Showing papers on "Feature (computer vision) published in 1980"

Ultrasonic B-scanning: a computer simulation.

Abstract: A method has been developed which can predict the appearance and properties of B-scan images. The theoretical basis for the tissue models used, and the assumptions made in the simulation concerning the nature of pulse-echo imaging, are discussed. A key feature of the simulation is the Fourier domain synthesis of the tissue model, which permits convenient specification of some statistical properties of a randomly inhomogeneous scattering medium. Other characteristics that may be specified include the ultrasonic pulse and beam shapes, and subsequent signal processing. Both the initial tissue model and the simulated B-scan image are displayed as grey-scale pictures, allowing visual comparison in the same way that clinical B-scans are currently observed. Preliminary results of applying the simulation are shown to have a number of features in common with clinical images and with scans of a test object. A better understanding of the nature of pulse-echo images is gained and conclusions drawn regarding the range of system and tissue parameters over which these images convey information about the tissue structure. The method may also be of use to determine optimum design of equipment for imaging and tissue characterisation, and to investigate the extent to which the acoustic structure of tissues can be described in terms of simple mathematical models.

Estimating workpiece pose using the feature points method

Abstract: The ability of a robot to estimate workpiece pose is necessary for many industrial tasks. An automatic method of visually estimating the pose of a workpiece in a robot hand has been investigated. This method is applicable to workpieces that have six continuous unknown degrees of freedom. Furthermore, partial occlusion of the workpiece by the robot hand is allowed. Workpiece pose was estimated using the three-dimensional locations of at least three noncollinear workpiece feature points. A second view of the workpiece was obtained by rotating the workpiece in front of the camera. Corresponding image features on the second view were found by searching along lines on the image which were determined by the rotation of the workpiece. A very accurate camera calibration procedure has been developed to compute rays in space from image locations. The location of workpiece features was computed by trigonometric relations between rays of corresponding image features from two views of the workpiece. The pose of a workpiece was estimated by the correspondence between the workpiece features located and the feature points of a workpiece model. Experiments have been performed on a complete functional system. The major limitation of the current system was due to the image feature extraction algorithm which only detected corners and small holes.

Warning: Even memory for faces may be contagious.

Abstract: College students (521) participated in this research program designed to study the extent to which memory for faces can be altered. Pilot results indicated that subjects who viewed a face and then heard a description of that face ostensibly written by another witness were influenced by that description. Specifically, subjects adopted the verbal expressions of another witness even when those expressions were in error. Furthermore, subjects who heard a misleading detail had a tendency to incorporate that detail into their reconstructions of the original face; subjects who did not hear the misleading detail rarely did so. These findings were further explored in three larger-scale experiments. In each of the three experiments, subjects viewed a target individual in a photograph (Experiment 2), in a film (Experiment 1), or live (Experiment 3). Subsequently, some subjects were exposed to misleading information via a version of the target individual ostensibly given by another witness (Experiments 1 and 2). The major results were as follows: (1) Experiment 1: If another witness referred to a misleading feature, over a third of the subjects included that detail in their own description, using the exact wording that the other witness had used. Control subjects rarely did so (5%). (2) Experiment 2: If the other witness referred to a misleading detail, nearly 70% of the subjects later “recognized” an individual with that feature. Control subjects did so far less often (13%). (3) If subjects were questioned with leading questions containing misinformation about a critical feature (moustache), over 30% indicated that they had seen the critical feature. Control subjects rarely did so (4%). These results show that memory for a face is affected by the introduction of subsequent misleading information about that face, contradicting the view that faces are special in their lack of susceptibility to interference. These results have important implications for police practices regarding eyewitness recognition.

Device for extracting a density as one of pattern features for each feature point of a streaked pattern

Abstract: In addition to positions and directions of feature points of a streaked pattern, such as minutiae of a fingerprint on a background, a plurality of novel counts and a density are automatically extracted for each feature point selected as a reference feature point. The density is determined in connection with adjacent feature points that are present in a predetermined neighborhood of the reference feature point. Each count is decided by the number of streaks or ridges intervening between the reference feature point and a related feature point that is nearest to the reference feature point among the feature points in a predetermined sector of the neighborhood.

