Three-dimensional(3D) imaging has attracted more and more interest because of its wide spread applications, especially in information and life science. These techniques can be broadly divided into two types: ray-based and wavefront-based 3D imaging. Issues such as imaging quality and system complexity of these techniques limit the applications significantly, and therefore many investigations are focused on 3D imaging from depth measurements. An overview of 3D imaging from depth measurements was presented, providing a summary of the connection between the ray-based and wavefront-based 3D imaging techniques, and showed the research direction of the depth measurement based 3D imaging research.