Showing papers in "electronic imaging in 1999"
TL;DR: An evaluation procedure of image watermarking systems is presented and how to efficiently evaluate the watermark performance in such a way that fair comparisons between different methods are possible is shown.
Abstract: Since the early 90s a number of papers on 'robust' digital watermarking systems have been presented but none of them uses the same robustness criteria. This is not practical at all for comparison and slows down progress in this area. To address this issue, we present an evaluation procedure of image watermarking systems. First we identify all necessary parameters for proper benchmarking and investigate how to quantitatively describe the image degradation introduced by the watermarking process. For this, we show the weaknesses of usual image quality measures in the context watermarking and propose a novel measure adapted to the human visual system. Then we show how to efficiently evaluate the watermark performance in such a way that fair comparisons between different methods are possible. The usefulness of three graphs: 'attack vs. visual-quality,' 'bit-error vs. visual quality,' and 'bit-error vs. attack' are investigated. In addition the receiver operating characteristic (ROC) graphs are reviewed and proposed to describe statistical detection behavior of watermarking methods. Finally we review a number of attacks that any system should survive to be really useful and propose a benchmark and a set of different suitable images.
591 citations
TL;DR: Digital image watermarking techniques known as perceptually watermarks that are designed to exploit aspects of the human visual system in order to produce a transparent, yet robust watermark are described.
Abstract: The growth of new imaging technologies has created a need for techniques that can be used for copyright protection of digital images. One approach for copyright protection is to introduce an invisible signal known as a digital watermark in the image. In this paper, we describe digital image watermarking techniques known as perceptually watermarks that are designed to exploit aspects of the human visual system in order to produce a transparent, yet robust watermark.
422 citations
TL;DR: This paper reviews proposed attacks on spread spectrum watermarks are systematically, and modifications for watermark embedding and extraction are presented to avoid and counterattack these attacks.
Abstract: Most watermarking methods for images and video have been proposed are based on ideas from spread spectrum radio communications, namely additive embedding of a (signal adaptive or non-adaptive) pseudo-noise watermark pattern, and watermark recovery by correlation. Even methods that are not presented as spread spectrum methods often build on these principles. Recently, some skepticism about the robustness of spread spectrum watermarks has arisen, specifically with the general availability of watermark attack software which claim to render most watermarks undetectable. In fact, spread spectrum watermarks and watermark detectors in their simplest form are vulnerable to a variety of attacks. However, with appropriate modifications to the embedding and extraction methods, spread spectrum methods can be made much more resistant against such attacks. In this paper, we review proposed attacks on spread spectrum watermarks are systematically. Further, modifications for watermark embedding and extraction are presented to avoid and counterattack these attacks. Important ingredients are, for example, to adapt the power spectrum of the watermark to the host signal power spectrum, and to employ an intelligent watermark detector with a block-wise multi-dimensional sliding correlator, which can recover the watermark even in the presence of geometric attacks.
298 citations
TL;DR: In this article, the authors present a video watermarking technology for broadcast monitoring, which has been developed at the Philips Research Laboratories in Eindhoven in the context of the European ESPRIT project VIVA (Visual Identity Verification Auditor).
Abstract: This paper presents a video watermarking technology for broadcast monitoring. The technology has been developed at the Philips Research Laboratories in Eindhoven in the context of the European ESPRIT project VIVA (Visual Identity Verification Auditor). The aim of the VIVA project is to investigate and demonstrate a professional broadcast surveillance system. The key technology in the VIVA project is a new video watermarking technique by the name of JAWS (Just Another Watermarking System). The JAWS system has been developed such that the embedded watermarks (1) are invisible, (2) are robust with respect to all common processing steps in the broadcast transmission chain, (3) have a very low probability of false alarms, (4) have a large payload at high rate, and (5) allow for a low complexity and a real-time detection. In this paper we present the basic ingredients of the JAWS technology. We also briefly discuss the performance of JAWS with respect to the requirements of broadcast monitoring.
276 citations
TL;DR: A new CFA recovery algorithm is presented, which recovers full-color images from single-detector digital color cameras more accurately than previously published techniques and reduces the MSE by over 50 percent compared to conventional color recovery algorithms.
