Jan. P. Allebach | |
---|---|
Alma mater | Princeton University, University of Delaware |
Known for | Contributions to imaging science |
Awards | Member, National Academy of Engineering; 2004 Electronic Imaging Scientist of the Year; 2013 Daniel E. Noble Award for Emerging Technologies; 2016 Edwin H. Land Medal; Society for Imaging Science and Technology Honorary Membership; Fellow, National Academy of Inventors; 2020 Johann Gutenberg Prize |
Scientific career | |
Fields | Electronic imaging systems, image capture and rendering, color image processing, image quality, document imaging |
Institutions | Purdue University, School of Electrical and Computer Engineering |
Thesis | Digital - Optical Signal Processing |
Doctoral advisor | Bede Liu |
Jan P. Allebach is an American engineer, educator and researcher known for contributions to imaging science including halftoning, digital image processing, color management, visual perception, and image quality. He is Distinguished Professor Emeritus of Electrical and Computer Engineering at Purdue University. [1]
Allebach earned a Bachelor of Science in Electrical Engineering from the University of Delaware in 1972, and a MSE and PhD in Electrical Engineering from Princeton University in 1975 and 1976 respectively. After receiving his PhD, he joined the Department of Electrical Engineering at the University of Delaware. In 1983, Allebach accepted a position with the School of Electrical Engineering at Purdue University. After more than 40 years of service, Allebach retired from the university in 2024.
Allebach is known for his contributions to digital halftoning, which is the process of rendering continuous-tone images with printing or display devices that can only directly represent a relatively small number of different output levels. Digital halftoning uses algorithms to generate a pattern of textures that have the appearance of continuous tones when perceived by the viewer at the appropriate distance, given the limited ability of the human visual system to resolve high spatial frequencies. In 1977 Allebach published a paper that provided a framework for understanding and developing screening-based digital halftoning algorithms. [2] In 1979 he reported on the very first algorithm for computer-aided design of dither matrices. [3] Such search-based methods are now routinely used for the design of halftone screens. After 1980 Allebach turned his attention elsewhere due to the lack of practical applications at that time for his halftoning work. He continued his investigation of the synthesis of digital diffractive elements (holograms). During this time Allebach developed a novel search-based algorithm for the design of digital diffractive elements that he called Direct Binary Search or DBS. [4] Building on this research, in 1992 Allebach and his student, Mostafa Analoui, reported the invention of the Direct Binary Search (DBS) digital halftoning algorithm. [5] In the context of halftoning, DBS is a search-based algorithm that minimizes the total-squared error between the perceived continuous-tone image and the perceived halftone image. A key aspect of the algorithm is a very efficient mechanism for evaluating the effect on the error metric of trial changes to the halftone image. The model for the human visual system that is used to generate the perceived images is based on filtering the input image with a point-spread function that is derived from psychophysical measurements of the spatial contrast sensitivity of the human viewer. Eight years of further work led to the seminal publication on DBS by Allebach and his student, David Lieberman, in 2000. [6] DBS is an iterative search-based algorithm, and thus is not practical for implementation as an embedded application in a printer. It is used as a tool for the design of other halftoning algorithms implemented in many printers.
In 2004, Allebach and his student, Pingshan Li, reported on the invention of the tone-dependent error diffusion (TDED) halftoning algorithm. [7] The TDED halftoning algorithm is developed via an off-line process in which the error diffusion weights and thresholds are trained level-by-level to yield a halftone image at each level for which the 2D Fourier spectrum matches that produced by DBS. When applied to pictorial content, what results is an image that at a microscopic scale has colorant dots in locations that do not match the DBS reference image, but which at a macroscopic scale, has effectively the same visual quality as the DBS reference image. The TDED halftoning algorithm generates high quality halftone images with greater computational efficiency than the DBS halftoning algorithm. HP Inc. is assigned the patent for Tone Dependent Error Diffusion. [8]
Allebach has extended his work with digital halftoning to the printing of color images with the use of a novel spatio-chromatic model for the human visual system, [9] as well as to 3D printing. [10]
In 2014, Allebach was elected into the National Academy of Engineering for the development of algorithms for digital image half-toning for imaging and printing.
