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Guest Editors’ Introduction: DIGITAL IMAGING

Humans interact with each other pled device (CCD) technologies, image sen- and with the computer via audio and visual sor chips based on CMOS imaging technolo- clues. The user has favorably received the gies are expected to capture a notable fraction incorporation of audio capabilities in person- of the application space. Micro has already al computers, which began in the early 1980s. reviewed CMOS imaging technologies (see E. Today, audio capabilities are standard features Fossum, “Digital Camera System on a Chip,” in personal computers. Visual information IEEE Micro, May-June 1998, p. 8-15), and capture, display, transmission, and storage, will we do not repeat it here. The Proceedings of be the next leap in improved human-comput- the International Solid-State Circuits Confer- er interactions. In this special issue of IEEE ence (ISSCC) provide recent advances in image Micro, we feature digital imaging, with empha- sensor technologies. sis on still digital imaging for consumers. Our next article, by J. Adams, K. Parulski, Our articles span the gamut of image cap- and K. Spaulding of Kodak, reviews one of ture, manipulation, and display. The first arti- the most important aspects of digital image H.-S. Philip Wong cle by S. Kawamura of Olympus describes an capture—the process of converting the raw example of the system architecture of a con- captured color pixels into a pleasing image IBM T.J. Watson sumer digital still camera. The sales of digital that retains its color fidelity. A mosaic of color still cameras topped two million units in 1997 filter materials is placed in front of the solid- Research Center and should reach four million units at the end state imaging chip to encode color informa- of 1998. Industry projections invariably predict tion into the pixel response. While each pixel sales of about 10 million units by the year 2000. on the chip contains only a single color (red, Albert J.P. With the proliferation of digital still cam- green, blue, or some combinations of the pri- eras, direct digital imaging is fast replacing the mary and complementary colors), the final Theuwissen scanning of conventional silver-halide pho- output must present the full tricolor (RGB) tographs as the preferred means to input a still information. Philips Imaging image into a computer. Both consumer and Adams and colleagues detail the processes professional use of the digital still camera con- of color filter array interpolation, color cali- Technology tinues to increase. With most digital still cam- bration, anti-aliasing, infrared rejection, and eras offering instant preview and playback of white-point correction. The article provides the captured image, the user is lured by the an example of how the components of the instant nature of digital capture. Instant pre- color-processing chain are assembled in a view and playback enable the user to share the commercially available digital still camera. picture instantly with others as well as to As the use of digital still images proliferates, ensure that the picture taken has the intended creators and owners need to protect their effect (and to retake the picture if necessary). rights and be able to authenticate the owner- The proliferation of the World Wide Web pro- ship of digital images. This may become a cor- vides a new avenue for distributing pho- nerstone for the wide dissemination and use tographs. People can conveniently and of digital images. M. Yeung, B.L. Yeo, and M. instantly distribute pictures of weddings and Holliman of Intel survey the emerging field corporate functions to a variety of destinations. of digital watermarking for image protection Although Kawamura describes a digital still and authentication. We expect that digital camera based on conventional charged-cou- watermarking will become a standard feature

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in all future image capture, transmission, and viewing technologies. As the use of digital still Finally, image display is an indispensable link in the chain from image capture to user. images proliferates, creators P. Alt of IBM provides an overview of display technologies with an emphasis on the con- and owners need to protect sumer application arena. While there are a variety of display technologies, it is most infor- their rights and be able to mative to examine the display phase space in a plot of pixel count versus image diagonal, as authenticate the ownership of the article shows. Recent display prototypes have begun to reach into the limiting resolu- digital images. tion of the human visual system. Alt describes displays for small, handheld gadgets; head- mounted displays; large projection displays; and typical flat-panel, active-matrix amor- Lehigh University, Bethlehem, Pennsylvania. phous silicon, thin-film-transistor liquid crys- He serves on the ISSCC and the IEDM tal displays (AMLCDs). He points out that (International Electron Devices Meeting) pro- there are no technology barriers for a device gram committees and is a Senior Member of that combines a camera, an image processor, the IEEE Electron Devices Society. and a display with photographic quality in a shirt-pocket-size package. Albert J.P. Theuwissen is the department e thank the authors and many review- head of the Imaging Devices Division at Wers who spent time writing and review- Philips Imaging Technology in Eindhoven, ing the articles published here. As the the Netherlands, which includes solid-state application of images in the computer gain imaging activities. His previous work at the increasing importance, we expect to be return- ESAT Laboratory of the Catholic University ing to this theme in the not too distant future, of Leuven, Belgium, focused on transparent with emphases on other aspects of digital gate electrode technology for linear CCD imaging not covered in this special issue. MICRO image sensors. Theuwissen received the degree in electrical engineering and his PhD from the Catholic University of Leuven. He is the H.-S. Philip Wong is a manager of the Logic author or coauthor of various technical papers Devices and Applications Group at the IBM in the solid-state imaging field and holds sev- Thomas J. Watson Research Center, York- eral patents. He served as coeditor of the IEEE town Heights, New York. He has been work- Transactions on Electron Devices special issues ing on exploratory devices, processes, and on solid-state image sensors in May 1991 and applications for sub-50-nm CMOS tech- October 1997. He also acted as general chair nologies. His recent work included simula- of the 1997 IEEE Workshop on Charge-Cou- tions of discrete, random dopant fluctuation pled Devices and Advanced Image Sensors. effects in small MOSFETs; the physics and He is a member of the IEEE Electron Devices technology of sub-50-nm double-gate and Society and SPIE (Society of Photo-Optical back-gate MOSFETs; CMOS projection dis- Instrumentation Engineers). plays; and CMOS image sensors. Earlier, he had worked on the design, fabrication, and characterization of a high-resolution, high- color-fidelity CCD image scanner for artwork archiving. These scanners are now in use at several premier museums, including the Direct questions concerning this special issue National Gallery of Art (Washington, D.C.) to Philip Wong, IBM T.J. Watson Research and the Vatican Library. Wong received the Center, PO Box 218, Yorktown Heights, NY PhD degree in electrical engineering from 10598; [email protected].

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