Abstract: The increase in the popularity of digital cameras over the past few years has provided motivation to improve all elements of the digital photography signal chain. As a contribution towards this common goal, we present a new CFA recovery algorithm, which recovers full-color images from single-detector digital color cameras more accurately than previously published techniques. This CFA recovery algorithm uses a threshold-based variable number of gradients. In order to recover missing color information at each pixel, we measure the gradient in eight directions based on a 5 X 5 neighborhood surrounding that pixel. Each gradient value is defined as a linear combination of the absolute differences of the like-colored pixels in this neighborhood. We then consider the entire set of eight gradients to determine a threshold of acceptable gradients. For all of the gradients that pass the threshold test, we use color components from the corresponding areas of the 5 X 5 neighborhoods to determine the missing color values. We test our CFA recovery algorithm against bilinear interpolation and a single- gradient method. Using a set of standard test images, we show that our CFA recovery algorithm reduces the MSE by over 50 percent compared to conventional color recovery algorithms. In addition, the resolution test we developed also show that the new CFA recovery algorithm increases the resolution by over 15 percent. The subjective qualities of test images recovered using the new algorithm also show noticeable improvement.
176 citations
TL;DR: The method presented here is based on the discrete Fourier transform of three dimensional chunks of video scene, in contrast with previous works on video watermarking where each video frame was marked separately, or where only intra-frame or motion compensation parameters were marked in MPEG compressed videos.
Abstract: This paper proposes a new approach for digital watermarking and secure copyright protection of videos, the principal aim being to discourage illicit copying and distribution of copyrighted material. The method presented here is based on the discrete Fourier transform (DFT) of three dimensional chunks of video scene, in contrast with previous works on video watermarking where each video frame was marked separately, or where only intra-frame or motion compensation parameters were marked in MPEG compressed videos. Two kinds of information are hidden in the video: a watermark and a template. Both are encoded using an owner key to ensure the system security and are embedded in the 3D DFT magnitude of video chunks. The watermark is a copyright information encoded in the form of a spread spectrum signal. The template is a key based grid and is used to detect and invert the effect of frame-rate changes, aspect-ratio modification and rescaling of frames. The template search and matching is performed in the log-log-log map of the 3D DFT magnitude. The performance of the presented technique is evaluated experimentally and compared with a frame-by-frame 2D DFT watermarking approach.
169 citations
TL;DR: In this article, a generic expression for the relation between LCD pixels and the multiple perspective views is derived that can be used in the image preparation for different 3D-LCD systems.
Abstract: The simplicity and inherent robustness of the Philips 3D- LCD, both in manufacturing and usage, make it highly suitable for a cost effective, mass-market autostereoscopic display. For successful adoption in a wide range of applications, efficient 3D image preparation is very important. A generic expression for the relation between LCD pixels and the multiple perspective views is derived that can be used in the image preparation for different 3D-LCD systems. This paper then describes two approaches to 3D image preparation. One is an intuitive graphical user interface and the second is at source code programming level as an extension to the existing OpenGL 3D graphics API. Using the latter we examine the computer overhead of the 3D image preparation process.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
162 citations
TL;DR: The aim is to bring together the knowledge from various fields, unifying the issues that should be considered when building a digital image library, and provides a systematic way of indexing images based on syntax and semantics.
Abstract: In this paper, we present a conceptual framework for indexing different aspects of visual information. Our framework unifies concepts from this literature in diverse fields such as cognitive psychology, library sciences, art, and the more recent content-based retrieval. We present multiple level structures for visual and non-visual and non- visual information. The ten-level visual structure presented provides a systematic way of indexing images based on syntax and semantics, and includes distinctions between general concept and visual concept. We define different types of relations at different levels of the visual structure, and also use a semantic information table to summarize important aspects related to an image. While the focus is on the development of a conceptual indexing structure, our aim is also to bring together the knowledge from various fields, unifying the issues that should be considered when building a digital image library. Our analysis stresses the limitations of state of the art content-based retrieval systems and suggests areas in which improvements are necessary.
157 citations
TL;DR: QIM and dither modulation systems have considerable performance advantages over previously proposed spread-spectrum and low-bit(s) modulation systems in terms of the achievable performance trade-offs among distortion, rate, and robustness of the embedding.
