RESUMO
This paper proposes a newly developed fast measurement of a modulation transfer function (MTF) optical system inclusive of on-axis and off-axis measurement. First, we discuss how a description of an imager in terms of its optical transfer function is not appropriate for a discrete imaging system when aliasing occurs, since these optical systems transform high spatial frequencies into low frequencies; we then measure how an efficient microscanning method could remove the aliasing effects from assigned telecentric optics and nontelecentric optics. A knife edge function and a slit function as a light source are employed in this measurement. The experiment with the newly designed MTF measurement system synchronizes on-axis and off-axis measurement. In addition, a microscan method with a specially written macro is introduced in this experiment to eliminate aliasing effects. After simulation and experimental analysis, first the slit function as a target delivers decent MTF repeatability for this newly developed MTF measurement system, which synchronizes with on-axis and off-axis measurement simply in 2 s after all equipment is ready and aligned. Second, after the six-step microscanning, aliasing will be eliminated to near zero in most cases. Finally, it is concluded that during the microscan, there is no difference between telecentric and nontelecentric optics.
RESUMO
A novel design is the concept of using charge coupled device camera embedded with calibrated image processing algorithm as a two-dimensional luminance meter to measure the luminance and uniformity of small-scale backlight of unit. A small-scale backlight unit tester was successfully realized and performed to verify this concept.