Expanding the field of view for a scattering imaging system by illumination modulating with attenuation plates

Abstract

Seeing through a scattering medium is challenging in optical imaging. The speckle autocorrelation technique based on the optical memory effect (OME) is one of the most promising methods for the noninvasive observation of hidden objects. However, the field of view is usually limited to a very small area where the optical memory effect is exerted. Here, we propose and experimentally demonstrate the “ratio function extremum method” to image two separated but small objects regardless of the optical memory effect range. The independent speckle components of each object are blindly separated from two captured mixed speckle patterns by modulating the illuminating light intensity. With these separated, independent speckle images, we can easily reconstruct the two hidden objects located at different memory effect ranges using the famous speckle autocorrelation technique. In this sense, our method enlarges the field of view regarding the typical speckle autocorrelation imaging technique which relied on the OME principle. Additionally, we demonstrate that our method has high efficiency in separating the speckle components.