Image Warping Among Arbitrary Planar Shapes

Image warping refers to the 2D resampling of a source image onto a target image. Despite the variety of techniques proposed, a large class of image warping problems remains inadequately solved: mapping between two images which are delimited by arbitrary, closed, planar curves, e.g., hand-drawn curves. This paper describes a novel algorithm to perform image warping among arbitrary planar shapes whose boundary correspondences are known. A generalized polar coordinate parameterization is introduced to facilitate an efficient mapping procedure. Images are treated as collections of interior layers, extracted via a thinning process. Mapping these layers between the source and target images generates the 2D resampling grid that defines the warping. The thinning operation extends the standard polar coordinate representation to deal with arbitrary shapes

A Syntactic Omni-Font Character Recognition System

The author introduces a syntactic omni-font character recognition system that recognizes a wide range of fonts, including handprinted characters. A structural pattern-matching approach is used. Essentially, a set of loosely constrained rules specify pattern components and their interrelationships. The robustness of the system is derived from the orthogonal set of pattern descriptors, location functions, and the manner in which they are combined to exploit the topological structure of characters. By virtue of the new pattern description language, PDL, the user may easily write rules to define new patterns for the system to recognize. The system also features scale-invariance and user-definable sensitivity to tilt orientation. The system has achieved a 95. 2% recognition rate

Cubic Spline Interpolation: A Review

The purpose of this paper is to review the fundamentals of interpolating cubic splines. We begin by defining a cubic spline in Section 1. Since we are dealing with interpolating splines, constraints are imposed to guarantee that the spline actually passes through the given data points. These constraints are described in Section 2. They establish a relationship between the known data points and the unknown coefficients used to completely specify the spline. Due to extra degrees of freedom, the coefficients may be solved in terms of the first or second derivatives. Both derivations are given in Section 3. Once the coefficients are expressed in terms of either the first or second derivatives, these unknown derivatives must be determined. Their solution, using one of several end conditions, is given in Section 4. Finally source code, written in C, is provided in Section 5 to implement cubic spline interpolation for uniformly and nonuniformly spaced data points

Fast Fourier Transforms: A Review

The purpose of this paper is to provide a detailed review of the Fast Fourier Transform. Some familiarity with the basic concepts of the Fourier Transform is assumed. The review begins with a definition of the discrete Fourier Transform (DFT) in section 1. Directly evaluating the DFT is demonstrated there to be an 0 (N2) process. The efficient approach for evaluating the OFT is through the use of FFT algorithms. Their existence became generally known in the mid-1960s, stemming from the work of J. W. Cooley and J. W. Tukey. Although they pioneered new FFT algorithms, the original work was actually discovered over 20 years earlier by Danielson and Lanczos. Their formulation, known as the Danielson-Lanczos Lemma, is derived in section 2. Their recursive solution is shown to reduce the computational complexity to 0 (N log2 N). A modification of that method, the Cooley-Tukey algorithm, is given in section 3. Yet another variation, the Cooley-Sande algorithm, is described in section 4. These last two techniques are also known in the literature as the decimation-in-time and decimation-in-frequency algorithms. respectively. Finally, source code, written in C, is provided in the appendix

Dynamic 3D Urban Scene Modeling Using Multiple Pushbroom Mosaics

In this paper, a unified, segmentation-based approach is proposed to deal with both stereo reconstruction and moving objects detection problems using multiple stereo mosaics. Each set of parallel-perspective (pushbroom) stereo mosaics is generated from a video sequence captured by a single video camera. First a colorsegmentation approach is used to extract the so-called natural matching primitives from a reference view of a pair of stereo mosaics to facilitate both 3D reconstruction of textureless urban scenes and man-made moving targets (e.g. vehicles). Multiple pairs of stereo mosaics are used to improve the accuracy and robustness in 3D recovery and occlusion handling. Moving targets are detected by inspecting their 3D anomalies, either violating the epipolar geometry of the pushbroom stereo or exhibiting abnormal 3D structure. Experimental results on both simulated and real video sequences are provided to show the effectiveness of our approach. 1

