Registration is a fundamental task in image processing used to match two or more pictures taken, for example, at different times, from different sensors or from different viewpoints. Over the years, a broad range of techniques have been developed for the various types of data and problems. These techniques have been independently studied for several different applications resulting in a large body of research. This paper organizes this material by establishing the relationship between the distortions in the image and the type of registration techniques which are most suitable. Two major types of distortions are distinguished. The first type are those which are the source of misregistration, i.e., they are the cause of the misalignment between the two images. Distortions which are the source of misregistration determine the transformation class which will optimally align the two images. The transformation class in turn influences the general technique that should be taken....

Image-space simplifications have been used to accelerate the calculation of computer graphic images since the dawn of visual simulation. Texture mapping has been used to provide a means by which images may themselves be used as display primitives. The work reported by this paper endeavors to carry this concept to its logical extreme by using interpolated images to portray three-dimensional scenes. The special-effects technique of morphing, which combines interpolation of texture maps and their shape, is applied to computing arbitrary intermediate frames from an array of prestored images. If the images are a structured set of views of a 3D object or scene, intermediate frames derived by morphing can be used to approximate intermediate 3D transformations of the object or scene. Using the view interpolation approach to synthesize 3D scenes has two main advantages. First, the 3D representation of the scene may be replaced with images. Second, the image synthesis time is independent of the scene complexity. The correspondence between images, required for the morphing method, can be predetermined automatically using the range data associated with the images. The method is further accelerated by a quadtree decomposition and a view-independent visible priority. Our experiments have shown that the morphing can be performed at interactive rates on today’s high-end personal computers. Potential applications of the method include virtual holograms, a walkthrough in a virtual environment, image-based primitives and incremental rendering. The method also can be used to greatly accelerate the computation of motion blur and soft shadows cast by area light sources.

We present an extension to texture mapping that supports the representation of 3-D surface details and view motion parallax. The results are correct for viewpoints that are static or moving, far away or nearby. Our approach is very simple: a relief texture (texture extended with an orthogonal displacement per texel) is mapped onto a polygon using a two-step process: First, it is converted into an ordinary texture using a surprisingly simple 1-D forward transform. The resulting texture is then mapped onto the polygon using standard texture mapping. The 1-D warping functions work in texture coordinates to handle the parallax and visibility changes that result from the 3-D shape of the displacement surface. The subsequent texture-mapping operation handles the transformation from texture to screen coordinates. CR Categories and Subject Descriptors: I.3.3 [Computer Graphics]: Picture/Image Generation I.3.6 [Computer Graphics]: Methodologies and Techniques; I.3.7 [Computer Graphics]: Three-...

Image warping has many applications in art as well as in image processing. Usually, displacements are computed with mathematical functions or by transformations of a triangulation of control points. Here, different approaches based on scattered data interpolation methods are presented. These methods provide smooth deformations with easily controllable behavior. The usefulness and performance of some selected classes of scattered data interpolation methods in this context is analyzed.

In traditional stereoscopic displays, the virtual three-dimensional object does not appear to be fixed in space as the viewer's head moves. This apparent motion results from the fact that a correct stereo image can only be formed for a particular viewpoint and interpupillary distance. At other viewpoints, our brain interprets the stereo image as a slightly skewed and rotated version of the original. When moving the head, this skewing of the image is perceived as apparent motion of the object. This apparent

The problem of deforming a given spatial shape is treated. There are many examples of applications in visual computing: fitting surfaces to sampled data points in space, correction of distortions in tomographic imaging, modeling of free form geometric shapes, and animating metamorphoses of geometric objects. Our solution warps the space surrounding the given shape with the effect of deforming the embedded shape, too, with a function derived with scattered data interpolation methods from the displacements of a finite set of control points that can be placed arbitrarily and adaptively. We present algorithms implementing this idea on parametric surfaces and rasterized volume data.

Traditionally, texture coordinates have been generated based solely on the model's geometry, often even before a model's textures have been created. With the arrival of new technologies, such as 3D paint programs, weaknesses of a static optimization pre-process are becoming apparent. These weaknesses arise from constructing a parameterization based solely on the model's geometry, ignoring the fact that detail is not uniformly spaced throughout the texture space. In fact, certain regions of the texture are more important than other regions. In this paper we introduce the notion of the "importance map" and describe how importance values are derived from both intrinsic properties of the texture and user-guided highlights. Furthermore, we describe how importance maps are used to drive the texture coordinate optimization. Finally, we show how this optimization process can be integrated into a 3D painting environment, enabling periodic optimization at any stage of texture design. Ad...

The problem of chromatic aberration arises because each wavelength of light is refracted differently by the elements of a lens. Unfortunately, this means that is image will be blurred and distorted. In color imaging these distortions cause measurable differences between the images. Recent research has proposed an approach for dealing with this aberrations by actively controlling the optics of the imaging system. This paper addresses the same problem, but instead of adapting the optics, we adapt the geometry of the (already obtained) images; we do chromatic aberration correction by image warping. We briefly discuss the image restoration /reconstruction techniques used, since they are non-standard. This is followed by a discussion of the techniques used to define the chromatic aberration correcting warp. The technique is demonstrated and analyzed on two test cases and is directly compared to the active optics approach. 1 Introduction The first stage of an imaging system is the lens, wh...

We have developed a new method for transforming images with per-pixel displacements into textures that have correct parallax when texture-mapped, in the usual way, onto polygons. Our new method results from factoring the 3-D image-warping equations of McMillan and Bishop into a prewarp followed by standard texture mapping. The pre-warp handles only the parallax effects resulting from the direction of view and the displacement of texture elements; the subsequent texture-mapping operation handles scaling, rotation, and the remaining perspective transformation. The pre-warp equations have a very simple 1-D structure that enables the pre-warp to be implemented using only 1-D image operations along scan lines and columns and requires interpolation between only two adjacent pixels at a time. This allows efficient implementation in software and should allow a simple and efficient hardware implementation. The texture-mapping hardware already very common in graphics systems efficiently impleme...

Spatial image warping is useful for image processing and graphics. In this paper, we present concurrent-read-exclusive-write (CREW) and exclusive-read-exclusive-write (EREW) parallel-random -access-machine (PRAM) algorithms that achieve asymptotic run time. The significant result is the creative processor assignment that results in an EREW PRAM algorithm. The forward algorithm calculates any nonscaling affine transform including arbitrary skewings, translations, and rotations. The EREW algorithm is the most efficient in practice, and the MasPar MP-1 with 16k processors rotates a four million element image in under a second and a two million element volume in one half of a second. This high performance allows interactive viewing of volumes from arbitrary viewpoints and illustrates linear speedup. This practical efficiency is analyzed and illustrated by using a bridging model of computation. We develop the mixed cost communication machine (MCCM) to quantify the communication costs and co...