Depth map sensor based on optical doped lens with multi-walled carbon nanotubes of liquid crystal

Monocular Real Time Full Resolution Depth Estimation Arrangement with a Tunable Lens

This work introduces a real-time full-resolution depth estimation device, which allows integral displays to be fed with a real-time light-field. The core principle of the technique is a high-speed focal stack acquisition method combined with an efficient implementation of the depth estimation algorithm, allowing the generation of real time, high resolution depth maps. As the procedure does not depend on any custom hardware, if the requirements are met, the described method can turn any high speed camera into a 3D camera with true depth output. The concept was tested with an experimental setup consisting of an electronically variable focus lens, a high-speed camera, and a GPU for processing, plus a control board for lens and image sensor synchronization. The comparison with other state of the art algorithms shows our advantages in computational time and precision.

Resolution Improvement of Light Field Imaging via a Nematic Liquid Crystal Microlens with Added Multi-Walled Carbon Nanotubes

A relatively simple method to improve the image resolution of light field based on a liquid crystal (LC) microlens doped with multi-walled carbon nanotubes (MWCNTs) was developed and evaluated. As the nanoparticles were doped in LC, its electro-optical features could enhance, leading to a short response time compared to the pure LC microlens. With the maximum use of the proposed LC microlens, a method combining aperiodicity extraction and weighted average algorithm was adopted to realize the high-resolution light field imaging. The aperiodicity extraction method was proposed, which could effectively improve resolution of view angle image. For synthesizing the full resolution image at 0 Vrms and the extracted view angle image of light field imaging at 2.0 Vrms, the final high-resolution light field imaging could be obtained in a short time by weighted average algorithm. In this way, the common problem of low resolution in light field imaging could be solved. This proposed method was in good agreement with our experimental results. And it was also in line with the development of the trend of the smart imaging sensor combining algorithm with hardware.

Focal stack camera in all-in-focus imaging via an electrically tunable liquid crystal lens doped with multi-walled carbon nanotubes

A focal stack camera, based on an electrically tunable-focusing liquid crystal (LC) lens doped with multi-walled carbon nanotubes, is proposed to generate a single all-in-focus image of a 3D scene without depth map in a relatively short time. Focal sweep strategy of the camera is devised. Both its depth of field (DOF) and focal sweep speed are analyzed and deduced. Nano doping method is adopted to improve electro-optical features of the LC lens. To efficiently produce all-in-focus image, a weighted average algorithm for all images in the focal stack is utilized. The experiments show that the result is a high contrast at sensor resolution. It is greatly potential in optical compact 3D imaging system.

Improvement in imaging contrast feature of liquid crystal lens with the dopant of multi-walled carbon nanotubes

An effective method to fabricate a high-contrast imaging liquid crystal (LC) lens with a relatively fast response time is proposed. This electrically tunable-focus LC lens is doped with multi-walled carbon nanotubes (MWCNTs) and has a high-resistance layer. A grinding method is utilized to lower agglomeration of doping MWCNTs. With respect to the high-resistance layer, it can make maximum use of doped nanoparticles to behave with high-quality lens character. The principles of improvement in electro-optical properties are discussed. The experimental results show that the proposed LC lens is effectively improved. The LC lens has great potential in compact imaging systems.

Large aperture liquid crystal lens with an imbedded floating ring electrode

We propose a hole-patterned large aperture (LA) liquid crystal (LC) lens with a diameter of 6 mm. In our design, a floating ring electrode is embedded into the interface between the dielectric layer and the LC layer. This structure increases the electric field strength around the floating ring electrode located near the aperture center and assists in distributing the fringing electric field throughout the LC layer. Therefore, the thick dielectric layer used in the conventional hole-patterned LA LC lens can be effectively decreased. Consequently, the proposed LA LC lens has low operation voltage, large lens power, and introduces a low wavefront error of approximately 0.07 λ.