Abstract: We consider the problem of embedding one signal (e.g., a digital watermark), within another 'host' signal to form a third, 'composite' signal. The embedding must be done in such a way that minimizes distortion between the host signal and composite signal, maximizes the information-embedding rate, and maximizes the robustness of the embedding. In general, these three goals are conflicting, and the embedding process must be designed to efficiently trade-off the three quantities. We propose a new class of embedding methods, which we term quantization index modulation (QIM), and develop a convenient realization of a QIM system that we call dither modulation in which the embedded information modulates a dither signal and the host signal is quantized with an associated dithered quantizer. QIM and dither modulation systems have considerable performance advantages over previously proposed spread-spectrum and low-bit(s) modulation systems in terms of the achievable performance trade-offs among distortion, rate, and robustness of the embedding. We also demonstrate these performance advantages in the context of 'no-key' digital watermarking applications, in which attackers can access watermarks in the clear. We also examine the fundamental limits of digital watermarking from an information theoretic perspective and discuss the achievable limits of QIM and alternative systems.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
140 citations
TL;DR: It is argued that CMOS technology scaling will make pixel level processing increasingly popular and interpixel analog processing is not likely to become mainstream even for computational sensors due to the poor scaling popular since it minimizes analog processing, and requires only simple and imprecise circuits to implement.
Abstract: Pixel level processing promises many significant advantages including high SNR, low power, and the ability to adapt image capture and processing to different environments by processing signals during integration. However, the severe limitation on pixel size has precluded its mainstream use. In this paper we argue that CMOS technology scaling will make pixel level processing increasingly popular. Since pixel size is limited primarily by optical and light collection considerations, as CMOS technology scales, an increasing number of transistors can be integrated at the pixel. We first demonstrate that our argument is supported by the evolution of CMOS image sensor from PPS to APS. We then briefly survey existing work on analog pixel level processing an d pixel level ADC. We classify analog processing into intrapixel and interpixel. Intrapixel processing is mainly used to improve sensor performance, while interpixel processing is used to perform early vision processing. We briefly describe the operation and architecture of our recently developed pixel level MCBS ADC. Finally we discuss future directions in pixel level processing. We argue that interpixel analog processing is not likely to become mainstream even for computational sensors due to the poor scaling popular since it minimizes analog processing, and requires only simple and imprecise circuits to implement. We then discuss the inclusion of digital memory and interpixel digital processing in future technologies to implement programmable digital pixel sensors.
129 citations
TL;DR: This paper compares two fragile watermarks and describes how images can be hashed so that any changes can be spatially localized and under what circumstances one would use a particular technique.
Abstract: Two classes of digital watermarks have been developed to protect the copyright ownership of digital images. Robust watermarks are designed to withstand attacks on an image (such as compression or scaling), while fragile watermarks are designed to detect minute changes in an image. Fragile marks can also identify where an image has been altered. This paper compares two fragile watermarks. The first method uses a hash function to obtain a digest of the image. An altered or forged version of the original image is then hashed and the digest is compared to the digest of the original image. If the image has changed the digests will be different. We will describe how images can be hashed so that any changes can be spatially localized. The second method uses the Variable-Watermark Two- Dimensional algorithm (VW2D). The sensitivity to changes is user-specific. Either no changes can be permitted (similar to a hard hash function), or an image can be altered and still be labeled authentic. Latter algorithms are known as semi-fragile watermarks. We will describe the performance of these two techniques and discuss under what circumstances one would use a particular technique.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: This paper discusses issues of authenticating MPEG videos under various transcoding situations, including dynamic rate shaping, requantization, frame type conversion, and re-encoding, and proposes a robust video authentication system which accepts some MPEG transcoding processes but is able to detect malicious manipulations.
Abstract: Video authentication techniques are used to prove the originality of received video content and to detect malicious tampering. Existing authentication techniques protect every single bit of the video content and do not allow any form of manipulation. In real applications, this may not be practical. In several situations, compressed videos need to be further processed to accommodate various application requirements. Examples include bitrate scaling, transcoding, and frame rate conversion. The concept of asking each intermediate processing stage to add authentication codes is flawed in practical cases. In this paper, we extend our prior work on JPEG- surviving image authentication techniques to video. We first discuss issues of authenticating MPEG videos under various transcoding situations, including dynamic rate shaping, requantization, frame type conversion, and re-encoding. Different situations pose different technical challenges in developing robust authentication techniques. In the second part of this paper, we propose a robust video authentication system which accepts some MPEG transcoding processes but is able to detect malicious manipulations. It is based on unique invariant properties of the transcoding processes. Digital signature techniques as well as public key methods are used in our robust video authentication system.
