Liquid lens confocal microscopy with advanced signal processing for higher resolution 3D imaging

The paper first highlights the use of multiple electronically controlled optical lenses, specifically, liquid lenses to realize an axial scanning confocal microscope with potentially less aberrations. Next, proposed is a signal processing method for realizing high resolution three dimensional (3-D) optical imaging using diffraction limited low resolution optical signals. Using axial shift-based signal processing via computer based computation algorithm, three sets of high resolution optical data is determined along the axial (or light beam propagation) direction using low resolution axial data. The three sets of low resolution data are generated by illuminating the 3-D object under observation along its three independent and orthogonal look directions (i.e., x, y, and z) or by physically rotating the object by 90 degrees and also flipping the object by 90 degrees. The three sets of high resolution axial data is combined using a unique mathematical function to interpolate a 3-D image of the test object that is of much higher resolution than the diffraction limited direct measurement 3-D resolution. Confocal microscopy or optical coherence tomography (OCT) are example methods to obtain the axial scan data sets. The proposed processing can be applied to any 3-D wave-based 3-D imager including ones using electromagnetic waves and sound (ultrasonic) waves. Initial computer simulations are described to test the robustness of the proposed high resolution signal processing method.