We propose a method and a system to measure distances to a target and at the same time obtaining an image of
the target. The system is based on a wavefront coded lens and an image processing unit. The method requires
a calibration phase where a blur metric is related to the distance of the target. The distance to the target for
any position is then obtained by computing the blur metric of the target and using the calibration data. The
method and system are easy to manufacture and provide an alternative to other distance measuring methods
and devices, while also producing an image of the scene. The target is a printed image of pseudo random black
and white elements which can be stick or placed nearby objects of which distance is to be evaluated.
Computational imaging technology can capture extra information at the sensor and can be used for various photographic
applications, including imaging with extended depth of field or depth extraction for 3D applications. The depth
estimation from a single captured photograph can be achieved through a phase coded lens and image processing. In this
paper, we propose a new method to design a phase coded lens, using a blur metric (BM) as the design criterion. Matlab
and Zemax are used for the co-optimization of optical coding and digital image process. The purpose of the design is to
find a curve for which the BM changes continuously and seriously within a distance range. We verified our approach by
simulation, and got a axial symmetric phase mask as the coded lens. By using a pseudo-random pattern which contains
uniform black and white patches as the input image, and the on-axis point spread function (PSF) calculated from Zemax,
we can evaluate the BM of the simulated image which is convoluted by the pseudo-random pattern and PSF. In order to
ensure the BM curve evaluated from the on-axis PSF represents the result of the whole field of view, the PSF is also
optimized to get high off-axis similarity.
A method to convert a 2D video or 2D still image into a depth map is presented. The depth map can consequently
be converted into a pair of right and left images for viewing on a stereoscopic display. The depth map can be used for other applications such as multi-view generation. Our method is based on the use of an initial depth map and a bilateral filter approximated by a bilateral grid. For still images, the initial depth map is arbitrary set by default or can be chosen by the user, while for videos it is evaluated from motion estimation. Our method produces finely segmented depth maps; when converted to the appropriate format and seen on a stereoscopic display, the resulting image or video is both realistic and comfortable to watch.
This paper develops a digital decoding design for the imaging system with phase coded lens. The phase coded lens is
employed to extend the depth of filed (DoF), and the proposed design is used to restore the special-purpose blur caused
by the lens. Since in practice the imaging system inevitably contains manufacturing inaccuracy, it is often difficult to
obtain precise point spread function (PSF) for image restoration. To deal with this problem, we develop a flow for
designing filters without PSF information. The imaging system first takes a shot of a well-designed test chart to have a
blur image of the chart. This blur image is then corrected by using the perspective transformation. We use both of the
image of the test chart and the corrected blur image to calculate a minimum mean square error (MMSE) filter, so that the
blur image processed by the filter can be very alike to the test chart image. The filter is applied to other images captured
by the imaging system in order to verify its effectiveness in reducing the blur and for showing the capability of extending
the DoF of the integrated system.