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IBM Journal of Research and Development

Issue 5 • Date Sep. 1970

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Displaying Results 1 - 18 of 18
  • The Conference on Holography and the Computer

    Page(s): 476 - 477
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (337 KB)  

    Holography and modern digital computing technology represent two apparently unrelated aspects of information processing, both of which have matured rapidly in the last five years. Over the past few years, however, interactions between the two fields have become more apparent. To take note of these interactions, a Conference on Holography and the Computer was held in Houston, Texas, December 10–12, 1969, under the auspices of the Gulf Coast Section of the Optical Society of America and the IBM Corporation. The bulk of this issue of the IBM Journal of Research and Development is devoted to selected papers presented at that Conference. View full abstract»

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  • Some Effects of Fourier-domain Phase Quantization

    Page(s): 478 - 484
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    If the Fourier transform of a function g(x) is quantized, the function recovered by inverse transformation differs from g(x). By means of a biased limiter model, the effects of Fourier-domain phase quantization are studied. Amplitude information is assumed fully retained, while phase is quantized to N equally spaced levels. The recovered function is shown to consist of several different contributions, the relative strengths of which depend on the number of phase quantization levels. Several specific examples are given. Motivation and interpretation are presented in terms of digitally constructed holograms. View full abstract»

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  • Incoherent Filtering Using Kinoforms

    Page(s): 485 - 491
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (658 KB)  

    Incoherent optical filtering with the kinoform used as a filtering element is discussed. Kinoform theory is briefly reviewed and initial results with “fan” and correlation filters are presented. View full abstract»

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  • Acoustic Holography with Crossed Linear Arrays

    Page(s): 492 - 500
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (747 KB)  

    This paper is an analysis of how acoustic (or microwave) holography can be applied to large masses, such as natural bodies of water or the earth, by means of a linear array of microphones and by scanning with one or more transmitters to produce holographic phase shifts. This type of hologram, in which the phased array has a conical antenna pattern, is shown to be superior to the area hologram for computing images in the near field. Computer simulations are given of virtual holograms and image reconstructions for specular and diffuse reflectors; simulations are also made for the case of pulse holography, which yields genuine three-dimensional images with reduced highlight distortions. View full abstract»

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  • Structural-information Storage in Holograms

    Page(s): 501 - 508
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    The number of degrees of freedom, or structural-information content, of the object wave field recorded in a Leith-Upatnieks hologram is expressed in terms of the resolving power and dimensions of the recording medium, the coherence properties of the primary illumination and the position of the point reference source. In contrast with previous studies, the calculation does not involve the paraxial approximation. It is shown that of all holograms, the Fourier-transform hologram makes the most efficient use of available resolving power and coherence length. View full abstract»

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  • Laser Speckle and Its Elimination

    Page(s): 509 - 514
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (631 KB)  

    “Objective” speckle arises from the uneven illumination of an object with a multiplicity of waves that interfere at its surface. “Subjective” speckle arises at rough objects even if they are illuminated evenly by a single wave. The noise in the image is caused by the interference of the point-figures, which have random phases. Subjective speckle cannot be reduced except by extending the aperture. On the other hand the “objective” speckle in a plane, for instance in the plane of a transparency, can be reduced, and in the limit made invisible, by a special type of wide-angle illumination. This consists of a one-parameter family of plane waves, which can be produced by diffraction at a special grating, or two crossed gratings, close to the object plane. This makes it possible to produce multiple holograms, with the same insensitivity to dust or scratches as diffused holograms, but without any visible speckle in the reconstruction. View full abstract»

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  • A Theory of Granularity and Bleaching for Holographic Information Recording

    Page(s): 515 - 520
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (670 KB)  

    The Kelly three-stage model of photographic information recording is a mathematical model of black-and-white silver-halide film with granularity neglected. In the work reported here, the theory is extended for use in phase-holographic applications. Granularity effects are contained in the fourth and final stage, a two-dimensional, nonhomogeneous, filtered Poisson process. The output of this stage is a sample function of the random process that describes the pattern of modification of the emulsion. Formulas for the signal-to-noise ratio of a hologram and the optimum granular behavior are derived as examples of the use of the granularity model. View full abstract»

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  • Noise and Distortion in Photographic Data Storage

    Page(s): 521 - 526
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (599 KB)  

    Noise and distortion limit the usefulness of the photographic transparency as a data-storage medium. The noise, which tends to be multiplicative, derives from the random distribution of silver grains in the photographic image, as well as from thickness variations in the developed emulsion. Distortion, on the other hand, results from 1) the nonlinear relation between transmittance and exposure, 2) the finite width of the emulsion's point-spread function and 3) the existence of an adjacency-enhancement function. Although grain noise remains intrinsic and untreatable, nonlinear distortion—both global and local—may be treated by lowering the contrast of the exposure pattern or, preferably, by recording the data in the form of a phase-modulated carrier wave, as in holography. A solution to the remaining difficulty, namely, linear-global distortion, is obtained through the use of high-resolution, Lippmann-type emulsions. View full abstract»

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  • Characteristics of Dielectric Holograms

    Page(s): 527 - 532
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (619 KB)  

