Tiefenmessung mithilfe einer Kamera mit programmierbarer Apertur

Abstract

Computational imaging adjusts the traditional optics of a camera in order to process the light signal prior to digitalization. A major problem is the effort of subsequent adjustments of the optical components, limiting such cameras to very narrow fields of application. This article analyzes a camera that uses a transparent liquid crystal display instead of a mechanical aperture. The simple adjustability of the optical transfer function enables a flexible application and adaptation to varying ambient conditions. The performance of the camera is exemplariliy analyzed in the scope of depth estimation with the depth-from-defocus method. Our algorithm estimates the scale of the point spread function in a single image by comparing the power spectral density of the observed image with the known aperture shape used to capture the image. The analysis of a test scene shows that the camera is capable to reproduce previous simulative results and that object distances can be reliably estimated from single images.

A simulation framework for the design and evaluation of computational cameras

“…In general, the aperture can be defined by a binary or grayscale mask, using the ImageAperture implementation. This allows to simulate coded apertures, which in real applications can be used to extract depth information 3,4 or to improve the depth-of-field, to name two examples. The principle of the ImageAperture can be easily applied to arbitrary spectral components, allowing spectral filters to be modeled.…”

“…Through the physically correct implementation of the contributing camera components, including a physical model of the camera sensor, it is ensured that the system performance is comparable to a real prototype. 4 Furthermore, the simulation framework allows for the implementation of reference systems that do not posses a physical counterpart, for example by directly rendering intermediate simulation data like the image depth, surface normal or spectrum, or by simulating technically impossible aperture stops.…”