Electronic Image Processing Research Articles

Manipulated radiographic material--capability and risk for the forensic consultant?

As interest is being increasingly focused on the digital processing of radiographs for identification of the deceased, the benefits and risks of electronic image processing are presented. With digitization of all kinds of radiographic equipment being on the increase and image processing personal computers being readily accessible, increasing quantities of manipulated radiographic material are to be expected in the future. This potential risk is meanwhile highlighted from the legal aspect.

Accuracy of Specification of Dose Reference Values and Detail Detectability by a Statistical Phantom

The introduction of modern electronic image sensors and image processing techniques has lightened the link between dose and image quality. A properly exposed image is made with any dose, even at the cost of image quality. Therefore a test is needed to maintain minimum 'reference' image quality when determining reference doses. The underlying theory of image quality and detail detectability is outlined. Reference image quality can be expressed in terms of a minimum signal-to-noise ratio (SNR) of a given detail The accuracy of detail detectability testing with the statistical phantom for a storage phosphor system has been investigated For four observers, each with 50 answers, ROC curves were calculated by the ROCFIT program. A simplified score-sum method of evaluation recommended for the ALVIM statistical phantom is then employ ed and the accuracy of both methods is evaluated It can be shown that detail detectability tests using a statistical phantom are suitable for the needs of quality assurance from constancy to acceptance testing. The accuracy of ROC tests would he sufficient to specify sensitivity values for modern imaging systems by measuring the dose required for visualising a detail.

Latitude expansion by electronic image processing : Murata, Y.; Mochiki, K.; Taguchi, A.; Suzuoki, Z.; Takaura, K.; Ohkuma, T. Neutron Radiography (4) Proceedings of the 4th World Conference, San Francisco, California (United States), 10–16 May 1992. pp. 503–510. Edited by J.P. Barton. Gordon and Breach Science Publishers (1993) ISBN 2-88124-624-9

Latitude expansion by electronic image processing : Murata, Y.; Mochiki, K.; Taguchi, A.; Suzuoki, Z.; Takaura, K.; Ohkuma, T. Neutron Radiography (4) Proceedings of the 4th World Conference, San Francisco, California (United States), 10–16 May 1992. pp. 503–510. Edited by J.P. Barton. Gordon and Breach Science Publishers (1993) ISBN 2-88124-624-9

Bedknobs and Broomsticks: Using a Distressed Work Print as a Color Master Positive

A 25-year-old, color-faded, heavily scratched 35mm Eastmancolor positive work print trim was the only existing preprint for one sequence of the restored special edition of Walt Disney Pictures 1971 feature film Bedknobs and Broomsticks. The objective was to resurrect the degraded color imagery to a 35mm internegative of sufficient integrity so that this sequence could be reasonably integrated with original camera negative. Liquid gate duplication of the master print to a color-corrected internegative yielded an improved element for digital scanning. Electronic image processing permitted further image reconstruction before the data were output as an analog motion picture negative suitable for conventional motion picture laboratory printing.

Nondestructive testing by ESPI and quasi phase shift gradient technique

A new nondestructive testing (NDT) technique, which is based on Electronic Speckle Pattern Interferometry (ESPI) and digital image processing with quasi phase shift and gradient technique, is presented. A simple phase reduction algorithm is developed, which replaced an accurate phase shifter. Compared with other phase shift techniques, this method is insensitive to environmental vibration and air disturbance, has visible procedures and results allows the object to move slowly during the inspection procedure, does not need phase unwrapping, and has a quick image processing speed. As an application, this NDT technique is used to detect defects in composite materials and the resulting deformation phase gradient image shows a better visual effect than normal ESPI.

TV‐shearography for measuring 3D‐strains

AbstractThe shearographic interferometry is employed as a nondestructive full field, optical testing and measuring method without contact. Fringes of constant strain (so called isotase, tasis (Greek)=strain) can he observed in real time on the surface of the investigated machine parts and structures of any material and are represented by the shearogram. Using shearography two states of “deformation are recorded by doubly exposing a Holotesl film in an ordinary camera or stored by an electronic image processing system. In the lens of the camera a shearing element inside or outside the focus is integrated or the lateral Michelson shearing interferometer is used. Rigid body motions of the object are not recorded. Local deformation irregularities caused by a defect under or on the surface of the specimen create, strain concentrations; the homogeneous surrounding is poorly superimposed by an interference pattern. The shearogram shows dark and bright fringes which are the functions of the displacement derivative. The holographic interferometry measures the out of plane deformations directly. Terms of the out of plane strain can be determined by the shearographic method as well as the in plane strain fringes which are described in the following.

