Wafer-level optics is considered to yield imaging lenses for cameras of the smallest possible form factor. The high accuracy of the applied microsystem technologies and the parallel fabrication of thousands of modules on the wafer level make it a hot topic for high-volume applications with respect to quality and costs. However, the adaption of existing materials and technologies from microoptics for the manufacturing of millimeter scale lens diameters led to yield problems due to material shrinkage and z-height accuracy. A multi-aperture approach to real-time vision systems is proposed that overcomes these issues because it relies on microlens arrays. The demonstrated prototype achieves VGA (Video Graphics Array, 640×480 pixels) resolution with a thickness of 1.4 mm, which is a thickness reduction of 50% compared to single-aperture equivalents. The partial images that are separately recorded in different channels are stitched together to form a final image of the whole field of view by means of image processing. Distortion is corrected within the processing chain. The microlens arrays are realized by state-of-the-art micro-optical fabrication techniques on wafer level that are suitable for a potential application in high volume, e.g., for consumer electronic products

We propose a microoptical approach to ultra-compact optics for real-time vision systems that are inspired by the compound eyes of insects. The demonstrated module achieves 720p resolution with a total track length of 2.0 mm which is about 1.5 times shorter than comparable conventional miniaturized optics. The partial images that are separately recorded in multiple optical channels are stitched together to form a final image of the whole FOV by means of image processing. The microlens arrays are realized by microoptical fabrication techniques on wafer-level which are suitable for a potential application in high volume e.g. for consumer electronic products

A digital camera samples the continuous real world. As with any sampling process, questions of aliasing for certain sampling frequencies and the prevention thereof arise. In this paper we will discuss the spatial domain sampling and prevention of aliasing in digital cameras. We focus on the widely used birefringent anti alias filters that are often called optical low pass filters (OLPF). We show 2D models for all contributions to spatial domain sampling and derive optimum filter parameters for minimum aliasing and best possible image sharpness. Compared to previously used selection rules, we can show that the optimum selection of filter parameters can easily deliver more sharpness and reduce aliasing by a factor of 2. The simulated results are finally confirmed in real world experiments

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Multi-aperture imaging systems inspired by insect compound eyes promise advances in both miniaturization and cost reduction of digital camera systems. Instead of a single lens stack with size and sag in the order of a few millimeters, the optical system consists of an array of microlenses. At a given field of view of the complete system, the focal lengths of the microlenses is a fraction of the focal length of a single-aperture system, reducing track length and increasing depth of field significantly. As each microimage spans only a small field of view, the optical systems can be simple. Because the microlenses have a diameter of hundreds of microns and a sag of tens of microns, they can be manufactured cost-effectively on wafer scale and with high precision. However, reaching a sufficient resolution for applications such as camera phones has been a challenge so far. We demonstrate a multi-aperture color camera system with approximately VGA resolution (700x550 pixels) and a remarkably short track length of 1.4 mm. The algorithm for correcting optical distortion of the microlenses and combining the microimages into a single image is the focus of this presentation