Track-and-Tune Light Field Image Sensor

Abstract

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

Polarization-Based Angle Sensitive Pixels for Light Field Image Sensors With High Spatio-Angular Resolution

“…The following subsection gives a brief overview of the angle sensitive Talbot pixels. For a more complete description the reader is encouraged to refer [9], [16] or [50]. …”

“…In [16] and [19] we proposed an alternative approach to the Talbot-only technique of angle detection. We proposed to combine the response from the Talbot pixels with the response from a quadrature pixel cluster (QPC).…”

“…One such technique [16] -the track and tune image sensor, was based on using the metal shading based [17], [18] quadrature pixel cluster [19] in order to achieve a high spatial resolution (13 pixels for bi-directional angle detection) while enabling a wide angular resolution (±35 • ). The essence of the trackand-tune technique was to use a group of pixels with low sensitivity, but high linearity (quadrature pixel cluster) along with another group of pixels with high sensitivity, but low linearity (Talbot pixels) to determine the local incidence angle.…”

A Novel Hybrid CMOS Pixel-Cluster for Local Light Angle, Polarization and Intensity Detection with Determination of Stokes Parameters

“…The PPC embeds an unshielded pixel for local light intensity detection, a horizontal grated pixel strongly sensitive to 90º polarized light, a vertical grated pixel strongly sensitive to 0º polarized light, and a 45º sensitivity pixel used to determine the Stokes parameters [4,10,12]. The second set of pixels, to determine the incident angle sign is the quadrature pixel cluster (QPC) with a block of metal on the top of the four photodiodes [13][14], as shown in Fig. 2(b).…”

Design of a Low Noise Active Pixel Sensor using Complementary Metal-Oxide-Semiconductor Technology

“…The emergence of CMOS image sensor technology is one of the most important developments in solid-state imaging since the invention of the charge coupled device (CCD) [1][2][3][4][5][6]. The attraction is mostly due to the nature of CMOS technology in that many millions of transistors can be integrated on a single silicon circuit.…”