Resolution enhancement by time-multiplexed acquisition of sub-pixel shifted images employing a Spatial Light Modulator

Abstract

We present an opto-electronic sub-pixel shifting method for resolution enhancement in monochromatic imaging. It is based on a Spatial Light Modulator (SLM) in the Fourier domain of a 4f-configuration. The SLM is used to modulate the incident light with the transfer function of a lateral subpixel shift. Therefore, a set of laterally shifted representations of the wave field incident on the 4f-setup can be generated in the corresponding camera domain. By numerically combining these images a high resolution image can be calculated. The use of an SLM as a wave field shifting device promises fast and flexible subpixel shifting with a high reproducibility. Exemplarily the method will be introduced for the case of monochromatic imaging, although it can easily be adopted to holography, phase shifting interferometry or other optical measurement techniques. The theoretical analysis includes modeling of the sampling process and the resolution enhancement approach as well as the effects associated with using an SLM as the shifting device. Furthermore the technical limits arising from the pixel pitch and pixel size of the sensor and the SLM are investigated. Finally the feasibility of the presented method is verified experimentally.