In this paper, we show that optical inverse tone-mapping (OITM) in light microscopy can improve the visibility of specimens, both when observed directly through the oculars and when imaged with a camera. In contrast t...
详细信息
In this paper, we show that optical inverse tone-mapping (OITM) in light microscopy can improve the visibility of specimens, both when observed directly through the oculars and when imaged with a camera. In contrast to previous microscopy techniques, we premodulate the illumination based on the local modulation properties of the specimen itself. We explain how the modulation of uniform white light by a specimen can be estimated in real time, even though the specimen is continuously but not uniformly illuminated. This information is processed and back-projected constantly, allowing the illumination to be adjusted on the fly if the specimen is moved or the focus or magnification of the microscope is changed. The contrast of the specimen's optical image can be enhanced, and high-intensity highlights can be suppressed. A formal pilot study with users indicates that this optimizes the visibility of spatial structures when observed through the oculars. We also demonstrate that the signal-to-noise (S/N) ratio in digital images of the specimen is higher if captured under an optimized rather than a uniform illumination. In contrast to advanced scanning techniques that maximize the S/N ratio using multiple measurements, our approach is fast because it requires only two images. This can improve image analysis in digital microscopy applications with real-time capturing requirements.
This paper proposes a framework for single-image super-resolution. The underlying idea is to learn a map from input low-resolution images to target high-resolution images based on example pairs of input and output ima...
详细信息
This paper proposes a framework for single-image super-resolution. The underlying idea is to learn a map from input low-resolution images to target high-resolution images based on example pairs of input and output images. Kernel ridge regression (KRR) is adopted for this purpose. To reduce the time complexity of training and testing for KRR, a sparse solution is found by combining the ideas of kernel matching pursuit and gradient descent. As a regularized solution, KRR leads to a better generalization than simply storing the examples as has been done in existing example-based algorithms and results in much less noisy images. However, this may introduce blurring and ringing artifacts around major edges as sharp changes are penalized severely. A prior model of a generic image class which takes into account the discontinuity property of images is adopted to resolve this problem. Comparison with existing algorithms shows the effectiveness of the proposed method.
Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer...
详细信息
Spatial augmented reality is especially interesting for the design process of a car, because a lot of virtual content and corresponding real objects are used. One important issue in such a process is that the designer can trust the visualized colors on the real object, because design decisions are made on basis of the projection. In this paper, we present an interactive visualization technique which is able to exactly compute the RGB values for the projected image, so that the resulting colors on the real object are equally perceived as the real desired colors. Our approach computes the influences of the ambient light, the material, the pose and the color model of the projector to the resulting colors of the projected RGB values by using a physically based computation. This information allows us to compute the adjustment for the RGB values for varying projector positions at interactive rates. Since the amount of projectable colors does not only depend on the material and the ambient light, but also on the pose of the projector, our method can be used to interactively adjust the range of projectable colors by moving the projector to arbitrary positions around the real object. We further extend the mentioned method so that it is applicable to multiple projectors. All methods are evaluated in a number of experiments.
Supercomputers are coming into wider use for generating realistic imagery for commercial animation, special effects, and scientific simulation. The Connection Machine requires a more radical rethinking of rendering al...
详细信息
Supercomputers are coming into wider use for generating realistic imagery for commercial animation, special effects, and scientific simulation. The Connection Machine requires a more radical rethinking of rendering algorithms than previous supercomputers since it is not intended to function as a scalar processor. A fascinating mix of changes from conventional approaches is emerging. Some procedures can run virtually unchanged while others must be turned completely inside out. We have confidence in the viability of the Connection Machine as an architecture for high-end computer graphics. For complex scenes resulting in at least tens of thousands of polygons per frame, most steps of the rendering pipeline can make effective use of the massive number of processors available. Early approaches to massively parallel graphics systems have focused on processor per pixel organizations. We show that a dynamic mix of organizations, including processor per pixel, processor per vertex, and processor per polygon are necessary. Additionally, we note that an apparent consequence of the style of algorithm enforced by the Connection Machine is an enormously increased appetite for memory. We explore standard algorithms for image generation and note the differences that arise in an implementation for the Connetion Machine. We conclude by attempting a comparison of the viability of alternative computing environments for our application.
Steiner patches are triangular surface patches for which the Cartesian coordinates of points on the patch are defined parametrically by quadratic polynomial functions of two variables. It has recently been shown that ...
详细信息
ISBN:
(纸本)9780897911382
Steiner patches are triangular surface patches for which the Cartesian coordinates of points on the patch are defined parametrically by quadratic polynomial functions of two variables. It has recently been shown that it is possible to express a Steiner patch in an implicit equation which is a degree four polynomial in x,y,z. Furthermore, the parameters of a point known to be on the surface can be computed as rational polynomial functions of x,y,z. These findings lead to a straightforward algorithm for ray tracing Steiner patches in which the ray intersection equation is a degree four polynomial in the parameter of the ray. The algorithm presented represents a major simplification over existing techniques for ray tracing free-form surface patches.
The system described in this paper provides a real-time 3D visual experience by using an array of 64 video cameras and an integral photography display with 60 viewing directions. The live 3D scene in front of the came...
详细信息
The system described in this paper provides a real-time 3D visual experience by using an array of 64 video cameras and an integral photography display with 60 viewing directions. The live 3D scene in front of the camera array is reproduced by the full-color, full-parallax autostereoscopic display with interactive control of viewing parameters. The main technical challenge is fast and flexible conversion of the data from the 64 multicamera images to the integral photography format. Based on image-based rendering techniques, our conversion method first renders 60 novel images corresponding to the viewing directions of the display, and then arranges the rendered pixels to produce an integral photography image. For real-time processing on a single PC, all the conversion processes are implemented on a GPU with GPGPU techniques. The conversion method also allows a user to interactively control viewing parameters of the displayed image for reproducing the dynamic 3D scene with desirable parameters. This control is performed as a software process, without reconfiguring the hardware system, by changing the rendering parameters such as the convergence point of the rendering cameras and the interval between the viewpoints of the rendering cameras.
A supervisory process is used to distribute picture-generation tasks to heterogeneous subprocesses. Significant advantages accrue by tailoring the subprocesses to their tasks. In particular, scan conversion algorithms...
详细信息
ISBN:
(纸本)9780897910767
A supervisory process is used to distribute picture-generation tasks to heterogeneous subprocesses. Significant advantages accrue by tailoring the subprocesses to their tasks. In particular, scan conversion algorithms tailored to different surface types may be used in the same image, a changing mixture of processors is possible, and, by multiprogramming, a single processor may be used more effectively. A two-level shape data structure supports this execution environment, allowing top-level priority decisions which avoid comparisons between surface elements from non-interfering objects during image construction.
暂无评论