This paper presents a new angle sensitive pixel design for use in light field image sensors. This new pixel, referred to as the macro-pixel, is comprised of seven sub-pixels, and can determine the light angles in the range from −45°to +45°. The range of detectable angles is only limited by the presence of routing metals in the vicinity of the pixels. Each macro-pixel captures incident light angle through the aid of sub-wavelength metallic structures at its focal plane. Unlike previous designs that needed a large number of sub-pixels to determine a limited range of the incident angles, the presented design requires only half as many sub-pixels while offering a comparatively large angle detection range.Index Terms-Polarization pixels, angle detection, quadrature pixel cluster, light field image sensor, linear angle sensitive pixels, Talbot pixels.
In this paper we present a new technique for determining the angle of incident light using an image sensor. This technique makes use of two distinct pixel types for simultaneous coarse angle estimation and fine angle detection. A new type of pixel structure, the quadrature pixel cluster (QPC) is introduced, which produces response that varies linearly with incident light angle. The proposed technique greatly reduces the overall sensor complexity and is very area efficient compared to the previous work on angle detection. The sensor is fabricated in 65 nm mixedsignal CMOS process and can accurately distinguish between angles in the range from -35 • to +35 • . Index Terms-Angle detection; linear angle sensitive pixels; quadrature pixel cluster; light field sensor; track-and-tune angle detection; CMOS image sensor.This 5D function can be further reduced to a 4D one by considering the fact that the radiance along any ray does not change unless blocked [3][4]. This 4D representation can be used to completely describe any visual scene around us. Conventional image sensors sample only a 2D version of the imaging scene and hence are limited in their capabilities for post capture image processing. Extraction of the complete 4D parameters from light field allows for certain image processing Vigil Varghese, Xinyuan Qian and Shoushun Chen are with VIRTUS
In this paper we present the design of an image sensor pixel which produces a linear response proportional to the incident light angle. Unlike conventional pixels, the proposed pixel encodes incident angles in terms of linear intensity variations. A set of four pixels can distinguish between incident light angles along both the vertical and horizontal directions. This coarse linear angle information can be combined with the precise nonlinear Talbot effect based pixel response to deduce the exact incident angle. This technique greatly reduces the complexity of the Talbot effect based technique. Fabricated in a 65 nm GlobalFoundries mixed-signal CMOS process, the sensor can distinguish between angles in the range from -35 • to +35 • .
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