Weld bead placement system for multipass welding

A transputer-based laser triangulation vision system has been developed for use with automated tungsten inert gas (TIG) welding. The object of the vision system is to provide real-time seam tracking and weld bead profile monitoring at all stages of the multipass welding process to allow control of the welding process. The laser triangulation technique was used to measure the 3-D geometric profile in a single pass. The electronic image processing hardware was based on a vision system developed in-house by the University of Liverpool called the Transputer Image Processing System (TIPS). A prototype sensor system has been developed and used to track the position of the two corner positions of a V-preparation joint and to measure the weld profile between these positions as the multipass welding progresses. The concept and the design of the system are presented.

Spatial multiplexing technique for interrogation of interferometric optical fibre sensor arrays

A new spatial multiplexing technique for interferometric optical fibre sensors is reported. It makes use of digital electronic image processing techniques to greatly reduce the number of fibre optical devices in the network system. The basic system set-up and phase-retrieval algorithm are described and a computer simulation of system performance is presented.

Electronic light microscopy: present capabilities and future prospects

Electronic light microscopy involves the combination of microscopic techniques with electronic imaging and digital image processing, resulting in dramatic improvements in image quality and ease of quantitative analysis. In this review, after a brief definition of digital images and a discussion of the sampling requirements for the accurate digital recording of optical images, I discuss the three most important imaging modalities in electronic light microscopy--video-enhanced contrast microscopy, digital fluorescence microscopy and confocal scanning microscopy--considering their capabilities, their applications, and recent developments that will increase their potential. Video-enhanced contrast microscopy permits the clear visualisation and real-time dynamic recording of minute objects such as microtubules, vesicles and colloidal gold particles, an order of magnitude smaller than the resolution limit of the light microscope. It has revolutionised the study of cellular motility, and permits the quantitative tracking of organelles and gold-labelled membrane bound proteins. In combination with the technique of optical trapping (optical tweezers), it permits exquisitely sensitive force and distance measurements to be made on motor proteins. Digital fluorescence microscopy enables low-light-level imaging of fluorescently labelled specimens. Recent progress has involved improvements in cameras, fluorescent probes and fluorescent filter sets, particularly multiple bandpass dichroic mirrors, and developments in multiparameter imaging, which is becoming particularly important for in situ hybridisation studies and automated image cytometry, fluorescence ratio imaging, and time-resolved fluorescence. As software improves and small computers become more powerful, computational techniques for out-of-focus blur deconvolution and image restoration are becoming increasingly important. Confocal microscopy permits convenient, high-resolution, non-invasive, blur-free optical sectioning and 3D image acquisition, but suffers from a number of limitations. I discuss advances in confocal techniques that address the problems of temporal resolution, spherical and chromatic aberration, wavelength flexibility and cross-talk between fluorescent channels, and describe new optics to enhance axial resolution and the use of two-photon excitation to reduce photobleaching. Finally, I consider the desirability of establishing a digital image database, the BioImage database, which would permit the archival storage of, and public Internet access to, multidimensional image data from all forms of biological microscopy. Submission of images to the BioImage database would be made in coordination with the scientific publication of research results based upon these data.(ABSTRACT TRUNCATED AT 400 WORDS)

Number and size spectra of non-myelinated axons of human premolars

The aim of this study was to determine the number and size of apical non-myelinated (C) axons of healthy human premolars. The material was derived from a large collection of specimens prepared for a previous quantitative investigation on the myelinated (A) axons of human premolars. A total of 16 teeth (six maxillary first and five each of mandibular first and second premolars), removed from adolescents for orthodontic reasons, were used. Root discs of about 0.6 mm thickness were prepared at about 2 mm cervical to the root apex and processed for light and electron microscopy. The number of non-myelinated axons was determined by taking a total census of such fibres that could be identified and reconstructed by standardized composite electron micrographs from each root disc. The measurement of axons was done on a statistically representative sample of axons (n = 1810) using an electronic image processing unit. The 16 teeth had an average of 2000 +/- 1023 non-myelinated axons at the juxta-apical level (range 534-3912). The average diameter of the non-myelinated axons was found to be 0.5 +/- 0.4 microns (range 0.05-2.4 microns).

An alternative method of optoelectronic color analysis for slides

In spite of the remarkable progress in electronic imaging the conventional color film is still one of the best media for the primary shooting of images at high spatial resolution. Therefore, it is an important source of high graded images for electronic image processing. This paper presents a method for a complete color correction in electronic slide scanning. The method is based on the color signals delivered from a conventional RGB slide scanner. These signals, however, do not represent exact color values as the scanner is not capable of perceiving color as is the human eye. Contrary to other methods, in the following approach the primary signals are used to determine the spectral color stimulus via the color pigment concentrations in every pixel. Using a known color stimulus allows the calculation of correct RGB color values. The sufficiently accurate numerical modeling of the scanning process is essential for this method. As a considerable long calculation time is needed if the algorithm is implemented on workstations presently available, multidimensional tables used in combination with linear interpolations permit the time for correction to be reduced significantly.