Evidence for feature perturbations

Abstract: Feature perturbations were proposed by Wolford (1975) to explain the pattern of errors generated by subjects in experiments involving speeded presentations. These experiments were carried out to test the notion of feature perturbations in a fairly direct fashion. The logic of the experiments involved the creation of an artificial alphabet in which feature perturbations, if they occurred, would lead to predictable error patterns. The results of the three experiments supported the notion of feature perturbations. Evidence was also found for errors which resulted from items that were correctly identified but that were reported in an incorrect order. These latter errors were shown to be distinct from errors resulting from feature perturbations.

Shore platforms; a neglected coastal feature

Abstract: number of workers, is undoubtedly only a minute sample of the platforms which exist around the world. Until the early 1960s, the study of shore platforms was by default the almost exclusive domain of Australasian workers. This work, which still exerts a strong influence on the treatment of shore platforms in modern texts, was descriptive and generally concerned with determining whether platforms are the product of wave erosion or weathering processes. Genetic criteria usually included the degree of shelter provided by platform sites, and the elevation of the platforms in relation to specific tidal levels. It is ironic that in Britain the neglect of contemporary shore platforms occurred at a time when great importance was attached to the identification and interpretation of their ’raised’ counterparts. The first studies specifically concerned with British shore platforms are less than twenty years old. Recent work has been particularly concerned with:

Pattern position detecting system

Abstract: A pattern position detecting system includes an image pickup device to pick up the image of an object which includes a target pattern which is to be detected. On the basis of the output of the pickup device, local patterns of the image surface are successively cut out and positional coordinates of the local patterns are successively generated to indicate the typical positions of each of these local patterns. The respective local patterns are then compared with a standard pattern having the same feature as that of the target pattern and the degree of coincidence therebetween is detected. The different degrees of coincidence of the local patterns in the vicinity of a particular local pattern are then compared so as to successively sample the local pattern whose degrees of coincidence become a maximum, and the positional coordinates and degrees of coincidence of the respective local patterns whose degrees of coincidence become a maximum are then stored. The positional coordinates fulfilling the positional relationship inherent to the target pattern from among the positional coordinates finally selected are then sampled and the sampled positional coordinates are identified as indicating a position of the target pattern.

Generalized Texture Representation and Metric

Abstract: A new approach to texture representation and discrimination is proposed. The representation is devised to reflect various perceptual aspects of image texture by retaining as much as possible the extracted texture information. Information thus extracted is then organized as a set of line or circular frequency diagrams for various texture features at different resolution levels. Based upon the properties of the two types of frequency diagrams, new metrics are defined to enhance the feature dissimilarities. The effectiveness of the proposed representation and metric for texture analysis is also illustrated by a set of actual data.

Methods and apparatus for blending computer image generated features

Abstract: Methods and apparatus for determining dynamically a blending ratio for blending features in a computer image generated scene are disclosed. The invention is for use with a computer image generation system which provides a dynamic scene as viewed by the pilot of an aircraft simulator. Such a computer image generator system includes a main data base (62) which contains information representing features of the scene to be presented, a display means (76) and a main computational unit (74) for generating the dynamic visual scene. Apparatus of the present invention includes a control data base (78) which contains selected information related to selected features contained within main data base (62). The selected information contained in control data base (78) includes the spatial coordinates of a control point of the selected feature, and the range at which the feature should be included. Also included in computational unit (74) is a means for determining the location of the central point on a theoretical image plane (61). Means such as CRT (92) which has a pie shaped cut out (98) works in conjunction with a light detector (100) and A/D convertor (106) to determine a proper blending ratio signal. This blending ratio signal is then provided to computational unit (74) to provide the blending of a new feature into the dynamic visual scene. Alternately, a read only memory (ROM) (108) could be used to replace CRT (92), photo detector (100) and A/D convertor (106).

Image Texture Analysis Techniques - a Survey

Abstract: This paper contains a survey of image texture analysis techniques. Three broad classes of methods are discussed: pixel-based, local-feature based and region-based. The pixelbased models include grey level cooccurrence matrices, difference histograms and energy-measures. The local feature-based models mostly rely on edges as local features and include Marr’s primal sketch model and a generalization of cooccurrence matrices. Region-based models include a region-growing model and a topographic model which treats the texture image as a digital terrain model.

