Visibility Enhancement by Integrating Refocusing and Direct-Global Separation with Contact Imaging

Abstract

Contact imaging is a compact lensless microscopy technique that allows observation of living cells placed directly on a charge-coupled device sensor. However, captured images exhibit low visibility in general. This work is aimed at integrating computational refocusing and high-frequency illumination into contact imaging to enhance the visibility of the captured images. Refocusing contributes to the synthesis of shallow depth-of-field images from the light field captured by moving a point light source. The visibility may be enhanced via high-frequency illumination. Naïve integration of both techniques requires several observations. Therefore, we propose an efficient integration from reduced observations by reformulating the computational refocusing applied in contact imaging. Furthermore, we developed a prototype system that demonstrates the effectiveness of the proposed method.