Detection of a Focal Plane under Corrections of Chromatic Aberration in Microscopic Field

In microscopic field, measuring a depth distance and a direction of a focal plane on an optical axis is very difficult. In our previous study, the depth estimation method are proposed based on difference between blur widths of objects in a single shot. However, the direction of a focal plane is unknown by the method. In this study, we propose an effective approach to detect the focal plane in microscopic field. We focus on different corrections of chromatic aberration to detect the plane. The corrections is roughly classified into four types. These types show different focus shifts for each light wavelength. Therefore, color appearance on the blur width of a target differ from each types. Extracting the color appearance by image processing, we detect the focal plane. From experimental results, we showed the effectiveness of the proposal approach considering focus shifts of chromatic aberration.