imaging science to ubiquitous imaging

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    Imaging Science to Ubiquitous Imaging

    An image of a bird sometime in the future may be more than just a picture. It

    could also carry date and models that can produce the birds song, display its

    feeding or mating behavior, and describe its habitat and food preferences-

    Excerpts from the keynote address titled The Ubiquitous imaging, delivered at the

    International Congress of Imaging Science, 2006.

    Images have become ubiquitous part in our everyday life and culture. The

    application of images have become very much essential for the advancement of

    different fields ranging from science and technology, to biomedical research

    and clinical practice, to commerce and industry, to entertainment andadvertising, and to communication and education and so forth. Imaging science

    is an interdisciplinary field which requires knowledge of the disciplines of

    physics, engineering, chemistry, biology, and medicine. The rapid advances in

    imaging technology and techniques have led to the ever increasing growth of

    this field of study. It mainly deals with the detection, spatiotemporal

    localization, recording, display, visual observation, and measurement of object

    properties from images that are obtained from various imaging modalities.

    Properties of various objects of interests are studied by means of computer-

    based imaging systems that provide information needed for an understanding oftheir structure and functions. The main goal of imaging science is to develop an

    imaging system to yield images that are:

    1. more accurate representations of objects, by reducing blurring,

    distortions, and other artifacts.

    2. more reproducible, by reducing random fluctuations or noise without

    increasing observation time.

    3. complete, by producing three-dimensional images of three-dimensional

    objects, and by increasing the number of object properties that can be

    imaged.

    4. intelligent, by rendering and displaying them in a manner that makes the

    extraction, interpretation, and assimilation of information more accurate

    and reproducible.

    Subfields within imaging science include: image processing, 3D computer

    graphics, animations, atmospheric optics, astronomical imaging, digital

    imaging, color science, digital photography, holography, magnetic resonance

    imaging, optics, remote sensing, radar imaging, radiometry, ultrasound imaging,

    thermal imaging, visual perception, and various printing technologies.

    Dr. Bhabesh Deka

    Associate Professor

    Dept. of ECE

    Tezpur University

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    Various issues involved in imaging science1. Image-data acquisition

    Detection and angular/spatial/temporal localization of radiation or other

    property associated with the objects. It reflects in the design of the front-

    end hardware of any imaging device (e.g., the optical components of amicroscope) which, in turn, determines the sensitivity, resolution, and

    other quality characteristics of the imaging system.

    2. Image recovery and enhancement

    It involves the mathematical concepts and algorithms for producing an

    image from the acquired data (e.g., image reconstruction from

    projections, e.g. MRI, CT, etc.). Image enhancement aims to improve the

    quality (e.g., to sharpen edges and to reduce distortion, interference,

    artifacts, and image noise) of an image by using linear and non-linear

    image processing algorithms.3. Image recording and distribution

    It involves the mathematical algorithms for image compression, storage,

    retrieval and transmission.

    4. Image display/visualization

    Monochrome/colour; 2-D and 3-D display of images of real objects or of

    hypothetical objects and processes obtained from computer simulations

    based on mathematical models.

    5. Image observation and observer performance

    It involves the response characteristics of the eye-brain system and

    measures the ability of the observer to perform visual tasks, as well as

    strategies for the development of interactive, analytic, diagnostic, and

    adaptive software to facilitate observer performance, based on knowledge

    of human vision.

    6. Image analysis

    Segmentation and measurement; morphological analysis; pattern

    recognition; feature extraction; artificial intelligence

    7. Image evaluation

    Evaluation involves measures of image quality (maximum signal-to-

    noise-ratio, information content). Subjective evaluation of images byconsidering viewer performance. Social, cultural, aesthetic criteria, etc.

    Various Imaging modalitiesThere are many techniques through which an image can be generated.

