Delineation of ECT images using global constraints and dynamic programming

A model-based delineation algorithm is presented. It is a flexible model fitting algorithm, approaching contour detection as an optimization problem. An objective function is introduced, which depends not only on local contour features, but also on a global shape constraint. The latter is implemented as the similarity to the instance of a parametric shape model. The algorithm optimizes both the contour points and the parameters of the model. As a result, both global and local characteristics of the contour are determined as a compromise between photometric data and prior knowledge. The method was applied to myocardial perfusion SPECT images, to delineate the entire left ventricle (endocardium and epicardium), including possible regions of reduced perfusion. By adapting the balance between the image data and the shape model, images with different characteristics can be processed, including Thallium-201 and MIBI scans.     

Membrano-bulbo-urethral junction stenosis. Posterior urethra obstruction due to extreme caliber disproportion in the male urethra

OBJECTIVE: Based on 4 cases of infravesical obstruction due to extreme caliber disproportion between the posterior urethra and the penile urethra, a pathophysiological mechanism for this dynamic obstruction is given and endoscopic treatment is described. SUBJECTS: Four cases of membrano-bulbo-urethral junction (MBUJ) stenosis, seen between September 1995 and April 1996, are described. Two boys had previous successful valve resection but still showed extreme ballooning of the posterior urethra. The other 2 boys showed bladder instability on urodynamics and the male variant of the spinning top urethra on voiding cystourethrography (VCUG). RESULTS: All cases were successfully treated by endoscopic incision at the 12 o'clock position of the kink between the posterior and the penile urethra which is seen when the full bladder is expressed. Disproportion in the posterior urethra, seen on VCUG, together with bad urinary flow measured on uroflowmetry raise the suspicion of MBUJ stenosis. CONCLUSION: Although rarely seen, extreme caliber disproportion in the male urethra can cause obstruction. Ballooning of the posterior urethra, caused by urethral valves, bladder instability resisted by voluntary sphincter contraction or congenital posterior urethral dilatation, creates an obstructive kink in the urethra comparable to some obstructions in ureteropelvic junction stenosis. If suspicion of such a form of obstruction arises, cystoscopy during pressure on the full bladder is mandatory in order to see the obstruction, descending as a membrane from the vault of the urethra.     

Iconic representation of visual data and models

Knowledge based image analysis is a combination of digital signal processing and symbolic reasoning. In this paper, we will look at some problems connected to the symbolic reasoning approach to image interpretation and see how an iconic representation can help to solve some of them. We will show that many of the features and problems connected with both symbolic and iconic representation are complementary.     

Knowledge-based improvement of automatic image interpretation for restricted scenes: two case studies

The paper explores the usefulness and applicability of knowledge-based image interpretation. By limiting the analysis to ‘restricted’ scenes, a bottom-up strategy has been developed to improve a primal image segmentation. Two case studies are discussed: the first deals with medical X-rays, the second with satellite images (SPOT). In both projects, generic geometrical knowledge is encoded in the format of production rules. The results obtained so far are encouraging and are already of practical use. Ways to extend the knowledge bases by more specific domain knowledge are mentioned.     

Range image acquisition with a single binary-encoded light pattern

The problem of strike identification in range image acquisition systems based on triangulation with periodically structured illumination is discussed. A coding scheme is presented based on a single fixed binary encoded illumination pattern, which contains all the information required to identify the individual strikes visible in the camera image. Every sample point indicated by the light pattern is made identifiable by means of a binary signature, which is locally shared among its closest neighbors. The applied code is derived from pseudonoise sequences, and it is optimized so that it can make the identification fault-tolerant to the largest extent. A prototype measurement system based on this coding principle is presented. Experimental results obtained with the measurement system are also presented     

Enhancing the Rheological Performance of Wheat Flour Dough with Glucose Oxidase,Transglutaminase or Supplementary Gluten

The enzymes glucose oxidase and transglutaminase are frequently used to improve the breadmaking performance of wheat flours, as they have the ability to considerably alter the viscoelastic nature of the gluten network. To evaluate a flour’s breadmaking performance, rheological tests offer an attractive framework. In this study, the rheological impact of adding glucose oxidase or transglutaminase to wheat flour dough is investigated by means of linear oscillatory shear tests, creep-recovery shear tests and startup extensional tests. The former tests reveal that the enzymes render the dough stiffer and enhance its elastic character, until saturation is reached. In the breadmaking process, the use of excessive amounts of enzyme is known to be counterproductive. The strain-hardening index clearly reveals this overcross-linking effect. Besides enzymes, the gluten network can also be reinforced by adding supplementary gluten, which was indeed found to enhance the extent of strain-hardening.     

Two-dimensional shape decomposition using fuzzy subset theory applied to automated chromosome analysis

This paper describes a technique to transform a two-dimensional shape into a generalized fuzzy binary relation whose clusters represent the meaningful simple parts of the shape. The fuzzy binary relation is defined on the set of convex and concave boundary points, implying a piecewise linear approximation of the boundary, and describes the dissemblance of two vertices to a common cluster. Next some fuzzy subsets are defined over the points which determine the connection between the clusters.The decomposition method first determines nearly convex regions, which are subgraphs of the total graph, and then selects the greatest nearly convex region which satisfies best the defined fuzzy subsets and relations. Using this procedure on touching chromosomes defining the simple parts to be the separated chromosomes, the decomposition often corresponds well to the decomposition that a human might make.