Surface defect inspection system

Abstract: A surface defect inspection system comprises an image pick-up device for picking up an image by sequentially scanning the surface of an object two-dimensionally, a threshold circuit for quantizing the image signal produced from the image pick-up device as a binary code, a pattern feature extracting device for making calculations for extracting the features of image patterns from the quantized signal in synchronism with the scanning, and for temporarily storing the result of the calculations, a pattern region end decision device for deciding that individual pattern regions have ended in one direction, and a defect decision device for reading out from the pattern feature extracting device the result of the calculations on the pattern features corresponding to the positions each of the patterns in the direction perpendicular to the one direction each time of the decision that each pattern region has ended, so that the feature of each pattern scanned is compared with a predetermined reference, thus deciding and an indication of producing the presence or absence of a defect.

Habitat Requirements of the Red Fox

Abstract: Choosing a place to live is a feature that the more mobile animals can enjoy compared with the more passive or accidental ways of securing suitable habitats by sessile species.

Objective feature extraction applied to the diagnosis of carotid artery disease using a Doppler ultrasound technique

Abstract: Using the maximum frequency envelope obtained from the sonogram of the Doppler shifted frequencies a mathematical feature extraction technique has been used to provide an objective identification of the significant waveform features. The technique described is that of principal component factor analysis. The data used were taken from an eighteen month programme in which techniques based on the use of directional Doppler ultrasound were evaluated in comparison with direct percutaneous carotid angiography and arch aortography. A tracing of the vessel outlined based on the anterior-posterior view of the angiogram was used to classify each vessel segment studied. Two groups only are considered in this initial study, a normal group (25 vessel segments) and a stenosis group (18 vessel segments). The principal component analysis technique was shown to provide a superior classification of the vessel segments when compared with the more familiar A/B ratio. Nevertheless the principal diagnostic feature is shown to be the A/B ratio.

Extracting linear features from images using pyramids

Abstract: : A method is described of extracting linear features from images. The approach is to construct a series of lower-resolution versions of the original image (a pyramid), and to look for lines in these images. A line in a low- resolution image corresponds to a thicker linear feature in a high-resolution image. The position and extent of this linear feature is calculated from the low-resolution image, and a threshold is found which, when applied in the neighborhood of the feature in the high-resolution image, segments the linear feature from its background. Advantages of the method are that only the parts of the image in the neighborhood of linear features need be thresholded, and that different thresholds may be used to extract the various linear features in the image.

Circuit interrupter with solid state digital trip unit and positive power-up feature

Abstract: A circuit interrupter includes a microcomputer controlled trip unit having a front panel numeric display and a plurality of LED displays for providing post tripping indication of cause-of-trip and trip current value. Reliable operation is provided during power up conditions. Means are also provided for accurate performance of long delay and ground fault tripping operation.

Topographic feature extraction using sensor array system

Abstract: A method and apparatus for topographic feature extraction by masking a video signal representation of an optical image using a two-dimension Walsh function is disclosed. The optical energy of an image is converted into a video signal. A Walsh function signal in accordance with a two-dimension Walsh is generated. The video signal is multiplied with the Walsh function signal to produce a Walsh transform coefficients signal indicative of the decomposed spectral components of the image. The method and apparatus can further include providing selected topographical feature signals in accordance with the Walsh transform coefficients of selected topographic features. A selected topographical feature can be detected by comparing the Walsh transform coefficients signal with the selected topographical feature signals. The Walsh transform coefficients signal is unique to the selected topographical feature being detected.

Reconstructing the Lenis Feature in Proto-Ẹdoid

Abstract: The group of languages here called Edoid are those earlier called \"Edo\" (Thomas 1910) and the \"Beningruppe\" (Melzian 1942). Greenberg (1966) does not call them by any common name but says they are a sub-branch of Kwa, listing them äs group \"e. Bini, Ishan, Kukuruku, Sobo\". None of the above-mentioned scholars, however, seems to have been aware of the presence of Edoid-speaking peoples in the eastern part of the Niger Delta äs well äs in Akoko and Owo Divisions of Ondo State to the north of Bendel (formerly Mid-western) State. In fact, there are Edoid languages in the eastern Niger Delta, namely Epie-Atisa, Egene (Engenni), and Degema. They are first mentioned by Talbot (1932) and discussed extensively in Wescott (1962) and Thomas and Williamson (1967). Wescott applied the term \"Delta Edo\" to them and it was further made populär by Williamson (1968), Thomas and Williamson (1967), and Elugbe (1973). The Edoid languages spoken to the north and north-west of Bendel State are Uhami, Ehueun (Ekpenmen, Epenmi), Ukue (Ukpe, Dcpe), and lyayu (spoken at Idoani). As far äs I know, these languages are first clearly mentioned in Williamson (1968) while a more detailed account of their geographical spread is given in Elugbe (1971). Elugbe (1973) presents a detailed classification of the Edoid languages in addition to a comprehensive account of their geographical distribution. The classification of 1973, which proposed a primary two-way split of the main Proto-Edoid (henceforth PE) stem, is revised in Elugbe (in press) where an initial four-way split is postulated (see fig. 1). Delta Edoid (DE) languages are the most southerly and are spoken in Rivers State. South-western Edoid (SWE) languages are spoken in the Delta Province of Bendel State and specifically in the Ughelli, Isoko, Ethiope, and Okpe Local Government Areas. Isekiri and some SWE languages exist side by side in the Warri Local Government Area while some