TL;DR: In this paper, the effects of watermarking fingerprint images on the recognition and retrieval accuracy using a proposed invisible fragile water-marking technique for image verification applications on a specific fingerprint recognition system.
Abstract: Current 'invisible' watermarking techniques aim at producing watermarked data that suffer no or little quality degradation and perceptually identical to the original versions. The most common utility of a watermarked image is (1) for image viewing and display, and (2) for extracting the embedded watermark in subsequent copy protection applications. The issue is often centered on the robustness of the watermark for detection and extraction. In addition to robustness studies, a fundamental question will center on the utilization value of the watermarked images beyond perceptual quality evaluation. Essentially we have to study how the watermarks inserted affect the subsequent processing and utility of images, and what watermarking schemes we can develop that will cater to these processing tasks. This work focuses on the study of watermarking on images used in automatic personal identification technology based fingerprints. We investigate the effects of watermarking fingerprint images on the recognition and retrieval accuracy using a proposed invisible fragile watermarking technique for image verification applications on a specific fingerprint recognition system. We shall also describe the watermarking scheme, fingerprint recognition and feature extraction techniques used. We believe that watermarking of images will provided value-added protection, as well as copyright notification capability, to the fingerprint data collection processes and subsequent usage.
TL;DR: The proposed technology for a maximal number d of pirates, puts enough information in the intersection of up to d fingerprints to uniquely identify all the pirates.
Abstract: Digital watermarking is the enabling technology to prove ownership on copyrighted material, detect originators of illegally made copies, monitor the usage of the copyrighted multimedia data and analyze the spread spectrum of the data over networks and servers. Embedding of unique customer identification as a watermark into data is called fingerprinting to identify illegal copies of documents. Basically, watermarks embedded into multimedia data for enforcing copyrights must uniquely identify the data and must be difficult to remove, even after various media transformation processes. Digital fingerprinting raises the additional problem that we produce different copies for each customer. Attackers can compare several fingerprinted copies to find and destroy the embedded identification string by altering the data in those places where a difference was detected. In our paper we present a technology for combining a collusion-secure fingerprinting scheme based on finite geometries and a watermarking mechanism with special marking points for digital images. The only marking positions the pirates can not detect are those positions which contain the same letter in all the compared documents, called intersection of different fingerprints. The proposed technology for a maximal number d of pirates, puts enough information in the intersection of up to d fingerprints to uniquely identify all the pirates.
TL;DR: In this article, a novel system for image watermarking, which exploits the similarity exhibited by the Digital Wavelet Transform with respect to the models of the human visual system, for robustly hiding watermarks is presented.
Abstract: The growth of the Internet and the diffusion of multimedia applications requires the development of techniques for embedding identification codes into images, in such a way that it can be granted their authenticity and/or protected the copyright. In this paper a novel system for image watermarking, which exploits the similarity exhibited by the Digital Wavelet Transform with respect to the models of the Human Visual System, for robustly hiding watermarks is presented. In particular, a model for estimating the sensitivity of the eye to noise, previously proposed for compression applications, is used to adapt the watermark strength to the local content of the image. Experimental results are shown supporting the validity of the approach.
TL;DR: A simple model is introduced to describe the sensor output response as a function of the photogenerate signal, dark signal, and noise for sensors operation in integration mode with and without dynamic range enhancement schemes.
Abstract: Dynamic range is a critical figure of merit for image sensors. Often a sensor with higher dynamic range is regarded as higher quality than one with lower dynamic range. For CCD and CMOS sensors operating in the integration mode the sensor SNR monotonically increases with the signal. Therefore, a sensor with higher dynamic range, generally, produces higher quality images than one with lower dynamic range. This, however, is not necessarily the case when dynamic range enhancement schemes are used. For example, suing the well capacity adjusting scheme dynamic range is enhanced but at the expense of substantial degradation in SNR. On the other hand, using multiple sampling dynamic range can be enhanced without degrading SNR. Therefore, even if both schemes achieve the same dynamic range the latter can produce higher image quality than the former. The paper provides a quantitative framework for comparing SNR for image sensors with enhanced dynamic range. We introduce a simple model to describe the sensor output response as a function of the photogenerate signal, dark signal, and noise for sensors operation in integration mode with and without dynamic range enhancement schemes. We use the model to quantify and compare dynamic range and SNR for three sensor operation modes, integration with shuttering, using the well capacity adjusting scheme, and using multiple sampling.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The objective of this paper is to detail the grating light valve technology and demonstrate its flexibility in attaining high performance in a variety of optical systems and applications, concentrating particularly on its application toward projection display systems.
