Programmable Aperture Camera Using LCoS

Abstract

Abstract. Since 1960s, aperture patterns have been studied extensively and a variety of coded apertures have been proposed for various applications, including extended depth of field, defocus deblurring, depth from defocus, light field acquisition, etc. Researches have shown that optimal aperture patterns can be quite different due to different applications, imaging conditions, or scene contents. In addition, many coded aperture techniques require aperture patterns to be temporally changed during capturing. As a result, it is often necessary to have a programmable aperture camera whose aperture pattern can be dynamically changed as needed in order to capture more useful information. In this paper, we propose a programmable aperture camera using a Liquid Crystal on Silicon (LCoS) device. This design affords a high brightness contrast and high resolution aperture with a relatively low light loss, and enables one change the pattern at a reasonably high frame rate. We build a prototype camera and evaluate its features and drawbacks comprehensively by experiments. We also demonstrate two coded aperture applications in light field acquisition and defocus deblurring.

Video from a single coded exposure photograph using a learned over-complete dictionary

“…We simulate fast per-pixel shutter using a liquid crystal on silicon (LCoS) device. These devices have been used as spatial light modulators in various imaging applications [23,11], and can display binary patterns at fast rates (up to 3000Hz. ), making them ideally suited to our application.…”

“…While we have not yet fabricated a CMOS image sensor chip with per-pixel exposure control, we constructed an emulation imaging system with an LCoS device to achieve pixel-wise exposure control [11]. We compared our approach to several existing techniques via extensive simulations and experiments.…”

Towards Motion Aware Light Field Video for Dynamic Scenes

“…LF capture: Existing LF cameras can be divided into two main categories: (a) single shot [24,13,30,20,27,12,22], and (b) multiple shot [18,23,3]. Most single shot light field cameras multiplex the 4-D LF onto the 2D sensor, losing spatial resolution to capture the angular information in the LF.…”

“…It can be controlled at a maximum frame rate of ≈ 5000 fps. We follow the optical design in [23]. The LCoS modulator is at the effective aperture plane of the imaging system.…”

Computational Cameras: Convergence of Optics and Processing

“…5) Intensity modulator is an optical device that attenuates the intensity of the incoming rays [see Fig. 5(e)] and can be made of many materials [e.g., photomasks [33]- [36], liquid crystal display (LCD) [37], liquid crystal on silicon (LCoS) [38] and digital micromirror device (DMD) [39]- [42]]. The color filter is also a type of intensity modulator whose attenuation is wavelength dependent [43]- [45].…”