Patent ID: 8218000

Claim:
A method for size calibration of an electronically generated image of a specimen, wherein the image is generated by a digital camera coupled to an optical instrument imaging the specimen in a single plane and operable in at least three reproduction modes, the method comprising the steps of: A) specifying only a single reproduction mode of the camera; B) determining only a single reference calibration value consisting solely of a ratio of said specimen dimension to an image dimension for the single specified reproduction mode for a given magnification setting of the optical instrument; C) storing the single reference calibration value in association with the single specified reproduction mode; D) comparing the single specified reproduction mode to a reproduction mode chosen from the at least three reproduction modes to derive a reproduction mode correction factor; and E) calculating a calibration value applicable to the chosen reproduction mode from the single reference calibration value and the reproduction mode correction factor, wherein the calibration value applicable to the chosen reproduction mode consists solely of the single reference calibration value multiplied by the reproduction mode correction factor for the given magnification setting; wherein steps (D) and (E) are applied regardless of which of the at least three reproduction modes is chosen, wherein the optical instrument is operable at a plurality of different magnification settings, and a respective said single reference calibration value is determined in accordance with step (B) and stored for each of the plurality of magnification settings, and for a specified magnification setting of the optical instrument, the single reference calibration value is determined and stored in association with the specified magnification setting; and a chosen magnification setting is compared to the specified magnification setting to derive a magnification setting correction factor, whereby a calibration value applicable to the chosen reproduction mode and chosen magnification setting can be calculated by multiplying the single reference calibration value by the reproduction mode correction factor and the magnification setting correction factor.