A test of visual feature sampling independence with orthogonal straight lines

Abstract: Well-specified feature detection models of visual character recognition typically assume feature sampling independence; that is, they assume that the detection of one feature is probabilistically independent of the detection of others. Recent results have suggested this assumption may be suspect with letter-like stimuli. The present study utilized very simple stimuli consisting of up to two straight-line segments that were either physically connected or separated by a gap. A strong model that assumed that features are reported if and only if they are sampled together with independence could not be rejected even when the lines were connected.

Pattern generation by laser-induced oxidation of thin metal films (microcircuit fabrication)

Abstract: Laser-activated oxidation of thin Cr films has been used for image recording by means of a Q-switched Nd:glass laser and an optical projection system. Metal patterns of total dimensions up to 10*10 mm have been generated. The smallest feature of the pattern obtained is 3 mu m.

Electrical measurement of feature sizes in MOS Si 2 -gate VLSI technology

Abstract: The reduced device dimensions of VLSI circuits resulting from improved lithographic techniques require very careful control of the feature sizes during the production process. For this purpose, test patterns and measurement techniques for automatic electrical measurements of misalignments and feature sizes have been developed for the control of an MOS Si2-gate process. Using these methods, correlations between the electrically relevant device parameters and the feature sizes are obtained. A sensitivity analysis for the threshold voltage has been made. It was found that for the technology under consideration, the variation of the feature sizes predominates over the influences of all other technological parameters at transistor lengths of 1-2 µm.

The Selection of Critical Subsets for Signal, Image, and Scene Matching

Abstract: A basic matching problem consists of locating a reference subset in a larger set of data subject to a given criterion. Variations of the problem include template matching for object recognition, matched filtering for signal detection, image registration, change detection, cartography feature location, correlation guidance, and scene matching. In the general case the data sets may be made by completely different sensors at different geometrical orientations. A data set in N dimensions can be considered as a function in N-space. The critical subset selection problem arises when one is given a function and must select some subset of the function to match with the original. In some cases uniqueness is a key feature of the best subset. Uniqueness may be measured by the number and relative magnitudes of the peaks in the cross correlation function of the original and subset functions. For a unique subset, another desirable characteristic is lack of ambiguity. This characteristic may be measured using the correlation length or 50 percent width of the main correlation peak. The smaller the correlation length, the greater the certainty one has in detecting the correct match position. In this paper a method is presented for selecting the ``best'' subset of a scene where best is defined in terms of the minimum correlation length. The best solution is shown to be a function of the entire scene, i.e., an improper subset.

Feature space transform for multitarget detection

Abstract: This approach to multitarget tracking is from the perspective of an unsupervised pattern recognition problem. In the usual formulation the target data are processed to produce feature points, which may be track points. The feature points that correspond to the same track are identified when mapped as a dense region in the parameter space. Parameter space representation of crossing and nearly coincident tracks forms overlapping clusters that are not separable. This factor makes the transform approach in its usual form unworkable. Nevertheless, the transform technique need not be abandoned, for the diameter of the aggregate of tracts is evident in the parameter space. Once the direction and location of the aggregate of tracts is located, the individual tracks within the group can be identified by proven techniques.

Squamous carcinoma of thyroglossal duct remnants: a case report and review of the literature.

Abstract: The first reported case in Australia of a squamous carcinoma arising in a thyroglossal duct remnant is presented. This case shows the previously unreported feature of associated hyperthyroidism.