Self-Calibrated Measurement Method Based on Structured Illumination Microscopy

Structured illumination microscopy (SIM) has attracted many attentions due to high-precision, high-efficiency and strong adaptability. In most SIM, two essential parameters need to be accurately obtained to restore the 3D shape of the object which are the focus position of each pixel z
_max
and the scan step Δz. For years, researchers have constantly improving the structure of SIM system to obtain more accurate z
_max
to realize optimized measurement results. Meanwhile, the preset value of Δz is directly substituted into calculation. However, the actual value of Δz is very likely inconsistent with the preset value due to various factors in practical such as nonlinear motion of scan actuator, which will introduce great error into the measurement result. In this letter, a self-calibrated measurement method is proposed to resolve this problem. As we know, the full width at half maximum (FWHM) of the modulation curve is uniquely determined when the optical measurement system is determined. In this letter, a self-calibrated measurement method based on SIM (SC-SIM) is proposed and the determined FWHM is utilized to calculate the actual value of Δz to realize more accurate and reliable measurement result. Simulation and experiment are carried out to demonstrate the feasibility of the proposed method.