METHOD AND APPARATUS TO REDUCE REFLECTANCE ERRORS DUE TO NON-UNIFORM COLOR DEVELOPMENT

摘要

A method and apparatus for decreasing measurement error in the colorimetric analysis of two-dimensional optical sample strips. In one embodiment the apparatus (60) includes a pair of photodetectors (24) with a light source (22) centered therebetween. An opaque shield around the light source (22) prevents direct illumination of the optical detectors (24), while a window (32) in the opaque shield allows illumination of the optical sample strip (42). Light is reflected from the strip (32) onto the two detectors (24). A microprocessor is operationally coupled to the photodetectors (24) to interrogate and compare their output signals. The microprocessor is adapted to calculate the optical uniformity of the optical sample (32) and map the variations of reflectance thereof.