Verifying keyed medical research data.

Although diminished use of double keying for the verification of keyed medical research data has occurred, there are no published data that demonstrate the existence of equivalent or better replacement. The simple replacement of double keying with visual comparison is not recommended because visual comparison is too susceptible to the transient energy levels of the individual who makes the comparison. Some system design innovations applicable in specific situations allow elimination of verification by providing nearly equivalent or possibly even superior data quality assurance opportunities. These alternatives include designs where one replaces the transcription to data forms by direct keying from original source documents coupled with extensive quality reviews, and designs with direct data base input of data subjected to intense automated consistency checking and immediate analytic use. In both cases, the absence of keyed data verification places a greater burden for data quality assurance on other subsystems, such as quality review, and ultimately the analytic process. Data entry systems based on new technologies, such as tablet computers, electronic image processing, and voice input, will require similar considerations for assuring data quality.

Contrast enhancement as an aid to interpretation in digital subtraction radiography

An initial study was performed to demonstrate the feasibility of pseudocolor contrast enhancement technique in digital subtraction radiography (DSR). DSR is an electronic image processing technique that has been shown to be of greater diagnostic value in the detection of small periodontal bone lesions than conventional radiography. Pseudocolor enhancement involves selectively assigning a unique color to each shade of gray present in a black-and-white subtracted image. Two image enhancement techniques were developed and tested in a phantom system consisting of extracted teeth set in blocks of plaster mixed with sawdust to simulate trabecular bone. It was found that experimentally induced periodontal lesions were more readily detected by the average clinician in both types of enhanced subtraction images than unenhanced subtractions. Furthermore, both enhancement techniques were of significantly greater diagnostic value for lesions smaller than 1.0 mm ( p < 0.001). The technique that colored an isolated area of interest was significantly more diagnostic at all depths tested ( p < 0.001 at 0.5 and 1.0 mm, and p < 0.05 at 0.5 mm). Contrast enhancement may be a significant aid to the average clinician for the interpretation of DSR and the detection of small periodontal defects.

Quantitative analysis of leaf area loss caused by insects: A method combining photography and electronic image processing

AbstractA method was developed to quantify leaf area reduction in the grey alder (Alnus incana L.) due to herbivorous insects. In the field the leaves are detached, placed on a white surface and photographed. Only 10 min per sample (40 to 80 leaves) are required for this step. Further processing is independent of the sampling day. On the photographic prints the missing outlines of the leaves are reconstructed. The prints are then scanned with a video camera and processed with an Image Processing System (IPS). The amount of time required for this analysis is between 30 and 55 min per sample, depending on the amount of insect damage to the leaves. Measurement error was less than 2 % of the total leaf area. This method has possible applications for quantifying leaf mine size and necrotic tissue.ZusammenfassungQuantitative Analyse von Blattflächenverlusten durch Insektenfraß: Eine Kombination von Fotografie und elektronischer BildanalyseEine Methode zur Quantifizierung der von herbivoren Insekten verursachten Reduktion der Fläche an Blättern der Grauerle (Alnus incana L.) wurde entwickelt. Beschädigte Blätter wurden von den Bäumen entfernt und direkt im Feld auf eine weiße Fläche gelegt und fotografiert. Für diesen Schritt wurden je Probe (40 bis 80 Blätter) 10 min benötigt. Alle folgenden Schritte der Analyse sind unabhängig vom Termin der Probenahme. Auf den Schwarzweiß‐Vergrößerungen wurden an Stellen mit Fraßschäden am Blattrand die fehlenden Teile der Umrisse der Blätter rekonstruiert. Anschließend wurden die Vergrößerungen mit einer Videokamera aufgenommen und die gespeicherten Bilder mit einem Bildverarbeitungssystem analysiert. Der Zeitaufwand für diese Teile der Analyse lag, je nach Stärke des Fraßschadens, zwischen 30 und 55 min je Probe. Der maximale Fehler der ganzen Analyse wurde auf 2 % der Gesamtblattfläche geschätzt. Mögliche Anwendungen der beschriebenen Methode zur Quantifizierung der Größe von Blattminen und von nekrotischem Gewebe werden diskutiert.

The centers of domain nucleation in hard magnetic TbFeCo-films with in-plane uniaxial anisotropy

The domain development during the magnetization reversal is studied in TbFeCo films with field-induced in-plane anisotropy (K/sub in/ approximately=10/sup 5/ Jm/sup -3/) by means of a Kerr microscope equipped with an electronic image processing system. The nucleation of the domains does not take place at the film edge, but rather at defects which have a strongly deviating polar component of their easy axis. The coercivity of the films is determined by wall friction. The threshold against the nucleation of reversed domains is taken at a lower external field. Nevertheless, the hysteresis curves in the easy direction are very steep due to the viscous continuous motion of the walls after domain nucleation. The reversal preferably starts at line defects that re perpendicular to the easy axis because of the demagnetizing fields that support the reversal. A unique relationship between the polar M-components in defects and the in-plane M in the adjacent regions is caused by a tilt in the local easy anisotropy axis within the defect. >

Mammographic microcalcifications: detection with xerography, screen-film, and digitized film display.

