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Sometimes, in computer graphics, there is a need to show a part or a piece of a specific picture to study it accurately. For this purpose a window can be used to select the interested part of the picture for display out of other parts. This window is called a clipping window and this process is called a clipping process .On the other hand, clipping is required when a part of a moving image becomes out of the visible zone for display. So the clipping process is one of the important issues in the field of computer graphic specially for real time applications. Therefore a study of the line clipping with respect to a rectangular window while looking to various methods to achieve clipping process in the image space is presented in this paper. In addition to that, performance measurements are conducted and compared. The paper develops a method to perform clipping in the object space in which the line segment is clipped against a viewing volume. Finally, pipelining is adopted to realize clipping algorithm in hardware. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we introduce new algorithm implementations of a new parametric image processing framework that will accurately process images and speed up computation for addition, subtraction, and multiplication. Its potential applications include computer graphics, digital signal processing and other multimedia applications. This Parameterized Digital Electronic Arithmetic (PDEA) model replaces linear operations with non-linear ones. The implementation of a parameterized model is presented. We also present the design of arithmetic circuits including parallel counters, adders and multipliers based in two high performance threshold logic gate implementations that we have developed. We will also explore new microprocessor architectures to take advantage of arithmetic. The experiments executed have shown that the algorithm provides faster and better enhancements from those described in the literature. The FPGA chips used is Spartan 3E from Xilinix. The critical length in the circuit implemented on the FPGA had the minimum period for the proposed subsystem is 10.209ns (maximum frequency 97.957MHz). Maximum power consumed is 2.4mW using 32nm process and we used parallelism and reuse of the Hardware components to accomplish and speed up the process. [Copyright &y& Elsevier]

Abstract: Volino and Thalmann have published a conjecture proposing sufficient conditions for non-selfintersection of surfaces. Such conditions may be used in solid modeling, computer graphics, and other application areas, as a basis for collision-detection algorithms. In this paper we clarify certain of the hypotheses of the proposed theorem, and give a proof. A brief summary of possible pitfalls related to using the conditions, when the hypotheses of the formal theorem given here are not satisfied, is also given. We also give examples, and show that the theorem can be extended to domains that are not simply connected. [Copyright &y& Elsevier]

A novel reversible data hiding algorithm, which can recover the original image without any distortion from the marked image after the hidden data have been extracted, is presented in this paper. This algorithm utilizes the zero or the minimum points of the histogram of an image and slightly modifies the pixel grayscale values to embed data into the image. It can embed more data than many of the existing reversible data hiding algorithms. It is proved analytically and shown experimentally that the peak signal-to-noise ratio (PSNR) of the marked image generated by this method versus the original image is guaranteed to be above 48 dB. This lower bound of PSNR is much higher than that of all reversible data hiding techniques reported in the literature. The computational complexity of our proposed technique is low and the execution time is short. The algorithm has been successfully applied to a wide range of images, including commonly used images, medical images, texture images, aerial images and all of the 1096 images in CorelDraw database. Experimental results and performance comparison with other reversible data hiding schemes are presented to demonstrate the validity of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Abstract: Image morphing has been extensively studied in computer graphics and it can be summarized as follows: given two input images, morphing algorithms produce a sequence of inbetween images which transforms the source image into the target image in a visually pleasant way. In this paper, we propose an algorithm, based on recent advances from texture-from-sample ideas, which synthesizes a metamorphosis sequence targeted specifically for textures. We use the idea of binary masks—or texton masks—to control and drive the morphing sequence. Our solution provides an automatic mapping from source texels into target texels and thus guarantees a coherent and visually smoothing transition from the source texture into the target texture. We compare our morphing results with prior work and with simple interpolation between corresponding pixels in the same source and target images. [Copyright &y& Elsevier]

This paper describes a new family of three-dimensional (3-D) representations for computer graphics and animation, called depth image-based representations (DIBR), which have been adopted into MPEG-4 Part16: Animation Framework extension (AFX). Idea of the approach is to build a compact and photorealistic representation of a 3-D object or scene without using polygonal mesh. Instead, images accompanied by depth values for each pixel are used. This type of representation allows us to build and render novel views of objects and scene with an interactive rate. There are many different methods for the image-based rendering with depths, and the DIBR format is designed to efficiently represent the information necessary for such methods. The main formats of the DIBR family are SimpleTexture (an image together with depth array), PointTexture (an image with multiple pixels along each line of sight), and Octreelmage (octree-like data structure together with a set of images containing viewport parameters). In order to store and transmit the DIBR object, we develop a compression algorithm and bitstream format for Octreelmage representation. [ABSTRACT FROM AUTHOR]