{"title":"Quasi-circular Splines: A Shape-Preserving Approximation","authors":"Howell G.W., Fausett D.W., Fausett L.V.","doi":"10.1006/cgip.1993.1007","DOIUrl":"10.1006/cgip.1993.1007","url":null,"abstract":"<div><p>The \"quasi-circular spline\" is introduced as a new method for approximating closed, smooth planar shapes from curvature information. A current application is the measurement of shapes of solid rocket booster cross-sections. Because of the efficiency of the algorithm and its desirable geometric properties, it is also particularly appropriate for computer graphics. The simplicity and efficiency of the quasi-circular spline compare well with previously proposed schemes which are important in graphical applications. It is invariant under the transformations of the Euclidean group. Furthermore, it is shape-preserving in that the quasi-circular spline approximation to a convex planar curve is also convex. Sufficient conditions for convergence are described, and <em>O</em>(<em>h</em><sup>2</sup>) approximation to sufficiently smooth curves is demonstrated.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 2","pages":"Pages 89-97"},"PeriodicalIF":0.0,"publicationDate":"1993-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131733056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Nonlinear Prefiltering and Difference of Estimates Approaches to Edge Detection: Applications of Stack Filters","authors":"Yoo J., Bouman C.A., Delp E.J., Coyle E.J.","doi":"10.1006/cgip.1993.1010","DOIUrl":"10.1006/cgip.1993.1010","url":null,"abstract":"<div><p>The theory of stack filtering, which is a generalization of median filtering, is used in two different approaches to the detection of intensity edges in noisy images. The first approach is a generalization of median prefiltering: a stack filter or another median-type filter is used to smooth an image before a standard gradient estimator is applied. These prefiltering schemes retain the robustness of the median prefilter, but allow resolution of finer detail. The second approach, called the Difference of Estimates (DoE) approach, is a new formulation of a morphological scheme [Lee <em>et al., IEEE Trans. Robotics Automat</em>. <strong>RA-3,</strong> Apr. 1987, 142-156, Maragos and Ziff, <em>IEEE Trans. Pattern Anal. Mach. Intell</em>. <strong>12</strong>(5), May 1990.] which has proven to be very sensitive to impulsive noise. In this approach, stack filters are applied to a noisy image to obtain local estimates of the dilated and eroded versions of the noise-free image. Thresholding the difference between these two estimates yields the edge map. We find, for example, that this approach yields results comparable to those obtained with the Canny operator for images with additive Gaussian noise, but works much better when the noise is impulsive. In both approaches, the stack filters employed are trained to be optimal on images and noise that are \"typical\" examples of the target image. The robustness of stack filters leads to good performance for the target image, even when the statistics of the noise and/or image vary from those used in training. This is verified with extensive simulations.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 2","pages":"Pages 140-159"},"PeriodicalIF":0.0,"publicationDate":"1993-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132564174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Codebook Edge Detection","authors":"Mclean G.F.","doi":"10.1006/cgip.1993.1003","DOIUrl":"10.1006/cgip.1993.1003","url":null,"abstract":"<div><p>This paper deals with the problem of extracting edge structure from compressed image representations. As image coding techniques become more common in image manipulation systems, it is reasonable to develop methods of analyzing an image using operations on the compressed image representation rather than the reconstructed image. Such an approach can be computationally efficient and produce an overall gain in computing performance.In this paper a technique for detecting edges directly from vector-quantized image representations is developed. The technique is shown to provide good performance in comparison to other gradient-type edge detectors, requiring no computation beyond the initial coding of the image. This approach provides a method ofextracting edge information which may be useful in the processing of very large image datasets.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 1","pages":"Pages 48-57"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121911617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Holes and Genus of 2D and 3D Digital Images","authors":"Lee C.N., Poston T., Rosenfeld A.","doi":"10.1006/cgip.1993.1002","DOIUrl":"10.1006/cgip.1993.1002","url":null,"abstract":"<div><p>\"Hole\" has been a confusing idea in the 3D digital literature. We replace counting holes by the clear geometrical idea of counting non-separating cuts, and show that this gives the Betti number <em>b</em><sub>1</sub>, while <em>b</em><sub>0</sub> counts components and <em>b</em><sub>2</sub> cavities. Connected sets with equal <em>b</em><sub>1</sub> and <em>b</em><sub>2</sub> must match topologically when <em>b</em><sub>1</sub> = 0 (implying simple connectedness). When <em>b</em><sub>1</sub> ≠ 0, contrary to digital folklore, they need not. This paper is a conceptually self-contained introduction for computer scientists to these numbers of 2D and 3D images, and to other topological features such as Euler and linking numbers.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 1","pages":"Pages 20-47"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120850764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Gibbs Random Fields, Fuzzy Clustering, and the Unsupervised Segmentation of Textured Images","authors":"Nguyen H.H., Cohen P.","doi":"10.1006/cgip.1993.1001","DOIUrl":"10.1006/cgip.1993.1001","url":null,"abstract":"<div><p>In this paper we present an unsupervised segmentation strategy for textured images, based on a hierarchical model in terms of discrete Markov Random Fields. The textures are modeled as Gaussian Gibbs Fields, while the image partition is modeled as a Markov Mesh Random Field. The segmentation is achieved in two phases: the first one consists of evaluating, from disjoint blocks which are classified as homogeneous, the model parameters for each texture present in the image. This unsupervised learning phase uses a fuzzy clustering procedure, applied to the features extracted from every pixel block, to determine the number of textures in the image and to roughly locate the corresponding regions. The second phase consists of the fine segmentation of the image, using Bayesian local decisions based on the previously obtained model parameters. The originality of the proposed approach lies in the three following aspects: (1) the Gibbs distribution corresponding to each texture type is expressed in terms of its <em>canonical</em> potential. This formulation leads to a compact formulation of the global field energy, in terms of the marginal probabilities over pixel cliques. A similar expression is also introduced in the partition model. Such formulations lead to the decomposition of the segmentation problem into a set of local statistical decisions; (2) the segmentation strategy consists of an unsupervised estimation, in which the model parameters are evaluated directly from the observation, by means of a fuzzy clustering technique; (3) no arbitrary assumption is made concerning the number of textures present. Rather, the fuzzy clustering procedure used to estimate the model parameters is applied in a hierarchical manner, searching for a cluster configuration of maximum plausibility.