Abstract: The objective of this paper is to detail the grating light valve technology and demonstrate its flexibility in attaining high performance in a variety of optical systems and applications, concentrating particularly on its application toward projection display systems. The GLV technology represent a unique approach to light modulation and offers remarkable performance in terms of contrast, efficiency, switching speed, and cost. The electro- mechanical response of the GLV device can be tuned through various design and operational modes to deliver desired performance for a given application. The design and fabrication of a linear array module of 1,088 GLV pixels is described. This module enables a scanned linear GLV architecture for HDTV projection products. The flexibility of the GLV technology and the scanned linear GLV architecture can support line sequential and frame sequential color, as well as 3-valve color systems. System level optical design either include embedded scanners to emulate 2D film source planes or external scanner elements for greater system simplicity. Results with actual projection display system yield unparalleled on-screen performance, having uniformity greater than 99 percent corner-to-corner, high contrast, 10-bits of grayscale per color, and no visible pixel boundaries.
TL;DR: Analyzing a specific statistical model of input images, leads to an optimal decoding algorithm in term of the rate- distortion trade-off of dither halftone images, and characterize optimal dither matrix pairs (i.e.: dither Matrix pairs whose use results in the most favorable rate-distortion).
Abstract: Image watermarking concerns embedding information in images, in a manner that does not affect the visual quality of the image. This paper focusses on watermarking of dither halftone images. The basic idea is to use a sequence of two dither matrices (instead of one) to encode the watermark information. Analyzing a specific statistical model of input images, leads to an optimal decoding algorithm in term of the rate- distortion trade-off. Furthermore, we characterize optimal dither matrix pairs (i.e.: dither matrix pairs whose use results in the most favorable rate-distortion). Finally, the results are demonstrated in a synthetic example. The example is synthetic in the sense that it does not resort to printing and re-scanning of the image.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this paper, an evaluation of the number of bits that can be hidden within an image by means of frequency-domain watermarking is given, and the capacity of each coefficient is evaluated by computing the channel transition matrix and by maximizing the mutual input/output information.
Abstract: An evaluation of the number of bits that can be hidden within an image by means of frequency-domain watermarking is given. Watermarking is assumed to consist in the modification of a set of full-frame DCT (DFT) coefficients. The amount of modification each coefficient undergoes is proportional to the magnitude of the coefficient itself, so that an additive- multiplicative embedding rule results. The watermark-channel is modeled by letting the watermark be the signal and the image coefficients the noise introduced by the channel. To derive the capacity of each coefficient, the input (i.e. the watermark) and the output (i.e. the watermarked coefficients) of the channel are quantized, thus leading to a discrete- input, discrete-output model. Capacity is evaluated by computing the channel transition matrix and by maximizing the mutual input/output information. Though the results we obtained do not take into account attacks, they represent a useful indication about the amount of information that can be hidden within a single image.
TL;DR: Compensation for the particular attributes of DMD imaging has allowed the creation of full-color holographic stereograms of high image quality.
Abstract: We describe the use of a digital micromirror device (Texas Instruments, Inc. ' s DMDTM) as a spatial light modulator forholographic applications. Questions of the interferometric effects of the moving mirror structure and the appropriateness ofpulse-width modulation for grayscale imaging are addressed. Compensation for the particular attributes of DMD imaginghas allowed the creation of full-color holographic stereograms of high image quality.Keywords: holography, spatial light modulator (SLM), digital micromirror device (DMD) 1. INTRODUCTION Spatial light modulators (SLMs) are key components of holographic stereogram printer systems. They are used to display the sequence of two-dimensional stereoscopic perspective views that are being holographically recorded. Because allinformation about the object scene is transduced by the SLM, it is a very important factor in the determination of the finalholographic image quality. Some SLMs typically used for holography include: positive transparency film (35
TL;DR: This paper is focused on authentication, using the labeling approach; a generic framework is firstly presented and two specific methods are then proposed for the particular cases of still images and videos.
