing through the field of the sample and the lenslets into an electronic data format;
• a positioner operable to selectively change the relative position of one or more of the chamber containing the lenslets, 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 at one or more predetermined wavelengths, and to determine a representative light transmittance intensity of the sample field at the wavelengths, and to determine a representative light transmittance intensity of at least one region of the lenslets at the wavelengths, 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.