    These are governed by different physical principles and sources of energy

    depending on the target applications ranging from simple photography to

    imaging of the living cells in a biological system. A brief classification of

    various imaging modalities can be made as follows.

    a) Microscopy- Light; UV; X-Ray; fluorescence; electron- & ion-beam, etc.

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    b) X-Ray imaging

    -Direct, screen-film, CT, etc.

    c) Magnetic resonance imaging

    -Conventional and spectroscopic

    d) Radionuclide imaging-Positron Emission Tomography (PET), Single photon emission

    computerized (SPECT) tomography

    e) Ultrasound

    -Material testing, biomedical

    f) Holography & pseudo-holography

    -Light, X-ray, gamma ray

    g) Telescopic imaging

    -X-ray, UV, Optical, Infra red, radio

    h) Computer generated-Image simulation/animation from mathematical models

    i) Graphic arts & sciences

    Drawing, etching, painting, photography/video, printing, television

    j) Computer vision

    -CCD arrays/robotics

    State-of-the-art applications of imaging scienceCurrently, imaging scientists around the globe are striving for the

    development of imaging systems that could interpret images acquired from

    different modalities: viz. images of natural scenes acquired by a camera, CT

    scans and other data obtained with biomedical imaging devices and aerial and

    satellite images acquired by remote sensing, etc. without any human

    intervention.

    Significant developments in the imaging technology have led to the

    development of high-tech cameras and other imaging devices. Also, a human

    observer can effortlessly make out the semantic understanding of various

    objects appearing in images, but, a machine cannot interpret the same via

    programming with meaning full accuracy. Therefore, it remains a major open

    challenge for the imaging scientists working in the related fields, including

    the automated medical diagnosis, the industrial automation, and the securityand surveillance to bridge this semantic gap.

    A few state-of-the-art applications of the imaging science are briefly

    mentioned below.

    1. Medical Image Analysis:

    Combining biomedical imaging science with

    computational modeling, it is possible to infer,

    noninvasively, the structural and functional

    properties of complex biological systems. For

    example, with the help of MRI it is possible todetect noninvasively the presence of tumors

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    and/or follow up the treatment after detection or studying the cardiac

    activity from a sequence of cardiac echo images.

    2. Computer Vision:

    Humans are naturally able to recognize the objects

    in a scene much better than computers. We caneffortlessly distinguish among a remarkable

    variety of objects, actions and interactions even in

    complex, cluttered scenes, e.g., recognizing a

    particular face in a crowd. In contrast,

    automatically interpreting such scenes using a

    computer is very difficult. The challenge here is to

    develop fully automatic computer vision algorithms for the interpretation

    of complex scenes. Examples: segmenting and tracking of moving

    objects in a video, recognizing dynamic textures (water, smoke, fire) in avideo, recognizing human activities in a video, and modeling and

    recognizing skill in surgical motion and video data.

    3. Computational Biology:

    A formidable challenge is the dissection of gene

    regulatory networks to show how eukaryotic cells

    coordinate and govern patterns of gene expression.

    Here the imaging scientist might develop graphical

    models to capture the statistical dependency

    structure among gene and protein expression

    values.

    The future of imaging science is very bright and challenging. We are already

    into the era of ubiquitous imaging, where imaging is everywhere yet

    unobtrusive. This is paralleled to the concept of ubiquitous computing where

    everything is intelligent and connected. There is a plenty of research scopes,

    in various domains including the machine vision, the biomedical imaging

    and analysis, and the digital imaging. Problems in machine vision, such as

    the automatic interpretation of shapes and other objects appearing in images,MR perfusion for assessing early solid tumor response to therapy, Diffusion

    Tensor Imaging with MR to delineate important nerve tracts in relation to

    brain tumors, etc. are some of the ongoing active research problems.

    [ Some of the contents of this article are written based on the paper that was presented

    at a colloquium entitled "Images of Science: Science of Images," organized by Albert V.

    Crewe, held January 13 and 14, 1992, at the National Academy of Sciences, Washington,

    DC. ]