Image Sensor With Focal Plane Extraction of Polarimetric Information (original) (raw)
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Integrated High Resolution Focal-Plane Polarization Imager
2000
The polarimetric vector is a more general descriptor of light than intensity information alone, and it con- tains physical information about the imaged objects in a scene that traditional intensity based sensors ig- nore. Polarimeters - devices that measure polarization - are used to extract physical features from an im- age such as specularities, occluding contours, and material properties. Scientists
ITE Transactions on Media Technology and Applications, 2014
step) with 0.35 µm standard CMOS process 8)-9). Combined with a linearly polarized light source with fixed polarization angle, we can obtain a polarization profile covering the whole angle in single frame measurement, without rotating the polarization of Abstract A polarization-analyzing CMOS image sensor with 65 nm standard fabrication process was designed and characterized. Polarization-analyzing image sensor pixel was realized using wire grid structures designed with a metal wiring layer within the standard CMOS process. Taking advantage of sub-100 nm CMOS process, a fine grid pitch was realized. Polarization-analyzing performance significantly higher than our previous sensors with 0.35 µm CMOS process was obtained. Polarization imaging capability was demonstrated for a scene with local polarization variation. With an aim of further performance improvement, subtraction readout scheme and multiple layer stacked on-pixel polarizer were proposed and discussed.
Image and Vision Computing, 1995
Recently, polarization vision has been shown to simplify some important image understanding tasks that can be more diff'cult to perform with intensity vision alone. This, together with the more general capabilities of polarization vision for image understanding, motivates the building of camera sensors that automatically sense and process polarization information. Described in this paper are a variety of designs for polarization camera sensors that have been built to automatically sense partial linearly polarized light, and computationally process this sensed polarization information at pixel resolution to produce a visualization of reflected polarization from a scene, and/or a visualization of physical information in a scene directly related to sensed polarization. The three designs for polarization camera sensors presented utilize (i) serial acquisition of polarization components using liquid crystals, (ii) parallel acquisition of polarization components using a stereo pair of cameras and a polarizing beamsplitter, and (iii) a prototype photosensing chip with three scanlines, each scanline coated with a particular orientation of polarizing material. As the sensory input to polarization camera sensors subsumes that of standard intensity cameras, they can potentially significantly expand the application potential of computer vision. A number of images taken with polarization cameras are presented, showing potential applications to image understanding, object recognition, circuit board inspection and marine biology.
Novel micro-polarizer array patterns for CMOS polarization image sensors
2016 5th International Conference on Electronic Devices, Systems and Applications (ICEDSA), 2016
In this paper, we present two novel "quasi-Bayer" micro-polarizer (MP) patterns for the polarization imaging based on the division-of-focal-plane polarimeters (DoFP). Compared with the traditional equally-weighted MP pattern with four different micro-polarizers, the "quasi-Bayer" pattern requires less photo-lithography-based selective etching steps, leading to a significant reduction of the MP array's fabrication complexity. In addition, for the mainstream bilinear interpolation algorithm, the proposed "quasi-Bayer" pattern with three micro-polarizers exhibits the lowest mean square error (MSE) of 0.43%. Moreover, the "quasi-Bayer" patterns take advantages not only at the fixed illumination level, but also for different illumination levels. Reported experimental results validate the effectiveness of the "quasi-Bayer" patterns by varying the input light intensity from 13 lux to 213 lux.
