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1

Flat Knitting Loop Deformation Simulation Based on Interlacing Point Model

Jiang G., Lu Z., Cong H., Zhang A., Dong Z., Jia D.

Autex Research Journal

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2017

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Vol. 17, no. 4

361--369

EN

In order to create realistic loop primitives suitable for the faster CAD of the flat-knitted fabric, we have performed research on the model of the loop as well as the variation of the loop surface. This paper proposes an interlacing point-based model for the loop center curve, and uses the cubic Bezier curve to fit the central curve of the regular loop, elongated loop, transfer loop, and irregular deformed loop. In this way, a general model for the central curve of the deformed loop is obtained. The obtained model is then utilized to perform texture mapping, texture interpolation, and brightness processing, simulating a clearly structured and lifelike deformed loop. The computer program LOOP is developed by using the algorithm. The deformed loop is simulated with different yarns, and the deformed loop is applied to design of a cable stitch, demonstrating feasibility of the proposed algorithm. This paper provides a loop primitive simulation method characterized by lifelikeness, yarn material variability, and deformation flexibility, and facilitates the loop-based fast computer-aided design (CAD) of the knitted fabric.

2

Detection of windows in building textures from airborne and terrestrial infrared image sequences

Iwaszczuk D., Hoegner L., Stilla U.

Archiwum Fotogrametrii, Kartografii i Teledetekcji

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2011

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Vol. 22

215--225

EN

Infrared (IR) images depict thermal radiation of physical objects. Imaging the building façades and the roofs with an IR camera, thermal inspections of the buildings can be carried out. In such inspections a spatial correspondence between IR-images and the existing 3D building models can be helpful. Texturing 3D building models with IR images this spatial correspondence can be created. Furthermore in textures heat leakages can be detected and the heat bridges can be stored together with 3D building data. However, before extracting leakages, the windows should be located. In IR images glass reflects the surrounding and shows false results for the temperature measurements. Consequently, the windows should be detected in IR images and excluded for the inspection. The most common algorithms for window detection were developed for the images in the visual band. In this paper, an algorithm for window detection in textures extracted from terrestrial IR images is proposed. In the first step, small objects have to be removed by scaling down the image (texture). Then in the scaled image, regions are detected using a local dynamic threshold. Morphological operations are used to remove false detections and unify substructures of the windows. For every extracted region, which is a candidate for a window, the center of gravity is calculated. It is assumed that windows on façades are ordered in regular rows and columns. First the points are grouped into rows using histogram of height created from extracted gravity centers. Then masked correlation is used to detect the position and size of the windows. Finally, the gaps in the grid of windows are completed. For the first experiments we use a dataset from densely build urban area captured in Munich, Germany. The IR image sequences were taken from a vehicle driving on the street around the test area. Camera was directed to the building in oblique view. According to the acquisition geometry, no façade could be completely seen in one frame. Therefore, we combine the textures from many frames. To these textures we applied our algorithm for window detection. First results are promising. Applying the method for our test dataset, 79% completeness and 80% correctness could be achieved.

3

A proposition of mobile fractal image decompression

Nikiel S.

International Journal of Applied Mathematics and Computer Science

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2007

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Vol. 17, no 1

129-136

EN

Multimedia are becoming one of the most important elements of the user interface with regard to the acceptance of modern mobile devices. The multimodal content that is delivered and available for a wide range of mobile telephony terminals is indispensable to bind users to a system and its services. Currently available mobile devices are equipped with multimedia capabilities and decent processing power and storage area. The most crucial factors are then the bandwidth and costs of media transfer. This is particularly visible in mobile gaming, where textures represent the bulk of binary data to be acquired from the content provider. Image textures have traditionally added visual realism to computer graphics. The realism increases with the resolution of textures. This represents a challenge to the limited bandwidth of mobile-oriented systems. The challenge is even more obvious in mobile gaming, where single image depicts a collection of shots or animation cycles for sprites and a backdrop scenery. In order to increase the efficiency of image and image texture transfer, a fractal based compression scheme is proposed. The main idea is to use an asymmetric server-client architecture. The resource demanding compression process is performed on the server side while the client part decompresses highly packed image data. The method offers a very high compression ratio for pictures representing image textures for natural scenes. It aims to minimize the transmission bandwidth that should speed up the downloading process and minimize the cost and time of data transfer. The paper focuses on the implementation of fractal decompression schemes suitable for most mobile devices, and opens a discussion on fractal image models for limited resource applications.