Abstract: The increasing availability of digitally stored information and the development of new multimedia broadcasting services, has recently motivated research on copyright protection and authentication schemes for these services. Possible solutions range from low-level systems based upon header description associated with the bit-stream (labelling), up to high level, holographically inlayed, non-deletable systems (watermarking). This paper is focused on authentication, using the labeling approach; a generic framework is firstly presented and two specific methods are then proposed for the particular cases of still images and videos. The resistance of both methods to JPEG and MPEG2 compression, as well as its sensitivity to image manipulations, are evaluated.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: A hand-held palette for touch-based interaction in virtual reality that incorporates a high-resolution digitizing touch screen for input and is see-through, which makes it suitable for direct manipulation techniques in a range of virtual reality display systems.
Abstract: We have built a hand-held palette for touch-based interaction in virtual reality. this palette incorporates a high-resolution digitizing touch screen for input. It is see-through, and therefore does not occlude objects displayed behind it. These properties make it suitable for direct manipulation techniques in a range of virtual reality display systems. We implemented several interaction techniques based on this palette for an interactive scientific visualization task. These techniques, the tool's design, and its limitations are discussed in this paper.
TL;DR: In this paper, a new see-through 3D HMD with high resolution, wide field of view (FOV) by improving the free form surface prism (FFS prism) technique was presented.
Abstract: The HMD optical system composed of 'free form surface prism' (FFS prism) was presented by Canon Inc. at the 1996 SPIE conference. This prism was consists of aspherical surfaces without rotational symmetry. This HMD was suitable for compact HMD and was the 180,000 pixels display which has 34 degrees horizontal FOV and less than 15mm prism thickness. We have developed a new see-through 3D HMD with high resolution, wide field of view (FOV) by improving this FFS prism technique. The new HMD with 51 degrees horizontal FOV and large viewing eyebox shows clear full color image with 920,000 pixels. In spite of the wide FOV, the thickness of this new FFS prism is very thin, 17.9 mm. In this paper, we report this new HMD and 'the AR2 hockey system' as an example of this HMD application.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: A watermarking algorithm suitable for embedding private watermarks into three dimensional polygon based models that modifies the models normal distribution to store information solely in the geometry of the model.
Abstract: This paper presents a watermarking algorithm suitable for embedding private watermarks into three dimensional polygon based models. The algorithm modifies the models normal distribution to store information solely in the geometry of the model. The watermarks show significant robustness against mesh simplifying methods.
TL;DR: In this paper, an accurate analysis of temporal noise in CMOS APS is presented, where the authors analyze the noise for each stage of the sensor operation, and identify the noise contribution from each source.
Abstract: Temporal noise sets a fundamental limit on image sensor performance, especially under low illumination and in video applications. In a CCD image sensor, temporal noise is well studied and characterized. It is primarily due to the photodetector shot noise and the thermal and 1/f noise of the output charge to voltage amplifier. In a CMOS APS several addition sources contribute to temporal noise, including the noise due to the pixel rest, follower, and access transistors. The analysis of noise is further complicated by the nonlinearity of the APS charge to voltage characteristics, which is becoming more pronounced as CMOS technology scales, and the fact that the reset transistor operates below threshold for most of the reset time. The paper presents an accurate analysis of temporal noise in APS. We analyze the noise for each stage of the sensor operation, and identify the noise contribution from each source. We analyze noise due to photodetector shot noise taking nonlinearity into consideration. We find that nonlinearity improves SNR reset transistor shot noise is at most half the commonly quoted value. Using HSPICE simulation, we find the noise due to the follower and access transistors. As expected we find that at low illumination reset noise dominates, while at high illumination photodetector shot noise dominates. Finally, we present experimental results from test structures fabricated in 0.35(mu) CMOS processes. We find that both measured peak SNR and reset noise values match well with the results of our analysis.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The MPEG-2 multiview profile extends hybrid coding towards exploitation of inter-viewchannel redundancies by implicitly defining disparity-compensated prediction as mentioned in this paper, which can be applied in the context of these standards.