Pulverized bone specks and aluminum oxide specks were measured by hand into sizes ranging from 0.2 mm to 1.0 mm and then arranged in clusters. These clusters were superimposed on a human breast tissue phantom, and xeromammograms and screen-film mammograms of the clusters were made. The screen-film mammograms were digitized using a high-resolution laser scanner and then displayed on cathode ray tube (CRT) monitors. Six radiologists independently counted the microcalcifications on the xeromammograms, the screen-film mammograms, and the digitized-film mammograms. The xeromammograms were examined with a magnifying glass; the screen-film images were examined with a magnifying glass and by hot light; and the digitized-film images were examined by electronic magnification and image processing. The bone speck size that corresponded to a mean 50% detectability level for each technique was as follows: xeromammography, 0.550 mm; digitized film, 0.573 mm; and screen-film, 0.661 mm. We postulate that electronic magnification and image processing with edge enhancement can improve the capability of screen-film mammography to enhance the detection of microcalcifications.

The Specificity of Media in the Arts

fine arts and the practical arts crystallized. Yet despite its age, the medium-specificity thesis continues to exercise a tenacious grip on the imaginations of artists and theorists alike. On the contemporary art scene, this is perhaps most evident in the arena of video aesthetics, where one group, the image processors, advocate their stylistic explorations on the grounds that they are concerned with the basic attributes of video. Summarizing their position, Shelley Miller writes: Electronic image processing uses as art-making material those properties inherent in the medium of video. Artists work at a fundamental level with various parameters of the electronic signal, for example, frequency, amplitude or phase, which actually define the resulting image and sound.' Undoubtedly many video avant-gardists are predisposed toward the medium-specificity thesis because, given backgrounds in the fine arts, their thinking has been and is swayed by the still influential tenets of Modernism a la Clement Greenberg. This approach to painting and sculpture is strongly essentialist. Greenberg proclaims:

Manhattan short cuts

Review| April 01 1982 Manhattan short cuts Japanese Experimental Film, at Japan House, Jan. 20, 21; Themes in Electronic Image Processing, at The Kitchen, December 1981; Joan Jonas/Memory Corridor, at P.S. 1, Jan.17-March 14; Joan Jonas and Jill Kroesen/Double Lunar Dogs, at the Performing Garage, January; Bill Stephens/Fire Walls Four, at the Whitney Museum, Dec. 23-Jan. 12; Bill Lundberg/Discord, at the Whitney Museum, Jan. 20-Feb. 9; and Al Robbins/Catch: The Speed of Shiver, at Anthology Film Archives, Jan. 25-Feb. 14. Ann-Sargent Wooster Ann-Sargent Wooster Ann-Sargent Wooster, an artist and a critic, teaches at the School of Visual Arts in New York and at Kean College, Union, N.J. Search for other works by this author on: This Site PubMed Google Scholar Afterimage (1982) 9 (9): 17–18. https://doi.org/10.1525/aft.1982.9.9.17 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Ann-Sargent Wooster; Manhattan short cuts. Afterimage 1 April 1982; 9 (9): 17–18. doi: https://doi.org/10.1525/aft.1982.9.9.17 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAfterimage Search This content is only available via PDF. © 1982 by The Regents of the University of California1982 Article PDF first page preview Close Modal You do not currently have access to this content.

Computed tomography and densitometric pattern of pulmonary lesions (author's transl)

Fifty-five peripheral pulmonary lesions in 46 patients were examined by computed tomography. The results were correlated with histologic diagnoses. The series comprised 26 bronchial carcinomas, 17 metastases, 4 chondromas, 5 tuberculomas and 3 echinacoccal cysts. The high resolution capacity of CT in the evaluation of macro pathologic pattern specially with the electronic image processing, with densitometry in regional interest is emphasised. Therefore cysts, fatty and other solid masses in the lung can be distinguished. Further more one can gain information of the underlying tissue on the basis of absorption profile.

Hybrid optical and electronic image processing for strain measurements by speckle photography

A Young's fringe processor for speckle photographs is described. It automatically measures fringe separation and orientation with an accuracy of 1% and 1 degrees , respectively. The fringe evaluation is fast and computer controlled. Fringe densities of one to twenty fringes within the diffraction pattern can be treated with the same resolution. Application to displacement and strain measurements by focused image speckle photography is reported. Local strains can be determined with an accuracy of ~E = 10(-5) for displacements between 10 and 100 microm and a spatial resolution of 10 mm.