IMPROC: An Interactive Image Processing Software Package

IMPROC is a general-purpose interactive image processing software package. The system includes a collection of library routines and a menu-driven environment in which to invoke all supported image operators. A wide range of image operations are available, including point, neighborhood, arithmetic, logic, and geometric processes. In addition, there are utilities for image transforms, compositing, colorization, look-up tables, and graphic display of images. Key features of IMPROC include its emphasis on simplicity, generality, and device independence. Flexibility and software utility is augmented by the simple, and general, canonical representation of internal images. Unlike most systems that place strict restrictions on the pixel data type, IMPROC accomodates images having pixels of variable precision and arbitrary dimensions. A consequence of this feature is that all supported image operations are equally useful for general-format data. This uniform treatment of data that vary in size and type is critical to advanced processing techniques. Finally, device independence protects IMPROC from the inevitable obsolesence of the supporting hardware. This paper is a complete guide to IMPROC. It includes a user's guide, programmer's manual, numerous examples, and an extensive bibligraphy. In addition, a discussion of the design philosophy is given to supply insight that maximizes user productivity and promotes uniform practices for code integration

Geometric Transformation Techniques for Digital Images: A Survey

This survey presents a wide collection of algorithms for the geometric transformation of digital images. Efficient image transformation algorithms are critically important to the remote sensing, medical imaging, computer vision, and computer graphics communities. We review the growth of this field and compare all the described algorithms. Since this subject is interdisciplinary, emphasis is placed on the unification of the terminology, motivation, and contributions of each technique to yield a single coherent framework. This paper attempts to serve a dual role as a survey and a tutorial. It is comprehensive in scope and detailed in style. The primary focus centers on the three components that comprise all geometric transformations: spatial transformations, resampling, and antialiasing. In addition, considerable attention is directed to the dramatic progress made in the development of separable algorithms. The text is supplemented with numerous examples and an extensive bibliography

Coupled Analysis of In Vitro and Histology Tissue Samples to Quantify Structure-Function Relationship

The structure/function relationship is fundamental to our understanding of biological systems at all levels, and drives most, if not all, techniques for detecting, diagnosing, and treating disease. However, at the tissue level of biological complexity we encounter a gap in the structure/function relationship: having accumulated an extraordinary amount of detailed information about biological tissues at the cellular and subcellular level, we cannot assemble it in a way that explains the correspondingly complex biological functions these structures perform. To help close this information gap we define here several quantitative temperospatial features that link tissue structure to its corresponding biological function. Both histological images of human tissue samples and fluorescence images of three-dimensional cultures of human cells are used to compare the accuracy of in vitro culture models with their corresponding human tissues. To the best of our knowledge, there is no prior work on a quantitative comparison of histology and in vitro samples. Features are calculated from graph theoretical representations of tissue structures and the data are analyzed in the form of matrices and higher-order tensors using matrix and tensor factorization methods, with a goal of differentiating between cancerous and healthy states of brain, breast, and bone tissues. We also show that our techniques can differentiate between the structural organization of native tissues and their corresponding in vitro engineered cell culture models

360 Image morphing: a survey

Image morphing has received much attention in recent years. It has proven to be a powerful tool for visual effects in film and television, enabling the fluid transformation of one digital image into another. This paper surveys the growth of this field and describes recent advances in image morphing in terms of feature specification, warp generation methods, and transition control. These areas relate to the ease of use and quality of results. We describe the role of radial basis functions, thin plate splines, energy minimization, and multilevel free-form deformations in advancing the state-of-the-art in image morphing. Recent work on a generalized framework for morphing among multiple images is described

Recent Advances in Image Morphing

Image morphing has been the subject of much attention in recent years. It has proven to be a powerful visual effects tool in film and television, depicting the fluid transformation of one digital image into another. This paper reviews the growth of this field and describes recent advances in image morphing in terms of three areas: feature specification, warp generation methods, and transition control. These areas relate to the ease of use and quality of results. We will describe the role of radial basis functions, thin plate splines, energy minimization, and multilevel free-form deformations in advancing the state-of-the-art in image morphing. Recent work on a generalized framework for morphing among multiple images will be described. 1. Introduction Image metamorphosis has proven to be a powerful visual effects tool. There are now many breathtaking examples in film and television depicting the fluid transformation of one digital image into another. This process, commonly known as mor..