Topic
Subpixel rendering
About: Subpixel rendering is a research topic. Over the lifetime, 3885 publications have been published within this topic receiving 82789 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: This article derives the exact generalized likelihood ratio test for the finite target matched filter (MF), which is an adjustment of the well-known MF, and shows it to outperform the standard target detectors on real data, especially for small covariance estimation windows.
Abstract: One of the main objectives of hyperspectral image processing is to detect a given target among an unknown background. The standard data to conduct such detection is a reflectance map, where the spectral signatures of each pixel’s components, known as endmembers, are associated with their abundances in the pixel. Due to the low spatial resolution of most hyperspectral sensors, such a target occupies a fraction of the pixel. A widely used model in the case of subpixel targets is the replacement model. Among the vast number of possible detectors, algorithms matched to the replacement model are quite rare. One of the few examples is the finite target matched filter (MF), which is an adjustment of the well-known MF. In this article, we derive the exact generalized likelihood ratio test for this model. This new detector can be used both with a local covariance estimation window or a global one. It is shown to outperform the standard target detectors on real data, especially for small covariance estimation windows.
29 citations
17 Dec 1993
TL;DR: Intense investigation of the proposed algorithms led to the new approach: by interpolating the template instead of the reference image, and by applying sort of an error- correction to the resulting subpixel-value, both computation time and accuracy can be improved.
Abstract: In 1972, Barnea and Silverman presented a new approach to the wide field of template matching, the SSD-algorithm. Further work has been done to adapt the method to gain subpixel accuracy. Intense investigation of the proposed algorithms led to our new approach: by interpolating the template instead of the reference image, and by applying sort of an error- correction to the resulting subpixel-value, both computation time and accuracy can be improved. Exhaustive experiments with a CCD-camera and various kinds of reference images showed that a maximum error of 10% of the pixel period can be expected. Depending on the kind of image, mean square errors range from 0.4% to 4%.
29 citations
TL;DR: A new accuracy index is proposed which considers SPM performances in classification and restoration of spatial structure simultaneously simultaneously, and shows that by considering the PSF effect, more accurate SPM results were produced and small-sized patches and elongated features were restored more satisfactorily.
29 citations
TL;DR: A feature-driven multilayer visualization technique that automatically chooses data visualization techniques based on the spatial distribution and importance of the endmembers so that it can simultaneously visualize the overall material distribution, subpixel level details, and target pixels and materials.
Abstract: Displaying the abundant information contained in a remotely sensed hyperspectral image is a challenging problem. Currently, no approach can satisfactorily render the desired information at arbitrary levels of detail. In this paper, we present a feature-driven multilayer visualization technique that automatically chooses data visualization techniques based on the spatial distribution and importance of the endmembers. It can simultaneously visualize the overall material distribution, subpixel level details, and target pixels and materials. By incorporating interactive tools, different levels of detail can be presented per users' request. This scheme employs five layers from the bottom to the top: the background layer, data-driven spot layer, pie-chart layer, oriented sliver layer, and anomaly layer. The background layer provides the basic tone of the display; the data-driven spot layer manifests the overall material distribution in an image scene; the pie-chart layer presents the precise abundances of endmember materials in each pixel; the oriented sliver layer emphasizes the distribution of important anomalous materials; and the anomaly layer highlights anomaly pixels (i.e., potential targets). Displays of the airborne AVIRIS data and spaceborne Hyperion data demonstrate that the proposed multilayer visualization scheme can efficiently display more information globally and locally.
29 citations
TL;DR: In this paper, a CCD camera and a subpixel resolution algorithm were used for the measurement of the deflection of a laser beam that propagates through the system, and an accuracy of 0.024 pixels was obtained on the determination of the beam position in the setup.
Abstract: A deflectometric method for the characterization of optical systems is presented. It is based on the use of a CCD camera and a subpixel resolution algorithm for the measurement of the deflection of a laser beam that propagates through the system. To obtain accurate results, three different algorithms for measuring the position of the deflected beam are tested and compared. Based on this comparison, an algorithm based on the calculation of the phase of the fast Fourier transform (FFT) is selected, and an accuracy of 0.024 pixels is obtained on the determination of the beam position in our setup. Using an XY scanning stage, the proposed method is completely automated and applied for the characterization of ophthalmic lenses. In this application, the gradients of the wavefront refracted by the lens are measured directly, and from them, the thickness and the local power of the lens are computed.
29 citations