In 2004, Allebach was named Electronic Imaging Scientist of the Year by the Society for Imaging Science and Technology (IS&T) “for his leadership as an educator and researcher in the electronic imaging community, for his contributions to image halftoning, color image processing, and the use of our understanding of the human visual system in image processing.” [11] Allebach was inducted into the National Academy of Engineering in 2014 “for development of algorithms for digital image half-toning for imaging and printing.” [12] He is a Fellow of IEEE, [13] IS&T, [14] SPIE, [15] and the National Academy of Inventors. [16] In 2007, Allebach was awarded Honorary Membership from IS&T. [17] In 2013, Allebach was honored with the IEEE’s Daniel E. Noble Award for Emerging Technologies, [18] and in 2016, with the Edwin H. Land Medal jointly awarded by the Optical Society of America (OSA) and IS&T. [19] In 2020, Allebach received the Johann Gutenberg Prize from IS&T.
In computer graphics and digital photography, a raster graphic represents a two-dimensional picture as a rectangular matrix or grid of pixels, viewable via a computer display, paper, or other display medium. A raster image is technically characterized by the width and height of the image in pixels and by the number of bits per pixel. Raster images are stored in image files with varying dissemination, production, generation, and acquisition formats.
Halftone is the reprographic technique that simulates continuous-tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect. "Halftone" can also be used to refer specifically to the image that is produced by this process.
Digital image processing is the use of a digital computer to process digital images through an algorithm. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing. It allows a much wider range of algorithms to be applied to the input data and can avoid problems such as the build-up of noise and distortion during processing. Since images are defined over two dimensions digital image processing may be modeled in the form of multidimensional systems. The generation and development of digital image processing are mainly affected by three factors: first, the development of computers; second, the development of mathematics ; third, the demand for a wide range of applications in environment, agriculture, military, industry and medical science has increased.
A binary image is one that consists of pixels that can have one of exactly two colors, usually black and white. Binary images are also called bi-level or two-level, Pixelart made of two colours is often referred to as 1-Bit or 1bit. This means that each pixel is stored as a single bit—i.e., a 0 or 1. The names black-and-white, B&W, monochrome or monochromatic are often used for this concept, but may also designate any images that have only one sample per pixel, such as grayscale images. In Photoshop parlance, a binary image is the same as an image in "Bitmap" mode.
Lenna is a standard test image used in the field of digital image processing, starting in 1973. It is a picture of the Swedish model Lena Forsén, shot by photographer Dwight Hooker and cropped from the centerfold of the November 1972 issue of Playboy magazine. The image has attracted controversy in recent years because of its subject matter, and many journals have deemed it inappropriate and discouraged its use, while others have banned it from publication outright. Forsén herself has called for it to be retired, saying "It's time I retired from tech."
Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is often one of the last stages of mastering audio to a CD.
Robert M. Haralick is Distinguished Professor in Computer Science at Graduate Center of the City University of New York (CUNY). Haralick is one of the leading figures in computer vision, pattern recognition, and image analysis. He is a Fellow of the Institute of Electrical and Electronics Engineers (IEEE) and a Fellow and past president of the International Association for Pattern Recognition. Professor Haralick is the King-Sun Fu Prize winner of 2016, "for contributions in image analysis, including remote sensing, texture analysis, mathematical morphology, consistent labeling, and system performance evaluation".
Thomas Shi-Tao Huang was a Chinese-born American computer scientist, electrical engineer, and writer. He was a researcher and professor emeritus at the University of Illinois at Urbana-Champaign (UIUC). Huang was one of the leading figures in computer vision, pattern recognition and human computer interaction.
Error diffusion is a type of halftoning in which the quantization residual is distributed to neighboring pixels that have not yet been processed. Its main use is to convert a multi-level image into a binary image, though it has other applications.
Image quality can refer to the level of accuracy with which different imaging systems capture, process, store, compress, transmit and display the signals that form an image. Another definition refers to image quality as "the weighted combination of all of the visually significant attributes of an image". The difference between the two definitions is that one focuses on the characteristics of signal processing in different imaging systems and the latter on the perceptual assessments that make an image pleasant for human viewers.