    The diffraction efficiency and signal-to-noise ratio for two-dimensional and volume diffuse-signal-beam holograms are calculated and experimentally determined. Calculations are based on the statistical properties of the signal beam, and exact integrals rather than series approximations are used. High signal-to-noise ratio and high diffraction efficiency are possible, with the peak calculated diffraction efficiency being 22% for two-dimensional and 64% for volume holograms. The experimentally achieved efficiencies were 12% for two-dimensional and 36% for volume holograms. View full abstract»

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  • High-efficiency Phase-hologram Gratings

    Page(s): 533 - 538
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (618 KB)  

    Optimum conditions for the generation of high-efficiency hologram gratings are presented. The most efficient phase holograms were obtained for exposures 10 to 20 times larger than those for optimally exposed amplitude holograms. Hologram gratings produced on Agfa Gevaert 8 E 70 recording plates diffracted 40 percent of the incident radiation into the holographic image. This experimentally obtained efficiency is 60 percent of the theoretical maximum for a hologram with a geometric parameter Q of 4.6. View full abstract»

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  • A Statistical Mechanical Approach to Systems Analysis

    Page(s): 539 - 547
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (778 KB)  

    The maximum entropy principle is used as the criterion for calculating the equilibrium state probabilities of a queuing or network system in which service rates are exponentially distributed. A configuration-independent partition function is given as the solution to this network problem; from this function the important properties of the system may be derived. Simple and well known examples are used to illustrate the method. A phenomenon similar to the phase transition of statistical mechanics is observed in a queuing model. View full abstract»

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  • Moment Normalization of Handprinted Characters

    Page(s): 548 - 557
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (919 KB)  

    Handprinted characters can be made more uniform in appearance than the as-written version if an appropriate linear transformation is performed on each input pattern. The transformation can be implemented electronically by programming a flying-spot raster-scanner to scan at specified angles rather than only along specified axes. Alternatively, curve-follower normalization can be achieved by transforming the coordinate waveforms in a linear combining network. Second-order moments of the pattern are convenient properties to use in specifying the transformation. By mapping the original pattern into one having a scalar moment matrix all linear pattern variations can be removed. Comparison experiments with three sets of handprinted numerals showed that error rates were reduced by integral factors if the patterns were normalized before scanning for recognition. View full abstract»

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  • Performance Equivalence of Suboptimally Controlled Nonlinear Systems

    Page(s): 558 - 562
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    A procedure is described that shows how a technique used to develop performance bounds for a large class of nonlinear dynamic systems with state-dependent control policies can be extended to determine whether a nonlinear system can be controlled so that it is at least “performance equivalent” to an associated optimally controlled linear system. A procedure for generating one or more control policies to attain this equivalence is also discussed. An example illustrates the fact that more than one control policy may satisfy the equivalence criterion. View full abstract»

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  • Concurrent Error Detection for Group Look-ahead Binary Adders

    Page(s): 563 - 573
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1016 KB)  

    This paper presents an evaluation of the relative merits of two schemes for performing concurrent error detection in group look-ahead adders. One of the schemes is a residue mod 3 check and the other is a parity prediction check. The Boolean statements that define the operation of group look-ahead adders, concurrent error detection and the Boolean difference serve as background for interpreting the results of the study. The Boolean difference is a tool for calculating the “coverage” of elements in a logical network by error-checking schemes. Some weaknesses in prior studies of coverage calculation are brought to light. Tables showing the number of circuit elements in the various portions of adder and error-checking circuits are given. It is shown that the residue mod 3 check adder is not economical unless the addition operands are already provided with the mod 3 check bits. Thus, a worthwhile comparison of the checking schemes should not proceed without considering the overall data flow checking strategy. In machine organizations with three or more data transfer checks, the parity-checked adder seems to offer a cost advantage. View full abstract»

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  • Recent Papers by IBM Authors

    Page(s): 574 - 578
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (495 KB)  

    Reprints of the papers listed here may usually be obtained most efficiently by writing directly to the authors. The authors' IBM divisions and locations are identified as follows: ASDD is the Advanced Systems Development Division; CD, Components Division; DPD, Data Processing Division; FED, Field Engineering Division; FSD, Federal Systems Division; GSD, General Systems Division; RES, Research Division; SDD, Systems Development Division and SMD, Systems Manufacturing Division. East Fishkill, Endicott, Kingston, Owego, Poughkeepsie, White Plains, and Yorktown Heights are in New York; Los Gatos, Palo Alto, and San Jose, California; Boulder, Colorado; Gaithersburg, Maryland; Cambridge, Massachusetts; Rochester, Minnesota; Huntsville, Alabama; Burlington, Vermont; Raleigh and Research Triangle Park, North Carolina; Vienna, Austria; Boeblingen, Germany; and Uithoorn, Netherlands. Papers are listed alphabetically by name of journal. Journals View full abstract»

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  • Patents Recently Issued to IBM Inventors

    Page(s): 579 - 580
    Save to Project icon | PDF file iconPDF (291 KB)  
    Freely Available from IEEE
  • Authors

    Page(s): 581 - 583
    Save to Project icon | PDF file iconPDF (457 KB)  
    Freely Available from IEEE
  • Contents of previous two issues

    Page(s): 584
    Save to Project icon | PDF file iconPDF (208 KB)  
    Freely Available from IEEE

Aims & Scope

The IBM Journal of Research and Development is a peer-reviewed technical journal, published bimonthly, which features the work of authors in the science, technology and engineering of information systems.

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Meet Our Editors

Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center