Integrated imaging linear polarimeter
ISA Transactions, 1999
The polarimetric vector is a more general descriptor of light than intensity information alone, and it contains physical information about the imaged objects in a scene that traditional intensity based sensors ignore. Polarimeters Ð devices that measure polarization Ð are used to extract physical features from an image such as specularities, occluding contours, and material properties. Scientists use polarization information to perform dicult tasks such as image segmentation and surface reconstruction, object orientation, material classi®cation, atmospheric and solar analysis. We will present an integrated CMOS sensor/imager that uses a unique polymer-based polarizing ®lter to sense two orthogonal directions of linear polarization. The CMOS imager uses analog translinear circuitry to compute, in real-time on the focal-plane, polarization contrast: a measure of the orientation and degree of linear polarization in an imaged scene. We will present the microfabrication technique that enables us to apply CMOS fabrication technology to bulk manufactured poly(vinyl alcohol) linearly polarizing ®lms. This technique allows us to de®ne lithographically micronscale linearly polarizing regions in polymer-based polarizing ®lters in order to make a high resolution polarization contrast imager. # (Z.K. Kalayjian) $ Based on``Integrated high-resolution focal-plane polarization imager,'' by Kalayjian and Andreou, published in the proceedings of the ISA Expo 98, 19±22 October Houston, TX.
IEEE Transactions on Electron Devices, 2022
In this article, We demonstrated an image sensor for detecting changes in polarization with high sensitivity. For this purpose, we constructed an optical system with a two-layer structure, comprising an external polarizer and polarizers on a pixel array. An external polarizer is used to enhance the polarization rotation while reducing the intensity to avoid pixel saturation of the image sensor. Using a two-layer structure, the two polarizers can be arranged under optimal conditions and the image sensor can achieve high polarization-change detection performance. We fabricated the polarization image sensor using a 0.35-µm CMOS process and, by averaging 50 × 50 pixels and 96 frames, achieved a polarization rotation detection limit of 5.2 × 10 −4 • at a wavelength of 625 nm. We also demonstrated the applicability of electric-field distribution imaging using an electrooptic crystal (ZnTe) for weak-polarization-change distribution measurements. Index Terms-CMOS image sensor, electric-field imaging, ON-chip polarizer, polarization image sensor, polarization modulation imaging. I. INTRODUCTION O PTICAL polarization detection can provide information that cannot be obtained by ordinary light intensity detection, such as the angle of the incident surface [1], differences in materials [2], distortions in a transparent material [3], and separation of reflected and transmitted components in
Compact and robust linear Stokes polarization camera
SPIE Proceedings, 2008
We present novel applications of Bossa Nova Technologies Linear Stokes polarization camera. The SALSA camera is able to perform live measurement of Linear Stokes parameters, usual polarization parameters (Degree Of Linear Polarization and Angle Of Polarization) and other polarization based parameters (polarized image, depolarized image, virtual polarizer, polarization difference). First a brief description of the SALSA camera and its calibration is given. Then we present and discuss several results of target detection and contrast enhancement experiments. We will also introduce a novel polarization based metrological method of 3D shape measurement for in-line control of optical surfaces and control of highly aspheric optical surfaces. The architecture of the hardware and calibration results is presented. A new algorithm based on polarization imaging leading to the construction of the gradient field is described. Finally experimental results and observations as well as possible further steps are discussed.
Sensors, 2020
Targeting 3D image reconstruction and depth sensing, a desirable feature for complementary metal oxide semiconductor (CMOS) image sensors is the ability to detect local light incident angle and the light polarization. In the last years, advances in the CMOS technologies have enabled dedicated circuits to determine these parameters in an image sensor. However, due to the great number of pixels required in a cluster to enable such functionality, implementing such features in regular CMOS imagers is still not viable. The current state-of-the-art solutions require eight pixels in a cluster to detect local light intensity, incident angle and polarization. The technique to detect local incident angle is widely exploited in the literature, and the authors have shown in previous works that it is possible to perform the job with a cluster of only four pixels. In this work, the authors explore three novelties: a mean to determine three of four Stokes parameters, the new paradigm in polarization cluster-pixel design, and the extended ability to detect both the local light angle and intensity. The features of the proposed pixel cluster are demonstrated through simulation program with integrated circuit emphasis (SPICE) of the regular Quadrature Pixel Cluster and Polarization Pixel Cluster models, the results of which are compliant with experimental results presented in the literature.