Abstract: Compression of stereoscopic and multiview video data is important, because the bandwidth necessary for storage and transmission linearly increase with the number of camera channels. This paper gives an overview about techniques that ISO's Moving Pictures Experts Group has defined in the MPEG- 2 and MPEG-4 standards, or that can be applied in the context of these standards. A good tradeoff between exploitation of spatial and temporal redundancies can be obtained by application of hybrid coding techniques, which combine motion-compensated prediction along the temporal axis, and 2D DCT transform coding within each image frame. The MPEG-2 multiview profile extends hybrid coding towards exploitation of inter-viewchannel redundancies by implicitly defining disparity-compensated prediction. The main feature of the new MPEG-4 multimedia standard with respect to video compression is the possibility to encode objects with arbitrary shape separately. As one component of the segmented object's shape, it shall be possible to encode a dense disparity map, which can be accurate enough to allow generation of alternative view s by projection. This way, a very high stereo/multiview compressions ratio can be achieved. While the main application area of the MPEG-2 multiview profile shall be in stereoscopic TV, it is expected that multiview aspects of MPEG-4 will play a major role in interactive applications, e.g. navigation through virtual 3D worlds with embedded natural video objects.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: A water marking scheme which allows the watermarked image to be authenticated by an authentication agent without revealing to the authentication agent the human-readable content of the image by combining privacy control with watermarking and authentication mechanisms is proposed.
Abstract: We propose a watermarking scheme which allows the watermarked image to be authenticated by an authentication agent without revealing to the authentication agent the human-readable content of the image by combining privacy control with watermarking and authentication mechanisms. This watermarking scheme has universal applicability to data sets such as image, video and audio bit streams. The watermark can be made to be imperceptible to humans. Usage of public key cryptography allows the authentication agent to authenticate without the capabilities to watermark an image.
TL;DR: The Haptic Workbench, the HCI issues that arose and its deployment in prototype industrial applications are presented, and conclusions are drawn about the appropriate use of co-located multi-sensory technologies in Virtual Environments.
Abstract: The Haptic Workbench combines stereo images, co-located force feedback and 3D audio to produce a small-scale hands- in virtual environment system. This paper present the Haptic Workbench, the HCI issues that arose and its deployment in prototype industrial applications. The problems associated with combining global graphic and local haptic rendering in an efficient and generalized manner are described. The benefits and the difficulties associated with this class of virtual environment system are discussed, the experience gained in applying it to industrial applications is described and conclusions are drawn about the appropriate use of co-located multi-sensory technologies in Virtual Environments.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The status of DLP-based projection display technology, including its manufacturing, performance improvements, and new applications, with emphasis on DLP Cinema is described, including brightness, resolution, contrast ratio, and border image.
Abstract: Digital Light Processing (DLP) projection displays based on the Digital Micromirror Device (DMD) were introduced to the market in 1996. Less than 3 years later, DLP-based projectors are found in such diverse applications as mobile, conference room, video wall, home theater, and large-venue. They provide high-quality, seamless, all-digital images that have exceptional stability as well as freedom from both flicker and image lag. Marked improvements have been made in the image quality of DLP-based projection display, including brightness, resolution, contrast ratio, and border image. DLP-based mobile projectors that weighted about 27 pounds in 1996 now weight only about 7 pounds. This weight reduction has been responsible for the definition of an entirely new projector class, the ultraportable. New applications are being developed for this important new projection display technology; these include digital photofinishing for high process speed minilab and maxilab applications and DLP Cinema for the digital delivery of films to audiences around the world. This paper describes the status of DLP-based projection display technology, including its manufacturing, performance improvements, and new applications, with emphasis on DLP Cinema.
TL;DR: In this paper, an optical approach for modeling the quantum efficiency (QE) of back-illuminated CCD optical imagers for astronomy was developed, which has the advantage of providing a complete fringing description for a real system.
Abstract: We have developed an optical approach for modeling the quantum efficiency (QE) of back-illuminated CCD optical imagers for astronomy. Beyond its simplicity, it has the advantage of providing a complete fringing description for a real system. Standard thin-film calculations are extended by (a) considering the CCD itself as a thin film, and (b) treating the refractive index as complex. The QE is approximated as the fraction of the light neither transmitted nor reflected, which basically says that all absorbed photons produce e-h pairs and each photoproduced e or h is collected. Near-surface effects relevant to blue response must still be treated by standard semiconductor modeling methods. A simple analytic expression describes the QE of a CCD without antireflective (AR) coatings. With AR coatings the system is more easily described by transfer matrix methods. A two-layer AR coating is tuned to give a reasonable description of standard thinned CCDs, while the measured QE of prototype LBNL totally depleted thick CCDs is well described with no adjustable parameters. Application to the new LBNL CCDs indicates that these device swill have QE > 70 percent at (lambda) equals 1000 nm and negligible fringing in optical system faster than approximately f4.0.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.