Optical instrument evaluation using modulation transfer function chart

Jack B. Stubbs (Inventor), John A. Cartmill (Inventor)

Research output: Patent


Recognizes and measures the extent to which resolution in a video or optical system is dependent on the contrast between the elements being resolved.

A novel chart permits rapid and inexpensive evaluation of an optical instrument for manufacturing purposes and/or by an operator of the instrument. For example, a user of an optical instrument may directly test the performance of an instrument without the assistance of trained personnel or a well-equipped laboratory facility. The chart comprises a plurality of levels defined by blocks having converging lines extending therein. The plurality of levels define a corresponding plurality of contrast levels between their blocks and the converging lines therein. The chart is used by viewing a plurality of levels within the chart and determining corresponding line frequency values at which the viewer is unable to discern multiple lines. These line frequency values are then compared to calibration line frequency values for the instrument being evaluated. The chart of the present invention is easily transported and used, and may be supplied along with an optical instrument to define operating characteristics of the instrument.
Original languageEnglish
Patent number5402225
Filing date28/03/95
Publication statusPublished - 28 Mar 1995
Externally publishedYes


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