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 1","pages":"Pages 1-19"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133442370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Extension of Chaiken′s Algorithm to B-Spline Curves with Knots in Geometric Progression","authors":"Goldman R., Warren J.","doi":"10.1006/cgip.1993.1004","DOIUrl":"10.1006/cgip.1993.1004","url":null,"abstract":"<div><p>Chaiken′s algorithm is a procedure for inserting new knots into uniform quadratic B-spline curves by doubling the control points and taking two successive averages. Lane and Riesenfeld showed that Chaiken′s algorithm extends to uniform B-spline curves of arbitrary degree. By generalizing the notion of successive averaging, we further extend Chaiken′s algorithm to B-spline curves of arbitrary degree for knot sequences in geometric and affine progression.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 1","pages":"Pages 58-62"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125687817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Local Image Reconstruction and Subpixel Restoration Algorithms","authors":"Boult T.E., Wolberg G.","doi":"10.1006/cgip.1993.1005","DOIUrl":"10.1006/cgip.1993.1005","url":null,"abstract":"<div><p>This paper introduces a new class of reconstruction algorithms that are fundamentally different from traditional approaches. We deviate from the standard practice that treats images as point samples. In this work, image values are treated as area samples generated by nonoverlapping integrators. This is consistent with the image formation process, particularly for CCD and CID cameras. We show that superior results are obtained by formulating reconstruction as a two-stage process: image restoration followed by application of the point spread function (PSF) of the imaging sensor. By coupling the PSF to the reconstruction process, we satisfy a more intuitive fidelity measure of accuracy that is based on the physical limitations of the sensor. Efficient local techniques for image restoration are derived to invert the effects of the PSF and estimate the underlying image that passed through the sensor. The reconstruction algorithms derived herein are local methods that compare favorably to cubic convolution, a well-known local technique, and they even rival global algorithms such as interpolating cubic splines. Evaluations are made by comparing their passband and stopband performances in the frequency domain, as well as by direct inspection of the resulting images in the spatial domain. A secondary advantage of the algorithms derived with this approach is that they satisfy an imaging-consistency property. This means that they exactly reconstruct the image for some function in the given class of functions. Their error can be shown to be at most twice that of the \"optimal\" algorithm for a wide range of optimality constraints.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"55 1","pages":"Pages 63-77"},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1006/cgip.1993.1005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126074768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fast generation and display of iso-surface wireframes","authors":"Michael J Laszlo","doi":"10.1016/1049-9652(92)90067-8","DOIUrl":"10.1016/1049-9652(92)90067-8","url":null,"abstract":"<div><p>The paper presents a method for generating and displaying wireframe approximations to surfaces of constant value (or <em>iso-surfaces</em>). Input to the method is a <em>data grid</em>, a volume decomposition with each of whose vertices is associated a scalar value. During a preprocessing phase, the method constructs a threshold-independent data structure based upon the given data grid. The data structure relates the edges of an iso-surface wireframe to the edges of the data grid, for all possible threshold values. During the subsequent rendering phase, the data structure supports efficient generation and display of the iso-surface wireframe corresponding to any selected threshold value. The technique is efficient enough to form the basis for an interactive software system for visualizing iso-surfaces.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"54 6","pages":"Pages 473-483"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/1049-9652(92)90067-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133682132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Author index for volume 54","authors":"","doi":"10.1016/1049-9652(92)90073-7","DOIUrl":"https://doi.org/10.1016/1049-9652(92)90073-7","url":null,"abstract":"","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"54 6","pages":"Page 436"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/1049-9652(92)90073-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137265487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Page segmentation and classification","authors":"Theo Pavlidis, Jiangying Zhou","doi":"10.1016/1049-9652(92)90068-9","DOIUrl":"10.1016/1049-9652(92)90068-9","url":null,"abstract":"<div><p>Page segmentation is the process by which a scanned page is divided into columns and blocks which are then classified as halftones, graphics, or text. Past techniques have used the fact that such parts form right rectangles for most printed material. This property is not true when the page is tilted, and the heuristics based on it fail in such cases unless a rather expensive tilt angle estimation is performed. We describe a class of techniques based on smeared run length codes that divide a page into gray and nearly white parts. Segmentation is then performed by finding connected components either by the gray elements or of the white, the latter forming white streams that partition a page into blocks of printed material. Such techniques appear quite robust in the presence of severe tilt (even greater than 10 °) and are also quite fast (about a second a page on a SPARC station for gray element aggregation). Further classification into text or halftones is based mostly on properties of the across scanlines correlation. For text correlation of adjacent scanlines tends to be quite high, but then it drops rapidly. For halftones, the correlation of adjacent scanlines is usually well below that for text, but it does not change much with distance.</p></div>","PeriodicalId":100349,"journal":{"name":"CVGIP: Graphical Models and Image Processing","volume":"54 6","pages":"Pages 484-496"},"PeriodicalIF":0.0,"publicationDate":"1992-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/1049-9652(92)90068-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126395423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}