From the Publisher: 
The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Plasmonic colours are structural colours that emerge from resonant interactions between light and metallic nanostructures. The engineering of plasmonic colours is a promising, rapidly emerging research field that could have a large technological impact. We highlight basic properties of plasmonic colours and recent nanofabrication developments, comparing technology-performance indicators for traditional and nanophotonic colour technologies. The structures of interest include diffraction gratings, nanoaperture arrays, thin films, and multilayers and structures that support Mie resonances and whispering-gallery modes. We discuss plasmonic colour nanotechnology based on localized surface plasmon resonances, such as gap plasmons and hybridized disk–hole plasmons, which allow for colour printing with sub-diffraction resolution. We also address a range of fabrication approaches that enable large-area printing and nanoscale lithography compatible with complementary metal-oxide semiconductor technologies, including nanoimprint lithography and self-assembly. Finally, we review recent developments in dynamically reconfigurable plasmonic colours and in the laser-induced post-processing of plasmonic colour surfaces. Plasmonic colours can be used to colour large surfaces, can be mass-produced and dynamically reconfigured, and can provide sub-diffraction resolution. In this Review, basic properties of plasmonic colours, different platforms supporting them and recent developments in the field are discussed.

Plasmonic colour generation

We report on the optical properties of plasmonic hole arrays as they apply to requirements for plasmonic color filters designed for state-of-the-art Si CMOS image sensors. The hole arrays are composed of hexagonally packed subwavelength sized holes on a 150 nm Al film designed to operate at the primary colors of red, green, and blue. Hole array plasmonic filters show peak transmission in the 40–50% range for large (>5 × 5 μm^2) size filters and maintain their filtering function for pixel sizes as small as 1 × 1 μm^2, albeit at a cost in transmission efficiency. Hole array filters are found to robust with respect to spatial crosstalk between pixel within our detection limit and preserve their filtering function in arrays containing random defects. Analysis of hole array filter transmittance and crosstalk suggests that nearest neighbor hole–hole interactions rather than long-range interactions play the dominant role in the transmission properties of plasmonic hole array filters. We verify this via a simple nearest neighbor model that correctly predicts the hole array transmission efficiency as a function of the number of holes.

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Plasmonic color filters for CMOS image sensor applications.

Major growth in the image sensor market is largely as a result of the expansion of digital imaging into cameras, whether stand-alone or integrated within smart cellular phones or automotive vehicles. Applications in biomedicine, education, environmental monitoring, optical communications, pharmaceutics and machine vision are also driving the development of imaging technologies. Organic photodiodes (OPDs) are now being investigated for existing imaging technologies, as their properties make them interesting candidates for these applications. OPDs offer cheaper processing methods, devices that are light, flexible and compatible with large (or small) areas, and the ability to tune the photophysical and optoelectronic properties − both at a material and device level. Although the concept of OPDs has been around for some time, it is only relatively recently that significant progress has been made, with their performance now reaching the point that they are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity. This review covers the progress made in the OPD field, describing their development as well as the challenges and opportunities.

Organic Photodiodes: The Future of Full Color Detection and Image Sensing

A single-pixel plasmonic complementary metal oxide semiconductor (CMOS) photo sensor consisting of a plasmonic color filter integrated on a CMOS photodiode was fabricated using electron beam lithography and dry etch. The photocurrent measurement results confirmed the three primary color filtering responses that could be achieved in a single layer of nanostructured aluminium film. Finite-difference time-domain simulation demonstrated a good agreement of the reflection spectra with the measured result. This research can lead to the development of advanced CMOS image sensors with low cost and low crosstalk.

CMOS Photodetectors Integrated With Plasmonic Color Filters

A small array of single photon avalanche detectors (SPADs) has been designed and fabricated in a standard $\hbox{0.18}\ \mu\hbox{m}$ CMOS process to test a new photon detecting system for optical communications. First numerical results are presented which show that using arrays of SPADs reduces the optical power density required at the receiver. Experimental results then show that the new system preserves the photon counting ability of the SPADs. Finally a simple method is presented which can be used to estimate the size of array needed to achieve a particular target bit error rate at a specific optical power density. Together these results indicate that by replacing the avalanche photodiode in a receiver with the new system it will be possible to count the received photons.

A SPAD-Based Photon Detecting System for Optical Communications

Multi-pixel, 4.5 × 9 μm, plasmonic colour filters, consisting of periodic subwavelength holes in an aluminium film, were directly integrated on the top surface of a complementary metal oxide semiconductor (CMOS) image sensor (CIS) using electron beam lithography and dry etch. The 100 × 100-pixel plasmonic CIS showed full colour sensitivities across the visible range determined by a photocurrent measurement. The filters were fabricated in a simple process utilising a single lithography step. This is to be compared with the traditional multi-step processing when using dye-doped polymers. The intrinsic compatibility of these plasmonic components with a standard CMOS process allows them to be manufactured in a metal layer close to the photodiodes. The incorporation of such plasmonic components may in the future enable the development of advanced CIS with low cost, low cross-talk and increased functionality.

A CMOS Image Sensor Integrated with Plasmonic Colour Filters

Visible light communications is an alternative method of indoor wireless communications that requires sensitive receivers. Ideally, single photon avalanche detectors (SPADs) could be used to create more sensitive receivers. However, the dead time, finite output pulse width, and photon detection efficiency of existing SPAD arrays limit their sensitivity and bandwidth. In this paper, an accurate equation for the impact of dead time on the sensitivity of a SPAD array is presented. In addition, the impact of the width of the output pulses on the on-off keying data rate is investigated. Finally, a comparison between receivers containing an avalanche photo-diode (APD) and a large array of SPADs shows that although the receiver containing the SPAD is more sensitive in the dark, the APD-based receiver is more sensitive in a normal operating condition. However, the models that predict the performance of both receivers suggest that newer SPAD arrays will enable significant improvements in receiver sensitivity.

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A Comparison of APD- and SPAD-Based Receivers for Visible Light Communications

At present, most CMOS image sensors use an array of pixels with a linear response. However, pixels with a logarithmic response are also possible and are capable of imaging high dynamic range scenes without saturating. Unfortunately, logarithmic image sensors suffer from fixed pattern noise (FPN). Work reported in the literature generally assumes the FPN is independent of illumination. This paper develops a nonlinear model y=a+bln(c+x)+/spl epsi/ of a pixel for the digital response y to an illuminance x and shows that the FPN arises from a variation of the offset a, gain b, and bias c from pixel to pixel. Equations are derived to estimate these parameters by calibrating images of uniform stimuli, taken with varying illuminances. Experiments with a Fuga 15d image sensor, demonstrating parameter calibration and FPN correction, show that the nonlinear model outperforms previous models that assume either only offset or offset and gain variation.

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Steve Collins

Papers

CMOS Photodetectors Integrated With Plasmonic Color Filters

A SPAD-Based Photon Detecting System for Optical Communications

A CMOS Image Sensor Integrated with Plasmonic Colour Filters

A Comparison of APD- and SPAD-Based Receivers for Visible Light Communications

Modeling, calibration, and correction of nonlinear illumination-dependent fixed pattern noise in logarithmic CMOS image sensors