Akram Halli

Using HMM Toolkit (HTK) for recognition of arabic manuscripts characters

In this paper, we propose an analytical approach of an offline recognition of handwritten Arabic. Our method is based on Hidden Markov Models (HMM) Toolkit (HTK), modeling type that takes into consideration the characteristics of Arabic script and possible inclinations of cursive words. The objective is to propose a methodology for rapid implementation of our approach. To this end, a preprocessing phase that can prepare the data was introduced. These data are then used by an extraction method of two groups of the characteristics (Features of Local Densities and Features Statistical) with the use of the technique of sliding windows, the results of this step are processed in sequence information as vectors to HTK (Hidden Markov Model Toolkit).

Revolution mapping with bump mapping support

Abstract Per-pixel Revolution Mapping is an image-based modeling and rendering technique or IBMR (Image-Based Modeling and Rendering). It consists of creating a virtual 3D objects without polygonal meshes. This technique uses a single RGBA texture that stores the needed data to generate the revolved surface. The main problem with this technique is that the 3D revolved models are rendered without realistic surface wrinkles. In this paper, we presented an improvement to enhance the realism of the 3D revolved models by combining the revolution mapping and the bump mapping. In order to synchronize between real-time depth scaling of the microrelief and the resulting shading, we have added a scaling factor that makes it possible to have a realistic depth animation. This new technique creates very convincing 3D models with realistic looking surface wrinkles and allows rendering at interactive frame rates.

Per-pixel displacement mapping using hybrid cone approach

The cone tracing is one of the best techniques for real time rendering of microreliefs. To find the intersection between the viewing ray and the microrelief, this technique use the empty space encoded in the form of top-opened cones. Cones are calculated in a preprocessing stage and are stored in a texture. There are two versions of this technique, the first one uses a conservative cone and the second uses a relaxed one. In this paper, we present the third version that uses the hybrid cone situated between the two already mentioned cones.

Fer-pixel extrusion mapping: The correction of the intersection point between the extrusion geometry and the viewing ray

Real-time rendering (Simulation, virtual Visits, 3D interactive, Games 3D) constitutes a major element of computer graphics, but the constraint of rendering speed does not allow to have high definition of all objects constituting the 3D scene. The traditional approach consists in using high definition meshes, having a very large number of vertices and triangles, but it is inappropriate for real-time rendering. Per-pixel extrusion mapping gives a serious alternative in this limitation by rendering the extruded surface without a polygonized silhouette. This paper takes advantage of programmable GPUs and related research as well as our approach the correction of the intersection points between the viewing ray and the surface generated by the extrusion of the binary shape and an extension of extrusion algorithm in order to create the outline extruded surfaces.

Off-line recognition handwriting Arabic words using combination of multiple classifiers

We present in this paper a system of Arabic handwriting recognition based on combining methods of decision fusion approach. The proposed approach introduces a methodology using the HMM-Toolkit (HTK) for a rapid implementation of our designed recognition system. After the image preprocessing, the text is segmented into lines, the obtained images are then used for features extraction with Sliding window technique. These features are extracted on binary images of characters and are modeled separately using Hidden Markov Models classifiers. The combination of the multiple HMMs classifiers was applied by using the different methods of decision fusion approach. The proposed system is evaluated using the IFN/ENIT database. Experimental results for Arabic handwritten recognition demonstrate that the Weighted Majority Voting (WMV) combination method have given better recognition rate 76.54% in top1, with Gaussian distribution.

Extrusion and revolution mapping

Extrusion, bevel, chamfer, and lathe tools are widely used in a large variety of computer graphics applications such as architectural designs and industrial prototyping of manufactured goods. However, such modeling is usually based on polygonal meshes which often require a considerable amount of graphics primitives. In this article, we present a new image-based approach for rendering extruded and revolved surfaces. We use only a single RGBA texture which stores a binary map (i.e. The profile curve), its Euclidean distance transform, and the two components of the unit gradient vector of the distance fields. All rendering algorithms are based on a ray-tracing procedure performed in texture space. The use of the distance fields allows culling of empty space and thus minimizes the number of ray-tracing steps. The extrusion and revolution mapping techniques produce very convincing models, and both are rendered at interactive frame rates.