This paper presents a new type of tabletop interface on Lumisight Table. Putting physical objects on a tabletop display is one of the typical methods for intuitive tangible input. To date, various interactive systems that can identify and track the tabletop objects by using a camera, have been proposed. However, in these systems, the existence of objects with special devices or markers can disturb users' natural interaction by hiding displayed information. To solve this problem, the authors propose a transparent tabletop interface that is transparent from users but visible from a camera installed inside the system. This paper describes our research motivation, design and implementation of this interface, and examples of interaction.