Ernest Lenard (Ernie) Hall, PhD, PE, is Professor Emeritus of Mechanical Engineering and Computer Science in the School of Dynamic Systems in the College of Engineering and Applied Science at the University of Cincinnati. He was also the Paul E. Geier Professor of Robotics in the Department of Mechanical Engineering at the University of Cincinnati. He has also held joint appointments at the University of Cincinnati with the Department of Electrical and Computer Engineering and Computer Science. He regularly collaborates with faculty and students in other colleges at University of Cincinnati, as well as civic groups, including the FIRST Lego League, the Ohio Academy of Science, and the Society of Manufacturing Engineers. While consulting with the Oak Ridge National Laboratory, he became interested in efforts to make useful robots for some of the dangerous tasks encountered by the Department of Energy, Department of Defense and NASA. He noted the importance of combining image processing algorithms with manipulators and controller to build intelligent robots, especially in automatic target recognition. He has founded and has co-chaired an annual conference on Intelligent Robots and Computer Vision for the past 25 years to provide a forum for new innovations in this field. He sits as the first Paul. E. Geier Professor of Robotics at the University of Cincinnati. At the University of Cincinnati, he established the Center for Robotics Research, which encourages robotics activities in industry, medicine, defense, and even at home with projects like a robot lawn mower. He also founded the UC Robot Team that has participated in the Intelligent Ground Vehicle Competition for the past 15 years and the DARPA Grand Challenge in 2005 and 2007. He has also served as a judge for the Cincinnati FIRST Lego League for two years and has been called the Woodie Flowers of Cincinnati for giving the Gracious Professionalism award. In 2006, Ernest L. Hall won the Grand Prize in the "Made in Express" contest sponsored by Microsoft. His entry for the contest was an all-terrain self-maneuverable robot developed using Microsoft Visual Studio Express. He donated the $10,000 cash prize from the contest back to the University of Cincinnati to support robotics.
Leah H. Jamieson is an American engineering educator, currently the Ransburg Distinguished Professor of Electrical and Computer Engineering at Purdue University. Jamieson was a co-founder of the Engineering Projects in Community Service program (EPICS), a multi-university engineering design program that operates in a service-learning context. She is a recipient of the Gordon Prize. From 2006-2017, she served as the John A. Edwardson Dean of Engineering at Purdue.
Alan Conrad Bovik is an American engineer, vision scientist, and educator. He is a professor at the University of Texas at Austin (UT-Austin), where he holds the Cockrell Family Regents Endowed Chair in the Cockrell School of Engineering and is Director of the Laboratory for Image and Video Engineering (LIVE). He is a faculty member in the UT-Austin Department of Electrical and Computer Engineering, the Machine Learning Laboratory, the Institute for Neuroscience, and the Wireless Networking and Communications Group.
Nasir Ahmed is an Indian-American electrical engineer and computer scientist. He is Professor Emeritus of Electrical and Computer Engineering at University of New Mexico (UNM). He is best known for inventing the discrete cosine transform (DCT) in the early 1970s. The DCT is the most widely used data compression transformation, the basis for most digital media standards and commonly used in digital signal processing. He also described the discrete sine transform (DST), which is related to the DCT.
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Edmund Y. Lam is a Chinese professor and associate dean of engineering at the University of Hong Kong.
Fauzia Ahmad is an associate professor of electrical engineering at Temple University. Her research considers statistical signal processing and ultrasonic guided wave structural health monitoring. She serves as associate editor of the IEEE Transactions on Aerospace and Electronic Systems and Geoscience and Remote Sensing Society. She is a Fellow of the Institute of Electrical and Electronics Engineers and SPIE.
A copy detection pattern (CDP) or graphical code is a small random or pseudo-random digital image which is printed on documents, labels or products for counterfeit detection. Authentication is made by scanning the printed CDP using an image scanner or mobile phone camera. It is possible to store additional product-specific data into the CDP that will be decoded during the scanning process. A CDP can also be inserted into a 2D barcode to facilitate smartphone authentication and to connect with traceability data.
Audrey K. Ellerbee Bowden is an American engineer and Dorothy J. Wingfield Phillips Chancellor's Faculty Fellow at Vanderbilt University, as well as an Associate Professor of Biomedical Engineering and Electrical Engineering. She is a Fellow of Optica, the American Institute for Medical and Biological Engineering and the International Society for Optics and Photonics (SPIE).
Farhan A. Baqai is a Senior Research Manager at Apple, working on camera technology. He was elevated to a fellow of the IEEE in 2023 for "contributions in leadership in digital camera image processing". A graduate of Purdue University, Baqai received his masters and doctoral degrees in 1997 and 2000 respectively; his doctoral advisor was Jan Philip Allebach. In addition to his work at Apple, Baqai formerly worked for Sony and Xerox. His positions with these companies includes work on the iPhone, Mac, iPad and CyberShot cameras.
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